@article {2188, title = {Discovery of genomic loci of the human cerebral cortex using genetically informed brain atlases.}, journal = {Science}, volume = {375}, year = {2022}, month = {2022 02 04}, pages = {522-528}, abstract = {

To determine the impact of genetic variants on the brain, we used genetically informed brain atlases in genome-wide association studies of regional cortical surface area and thickness in 39,898 adults and 9136 children. We uncovered 440 genome-wide significant loci in the discovery cohort and 800 from a post hoc combined meta-analysis. Loci in adulthood were largely captured in childhood, showing signatures of negative selection, and were linked to early neurodevelopment and pathways associated with neuropsychiatric risk. Opposing gradations of decreased surface area and increased thickness were associated with common inversion polymorphisms. Inferior frontal regions, encompassing Broca{\textquoteright}s area, which is important for speech, were enriched for human-specific genomic elements. Thus, a mixed genetic landscape of conserved and human-specific features is concordant with brain hierarchy and morphogenetic gradients.

}, keywords = {Adult, Aged, Aged, 80 and over, Cerebral Cortex, Child, Chromatin, Cohort Studies, Female, Gene Ontology, Genetic Association Studies, Genetic Loci, Genetic Variation, Genome, Human, Genome-Wide Association Study, Humans, Magnetic Resonance Imaging, Male, Mental Disorders, Middle Aged, Molecular Sequence Annotation, Multifactorial Inheritance, Polymorphism, Single Nucleotide, Regulatory Sequences, Nucleic Acid}, issn = {1095-9203}, doi = {10.1126/science.abe8457}, author = {Makowski, Carolina and van der Meer, Dennis and Dong, Weixiu and Wang, Hao and Wu, Yan and Zou, Jingjing and Liu, Cin and Rosenthal, Sara B and Hagler, Donald J and Fan, Chun Chieh and Kremen, William S and Andreassen, Ole A and Jernigan, Terry L and Dale, Anders M and Zhang, Kun and Visscher, Peter M and Yang, Jian and Chen, Chi-Hua} } @article {1687, title = {How struggling adult readers use contextual information when comprehending speech: Evidence from event-related potentials.}, journal = {Int J Psychophysiol}, volume = {125}, year = {2018}, month = {2018 03}, pages = {1-9}, abstract = {

We investigated how struggling adult readers make use of sentence context to facilitate word processing when comprehending spoken language, conditions under which print decoding is not a barrier to comprehension. Stimuli were strongly and weakly constraining sentences (as measured by cloze probability), which ended with the most expected word based on those constraints or an unexpected but plausible word. Community-dwelling adults with varying literacy skills listened to continuous speech while their EEG was recorded. Participants, regardless of literacy level, showed N400 effects yoked to the cloze probability of the targets, with larger N400 amplitudes for less expected than more expected words. However, literacy-related differences emerged in an earlier time window of 170-300 ms: higher literacy adults produced a reduced negativity for strongly predictable targets over anterior channels, similar to previously reported effects on the Phonological Mapping Negativity (PMN), whereas low-literacy adults did not. Collectively, these findings suggest that in auditory sentence processing literacy may not notably affect the incremental activation of semantic features, but that comprehenders with underdeveloped literacy skills may be less likely to engage predictive processing. Thus, basic mechanisms of comprehension may be recruited differently as a function of literacy development-even in spoken language.

}, keywords = {Adult, Aged, Brain Mapping, Comprehension, Electroencephalography, Evoked Potentials, Female, Humans, Literacy, Male, Middle Aged, Neuropsychological Tests, Photic Stimulation, Reaction Time, Reading, Speech, Young Adult}, issn = {1872-7697}, doi = {10.1016/j.ijpsycho.2018.01.013}, author = {Ng, Shukhan and Payne, Brennan R and Stine-Morrow, Elizabeth A L and Federmeier, Kara D} } @article {1682, title = {Mean signal and response time influences on multivoxel signals of contextual retrieval in the medial temporal lobe.}, journal = {Brain Behav}, volume = {5}, year = {2015}, month = {2015 Feb}, pages = {e00302}, abstract = {

INTRODUCTION: The medial temporal lobe supports integrating the "what," "where," and "when" of an experience into a unified memory. However, it remains unclear how representations of these contextual features are neurally encoded and distributed across medial temporal lobe subregions.

