@article {2481, title = {Violation of the ultrastructural size principle in the dorsolateral prefrontal cortex underlies working memory impairment in the aged common marmoset (Callithrix jacchus).}, journal = {Front Aging Neurosci}, volume = {15}, year = {2023}, month = {2023}, pages = {1146245}, abstract = {

Morphology and function of the dorsolateral prefrontal cortex (dlPFC), and corresponding working memory performance, are affected early in the aging process, but nearly half of aged individuals are spared of working memory deficits. Translationally relevant model systems are critical for determining the neurobiological drivers of this variability. The common marmoset (Callithrix jacchus) is advantageous as a model for these investigations because, as a non-human primate, marmosets have a clearly defined dlPFC that enables measurement of prefrontal-dependent cognitive functions, and their short (\~{}10 year) lifespan facilitates longitudinal studies of aging. Previously, we characterized working memory capacity in a cohort of marmosets that collectively covered the lifespan, and found age-related working memory impairment. We also found a remarkable degree of heterogeneity in performance, similar to that found in humans. Here, we tested the hypothesis that changes to synaptic ultrastructure that affect synaptic efficacy stratify marmosets that age with cognitive impairment from those that age without cognitive impairment. We utilized electron microscopy to visualize synapses in the marmoset dlPFC and measured the sizes of boutons, presynaptic mitochondria, and synapses. We found that coordinated scaling of the sizes of synapses and mitochondria with their associated boutons is essential for intact working memory performance in aged marmosets. Further, lack of synaptic scaling, due to a remarkable failure of synaptic mitochondria to scale with presynaptic boutons, selectively underlies age-related working memory impairment. We posit that this decoupling results in mismatched energy supply and demand, leading to impaired synaptic transmission. We also found that aged marmosets have fewer synapses in dlPFC than young, though the severity of synapse loss did not predict whether aging occurred with or without cognitive impairment. This work identifies a novel mechanism of synapse dysfunction that stratifies marmosets that age with cognitive impairment from those that age without cognitive impairment. The process by which synaptic scaling is regulated is yet unknown and warrants future investigation.

}, issn = {1663-4365}, doi = {10.3389/fnagi.2023.1146245}, author = {Glavis-Bloom, Courtney and Vanderlip, Casey R and Weiser Novak, Sammy and Kuwajima, Masaaki and Kirk, Lyndsey and Harris, Kristen M and Manor, Uri and Reynolds, John H} } @article {2220, title = {Differential mechanisms underlie trace and delay conditioning in Drosophila.}, journal = {Nature}, year = {2022}, month = {2022 Feb 16}, abstract = {

Two forms of associative learning-delay conditioning and trace conditioning-have been widely investigated in humans and higher-order mammals. In delay conditioning, an unconditioned stimulus (for example, an electric shock) is introduced in the final moments of a conditioned stimulus (for example, a tone), with both ending at the same time. In trace conditioning, a {\textquoteright}trace{\textquoteright} interval separates the conditioned stimulus and the unconditioned stimulus. Trace conditioning therefore relies on maintaining a neural representation of the conditioned stimulus after its termination (hence making distraction possible), to learn the conditioned stimulus-unconditioned stimulus contingency; this makes it more cognitively demanding than delay conditioning. Here, by combining virtual-reality behaviour with neurogenetic manipulations and in vivo two-photon brain imaging, we show that visual trace conditioning and delay conditioning in Drosophila mobilize R2 and R4m ring neurons in the ellipsoid body. In trace conditioning, calcium transients during the trace interval show increased oscillations and slower declines over repeated training, and both of these effects are sensitive to distractions. Dopaminergic activity accompanies signal persistence in ring neurons, and this is decreased by distractions solely during trace conditioning. Finally, dopamine D1-like and D2-like receptor signalling in ring neurons have different roles in delay and trace conditioning; dopamine D1-like receptor 1 mediates both forms of conditioning, whereas the dopamine D2-like receptor is involved exclusively in sustaining ring neuron activity during the trace interval of trace conditioning. These observations are similar to those previously reported in mammals during arousal, prefrontal activation and high-level cognitive learning.

}, issn = {1476-4687}, doi = {10.1038/s41586-022-04433-6}, author = {Grover, Dhruv and Chen, Jen-Yung and Xie, Jiayun and Li, Jinfang and Changeux, Jean-Pierre and Greenspan, Ralph J} } @article {2298, title = {Intestinal transgene delivery with native E.~coli chassis allows persistent physiological changes.}, journal = {Cell}, volume = {185}, year = {2022}, month = {2022 Aug 18}, pages = {3263-3277.e15}, abstract = {

Live bacterial therapeutics (LBTs) could reverse diseases by engrafting in the gut and providing persistent beneficial functions in the host. However, attempts to functionally manipulate the gut microbiome of conventionally raised (CR) hosts have been unsuccessful because engineered microbial organisms (i.e., chassis) have difficulty in colonizing the hostile luminal environment. In this proof-of-concept study, we use native bacteria as chassis for transgene delivery to impact CR host physiology. Native Escherichia coli bacteria isolated from the stool cultures of CR mice were modified to express functional genes. The reintroduction of these strains induces perpetual engraftment in the intestine. In addition, engineered native E.\ coli can induce functional changes that affect physiology of and reverse pathology in CR hosts months after administration. Thus, using native bacteria as chassis to "knock in" specific functions allows mechanistic studies of specific microbial activities in the microbiome of CR hosts and enables LBT with curative intent.

}, keywords = {Animals, Bacteria, Escherichia coli, Gastrointestinal Microbiome, Mice, Microbiota, Transgenes}, issn = {1097-4172}, doi = {10.1016/j.cell.2022.06.050}, author = {Russell, Baylee J and Brown, Steven D and Siguenza, Nicole and Mai, Irene and Saran, Anand R and Lingaraju, Amulya and Maissy, Erica S and Dantas Machado, Ana C and Pinto, Antonio F M and Sanchez, Concepcion and Rossitto, Leigh-Ana and Miyamoto, Yukiko and Richter, R Alexander and Ho, Samuel B and Eckmann, Lars and Hasty, Jeff and Gonzalez, David J and Saghatelian, Alan and Knight, Rob and Zarrinpar, Amir} } @article {2291, title = {knockout in excitatory neurons impairs postnatal synapse maturation and increases the repressive histone modification H3K27me3.}, journal = {Elife}, volume = {11}, year = {2022}, month = {2022 May 23}, abstract = {

Two epigenetic pathways of transcriptional repression, DNA methylation and polycomb repressive complex 2 (PRC2), are known to regulate neuronal development and function. However, their respective contributions to brain maturation are unknown. We found that conditional loss of the de novo DNA methyltransferase in mouse excitatory neurons altered expression of synapse-related genes, stunted synapse maturation, and impaired working memory and social interest. At the genomic level, loss of abolished postnatal accumulation of CG and non-CG DNA methylation, leaving adult neurons with an unmethylated, fetal-like epigenomic pattern at ~222,000 genomic regions. The PRC2-associated histone modification, H3K27me3, increased at many of these sites. Our data support a dynamic interaction between two fundamental modes of epigenetic repression during postnatal maturation of excitatory neurons, which together confer robustness on neuronal regulation.

}, keywords = {Animals, Brain, Disease Models, Animal, DNA Methyltransferase 3A, Histone Code, Histones, Mice, Mice, Knockout, Neurons, Polycomb Repressive Complex 2, Synapses}, issn = {2050-084X}, doi = {10.7554/eLife.66909}, author = {Li, Junhao and Pinto-Duarte, Ant{\'o}nio and Zander, Mark and Cuoco, Michael S and Lai, Chi-Yu and Osteen, Julia and Fang, Linjing and Luo, Chongyuan and Lucero, Jacinta D and Gomez-Castanon, Rosa and Nery, Joseph R and Silva-Garcia, Isai and Pang, Yan and Sejnowski, Terrence J and Powell, Susan B and Ecker, Joseph R and Mukamel, Eran A and Behrens, M Margarita} } @article {2179, title = {Valence opponency in peripheral olfactory processing.}, journal = {Proc Natl Acad Sci U S A}, volume = {119}, year = {2022}, month = {2022 Feb 01}, abstract = {

A hallmark of complex sensory systems is the organization of neurons into functionally meaningful maps, which allow for comparison and contrast of parallel inputs via lateral inhibition. However, it is unclear whether such a map exists in olfaction. Here, we address this question by determining the organizing principle underlying the stereotyped pairing of olfactory receptor neurons (ORNs) in sensory hairs, wherein compartmentalized neurons inhibit each other via ephaptic coupling. Systematic behavioral assays reveal that most paired ORNs antagonistically regulate the same type of behavior. Such valence opponency is relevant in critical behavioral contexts including place preference, egg laying, and courtship. Odor-mixture experiments show that ephaptic inhibition provides a peripheral means for evaluating and shaping countervailing cues relayed to higher brain centers. Furthermore, computational modeling suggests that this organization likely contributes to processing ratio information in odor mixtures. This olfactory valence map may have evolved to swiftly process ethologically meaningful odor blends without involving costly synaptic computation.

}, issn = {1091-6490}, doi = {10.1073/pnas.2120134119}, author = {Wu, Shiuan-Tze and Chen, Jen-Yung and Martin, Vanessa and Ng, Renny and Zhang, Ye and Grover, Dhruv and Greenspan, Ralph J and Aljadeff, Johnatan and Su, Chih-Ying} } @article {1805, title = {Neurally driven synthesis of learned, complex vocalizations}, journal = {Current Biology}, year = {2021}, abstract = {

Summary Brain machine interfaces (BMIs) hold promise to restore impaired motor function and serve as powerful tools to study learned motor skill. While limb-based motor prosthetic systems have leveraged nonhuman primates as an important animal model,1, 2, 3, 4 speech prostheses lack a similar animal model and are more limited in terms of neural interface technology, brain coverage, and behavioral study design.5, 6, 7 Songbirds are an attractive model for learned complex vocal behavior. Birdsong shares a number of unique similarities with human speech,8, 9, 10 and its study has yielded general insight into multiple mechanisms and circuits behind learning, execution, and maintenance of vocal motor skill.11, 12, 13, 14, 15, 16, 17, 18 In addition, the biomechanics of song production bear similarity to those of humans and some nonhuman primates.19, 20, 21, 22, 23 Here, we demonstrate a vocal synthesizer for birdsong, realized by mapping neural population activity recorded from electrode arrays implanted in the premotor nucleus HVC onto low-dimensional compressed representations of song, using simple computational methods that are implementable in real time. Using a generative biomechanical model of the vocal organ (syrinx) as the low-dimensional target for these mappings allows for the synthesis of vocalizations that match the bird{\textquoteright}s own song. These results provide proof of concept that high-dimensional, complex natural behaviors can be directly synthesized from ongoing neural activity. This may inspire similar approaches to prosthetics in other species by exploiting knowledge of the peripheral systems and the temporal structure of their output.