METHODS: This study conducted functional magnetic resonance imaging of the medial temporal lobe, while participants retrieved pair, spatial, and temporal source memories. Multivoxel classifiers were trained to distinguish between retrieval conditions before and after correction for mean signal and response times, to more thoroughly characterize the multivoxel signal associated with memory context.

RESULTS: Activity in perirhinal and parahippocampal cortex dissociated between memory for associated items and memory for their spatiotemporal context, and hippocampal activity was linked to memory for spatial context. However, perirhinal and hippocampal classifiers were, respectively, driven by effects of mean signal amplitude and task difficulty, whereas the parahippocampal classifier survived correction for these effects.

CONCLUSION: These findings demonstrate dissociable coding mechanisms for episodic memory context across the medial temporal lobe, and further highlight a critical distinction between multivoxel representations driven by spatially distributed activity patterns, and those driven by the regional signal.

}, keywords = {Adult, Brain Mapping, Female, Humans, Magnetic Resonance Imaging, Male, Memory, Photic Stimulation, Temporal Lobe, Young Adult}, issn = {2162-3279}, doi = {10.1002/brb3.302}, author = {Reas, Emilie T and Brewer, James B} } @article {203, title = {Gamma band activity and the P3 reflect post-perceptual processes, not visual awareness.}, journal = {Neuroimage}, volume = {101}, year = {2014}, month = {2014 Nov 1}, pages = {337-50}, abstract = {

A primary goal in cognitive neuroscience is to identify neural correlates of conscious perception (NCC). By contrasting conditions in which subjects are aware versus unaware of identical visual stimuli, a number of candidate NCCs have emerged; among them are induced gamma band activity in the EEG and the P3 event-related potential. In most previous studies, however, the critical stimuli were always directly relevant to the subjects{\textquoteright} task, such that aware versus unaware contrasts may well have included differences in post-perceptual processing in addition to differences in conscious perception per se. Here, in a series of EEG experiments, visual awareness and task relevance were manipulated independently. Induced gamma activity and the P3 were absent for task-irrelevant stimuli regardless of whether subjects were aware of such stimuli. For task-relevant stimuli, gamma and the P3 were robust and dissociable, indicating that each reflects distinct post-perceptual processes necessary for carrying-out the task but not for consciously perceiving the stimuli. Overall, this pattern of results challenges a number of previous proposals linking gamma band activity and the P3 to conscious perception.

}, keywords = {Adult, Attention, Awareness, Consciousness, Electroencephalography, Event-Related Potentials, P300, Female, Gamma Rhythm, Humans, Male, Psychomotor Performance, Visual Perception, Young Adult}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2014.07.024}, author = {Pitts, Michael A and Padwal, Jennifer and Fennelly, Daniel and Mart{\'\i}nez, Ant{\'\i}gona and Hillyard, Steven A} } @article {208, title = {Inhibitory motor control based on complex stopping goals relies on the same brain network as simple stopping.}, journal = {Neuroimage}, volume = {103}, year = {2014}, month = {2014 Dec}, pages = {225-34}, abstract = {

Much research has modeled action-stopping using the stop-signal task (SST), in which an impending response has to be stopped when an explicit stop-signal occurs. A limitation of the SST is that real-world action-stopping rarely involves explicit stop-signals. Instead, the stopping-system engages when environmental features match more complex stopping goals. For example, when stepping into the street, one monitors path, velocity, size, and types of objects and only stops if there is a vehicle approaching. Here, we developed a task in which participants compared the visual features of a multidimensional go-stimulus to a complex stopping-template, and stopped their go-response if all features matched the template. We used independent component analysis of EEG data to show that the same motor inhibition brain network that explains action-stopping in the SST also implements motor inhibition in the complex-stopping task. Furthermore, we found that partial feature overlap between go-stimulus and stopping-template led to motor slowing, which also corresponded with greater stopping-network activity. This shows that the same brain system for action-stopping to explicit stop-signals is recruited to slow or stop behavior when stimuli match a complex stopping goal. The results imply a generalizability of the brain{\textquoteright}s network for simple action-stopping to more ecologically valid scenarios.