}, keywords = {bioprosthetics, birdsong, brain machine interfaces, Electrophysiology, neural networks, nonlinear dynamics, Speech}, issn = {0960-9822}, doi = {https://doi.org/10.1016/j.cub.2021.05.035}, url = {https://www.sciencedirect.com/science/article/pii/S0960982221007338}, author = {Ezequiel M. Arneodo and Shukai Chen and Daril E. Brown and Vikash Gilja and Timothy Q. Gentner} } @article {1788, title = {Imaging brain activity during complex social behaviors in Drosophila with Flyception2.}, journal = {Nat Commun}, volume = {11}, year = {2020}, month = {2020 01 30}, pages = {623}, abstract = {

Optical in vivo recordings from freely walking Drosophila are currently possible only for limited behaviors. Here, we expand the range of accessible behaviors with a retroreflective marker-based tracking and ratiometric brain imaging system, permitting brain activity imaging even in copulating male flies. We discover that P1 neurons, active during courtship, are inactive during copulation, whereas GABAergic mAL neurons remain active during copulation, suggesting a countervailing role of mAL in opposing P1 activity during mating.

}, keywords = {Animals, Brain, Copulation, Courtship, Drosophila, Drosophila Proteins, Female, GABAergic Neurons, Male, Neuroimaging, Neurons, Olfactory Cortex, Sexual Behavior, Animal, Social Behavior}, issn = {2041-1723}, doi = {10.1038/s41467-020-14487-7}, author = {Grover, Dhruv and Katsuki, Takeo and Li, Jinfang and Dawkins, Thomas J and Greenspan, Ralph J} } @article {1685, title = {Apical-Basal Polarity Signaling Components, Lgl1 and aPKCs, Control Glutamatergic Synapse Number and Function.}, journal = {iScience}, volume = {20}, year = {2019}, month = {2019 Oct 25}, pages = {25-41}, abstract = {

Normal synapse formation is fundamental to brain function. We show here that an apical-basal polarity (A-BP) protein, Lgl1, is present in the postsynaptic density and negatively regulates glutamatergic synapse numbers by antagonizing the atypical protein kinase Cs (aPKCs). A planar cell polarity protein, Vangl2, which inhibits synapse formation, was decreased in synaptosome fractions of cultured cortical neurons from Lgl1 knockout embryos. Conditional knockout of Lgl1 in pyramidal neurons led to reduction of AMPA/NMDA ratio and impaired plasticity. Lgl1 is frequently deleted in Smith-Magenis syndrome (SMS). Lgl1 conditional knockout led to increased locomotion, impaired novel object recognition and social interaction. Lgl1+/- animals also showed increased synapse numbers, defects in open field and social interaction, as well as stereotyped repetitive behavior. Social interaction in Lgl1+/- could be rescued by NMDA antagonists. Our findings reveal a role of apical-basal polarity proteins in glutamatergic synapse development and function and also suggest a potential treatment for SMS patients with Lgl1 deletion.

}, issn = {2589-0042}, doi = {10.1016/j.isci.2019.09.005}, author = {Scott, John and Thakar, Sonal and Mao, Ye and Qin, Huaping and Hejran, Helen and Lee, Su-Yee and Yu, Ting and Klezovitch, Olga and Cheng, Hongqiang and Mu, Yongxin and Ghosh, Sourav and Vasioukhin, Valeri and Zou, Yimin} } @article {1648, title = {Fast near-whole-brain imaging in adult Drosophila during responses to stimuli and behavior.}, journal = {PLoS Biol}, volume = {17}, year = {2019}, month = {2019 Feb}, pages = {e2006732}, abstract = {

Whole-brain recordings give us a global perspective of the brain in action. In this study, we describe a method using light field microscopy to record near-whole brain calcium and voltage activity at high speed in behaving adult flies. We first obtained global activity maps for various stimuli and behaviors. Notably, we found that brain activity increased on a global scale when the fly walked but not when it groomed. This global increase with walking was particularly strong in dopamine neurons. Second, we extracted maps of spatially distinct sources of activity as well as their time series using principal component analysis and independent component analysis. The characteristic shapes in the maps matched the anatomy of subneuropil regions and, in some cases, a specific neuron type. Brain structures that responded to light and odor were consistent with previous reports, confirming the new technique{\textquoteright}s validity. We also observed previously uncharacterized behavior-related activity as well as patterns of spontaneous voltage activity.

}, issn = {1545-7885}, doi = {10.1371/journal.pbio.2006732}, author = {Aimon, Sophie and Katsuki, Takeo and Jia, Tongqiu and Grosenick, Logan and Broxton, Michael and Deisseroth, Karl and Sejnowski, Terrence J and Greenspan, Ralph J} } @article {1669, title = {Setd5 haploinsufficiency alters neuronal network connectivity and leads to autistic-like behaviors in mice.}, journal = {Transl Psychiatry}, volume = {9}, year = {2019}, month = {2019 01 17}, pages = {24}, abstract = {

SETD5, a gene linked to intellectual disability (ID) and autism spectrum disorder (ASD), is a member of the SET-domain family and encodes a putative histone methyltransferase (HMT). To date, the mechanism by which SETD5 haploinsufficiency causes ASD/ID remains an unanswered question. Setd5 is the highly conserved mouse homolog, and although the Setd5 null mouse is embryonic lethal, the heterozygote is viable. Morphological tracing and multielectrode array was used on cultured cortical neurons. MRI was conducted of adult mouse brains and immunohistochemistry of juvenile mouse brains. RNA-Seq was used to investigate gene expression in the developing cortex. Behavioral assays were conducted on adult mice. Setd5 cortical neurons displayed significantly reduced synaptic density and neuritic outgrowth in vitro, with corresponding decreases in network activity and synchrony by electrophysiology. A specific subpopulation of fetal Setd5 cortical neurons showed altered gene expression of neurodevelopment-related genes. Setd5 animals manifested several autism-like behaviors, including hyperactivity, cognitive deficit, and altered social interactions. Anatomical differences were observed in Setd5 adult brains, accompanied by a deficit of deep-layer cortical neurons in the developing brain. Our data converge on a picture of abnormal neurodevelopment driven by Setd5 haploinsufficiency, consistent with a highly penetrant risk factor.

}, keywords = {Animals, Autism Spectrum Disorder, Behavior, Animal, Brain, Female, Genetic Predisposition to Disease, Haploinsufficiency, Heterozygote, Magnetic Resonance Imaging, Male, Methyltransferases, Mice, Mice, Knockout, Mutation, Neurons}, issn = {2158-3188}, doi = {10.1038/s41398-018-0344-y}, author = {Moore, Spencer M and Seidman, Jason S and Ellegood, Jacob and Gao, Richard and Savchenko, Alex and Troutman, Ty D and Abe, Yohei and Stender, Josh and Lee, Daehoon and Wang, Sicong and Voytek, Bradley and Lerch, Jason P and Suh, Hoonkyo and Glass, Christopher K and Muotri, Alysson R} } @article {1581, title = {Deep(er) Learning.}, journal = {J Neurosci}, volume = {38}, year = {2018}, month = {2018 Aug 22}, pages = {7365-7374}, abstract = {

Animals successfully thrive in noisy environments with finite resources. The necessity to function with resource constraints has led evolution to design animal brains (and bodies) to be optimal in their use of computational power while being adaptable to their environmental niche. A key process undergirding this ability to adapt is the process of learning. Although a complete characterization of the neural basis of learning remains ongoing, scientists for nearly a century have used the brain as inspiration to design artificial neural networks capable of learning, a case in point being deep learning. In this viewpoint, we advocate that deep learning can be further enhanced by incorporating and tightly integrating five fundamental principles of neural circuit design and function: optimizing the system to environmental need and making it robust to environmental noise, customizing learning to context, modularizing the system, learning without supervision, and learning using reinforcement strategies. We illustrate how animals integrate these learning principles using the fruit fly olfactory learning circuit, one of nature{\textquoteright}s best-characterized and highly optimized schemes for learning. Incorporating these principles may not just improve deep learning but also expose common computational constraints. With judicious use, deep learning can become yet another effective tool to understand how and why brains are designed the way they are.

}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.0153-18.2018}, author = {Srinivasan, Shyam and Greenspan, Ralph J and Stevens, Charles F and Grover, Dhruv} } @article {1686, title = {Spatial fine-mapping for gene-by-environment effects identifies risk hot spots for schizophrenia.}, journal = {Nat Commun}, volume = {9}, year = {2018}, month = {2018 12 13}, pages = {5296}, abstract = {

Spatial mapping is a promising strategy to investigate the mechanisms underlying the incidence of psychosis. We analyzed a case-cohort study (n = 24,028), drawn from the 1.47 million Danish persons born between 1981 and 2005, using a novel framework for decomposing the geospatial risk for schizophrenia based on locale of upbringing and polygenic scores. Upbringing in a high environmental risk locale increases the risk for schizophrenia by 122\%. Individuals living in a high gene-by-environmental risk locale have a 78\% increased risk compared to those who have the same genetic liability but live in a low-risk locale. Effects of specific locales vary substantially within the most densely populated city of Denmark, with hazard ratios ranging from 0.26 to 9.26 for environment and from 0.20 to 5.95 for gene-by-environment. These findings indicate the critical synergism of gene and environment on the etiology of schizophrenia and demonstrate the potential of incorporating geolocation in genetic studies.

}, keywords = {Chromosome Mapping, Denmark, Environment, Genetic Predisposition to Disease, Geography, Humans, Proof of Concept Study, Risk Factors, Schizophrenia}, issn = {2041-1723}, doi = {10.1038/s41467-018-07708-7}, author = {Fan, Chun Chieh and McGrath, John J and Appadurai, Vivek and Buil, Alfonso and Gandal, Michael J and Schork, Andrew J and Mortensen, Preben Bo and Agerbo, Esben and Geschwind, Sandy A and Geschwind, Daniel and Werge, Thomas and Thompson, Wesley K and Pedersen, Carsten B{\o}cker} } @article {123, title = {Delayed intramuscular human neurotrophin-3 improves recovery in adult and elderly rats after stroke.}, journal = {Brain}, volume = {139}, year = {2016}, month = {2016 Jan}, pages = {259-75}, abstract = {

There is an urgent need for a therapy that reverses disability after stroke when initiated in a time frame suitable for the majority of new victims. We show here that intramuscular delivery of neurotrophin-3 (NT3, encoded by NTF3) can induce sensorimotor recovery when treatment is initiated 24 h after stroke. Specifically, in two randomized, blinded preclinical trials, we show improved sensory and locomotor function in adult (6 months) and elderly (18 months) rats treated 24 h following cortical ischaemic stroke with human NT3 delivered using a clinically approved serotype of adeno-associated viral vector (AAV1). Importantly, AAV1-hNT3 was given in a clinically-feasible timeframe using a straightforward, targeted route (injections into disabled forelimb muscles). Magnetic resonance imaging and histology showed that recovery was not due to neuroprotection, as expected given the delayed treatment. Rather, treatment caused corticospinal axons from the less affected hemisphere to sprout in the spinal cord. This treatment is the first gene therapy that reverses disability after stroke when administered intramuscularly in an elderly body. Importantly, phase I and II clinical trials by others show that repeated, peripherally administered high doses of recombinant NT3 are safe and well tolerated in humans with other conditions. This paves the way for NT3 as a therapy for stroke.