}, keywords = {Adolescent, Adult, Brain, Brain Mapping, Electroencephalography, Female, Goals, Humans, Inhibition (Psychology), Male, Psychomotor Performance, Reaction Time, Young Adult}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2014.09.048}, author = {Wessel, Jan R and Aron, Adam R} } @article {185, title = {Neural language processing in adolescent first-language learners.}, journal = {Cereb Cortex}, volume = {24}, year = {2014}, month = {2014 Oct}, pages = {2772-83}, abstract = {

The relation between the timing of language input and development of neural organization for language processing in adulthood has been difficult to tease apart because language is ubiquitous in the environment of nearly all infants. However, within the congenitally deaf population are individuals who do not experience language until after early childhood. Here, we investigated the neural underpinnings of American Sign Language (ASL) in 2 adolescents who had no sustained language input until they were approximately 14 years old. Using anatomically constrained magnetoencephalography, we found that recently learned signed words mainly activated right superior parietal, anterior occipital, and dorsolateral prefrontal areas in these 2 individuals. This spatiotemporal activity pattern was significantly different from the left fronto-temporal pattern observed in young deaf adults who acquired ASL from birth, and from that of hearing young adults learning ASL as a second language for a similar length of time as the cases. These results provide direct evidence that the timing of language experience over human development affects the organization of neural language processing.

}, keywords = {Adolescent, Adult, Age Factors, Cerebral Cortex, Critical Period (Psychology), Deafness, Female, Functional Laterality, Humans, Language Development, Learning, Magnetoencephalography, Male, Semantics, Sign Language, Young Adult}, issn = {1460-2199}, doi = {10.1093/cercor/bht137}, author = {Ferjan Ramirez, Naja and Leonard, Matthew K and Torres, Christina and Hatrak, Marla and Halgren, Eric and Mayberry, Rachel I} } @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 {197, title = {Tool morphology constrains the effects of tool use on body representations.}, journal = {J Exp Psychol Hum Percept Perform}, volume = {40}, year = {2014}, month = {2014 Dec}, pages = {2143-53}, abstract = {

What factors constrain whether tool use modulates the user{\textquoteright}s body representations? To date, studies on representational plasticity following tool use have primarily focused on the act of using the tool. Here, we investigated whether the tool{\textquoteright}s morphology also serves to constrain plasticity. In 2 experiments, we varied whether the tool was morphologically similar to a target body part (Experiment 1, hand; Experiment 2, arm). Participants judged the tactile distance between pairs of points applied to their tool-using target body surface and forehead (control surface) before and after tool use. We applied touch in 2 orientations, allowing us to quantify how tool use modulates the representation{\textquoteright}s shape. Significant representational plasticity in hand shape (increase in width, decrease in length) was found when the tool was morphologically similar to a hand (Experiment 1A), but not when the tool was arm-shaped (Experiment 1B). Conversely, significant representational plasticity was found on the arm when the tool was arm-shaped (Experiment 2B), but not when hand-shaped (Experiment 2A). Taken together, our results indicate that morphological similarity between the tool and the effector constrains tool-induced representational plasticity. The embodiment of tools may thus depend on a match-to-template process between tool morphology and representation of the body.