}, keywords = {Adenoviridae, Age Factors, Animals, Endothelin-1, Female, Genetic Vectors, Humans, Injections, Intramuscular, Locomotion, Magnetic Resonance Imaging, Microinjections, Muscle, Skeletal, Neuroimaging, Neurotrophin 3, Pyramidal Tracts, Rats, Recovery of Function, Spinal Cord, Stroke, Time Factors}, issn = {1460-2156}, doi = {10.1093/brain/awv341}, author = {Duricki, Denise A and Hutson, Thomas H and Kathe, Claudia and Soleman, Sara and Gonzalez-Carter, Daniel and Petruska, Jeffrey C and Shine, H David and Chen, Qin and Wood, Tobias C and Bernanos, Michel and Cash, Diana and Williams, Steven C R and Gage, Fred H and Moon, Lawrence D F} } @article {227, title = {Flyception: imaging brain activity in freely walking fruit flies.}, journal = {Nat Methods}, volume = {13}, year = {2016}, month = {2016 Jul}, pages = {569-72}, abstract = {

Genetically encoded calcium sensors have enabled monitoring of neural activity in vivo using optical imaging techniques. Linking neural activity to complex behavior remains challenging, however, as most imaging systems require tethering the animal, which can impact the animal{\textquoteright}s behavioral repertoire. Here, we report a method for monitoring the brain activity of untethered, freely walking Drosophila melanogaster during sensorially and socially evoked behaviors to facilitate the study of neural mechanisms that underlie naturalistic behaviors.

}, issn = {1548-7105}, doi = {10.1038/nmeth.3866}, author = {Grover, Dhruv and Katsuki, Takeo and Greenspan, Ralph J} } @article {128, title = {Generation of functional human serotonergic neurons from fibroblasts.}, journal = {Mol Psychiatry}, volume = {21}, year = {2016}, month = {2016 Jan}, pages = {49-61}, abstract = {

The brain{\textquoteright}s serotonergic system centrally regulates several physiological processes and its dysfunction has been implicated in the pathophysiology of several neuropsychiatric disorders. While in the past our understanding of serotonergic neurotransmission has come mainly from mouse models, the development of pluripotent stem cell and induced fibroblast-to-neuron (iN) transdifferentiation technologies has revolutionized our ability to generate human neurons in vitro. Utilizing these techniques and a novel lentiviral reporter for serotonergic neurons, we identified and overexpressed key transcription factors to successfully generate human serotonergic neurons. We found that overexpressing the transcription factors NKX2.2, FEV, GATA2 and LMX1B in combination with ASCL1 and NGN2 directly and efficiently generated serotonergic neurons from human fibroblasts. Induced serotonergic neurons (iSNs) showed increased expression of specific serotonergic genes that are known to be expressed in raphe nuclei. iSNs displayed spontaneous action potentials, released serotonin in vitro and functionally responded to selective serotonin reuptake inhibitors (SSRIs). Here, we demonstrate the efficient generation of functional human serotonergic neurons from human fibroblasts as a novel tool for studying human serotonergic neurotransmission in health and disease.

}, issn = {1476-5578}, doi = {10.1038/mp.2015.161}, author = {Vadodaria, K C and Mertens, J and Paquola, A and Bardy, C and Li, X and Jappelli, R and Fung, L and Marchetto, M C and Hamm, M and Gorris, M and Koch, P and Gage, F H} } @article {125, title = {Paradox of pattern separation and adult neurogenesis: A dual role for new neurons balancing memory resolution and robustness.}, journal = {Neurobiol Learn Mem}, volume = {129}, year = {2016}, month = {2016 Mar}, pages = {60-8}, abstract = {

Hippocampal adult neurogenesis is thought to subserve pattern separation, the process by which similar patterns of neuronal inputs are transformed into distinct neuronal representations, permitting the discrimination of highly similar stimuli in hippocampus-dependent tasks. However, the mechanism by which immature adult-born dentate granule neurons cells (abDGCs) perform this function remains unknown. Two theories of abDGC function, one by which abDGCs modulate and sparsify activity in the dentate gyrus and one by which abDGCs act as autonomous coding units, are generally suggested to be mutually exclusive. This review suggests that these two mechanisms work in tandem to dynamically regulate memory resolution while avoiding memory interference and maintaining memory robustness.

}, issn = {1095-9564}, doi = {10.1016/j.nlm.2015.10.013}, author = {Johnston, Stephen T and Shtrahman, Matthew and Parylak, Sarah and Gon{\c c}alves, J Tiago and Gage, Fred H} } @article {124, title = {Creating Patient-Specific Neural Cells for the In Vitro Study of Brain Disorders.}, journal = {Stem Cell Reports}, volume = {5}, year = {2015}, month = {2015 Dec 8}, pages = {933-45}, abstract = {

As a group, we met to discuss the current challenges for creating meaningful patient-specific in vitro models to study brain disorders. Although the convergence of findings between laboratories and patient cohorts provided us confidence and optimism that hiPSC-based platforms will inform future drug discovery efforts, a number of critical technical challenges remain. This opinion piece outlines our collective views on the current state of hiPSC-based disease modeling and discusses what we see to be the critical objectives that must be addressed collectively as a field.

}, issn = {2213-6711}, doi = {10.1016/j.stemcr.2015.10.011}, author = {Brennand, Kristen J and Marchetto, M Carol and Benvenisty, Nissim and Br{\"u}stle, Oliver and Ebert, Allison and Izpisua Belmonte, Juan Carlos and Kaykas, Ajamete and Lancaster, Madeline A and Livesey, Frederick J and McConnell, Michael J and McKay, Ronald D and Morrow, Eric M and Muotri, Alysson R and Panchision, David M and Rubin, Lee L and Sawa, Akira and Soldner, Frank and Song, Hongjun and Studer, Lorenz and Temple, Sally and Vaccarino, Flora M and Wu, Jun and Vanderhaeghen, Pierre and Gage, Fred H and Jaenisch, Rudolf} } @article {127, title = {Differential responses to lithium in hyperexcitable neurons from patients with bipolar disorder.}, journal = {Nature}, volume = {527}, year = {2015}, month = {2015 Nov 5}, pages = {95-9}, abstract = {

Bipolar disorder is a complex neuropsychiatric disorder that is characterized by intermittent episodes of mania and depression; without treatment, 15\% of patients commit suicide. Hence, it has been ranked by the World Health Organization as a top disorder of morbidity and lost productivity. Previous neuropathological studies have revealed a series of alterations in the brains of patients with bipolar disorder or animal models, such as reduced glial cell number in the prefrontal cortex of patients, upregulated activities of the protein kinase A and C pathways and changes in neurotransmission. However, the roles and causation of these changes in bipolar disorder have been too complex to exactly determine the pathology of the disease. Furthermore, although some patients show remarkable improvement with lithium treatment for yet unknown reasons, others are refractory to lithium treatment. Therefore, developing an accurate and powerful biological model for bipolar disorder has been a challenge. The introduction of induced pluripotent stem-cell (iPSC) technology has provided a new approach. Here we have developed an iPSC model for human bipolar disorder and investigated the cellular phenotypes of hippocampal dentate gyrus-like neurons derived from iPSCs of patients with bipolar disorder. Guided by RNA sequencing expression profiling, we have detected mitochondrial abnormalities in young neurons from patients with bipolar disorder by using mitochondrial assays; in addition, using both patch-clamp recording and somatic Ca(2+) imaging, we have observed hyperactive action-potential firing. This hyperexcitability phenotype of young neurons in bipolar disorder was selectively reversed by lithium treatment only in neurons derived from patients who also responded to lithium treatment. Therefore, hyperexcitability is one early endophenotype of bipolar disorder, and our model of iPSCs in this disease might be useful in developing new therapies and drugs aimed at its clinical treatment.

}, keywords = {Action Potentials, Antipsychotic Agents, Bipolar Disorder, Calcium Signaling, Dentate Gyrus, Endophenotypes, Humans, Induced Pluripotent Stem Cells, Lithium Compounds, Male, Mitochondria, Neurons, Patch-Clamp Techniques}, issn = {1476-4687}, doi = {10.1038/nature15526}, author = {Mertens, Jerome and Wang, Qiu-Wen and Kim, Yongsung and Yu, Diana X and Pham, Son and Yang, Bo and Zheng, Yi and Diffenderfer, Kenneth E and Zhang, Jian and Soltani, Sheila and Eames, Tameji and Schafer, Simon T and Boyer, Leah and Marchetto, Maria C and Nurnberger, John I and Calabrese, Joseph R and {\O}degaard, Ketil J and McCarthy, Michael J and Zandi, Peter P and Alda, Martin and Alba, Martin and Nievergelt, Caroline M and Mi, Shuangli and Brennand, Kristen J and Kelsoe, John R and Gage, Fred H and Yao, Jun} } @article {199, title = {From suffering to caring: a model of differences among older adults in levels of compassion.}, journal = {Int J Geriatr Psychiatry}, volume = {30}, year = {2015}, month = {2015 Feb}, pages = {185-91}, abstract = {

OBJECTIVE: Compassion is an important contributor to pro-social behavior and maintenance of interpersonal relationships, yet little is known about what factors influence compassion in late life. The aim of this study was to test theories about how past and current stressors and emotional functioning, resilience, and demographic indicators of life experiences are related to compassion among older adults.

METHODS: One thousand and six older adults (50-99 years) completed a comprehensive survey including self-report measures of compassion, resilience, past and present stress, and emotional functioning (i.e., stressful life events, perceived stress, and current and prior depression and anxiety), and demographic information. The sample was randomly split, and exploratory and confirmatory regression analyses were conducted testing hypothesized relationships with compassion.

RESULTS: Exploratory stepwise regression analysis (n = 650) indicated that participants who reported higher levels of compassion were more likely to be female, not currently in a married/married-like relationship, reported higher resilience levels, and had experienced more significant life events. Age, income level, past and current mental distress, and interactions between resilience and other predictors were not significantly related to compassion. The associations between greater self-reported compassion and being female, having greater resilience, and having experienced more significant life events were supported by a confirmatory stepwise regression analysis (n = 356).

CONCLUSIONS: Older women report more compassion than older men. Resilience and significant life events, independently, also appear to facilitate a desire to help others, while current stress and past and present emotional functioning are less relevant. Specificity of findings to older adults is not yet known.

}, keywords = {Age Factors, Aged, Aged, 80 and over, Empathy, Female, Humans, Life Change Events, Male, Marital Status, Middle Aged, Regression Analysis, Resilience, Psychological, Sex Factors, Socioeconomic Factors}, issn = {1099-1166}, doi = {10.1002/gps.4123}, author = {Moore, Raeanne C and Martin, A{\textquoteright}verria Sirkin and Kaup, Allison R and Thompson, Wesley K and Peters, Matthew E and Jeste, Dilip V and Golshan, Shahrokh and Eyler, Lisa T} } @inbook {171, title = {Genes and Behavior: Lessons from the fruit fly}, booktitle = {International Encyclopedia of the Social \& Behavioral Sciences}, year = {2015}, publisher = {Elsevier}, organization = {Elsevier}, edition = {2nd}, address = {Oxford, UK}, isbn = {9780080970868}, url = {http://store.elsevier.com/International-Encyclopedia-of-the-Social-and-Behavioral-Sciences/isbn-9780080970875/}, author = {Greenspan, Ralph J} } @article {168, title = {High-throughput and quantitative approaches for measuring circadian rhythms in cyanobacteria using bioluminescence.}, journal = {Methods Enzymol}, volume = {551}, year = {2015}, month = {2015}, pages = {53-72}, abstract = {

The temporal measurement of a bioluminescent reporter has proven to be one of the most powerful tools for characterizing circadian rhythms in the cyanobacterium Synechococcus elongatus. Primarily, two approaches have been used to automate this process: (1) detection of cell culture bioluminescence in 96-well plates by a photomultiplier tube-based plate-cycling luminometer (TopCount Microplate Scintillation and Luminescence Counter, Perkin Elmer) and (2) detection of individual colony bioluminescence by iteratively rotating a Petri dish under a cooled CCD camera using a computer-controlled turntable. Each approach has distinct advantages. The TopCount provides a more quantitative measurement of bioluminescence, enabling the direct comparison of clock output levels among strains. The computer-controlled turntable approach has a shorter set-up time and greater throughput, making it a more powerful phenotypic screening tool. While the latter approach is extremely useful, only a few labs have been able to build such an apparatus because of technical hurdles involved in coordinating and controlling both the camera and the turntable, and in processing the resulting images. This protocol provides instructions on how to construct, use, and process data from a computer-controlled turntable to measure the temporal changes in bioluminescence of individual cyanobacterial colonies. Furthermore, we describe how to prepare samples for use with the TopCount to minimize experimental noise and generate meaningful quantitative measurements of clock output levels for advanced analysis.

}, keywords = {Circadian Clocks, Culture Techniques, Cyanobacteria, Image Processing, Computer-Assisted, Luminescent Measurements}, issn = {1557-7988}, doi = {10.1016/bs.mie.2014.10.010}, author = {Shultzaberger, Ryan K and Paddock, Mark L and Katsuki, Takeo and Greenspan, Ralph J and Golden, Susan S} } @article {129, title = {Primate-specific ORF0 contributes to retrotransposon-mediated diversity.}, journal = {Cell}, volume = {163}, year = {2015}, month = {2015 Oct 22}, pages = {583-93}, abstract = {

LINE-1 retrotransposons are fast-evolving mobile genetic entities that play roles in gene regulation, pathological conditions, and evolution. Here, we show that the primate LINE-1 5{\textquoteright}UTR contains a primate-specific open reading frame (ORF) in the antisense orientation that we named ORF0. The gene product of this ORF localizes to promyelocytic leukemia-adjacent nuclear bodies. ORF0 is present in more than 3,000 loci across human and chimpanzee genomes and has a promoter and a conserved strong Kozak sequence that supports translation. By virtue of containing two splice donor sites, ORF0 can also form fusion proteins with proximal exons. ORF0 transcripts are readily detected in induced pluripotent stem (iPS) cells from both primate species. Capped and polyadenylated ORF0 mRNAs are present in the cytoplasm, and endogenous ORF0 peptides are identified upon proteomic analysis. Finally, ORF0 enhances LINE-1 mobility. Taken together, these results suggest a role for ORF0 in retrotransposon-mediated diversity.

}, keywords = {5{\textquoteright} Untranslated Regions, Amino Acid Sequence, Animals, Base Sequence, Cytoplasm, Humans, Long Interspersed Nucleotide Elements, Molecular Sequence Data, Nuclear Proteins, Open Reading Frames, Pan troglodytes, Retroelements, Ribosomes, RNA Processing, Post-Transcriptional, RNA, Antisense, RNA, Messenger, Sequence Alignment}, issn = {1097-4172}, doi = {10.1016/j.cell.2015.09.025}, author = {Denli, Ahmet M and Narvaiza, I{\~n}igo and Kerman, Bilal E and Pena, Monique and Benner, Christopher and Marchetto, Maria C N and Diedrich, Jolene K and Aslanian, Aaron and Ma, Jiao and Moresco, James J and Moore, Lynne and Hunter, Tony and Saghatelian, Alan and Gage, Fred H} } @article {126, title = {REST Regulates Non-Cell-Autonomous Neuronal Differentiation and Maturation of Neural Progenitor Cells via Secretogranin II.}, journal = {J Neurosci}, volume = {35}, year = {2015}, month = {2015 Nov 4}, pages = {14872-84}, abstract = {

UNLABELLED: RE-1 silencing transcription factor (REST), a master negative regulator of neuronal differentiation, controls neurogenesis by preventing the differentiation of neural stem cells. Here we focused on the role of REST in the early steps of differentiation and maturation of adult hippocampal progenitors (AHPs). REST knockdown promoted differentiation and affected the maturation of rat AHPs. Surprisingly, REST knockdown cells enhanced the differentiation of neighboring wild-type AHPs, suggesting that REST may play a non-cell-autonomous role. Gene expression analysis identified Secretogranin II (Scg2) as the major secreted REST target responsible for the non-cell-autonomous phenotype. Loss-of-function of Scg2 inhibited differentiation in vitro, and exogenous SCG2 partially rescued this phenotype. Knockdown of REST in neural progenitors in mice led to precocious maturation into neurons at the expense of mushroom spines in vivo. In summary, we found that, in addition to its cell-autonomous function, REST regulates differentiation and maturation of AHPs non-cell-autonomously via SCG2.

SIGNIFICANCE STATEMENT: Our results reveal that REST regulates differentiation and maturation of neural progenitor cells in vitro by orchestrating both cell-intrinsic and non-cell-autonomous factors and that Scg2 is a major secretory target of REST with a differentiation-enhancing activity in a paracrine manner. In vivo, REST depletion causes accelerated differentiation of newborn neurons at the expense of spine defects, suggesting a potential role for REST in the timing of the maturation of granule neurons.

}, keywords = {Animals, Cell Differentiation, Cells, Cultured, Female, Hippocampus, Mice, Mice, Inbred C57BL, Neural Stem Cells, Neurogenesis, Neurons, Rats, Wistar, Repressor Proteins, Secretogranin II}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.4286-14.2015}, author = {Kim, Hyung Joon and Denli, Ahmet M and Wright, Rebecca and Baul, Tithi D and Clemenson, Gregory D and Morcos, Ari S and Zhao, Chunmei and Schafer, Simon T and Gage, Fred H and Kagalwala, Mohamedi N} } @article {121, title = {Synaptic activity: An emerging player in schizophrenia.}, journal = {Brain Res}, year = {2015}, month = {2015 Dec 23}, abstract = {

Schizophrenia is a polygenic disorder with a complex etiology. While the genetic and molecular underpinnings of the disease are poorly understood, variations in genes encoding synaptic pathways are consistently implicated. Although its impact is still an open question, a deficit in synaptic activity provides an attractive model to explain the cognitive etiology of schizophrenia. Recent advances in high-throughput imaging and functional studies bring new hope for the application of in vitro disease modeling with patient-derived neurons to empirically ascertain the extent to which these synaptic pathways are involved in the disease. In addition, the emergent avenue of research targeted to probe neuronal connections is revealing critical insight into circuitry and may influence how we think about psychiatric disorders in the near future. This article is part of a Special Issue entitled SI: Exploiting human neurons.

}, issn = {1872-6240}, doi = {10.1016/j.brainres.2015.12.028}, author = {Sarkar, Anindita and Marchetto, Maria C and Gage, Fred H} } @article {122, title = {Transcriptional changes in sensory ganglia associated with primary afferent axon collateral sprouting in spared dermatome model.}, journal = {Genom Data}, volume = {6}, year = {2015}, month = {2015 Dec}, pages = {249-52}, abstract = {

Primary afferent collateral sprouting is a process whereby non-injured primary afferent neurons respond to some stimulus and extend new branches from existing axons. Neurons of both the central and peripheral nervous systems undergo this process, which contributes to both adaptive and maladaptive plasticity (e.g., [1], [2], [3], [4], [5], [6], [7], [8], [9]). In the model used here (the "spared dermatome" model), the intact sensory neurons respond to the denervation of adjacent areas of skin by sprouting new axon branches into that adjacent denervated territory. Investigations of gene expression changes associated with collateral sprouting can provide a better understanding of the molecular mechanisms controlling this process. Consequently, it can be used to develop treatments to promote functional recovery for spinal cord injury and other similar conditions. This report includes raw gene expression data files from microarray experiments in order to study the gene regulation in spared sensory ganglia in the initiation (7\ days) and maintenance (14\ days) phases of the spared dermatome model relative to intact ("na{\"\i}ve") sensory ganglia. Data has been deposited into GEO (GSE72551).

}, issn = {2213-5960}, doi = {10.1016/j.gdata.2015.10.005}, author = {Harrison, Benjamin J and Venkat, Gayathri and Hutson, Thomas and Rau, Kristofer K and Bunge, Mary Bartlett and Mendell, Lorne M and Gage, Fred H and Johnson, Richard D and Hill, Caitlin and Rouchka, Eric C and Moon, Lawrence and Petruska, Jeffrey C} } @article {173, title = {California can lead the way on brain research}, year = {2014}, url = {http://www.sacbee.com/opinion/op-ed/article2606601.html}, author = {Greenspan, RJ and Alivisatos, AP} } @article {179, title = {Changes in GABA and glutamate concentrations during memory tasks in patients with Parkinson{\textquoteright}s disease undergoing DBS surgery.}, journal = {Front Hum Neurosci}, volume = {8}, year = {2014}, month = {2014}, pages = {81}, abstract = {

Until now direct neurochemical measurements during memory tasks have not been accomplished in the human basal ganglia. It has been proposed, based on both functional imaging studies and psychometric testing in normal subjects and in patients with Parkinson{\textquoteright}s disease (PD), that the basal ganglia is responsible for the performance of feedback-contingent implicit memory tasks. To measure neurotransmitters, we used in vivo microdialysis during deep brain stimulation (DBS) surgery. We show in the right subthalamic nucleus (STN) of patients with PD a task-dependent change in the concentrations of glutamate and GABA during an implicit memory task relative to baseline, while no difference was found between declarative memory tasks. The five patients studied had a significant decrease in the percent concentration of GABA and glutamate during the performance of the weather prediction task (WPT). We hypothesize, based on current models of basal ganglia function, that this decrease in the concentration is consistent with expected dysfunction in basal ganglia networks in patients with PD.

}, issn = {1662-5161}, doi = {10.3389/fnhum.2014.00081}, author = {Buchanan, Robert J and Darrow, David P and Meier, Kevin T and Robinson, Jennifer and Schiehser, Dawn M and Glahn, David C and Nadasdy, Zoltan} } @article {140, title = {Non-cell-autonomous mechanism of activity-dependent neurotransmitter switching.}, journal = {Neuron}, volume = {82}, year = {2014}, month = {2014 Jun 4}, pages = {1004-16}, abstract = {

Activity-dependent neurotransmitter switching engages genetic programs regulating transmitter synthesis, but the mechanism by which activity is transduced is unknown. We suppressed activity in single neurons in the embryonic spinal cord to determine whether glutamate-gamma-aminobutyric acid (GABA) switching is cell autonomous. Transmitter respecification did not occur, suggesting that it is homeostatically regulated by the level of activity in surrounding neurons. Graded increase in the number of silenced neurons in cultures led to graded decrease in the number of neurons expressing GABA, supporting non-cell-autonomous transmitter switching. We found that brain-derived neurotrophic factor (BDNF) is expressed in the spinal cord during the period of transmitter respecification and that spike activity causes release of BDNF. Activation of TrkB receptors triggers a signaling cascade involving JNK-mediated activation of cJun that regulates tlx3, a glutamate/GABA selector gene, accounting for calcium-spike BDNF-dependent transmitter switching. Our findings identify a molecular mechanism for activity-dependent respecification of neurotransmitter phenotype in developing spinal neurons.