}, keywords = {Adolescent, Adult, Body Image, Discrimination (Psychology), Distance Perception, Female, Form Perception, Humans, Judgment, Male, Size Perception, Tool Use Behavior, Touch Perception, Young Adult}, issn = {1939-1277}, doi = {10.1037/a0037777}, author = {Miller, Luke E and Longo, Matthew R and Saygin, Ayse P} } @article {1675, title = {Using single-trial EEG to predict and analyze subsequent memory.}, journal = {Neuroimage}, volume = {84}, year = {2014}, month = {2014 Jan 01}, pages = {712-23}, abstract = {

We show that it is possible to successfully predict subsequent memory performance based on single-trial EEG activity before and during item presentation in the study phase. Two-class classification was conducted to predict subsequently remembered vs. forgotten trials based on subjects{\textquoteright} responses in the recognition phase. The overall accuracy across 18 subjects was 59.6\% by combining pre- and during-stimulus information. The single-trial classification analysis provides a dimensionality reduction method to project the high-dimensional EEG data onto a discriminative space. These projections revealed novel findings in the pre- and during-stimulus periods related to levels of encoding. It was observed that the pre-stimulus information (specifically oscillatory activity between 25 and 35Hz) -300 to 0ms before stimulus presentation and during-stimulus alpha (7-12Hz) information between 1000 and 1400ms after stimulus onset distinguished between recollection and familiarity while the during-stimulus alpha information and temporal information between 400 and 800ms after stimulus onset mapped these two states to similar values.

}, keywords = {Adolescent, Adult, Brain, Electroencephalography, Humans, Male, Memory, Young Adult}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2013.09.028}, author = {Noh, Eunho and Herzmann, Grit and Curran, Tim and de Sa, Virginia R} } @article {204, title = {Independence of early speech processing from word meaning.}, journal = {Cereb Cortex}, volume = {23}, year = {2013}, month = {2013 Oct}, pages = {2370-9}, abstract = {

We combined magnetoencephalography (MEG) with magnetic resonance imaging and electrocorticography to separate in anatomy and latency 2 fundamental stages underlying speech comprehension. The first acoustic-phonetic stage is selective for words relative to control stimuli individually matched on acoustic properties. It begins \~{}60 ms after stimulus onset and is localized to middle superior temporal cortex. It was replicated in another experiment, but is strongly dissociated from the response to tones in the same subjects. Within the same task, semantic priming of the same words by a related picture modulates cortical processing in a broader network, but this does not begin until \~{}217 ms. The earlier onset of acoustic-phonetic processing compared with lexico-semantic modulation was significant in each individual subject. The MEG source estimates were confirmed with intracranial local field potential and high gamma power responses acquired in 2 additional subjects performing the same task. These recordings further identified sites within superior temporal cortex that responded only to the acoustic-phonetic contrast at short latencies, or the lexico-semantic at long. The independence of the early acoustic-phonetic response from semantic context suggests a limited role for lexical feedback in early speech perception.

}, keywords = {Adult, Brain, Brain Mapping, Female, Humans, Magnetic Resonance Imaging, Magnetoencephalography, Male, Speech Perception, Young Adult}, issn = {1460-2199}, doi = {10.1093/cercor/bhs228}, author = {Travis, Katherine E and Leonard, Matthew K and Chan, Alexander M and Torres, Christina and Sizemore, Marisa L and Qu, Zhe and Eskandar, Emad and Dale, Anders M and Elman, Jeffrey L and Cash, Sydney S and Halgren, Eric} } @article {190, title = {Signed words in the congenitally deaf evoke typical late lexicosemantic responses with no early visual responses in left superior temporal cortex.}, journal = {J Neurosci}, volume = {32}, year = {2012}, month = {2012 Jul 11}, pages = {9700-5}, abstract = {

Congenitally deaf individuals receive little or no auditory input, and when raised by deaf parents, they acquire sign as their native and primary language. We asked two questions regarding how the deaf brain in humans adapts to sensory deprivation: (1) is meaning extracted and integrated from signs using the same classical left hemisphere frontotemporal network used for speech in hearing individuals, and (2) in deafness, is superior temporal cortex encompassing primary and secondary auditory regions reorganized to receive and process visual sensory information at short latencies? Using MEG constrained by individual cortical anatomy obtained with MRI, we examined an early time window associated with sensory processing and a late time window associated with lexicosemantic integration. We found that sign in deaf individuals and speech in hearing individuals activate a highly similar left frontotemporal network (including superior temporal regions surrounding auditory cortex) during lexicosemantic processing, but only speech in hearing individuals activates auditory regions during sensory processing. Thus, neural systems dedicated to processing high-level linguistic information are used for processing language regardless of modality or hearing status, and we do not find evidence for rewiring of afferent connections from visual systems to auditory cortex.