}, keywords = {Animals, Brain-Derived Neurotrophic Factor, Calcium, Cells, Cultured, Female, gamma-Aminobutyric Acid, Glutamic Acid, JNK Mitogen-Activated Protein Kinases, Neurons, Phosphorylation, Proto-Oncogene Proteins c-jun, Signal Transduction, Spinal Cord, Xenopus laevis}, issn = {1097-4199}, doi = {10.1016/j.neuron.2014.04.029}, author = {Guemez-Gamboa, Alicia and Xu, Lin and Meng, Da and Spitzer, Nicholas C} } @article {167, title = {Prospective Optimization.}, journal = {Proc IEEE Inst Electr Electron Eng}, volume = {102}, year = {2014}, month = {2014 May}, abstract = {

Human performance approaches that of an ideal observer and optimal actor in some perceptual and motor tasks. These optimal abilities depend on the capacity of the cerebral cortex to store an immense amount of information and to flexibly make rapid decisions. However, behavior only approaches these limits after a long period of learning while the cerebral cortex interacts with the basal ganglia, an ancient part of the vertebrate brain that is responsible for learning sequences of actions directed toward achieving goals. Progress has been made in understanding the algorithms used by the brain during reinforcement learning, which is an online approximation of dynamic programming. Humans also make plans that depend on past experience by simulating different scenarios, which is called prospective optimization. The same brain structures in the cortex and basal ganglia that are active online during optimal behavior are also active offline during prospective optimization. The emergence of general principles and algorithms for goal-directed behavior has consequences for the development of autonomous devices in engineering applications.

}, issn = {0018-9219}, doi = {10.1109/JPROC.2014.2314297}, author = {Sejnowski, Terrence J and Poizner, Howard and Lynch, Gary and Gepshtein, Sergei and Greenspan, Ralph J} } @article {213, title = {Sparse and distributed coding of episodic memory in neurons of the human hippocampus.}, journal = {Proc Natl Acad Sci U S A}, volume = {111}, year = {2014}, month = {2014 Jul 1}, pages = {9621-6}, abstract = {

Neurocomputational models hold that sparse distributed coding is the most efficient way for hippocampal neurons to encode episodic memories rapidly. We investigated the representation of episodic memory in hippocampal neurons of nine epilepsy patients undergoing intracranial monitoring as they discriminated between recently studied words (targets) and new words (foils) on a recognition test. On average, single units and multiunits exhibited higher spike counts in response to targets relative to foils, and the size of this effect correlated with behavioral performance. Further analyses of the spike-count distributions revealed that (i) a small percentage of recorded neurons responded to any one target and (ii) a small percentage of targets elicited a strong response in any one neuron. These findings are consistent with the idea that in the human hippocampus episodic memory is supported by a sparse distributed neural code.

}, keywords = {Epilepsy, Hippocampus, Humans, Memory, Episodic, Models, Neurological, Neurophysiological Monitoring, Neuropsychological Tests}, issn = {1091-6490}, doi = {10.1073/pnas.1408365111}, author = {Wixted, John T and Squire, Larry R and Jang, Yoonhee and Papesh, Megan H and Goldinger, Stephen D and Kuhn, Joel R and Smith, Kris A and Treiman, David M and Steinmetz, Peter N} } @article {180, title = {Speech-specific tuning of neurons in human superior temporal gyrus.}, journal = {Cereb Cortex}, volume = {24}, year = {2014}, month = {2014 Oct}, pages = {2679-93}, abstract = {

How the brain extracts words from auditory signals is an unanswered question. We recorded approximately 150 single and multi-units from the left anterior superior temporal gyrus of a patient during multiple auditory experiments. Against low background activity, 45\% of units robustly fired to particular spoken words with little or no response to pure tones, noise-vocoded speech, or environmental sounds. Many units were tuned to complex but specific sets of phonemes, which were influenced by local context but invariant to speaker, and suppressed during self-produced speech. The firing of several units to specific visual letters was correlated with their response to the corresponding auditory phonemes, providing the first direct neural evidence for phonological recoding during reading. Maximal decoding of individual phonemes and words identities was attained using firing rates from approximately 5 neurons within 200 ms after word onset. Thus, neurons in human superior temporal gyrus use sparse spatially organized population encoding of complex acoustic-phonetic features to help recognize auditory and visual words.

}, keywords = {Acoustic Stimulation, Adult, Humans, Male, Neurons, Phonetics, Speech Perception, Temporal Lobe}, issn = {1460-2199}, doi = {10.1093/cercor/bht127}, author = {Chan, Alexander M and Dykstra, Andrew R and Jayaram, Vinay and Leonard, Matthew K and Travis, Katherine E and Gygi, Brian and Baker, Janet M and Eskandar, Emad and Hochberg, Leigh R and Halgren, Eric and Cash, Sydney S} } @article {172, title = {Brain initiative a unique opportunity for San Diego}, year = {2013}, url = {http://www.sandiegouniontribune.com/news/2013/oct/03/brain-initiative-a-unique-opportunity-for-san/}, author = {Greenspan, Ralph J} } @article {166, title = {A comprehensive wiring diagram of the protocerebral bridge for visual information processing in the Drosophila brain.}, journal = {Cell Rep}, volume = {3}, year = {2013}, month = {2013 May 30}, pages = {1739-53}, abstract = {

How the brain perceives sensory information and generates meaningful behavior depends critically on its underlying circuitry. The protocerebral bridge (PB) is a major part of the insect central complex (CX), a premotor center that may be analogous to the human basal ganglia. Here, by deconstructing hundreds of PB single neurons and reconstructing them into a common three-dimensional framework, we have constructed a comprehensive map of PB circuits with labeled polarity and predicted directions of information flow. Our analysis reveals a highly ordered information processing system that involves directed information flow among CX subunits through 194 distinct PB neuron types. Circuitry properties such as mirroring, convergence, divergence, tiling, reverberation, and parallel signal propagation were observed; their functional and evolutional significance is discussed. This layout of PB neuronal circuitry may provide guidelines for further investigations on transformation of sensory (e.g., visual) input into locomotor commands in fly brains.

}, keywords = {Animals, Brain, Drosophila, Models, Biological, Neurons}, issn = {2211-1247}, doi = {10.1016/j.celrep.2013.04.022}, author = {Lin, Chih-Yung and Chuang, Chao-Chun and Hua, Tzu-En and Chen, Chun-Chao and Dickson, Barry J and Greenspan, Ralph J and Chiang, Ann-Shyn} } @article {141, title = {Jellyfish nervous systems.}, journal = {Curr Biol}, volume = {23}, year = {2013}, month = {2013 Jul 22}, pages = {R592-4}, keywords = {Animals, Behavior, Animal, Cnidaria, Nerve Net, Nervous System, Nervous System Physiological Phenomena}, issn = {1879-0445}, doi = {10.1016/j.cub.2013.03.057}, author = {Katsuki, Takeo and Greenspan, Ralph J} } @article {161, title = {Neurogenetics.}, journal = {Curr Opin Neurobiol}, volume = {23}, year = {2013}, month = {2013 Feb}, pages = {1-2}, keywords = {Animals, Behavior, Genetics, Humans, Neurosciences}, issn = {1873-6882}, doi = {10.1016/j.conb.2012.12.001}, author = {Greenspan, Ralph and Petit, Christine} } @article {158, title = {Neuroscience. The brain activity map.}, journal = {Science}, volume = {339}, year = {2013}, month = {2013 Mar 15}, pages = {1284-5}, keywords = {Brain Diseases, Brain Mapping, Hippocampus, Humans, Neural Pathways, Neurons}, issn = {1095-9203}, doi = {10.1126/science.1236939}, author = {Alivisatos, A Paul and Chun, Miyoung and Church, George M and Deisseroth, Karl and Donoghue, John P and Greenspan, Ralph J and McEuen, Paul L and Roukes, Michael L and Sejnowski, Terrence J and Weiss, Paul S and Yuste, Rafael} } @article {183, title = {Selection of distinct populations of dentate granule cells in response to inputs as a mechanism for pattern separation in mice.}, journal = {Elife}, volume = {2}, year = {2013}, month = {2013}, pages = {e00312}, abstract = {

The hippocampus is critical for episodic memory and computational studies have predicted specific functions for each hippocampal subregion. Particularly, the dentate gyrus (DG) is hypothesized to perform pattern separation by forming distinct representations of similar inputs. How pattern separation is achieved by the DG remains largely unclear. By examining neuronal activities at a population level, we revealed that, unlike CA1 neuron populations, dentate granule cell (DGC) ensembles activated by learning were not preferentially reactivated by memory recall. Moreover, when mice encountered an environment to which they had not been previously exposed, a novel DGC population-rather than the previously activated DGC ensembles that responded to past events-was selected to represent the new environmental inputs. This selection of a novel responsive DGC population could be triggered by small changes in environmental inputs. Therefore, selecting distinct DGC populations to represent similar but not identical inputs is a mechanism for pattern separation. DOI:http://dx.doi.org/10.7554/eLife.00312.001.

}, keywords = {Animals, Behavior, Animal, Brain Mapping, CA1 Region, Hippocampal, Conditioning (Psychology), Cues, Dentate Gyrus, Environment, Fear, Gene Expression Regulation, Genes, Reporter, Memory, Memory, Episodic, Mental Recall, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Transgenic, Neural Pathways, Neurons, Pattern Recognition, Physiological, Time Factors}, issn = {2050-084X}, doi = {10.7554/eLife.00312}, author = {Deng, Wei and Mayford, Mark and Gage, Fred H} } @article {164, title = {Vertebrate versus invertebrate neural circuits.}, journal = {Curr Biol}, volume = {23}, year = {2013}, month = {2013 Jun 17}, pages = {R504-6}, keywords = {Animals, Invertebrates, Nervous System, Nervous System Physiological Phenomena, Vertebrates}, issn = {1879-0445}, author = {Katz, Paul and Grillner, Sten and Wilson, Rachel and Borst, Alexander and Greenspan, Ralph and Buzs{\'a}ki, Gy{\"o}rgy and Martin, Kevan and Marder, Eve and Kristan, William and Friedrich, Rainer and Chklovskii, Dmitri Mitya} } @article {162, title = {Biological indeterminacy.}, journal = {Sci Eng Ethics}, volume = {18}, year = {2012}, month = {2012 Sep}, pages = {447-52}, abstract = {

Reductionist explanations in biology generally assume that biological mechanisms are highly deterministic and basically similar between individuals. A contrasting view has emerged recently that takes into account the degeneracy of biological processes--the ability to arrive at a given endpoint by a variety of available paths, even within the same individual. This perspective casts significant doubt on the prospects for the ability to predict behavior accurately based on brain imaging or genotyping, and on the ability of neuroscience to stipulate ethics.

}, keywords = {Brain, Genotype, Humans, Models, Biological, Morals, Neuroimaging, Neurosciences, Psychophysiology, Social Behavior}, issn = {1471-5546}, doi = {10.1007/s11948-012-9379-2}, author = {Greenspan, Ralph J} } @article {159, title = {The brain activity map project and the challenge of functional connectomics.}, journal = {Neuron}, volume = {74}, year = {2012}, month = {2012 Jun 21}, pages = {970-4}, abstract = {

The function of neural circuits is an emergent property that arises from the coordinated activity of large numbers of neurons. To capture this, we propose launching a large-scale, international public effort, the Brain Activity Map Project, aimed at reconstructing the full record of neural activity across complete neural circuits. This technological challenge could prove to be an invaluable step toward understanding fundamental and pathological brain processes.

}, keywords = {Action Potentials, Brain, Brain Mapping, Humans, Models, Neurological, Nerve Net, Neural Pathways, Neurons}, issn = {1097-4199}, doi = {10.1016/j.neuron.2012.06.006}, author = {Alivisatos, A Paul and Chun, Miyoung and Church, George M and Greenspan, Ralph J and Roukes, Michael L and Yuste, Rafael} } @article {163, title = {Genes involved in sex pheromone discrimination in Drosophila melanogaster and their background-dependent effect.}, journal = {PLoS One}, volume = {7}, year = {2012}, month = {2012}, pages = {e30799}, abstract = {

Mate choice is based on the comparison of the sensory quality of potential mating partners, and sex pheromones play an important role in this process. In Drosophila melanogaster, contact pheromones differ between male and female in their content and in their effects on male courtship, both inhibitory and stimulatory. To investigate the genetic basis of sex pheromone discrimination, we experimentally selected males showing either a higher or lower ability to discriminate sex pheromones over 20 generations. This experimental selection was carried out in parallel on two different genetic backgrounds: wild-type and desat1 mutant, in which parental males showed high and low sex pheromone discrimination ability respectively. Male perception of male and female pheromones was separately affected during the process of selection. A comparison of transcriptomic activity between high and low discrimination lines revealed genes not only that varied according to the starting genetic background, but varied reciprocally. Mutants in two of these genes, Shaker and quick-to-court, were capable of producing similar effects on discrimination on their own, in some instances mimicking the selected lines, in others not. This suggests that discrimination of sex pheromones depends on genes whose activity is sensitive to genetic context and provides a rare, genetically defined example of the phenomenon known as "allele flips," in which interactions have reciprocal effects on different genetic backgrounds.

}, keywords = {Animals, Animals, Genetically Modified, Behavior, Animal, Breeding, Courtship, Drosophila melanogaster, Female, Genes, Insect, Male, Mutation, Olfactory Perception, Reproduction, Sex Attractants, Sexual Behavior, Animal, Species Specificity}, issn = {1932-6203}, doi = {10.1371/journal.pone.0030799}, author = {Houot, Benjamin and Fraichard, St{\'e}phane and Greenspan, Ralph J and Ferveur, Jean-Fran{\c c}ois} } @conference {169, title = {A Drosophila Model of Williams Syndrome}, booktitle = {136th Annual Meeting of the American-Neurological-Association (ANA). San Diego, CA. Sep 25-27, 2011}, year = {2011}, publisher = {Annals of Neurology}, organization = {Annals of Neurology}, author = {Greenspan, Ralph J and Wagner, Jenee} } @article {174, title = {Adult neurogenesis: integrating theories and separating functions.}, journal = {Trends Cogn Sci}, volume = {14}, year = {2010}, month = {2010 Jul}, pages = {325-37}, abstract = {

The continuous incorporation of new neurons in the dentate gyrus of the adult hippocampus raises exciting questions about memory and learning, and has inspired new computational models to understand the function of adult neurogenesis. These theoretical approaches suggest distinct roles for new neurons as they slowly integrate into the existing dentate gyrus network: immature adult-born neurons seem to function as pattern integrators of temporally adjacent events, thereby enhancing pattern separation for events separated in time; whereas maturing adult-born neurons possibly contribute to pattern separation by being more amenable to learning new information, leading to dedicated groups of granule cells that respond to experienced environments. We review these hypothesized functions and supporting empirical research and point to new directions for future theoretical efforts.

}, keywords = {Adult, Adult Stem Cells, Animals, Cell Proliferation, Hippocampus, Humans, Models, Biological, Neurogenesis, Neurons}, issn = {1879-307X}, doi = {10.1016/j.tics.2010.04.003}, author = {Aimone, James B and Deng, Wei and Gage, Fred H} } @conference {170, title = {Genes involved in sex pheromones discrimination and their context-dependent effect}, booktitle = {The 13th European Drosophila Neurobiology Conference (Neurofly)}, year = {2010}, publisher = {Journal of Neurogenetics, 24, 20-20, Supplement 1}, organization = {Journal of Neurogenetics, 24, 20-20, Supplement 1}, author = {Houot, Benjamin and Greenspan, Ralph J and Ferveur, Jean-Fran{\c c}ois} } @book {156, title = {How Genes Influence Behavior}, year = {2010}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {London \& New York}, abstract = {

How important are genetic influences on behavior?
How many genes influence an individual behavior, and how much influence does a single gene have?\ 
How do genes interact with the environment to influence the development of behavioral traits?
What are the differences between humans and {\textquoteright}simpler{\textquoteright} organisms when it comes to the genetic control of behavior?\ 

How Genes Influence Behavior is a unique introduction to behavioral genetics, which combines conceptual rigor with accessibility to answer questions such as these--answers that carry important implications for the nature of who we are.\ 

Offering unparalleled insights into how behavioral genetics is probed through real-world research, it considers evidence from humans and the major model organisms of mouse, fruit-fly and nematode worm to demonstrate how much of our current understanding of the genetic basis of human behavior stems from our exploration of other animals. Further, it uses these studies to connect the key themes of the book--the nature of gene action, and the inter-relationship of genetic and environmental influences on behavior-across organisms, highlighting key commonalities and differences.

The book also shows the major impact that neurobiology is having on our understanding of the field, to give a true depiction of behavioral genetics in the 21st century. However, care is taken throughout not to overwhelm the reader with scientific detail. Instead, the authors make the book fun to read without sacrificing accuracy or devaluing the complexity of the subject matter: they {\textquoteright}personalize{\textquoteright} the science, mixing more standard narrative with biographical details to make the subject come alive.\ 

With the media filled with talk of the discovery of genes {\textquoteright}for{\textquoteright} an array of human behaviors, there has never been a more pressing need for today{\textquoteright}s students--tomorrow{\textquoteright}s researchers--to be equipped with a clear, balanced view of the field. How Genes Influence Behavior is the perfect guide for all students, delivered in the words of three researchers who have witnessed first-hand the emergence of this fascinating field, and whose own investigations have been central to our current understanding of it.

}, isbn = {9780199559909}, url = {https://www.amazon.com/Genes-Influence-Behavior-Jonathan-Flint/dp/0199559902}, author = {Flint, Jonathan and Greenspan, Ralph J and Kendler, Kenneth S} } @article {182, title = {New neurons and new memories: how does adult hippocampal neurogenesis affect learning and memory?}, journal = {Nat Rev Neurosci}, volume = {11}, year = {2010}, month = {2010 May}, pages = {339-50}, abstract = {

The integration of adult-born neurons into the circuitry of the adult hippocampus suggests an important role for adult hippocampal neurogenesis in learning and memory, but its specific function in these processes has remained elusive. In this article, we summarize recent progress in this area, including advances based on behavioural studies and insights provided by computational modelling. Increasingly, evidence suggests that newborn neurons might be involved in hippocampal functions that are particularly dependent on the dentate gyrus, such as pattern separation. Furthermore, newborn neurons at different maturation stages may make distinct contributions to learning and memory. In particular, computational studies suggest that, before newborn neurons are fully mature, they might function as a pattern integrator by introducing a degree of similarity to the encoding of events that occur closely in time.

}, keywords = {Adult Stem Cells, Animals, Hippocampus, Humans, Learning, Memory, Models, Neurological, Neurogenesis, Neurons}, issn = {1471-0048}, doi = {10.1038/nrn2822}, author = {Deng, Wei and Aimone, James B and Gage, Fred H} } @article {191, title = {Spatiotemporal dynamics of bilingual word processing.}, journal = {Neuroimage}, volume = {49}, year = {2010}, month = {2010 Feb 15}, pages = {3286-94}, abstract = {

Studies with monolingual adults have identified successive stages occurring in different brain regions for processing single written words. We combined magnetoencephalography and magnetic resonance imaging to compare these stages between the first (L1) and second (L2) languages in bilingual adults. L1 words in a size judgment task evoked a typical left-lateralized sequence of activity first in ventral occipitotemporal cortex (VOT: previously associated with visual word-form encoding) and then ventral frontotemporal regions (associated with lexico-semantic processing). Compared to L1, words in L2 activated right VOT more strongly from approximately 135 ms; this activation was attenuated when words became highly familiar with repetition. At approximately 400 ms, L2 responses were generally later than L1, more bilateral, and included the same lateral occipitotemporal areas as were activated by pictures. We propose that acquiring a language involves the recruitment of right hemisphere and posterior visual areas that are not necessary once fluency is achieved.

}, keywords = {Adolescent, Adult, Brain, Brain Mapping, Female, Functional Laterality, Humans, Magnetoencephalography, Male, Multilingualism, Nerve Net, Pattern Recognition, Visual, Reading, Semantics, Young Adult}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2009.12.009}, author = {Leonard, Matthew K and Brown, Timothy T and Travis, Katherine E and Gharapetian, Lusineh and Hagler, Donald J and Dale, Anders M and Elman, Jeffrey L and Halgren, Eric} } @article {175, title = {Computational influence of adult neurogenesis on memory encoding.}, journal = {Neuron}, volume = {61}, year = {2009}, month = {2009 Jan 29}, pages = {187-202}, abstract = {

Adult neurogenesis in the hippocampus leads to the incorporation of thousands of new granule cells into the dentate gyrus every month, but its function remains unclear. Here, we present computational evidence that indicates that adult neurogenesis may make three separate but related contributions to memory formation. First, immature neurons introduce a degree of similarity to memories learned at the same time, a process we refer to as pattern integration. Second, the extended maturation and change in excitability of these neurons make this added similarity a time-dependent effect, supporting the possibility that temporal information is included in new hippocampal memories. Finally, our model suggests that the experience-dependent addition of neurons results in a dentate gyrus network well suited for encoding new memories in familiar contexts while treating novel contexts differently. Taken together, these results indicate that new granule cells may affect hippocampal function in several unique and previously unpredicted ways.

}, keywords = {Age Factors, Algorithms, Animals, Cell Proliferation, Computer Simulation, Dentate Gyrus, Humans, Memory, Nerve Net, Neural Pathways, Neurogenesis, Neuronal Plasticity, Neurons, Stem Cells, Synapses, Time Perception}, issn = {1097-4199}, doi = {10.1016/j.neuron.2008.11.026}, author = {Aimone, James B and Wiles, Janet and Gage, Fred H} } @article {165, title = {The Drosophila foraging gene mediates adult plasticity and gene-environment interactions in behaviour, metabolites, and gene expression in response to food deprivation.}, journal = {PLoS Genet}, volume = {5}, year = {2009}, month = {2009 Aug}, pages = {e1000609}, abstract = {

Nutrition is known to interact with genotype in human metabolic syndromes, obesity, and diabetes, and also in Drosophila metabolism. Plasticity in metabolic responses, such as changes in body fat or blood sugar in response to changes in dietary alterations, may also be affected by genotype. Here we show that variants of the foraging (for) gene in Drosophila melanogaster affect the response to food deprivation in a large suite of adult phenotypes by measuring gene by environment interactions (GEI) in a suite of food-related traits. for affects body fat, carbohydrates, food-leaving behavior, metabolite, and gene expression levels in response to food deprivation. This results in broad patterns of metabolic, genomic, and behavioral gene by environment interactions (GEI), in part by interaction with the insulin signaling pathway. Our results show that a single gene that varies in nature can have far reaching effects on behavior and metabolism by acting through multiple other genes and pathways.

}, keywords = {Animals, Carbohydrate Metabolism, Cyclic GMP-Dependent Protein Kinases, Drosophila melanogaster, Drosophila Proteins, Ecosystem, Fats, Food Deprivation, Gene Expression, Signal Transduction}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1000609}, author = {Kent, Clement F and Daskalchuk, Tim and Cook, Lisa and Sokolowski, Marla B and Greenspan, Ralph J} } @article {160, title = {A proposal for a coordinated effort for the determination of brainwide neuroanatomical connectivity in model organisms at a mesoscopic scale.}, journal = {PLoS Comput Biol}, volume = {5}, year = {2009}, month = {2009 Mar}, pages = {e1000334}, abstract = {

In this era of complete genomes, our knowledge of neuroanatomical circuitry remains surprisingly sparse. Such knowledge is critical, however, for both basic and clinical research into brain function. Here we advocate for a concerted effort to fill this gap, through systematic, experimental mapping of neural circuits at a mesoscopic scale of resolution suitable for comprehensive, brainwide coverage, using injections of tracers or viral vectors. We detail the scientific and medical rationale and briefly review existing knowledge and experimental techniques. We define a set of desiderata, including brainwide coverage; validated and extensible experimental techniques suitable for standardization and automation; centralized, open-access data repository; compatibility with existing resources; and tractability with current informatics technology. We discuss a hypothetical but tractable plan for mouse, additional efforts for the macaque, and technique development for human. We estimate that the mouse connectivity project could be completed within five years with a comparatively modest budget.

}, keywords = {Animals, Brain, Databases, Factual, Humans, Macaca, Mice, Models, Neurological, Nerve Net, Neuroanatomy, Research Design}, issn = {1553-7358}, doi = {10.1371/journal.pcbi.1000334}, author = {Bohland, Jason W and Wu, Caizhi and Barbas, Helen and Bokil, Hemant and Bota, Mihail and Breiter, Hans C and Cline, Hollis T and Doyle, John C and Freed, Peter J and Greenspan, Ralph J and Haber, Suzanne N and Hawrylycz, Michael and Herrera, Daniel G and Hilgetag, Claus C and Huang, Z Josh and Jones, Allan and Jones, Edward G and Karten, Harvey J and Kleinfeld, David and K{\"o}tter, Rolf and Lester, Henry A and Lin, John M and Mensh, Brett D and Mikula, Shawn and Panksepp, Jaak and Price, Joseph L and Safdieh, Joseph and Saper, Clifford B and Schiff, Nicholas D and Schmahmann, Jeremy D and Stillman, Bruce W and Svoboda, Karel and Swanson, Larry W and Toga, Arthur W and Van Essen, David C and Watson, James D and Mitra, Partha P} } @article {142, title = {Selection, gene interaction, and flexible gene networks.}, journal = {Cold Spring Harb Symp Quant Biol}, volume = {74}, year = {2009}, month = {2009}, pages = {131-8}, abstract = {

Recent results from a variety of different kinds of experiments, mainly using behavior as an assay, and ranging from laboratory selection experiments to gene interaction studies, show that a much wider range of genes can affect phenotype than those identified as "core genes" in classical mutant screens. Moreover, very pleiotropic genes can produce specific phenotypes when mild variants are combined. These studies also show that gene networks readily change configuration and the relationships between interacting genes in response to the introduction of additional genetic variants, suggesting that the networks range widely and have a high degree of flexibility and malleability. Such flexibility, in turn, offers a plausible mechanism for the molding of phenotypes through microevolution, as a prerequisite to making a suitable environment for the acceptance of newly arising large-effect mutations in the transition from microevolution to macroevolution.

}, keywords = {Animals, Biological Evolution, Drosophila melanogaster, Epistasis, Genetic, Escherichia coli, Female, Gene Regulatory Networks, Genes, Insect, Genetic Association Studies, Male, Models, Genetic, Mutation, Selection, Genetic}, issn = {1943-4456}, doi = {10.1101/sqb.2009.74.029}, author = {Greenspan, R J} } @article {143, title = {Activation of EGFR and ERK by rhomboid signaling regulates the consolidation and maintenance of sleep in Drosophila.}, journal = {Nat Neurosci}, volume = {10}, year = {2007}, month = {2007 Sep}, pages = {1160-7}, abstract = {

Epidermal growth factor receptor (EGFR) signaling in the mammalian hypothalamus is important in the circadian regulation of activity. We have examined the role of this pathway in the regulation of sleep in Drosophila melanogaster. Our results demonstrate that rhomboid (Rho)- and Star-mediated activation of EGFR and ERK signaling increases sleep in a dose-dependent manner, and that blockade of rhomboid (rho) expression in the nervous system decreases sleep. The requirement of rho for sleep localized to the pars intercerebralis, a part of the fly brain that is developmentally and functionally analogous to the hypothalamus in vertebrates. These results suggest that sleep and its regulation by EGFR signaling may be ancestral to insects and mammals.

}, keywords = {Analysis of Variance, Animals, Animals, Genetically Modified, Behavior, Animal, Drosophila, Drosophila Proteins, Enzyme Activation, Extracellular Signal-Regulated MAP Kinases, Gene Expression Regulation, Developmental, Membrane Proteins, Motor Activity, Receptor, Epidermal Growth Factor, Signal Transduction, Sleep}, issn = {1097-6256}, doi = {10.1038/nn1957}, author = {Foltenyi, Krisztina and Greenspan, Ralph J and Newport, John W} } @book {157, title = {An Introduction to Nervous Systems}, year = {2007}, publisher = {Cold Spring Harbor Laboratory Press}, organization = {Cold Spring Harbor Laboratory Press}, address = {Cold Spring Harbor, NY}, abstract = {

An Introduction to Nervous Systems presents the principles of neurobiology from an evolutionary perspective{\textemdash}from single{\textendash}celled organisms to complex invertebrates such as flies{\textemdash}and is ideal for use as a supplemental textbook. Greenspan describes the mechanisms that allow behavior to become ever more sophisticated{\textemdash}from simple avoidance behavior of Paramecium through to the complex cognitive behaviors of the honeybee{\textemdash}and shows how these mechanisms produce the increasing neural complexity found in these organisms. The book ends with a discussion of what is universal about nervous systems and what may be required, neurobiologically, to be human. This novel and highly readable presentation of fundamental principles of neurobiology is designed to be accessible to undergraduate and graduate students not already steeped in the subject.

}, isbn = {978-087969821-8 }, url = {http://www.cshlpress.com/default.tpl?action=full\&cart=146982185827182421\&--eqskudatarq=597\&typ=ps\&newtitle=An\%20Introduction\%20to\%20Nervous\%20Systems}, author = {Greenspan, Ralph J} } @article {144, title = {Serotonin and neuropeptide F have opposite modulatory effects on fly aggression.}, journal = {Nat Genet}, volume = {39}, year = {2007}, month = {2007 May}, pages = {678-82}, abstract = {

Both serotonin (5-HT) and neuropeptide Y have been shown to affect a variety of mammalian behaviors, including aggression. Here we show in Drosophila melanogaster that both 5-HT and neuropeptide F, the invertebrate homolog of neuropeptide Y, modulate aggression. We show that drug-induced increases of 5-HT in the fly brain increase aggression. Elevating 5-HT genetically in the serotonergic circuits recapitulates these pharmacological effects, whereas genetic silencing of these circuits makes the flies behaviorally unresponsive to the drug-induced increase of 5-HT but leaves them capable of aggression. Genetic silencing of the neuropeptide F (npf) circuit also increases fly aggression, demonstrating an opposite modulation to 5-HT. Moreover, this neuropeptide F effect seems to be independent of 5-HT. The implication of these two modulatory systems in fly and mouse aggression suggest a marked degree of conservation and a deep molecular root for this behavior.

}, keywords = {Aggression, Analysis of Variance, Animals, Behavior, Animal, Biological Evolution, Brain, Drosophila melanogaster, Drosophila Proteins, Gene Silencing, Neuropeptides, Reverse Transcriptase Polymerase Chain Reaction, Serotonin}, issn = {1061-4036}, doi = {10.1038/ng2029}, author = {Dierick, Herman A and Greenspan, Ralph J} } @article {145, title = {Molecular analysis of flies selected for aggressive behavior.}, journal = {Nat Genet}, volume = {38}, year = {2006}, month = {2006 Sep}, pages = {1023-31}, abstract = {

Aggressive behavior is pervasive throughout the animal kingdom, and yet very little is known about its molecular underpinnings. To address this problem, we have developed a population-based selection procedure to increase aggression in Drosophila melanogaster. We measured changes in aggressive behavior in the selected subpopulations with a new two-male arena assay. In only ten generations of selection, the aggressive lines became markedly more aggressive than the neutral lines. After 21 generations, the fighting index increased more than 30-fold. Using microarray analysis, we identified genes with differing expression levels in the aggressive and neutral lines as candidates for this strong behavioral selection response. We tested a small set of these genes through mutant analysis and found that one significantly increased fighting frequency. These results suggest that selection for increases in aggression can be used to molecularly dissect this behavior.

}, keywords = {Aggression, Agonistic Behavior, Animals, Behavior, Animal, DNA Mutational Analysis, Drosophila melanogaster, Male, Oligonucleotide Array Sequence Analysis, RNA, Selection, Genetic}, issn = {1061-4036}, doi = {10.1038/ng1864}, author = {Dierick, Herman A and Greenspan, Ralph J} } @article {146, title = {The nature of genetic influences on behavior: lessons from "simpler" organisms.}, journal = {Am J Psychiatry}, volume = {163}, year = {2006}, month = {2006 Oct}, pages = {1683-94}, abstract = {

Substantial advances have been made in recent years in the understanding of the genetic basis of behavior in "simpler" organisms, especially the mouse and the fruit fly Drosophila. The authors examine the degree of similarity between the genetic underpinnings of psychiatric illness and genetic influences on behavior in such simpler organisms. Six topics are reviewed: 1) the extent of natural genetic variation, 2) the multigenic nature of natural variation, 3) the impact of individual genes on multiple traits, 4) gene-environment interactions, 5) genetic effects on the environment, and 6) gene-by-sex interactions. The results suggest that the pattern of results emerging in psychiatric genetics is generally consistent with the findings of behavioral genetics in simpler organisms. Across the animal kingdom, individual differences in behavior are nearly always influenced by genetic factors which, in turn, result from a substantial number of individual genes, each with a small effect. Nearly all genes that affect behavior influence multiple phenotypes. The impact of individual genes can be substantially modified by other genes and/or by environmental experiences. Many animals alter their environment, and the nature of that alteration is influenced by genes. For some behaviors, the pathway from genes to behavior differs meaningfully in males and females. With respect to the broad patterns of genetic influences on behavior, Homo sapiens appears to be typical of other animal species.

}, keywords = {Animals, Drosophila, Genetics, Behavioral, Humans, Mental Disorders, Mice, Physiology, Comparative}, issn = {0002-953X}, doi = {10.1176/ajp.2006.163.10.1683}, author = {Kendler, Kenneth S and Greenspan, Ralph J} } @article {147, title = {Dopaminergic modulation of arousal in Drosophila.}, journal = {Curr Biol}, volume = {15}, year = {2005}, month = {2005 Jul 12}, pages = {1165-75}, abstract = {

BACKGROUND: Arousal levels in the brain set thresholds for behavior, from simple to complex. The mechanistic underpinnings of the various phenomena comprising arousal, however, are still poorly understood. Drosophila behaviors have been studied that span different levels of arousal, from sleep to visual perception to psychostimulant responses.

RESULTS: We have investigated neurobiological mechanisms of arousal in the Drosophila brain by a combined behavioral, genetic, pharmacological, and electrophysiological approach. Administration of methamphetamine (METH) suppresses sleep and promotes active wakefulness, whereas an inhibitor of dopamine synthesis promotes sleep. METH affects courtship behavior by increasing sexual arousal while decreasing successful sexual performance. Electrophysiological recordings from the medial protocerebrum of wild-type flies showed that METH ingestion has rapid and detrimental effects on a brain response associated with perception of visual stimuli. Recordings in genetically manipulated animals show that dopaminergic transmission is required for these responses and that visual-processing deficits caused by attenuated dopaminergic transmission can be rescued by METH.

CONCLUSIONS: We show that changes in dopamine levels differentially affect arousal for behaviors of varying complexity. Complex behaviors, such as visual perception, degenerate when dopamine levels are either too high or too low, in accordance with the inverted-U hypothesis of dopamine action in the mammalian brain. Simpler behaviors, such as sleep and locomotion, show graded responses that follow changes in dopamine level.

}, keywords = {Animals, Animals, Genetically Modified, Arousal, Brain, Dopa Decarboxylase, Dopamine, Dose-Response Relationship, Drug, Drosophila, Drosophila Proteins, Dynamins, Electrophysiology, Methamphetamine, Mutation, Sexual Behavior, Animal, Sleep, Visual Perception}, issn = {0960-9822}, doi = {10.1016/j.cub.2005.05.025}, author = {Andretic, Rozi and van Swinderen, Bruno and Greenspan, Ralph J} } @article {130, title = {Activity-dependent homeostatic specification of transmitter expression in embryonic neurons.}, journal = {Nature}, volume = {429}, year = {2004}, month = {2004 Jun 3}, pages = {523-30}, abstract = {

Neurotransmitters are essential for interneuronal signalling, and the specification of appropriate transmitters in differentiating neurons has been related to intrinsic neuronal identity and to extrinsic signalling proteins. Here we show that altering the distinct patterns of Ca2+ spike activity spontaneously generated by different classes of embryonic spinal neurons in vivo changes the transmitter that neurons express without affecting the expression of markers of cell identity. Regulation seems to be homeostatic: suppression of activity leads to an increased number of neurons expressing excitatory transmitters and a decreased number of neurons expressing inhibitory transmitters; the reverse occurs when activity is enhanced. The imposition of specific spike frequencies in vitro does not affect labels of cell identity but again specifies the expression of transmitters that are inappropriate for the markers they express, during an early critical period. The results identify a new role of patterned activity in development of the central nervous system.

}, keywords = {Action Potentials, Animals, Calcium, Calcium Signaling, Cell Differentiation, Cells, Cultured, Gene Expression Regulation, Homeostasis, Humans, Neurons, Neurotransmitter Agents, Organ Specificity, Phenotype, Potassium Channels, Inwardly Rectifying, Rats, Sodium Channels, Spinal Cord, Xenopus laevis}, issn = {1476-4687}, doi = {10.1038/nature02518}, author = {Borodinsky, Laura N and Root, Cory M and Cronin, Julia A and Sann, Sharon B and Gu, Xiaonan and Spitzer, Nicholas C} } @article {148, title = {Cognitive consonance: complex brain functions in the fruit fly and its relatives.}, journal = {Trends Neurosci}, volume = {27}, year = {2004}, month = {2004 Dec}, pages = {707-11}, abstract = {

The fruit fly, Drosophila melanogaster, has become a model for the study of a growing number of human characteristics because of the power of its genetics. Higher cognitive functions, however, might be assumed to be out of reach for the little fly. But the cumulative history of cognitive studies in insects and some of their arachnid relatives, as well as specific probing of the capabilities of fruit flies, suggests that even in this ethereal realm these creatures have much to contribute. What are the degrees of sophistication in cognitive behavior displayed by these organisms, how have they been demonstrated, and what is their potential for understanding how our own brains work?

}, keywords = {Animals, Bees, Behavior, Animal, Brain, Cognition, Drosophila melanogaster, Humans, Perception, Spiders}, issn = {0166-2236}, doi = {10.1016/j.tins.2004.10.002}, author = {Greenspan, Ralph J and van Swinderen, Bruno} } @article {149, title = {Salience modulates 20-30 Hz brain activity in Drosophila.}, journal = {Nat Neurosci}, volume = {6}, year = {2003}, month = {2003 Jun}, pages = {579-86}, abstract = {

Fruit flies selectively orient toward the visual stimuli that are most salient in their environment. We recorded local field potentials (LFPs) from the brains of Drosophila melanogaster as they responded to the presentation of visual stimuli. Coupling of salience effects (odor, heat or novelty) to these stimuli modulated LFPs in the 20-30 Hz range by evoking a transient, selective increase. We demonstrated the association of these responses with behavioral tracking and initiated a genetic approach to investigating neural correlates of perception.

}, keywords = {Action Potentials, Animals, Attention, Behavior, Animal, Brain, Cues, Drosophila, Drosophila Proteins, Exploratory Behavior, Mutation, Neurons, Orientation, Retina, Smell, Synaptic Transmission, Thermosensing, Visual Pathways, Visual Perception}, issn = {1097-6256}, doi = {10.1038/nn1054}, author = {van Swinderen, Bruno and Greenspan, Ralph J} } @article {150, title = {Identification of genes involved in Drosophila melanogaster geotaxis, a complex behavioral trait.}, journal = {Nat Genet}, volume = {31}, year = {2002}, month = {2002 Aug}, pages = {349-53}, abstract = {

Identifying the genes involved in polygenic traits has been difficult. In the 1950s and 1960s, laboratory selection experiments for extreme geotaxic behavior in fruit flies established for the first time that a complex behavioral trait has a genetic basis. But the specific genes responsible for the behavior have never been identified using this classical model. To identify the individual genes involved in geotaxic response, we used cDNA microarrays to identify candidate genes and assessed fly lines mutant in these genes for behavioral confirmation. We have thus determined the identities of several genes that contribute to the complex, polygenic behavior of geotaxis.

}, keywords = {Animals, Animals, Genetically Modified, Behavior, Animal, DNA, Complementary, Drosophila melanogaster, Female, Genetics, Behavioral, Mutation, Oligonucleotide Array Sequence Analysis}, issn = {1061-4036}, doi = {10.1038/ng893}, author = {Toma, Daniel P and White, Kevin P and Hirsch, Jerry and Greenspan, Ralph J} } @article {151, title = {The flexible genome.}, journal = {Nat Rev Genet}, volume = {2}, year = {2001}, month = {2001 May}, pages = {383-7}, abstract = {

A principal assumption underlying contemporary genetic analysis is that the normal function of a gene can be inferred directly from its mutant phenotype. The interactivity among genes that is now being revealed calls this assumption into question and indicates that there might be considerable flexibility in the capacity of the genome to respond to diverse conditions. The reservoir for much of this flexibility resides in the nonspecificity and malleability of gene action.

}, keywords = {Animals, Chromosome Mapping, Genes, Genome, Humans, Phenotype}, issn = {1471-0056}, doi = {10.1038/35072018}, author = {Greenspan, R J} } @article {152, title = {Correlates of sleep and waking in Drosophila melanogaster.}, journal = {Science}, volume = {287}, year = {2000}, month = {2000 Mar 10}, pages = {1834-7}, abstract = {

Drosophila exhibits a circadian rest-activity cycle, but it is not known whether fly rest constitutes sleep or is mere inactivity. It is shown here that, like mammalian sleep, rest in Drosophila is characterized by an increased arousal threshold and is homeostatically regulated independently of the circadian clock. As in mammals, rest is abundant in young flies, is reduced in older flies, and is modulated by stimulants and hypnotics. Several molecular markers modulated by sleep and waking in mammals are modulated by rest and activity in Drosophila, including cytochrome oxidase C, the endoplasmic reticulum chaperone protein BiP, and enzymes implicated in the catabolism of monoamines. Flies lacking one such enzyme, arylalkylamine N-acetyltransferase, show increased rest after rest deprivation. These results implicate the catabolism of monoamines in the regulation of sleep and waking in the fly and suggest that Drosophila may serve as a model system for the genetic dissection of sleep.

}, keywords = {Animals, Arylamine N-Acetyltransferase, Behavior, Animal, Biogenic Monoamines, Caffeine, Carrier Proteins, Circadian Rhythm, Cytochrome P-450 Enzyme System, Drosophila melanogaster, Drosophila Proteins, Fatty Acid Synthases, Female, Gene Dosage, Gene Expression Profiling, Genes, Insect, Homeostasis, HSC70 Heat-Shock Proteins, HSP70 Heat-Shock Proteins, Hydroxyzine, Mutation, Rest, Sleep, Transcription, Genetic, Wakefulness}, issn = {0036-8075}, author = {Shaw, P J and Cirelli, C and Greenspan, R J and Tononi, G} } @article {153, title = {Natural behavior polymorphism due to a cGMP-dependent protein kinase of Drosophila.}, journal = {Science}, volume = {277}, year = {1997}, month = {1997 Aug 8}, pages = {834-6}, abstract = {

Naturally occuring polymorphisms in behavior are difficult to map genetically and thus are refractory to molecular characterization. An exception is the foraging gene (for), a gene that has two naturally occurring variants in Drosophila melanogaster food-search behavior: rover and sitter. Molecular mapping placed for mutations in the dg2 gene, which encodes a cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). Rovers had higher PKG activity than sitters, and transgenic sitters expressing a dg2 complementary DNA from rover showed transformation of behavior to rover. Thus, PKG levels affected food-search behavior, and natural variation in PKG activity accounted for a behavioral polymorphism.

}, keywords = {Animals, Animals, Genetically Modified, Cyclic GMP, Cyclic GMP-Dependent Protein Kinases, Drosophila melanogaster, Feeding Behavior, Genes, Insect, Larva, Phenotype, Polymorphism, Genetic, Signal Transduction}, issn = {0036-8075}, author = {Osborne, K A and Robichon, A and Burgess, E and Butland, S and Shaw, R A and Coulthard, A and Pereira, H S and Greenspan, R J and Sokolowski, M B} } @article {154, title = {Genetic feminization of brain structures and changed sexual orientation in male Drosophila.}, journal = {Science}, volume = {267}, year = {1995}, month = {1995 Feb 10}, pages = {902-5}, abstract = {

The neural basis of sexual orientation in Drosophila was studied by the production of males with regionally feminized brains. Such flies express the female form of the sex determination gene transformer in a limited number of neurons under the control of GAL4 enhancer trap inserts. This method facilitated the creation of lines with a stable pattern of feminization. In tests of sexual preferences, flies that were feminized in a portion of the antennal lobes or in a subset of the corpora pedunculata (mushroom bodies) courted both males and females. These two brain structures, both of which are involved in olfactory processing, may function in the recognition of sex-specific pheromones, in the control of sex-specific behaviors, or both.

}, keywords = {Animals, Bisexuality, Brain, Drosophila melanogaster, Female, Genes, Insect, Male, Sex Attractants, Sexual Behavior, Animal, Smell}, issn = {0036-8075}, author = {Ferveur, J F and St{\"o}rtkuhl, K F and Stocker, R F and Greenspan, R J} } @article {155, title = {Understanding the genetic construction of behavior.}, journal = {Sci Am}, volume = {272}, year = {1995}, month = {1995 Apr}, pages = {72-8}, keywords = {Animals, Drosophila melanogaster, Female, Genetics, Behavioral, Humans, Male, Sexual Behavior, Animal}, issn = {0036-8733}, author = {Greenspan, R J} }