}, keywords = {Adolescent, Adult, Brain Mapping, Deafness, Evoked Potentials, Female, Functional Laterality, Humans, Magnetic Fields, Magnetic Resonance Imaging, Magnetoencephalography, Male, Photic Stimulation, Semantics, Sign Language, Temporal Lobe, Time Factors, Young Adult}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.1002-12.2012}, author = {Leonard, Matthew K and Ferjan Ramirez, Naja and Torres, Christina and Travis, Katherine E and Hatrak, Marla and Mayberry, Rachel I and Halgren, Eric} } @article {202, title = {Visual processing of contour patterns under conditions of inattentional blindness.}, journal = {J Cogn Neurosci}, volume = {24}, year = {2012}, month = {2012 Feb}, pages = {287-303}, abstract = {

An inattentional blindness paradigm was adapted to measure ERPs elicited by visual contour patterns that were or were not consciously perceived. In the first phase of the experiment, subjects performed an attentionally demanding task while task-irrelevant line segments formed square-shaped patterns or random configurations. After the square patterns had been presented 240 times, subjects{\textquoteright} awareness of these patterns was assessed. More than half of all subjects, when queried, failed to notice the square patterns and were thus considered inattentionally blind during this first phase. In the second phase of the experiment, the task and stimuli were the same, but following this phase, all of the subjects reported having seen the patterns. ERPs recorded over the occipital pole differed in amplitude from 220 to 260 msec for the pattern stimuli compared with the random arrays regardless of whether subjects were aware of the patterns. At subsequent latencies (300-340 msec) however, ERPs over bilateral occipital-parietal areas differed between patterns and random arrays only when subjects were aware of the patterns. Finally, in a third phase of the experiment, subjects viewed the same stimuli, but the task was altered so that the patterns became task relevant. Here, the same two difference components were evident but were followed by a series of additional components that were absent in the first two phases of the experiment. We hypothesize that the ERP difference at 220-260 msec reflects neural activity associated with automatic contour integration whereas the difference at 300-340 msec reflects visual awareness, both of which are dissociable from task-related postperceptual processing.

}, keywords = {Adult, Attention, Awareness, Brain, Brain Mapping, Electroencephalography, Evoked Potentials, Visual, Female, Humans, Male, Perceptual Masking, Photic Stimulation, Reaction Time, Visual Perception}, issn = {1530-8898}, doi = {10.1162/jocn_a_00111}, author = {Pitts, Michael A and Mart{\'\i}nez, Ant{\'\i}gona and Hillyard, Steven A} } @article {192, title = {Language proficiency modulates the recruitment of non-classical language areas in bilinguals.}, journal = {PLoS One}, volume = {6}, year = {2011}, month = {2011}, pages = {e18240}, abstract = {

Bilingualism provides a unique opportunity for understanding the relative roles of proficiency and order of acquisition in determining how the brain represents language. In a previous study, we combined magnetoencephalography (MEG) and magnetic resonance imaging (MRI) to examine the spatiotemporal dynamics of word processing in a group of Spanish-English bilinguals who were more proficient in their native language. We found that from the earliest stages of lexical processing, words in the second language evoke greater activity in bilateral posterior visual regions, while activity to the native language is largely confined to classical left hemisphere fronto-temporal areas. In the present study, we sought to examine whether these effects relate to language proficiency or order of language acquisition by testing Spanish-English bilingual subjects who had become dominant in their second language. Additionally, we wanted to determine whether activity in bilateral visual regions was related to the presentation of written words in our previous study, so we presented subjects with both written and auditory words. We found greater activity for the less proficient native language in bilateral posterior visual regions for both the visual and auditory modalities, which started during the earliest word encoding stages and continued through lexico-semantic processing. In classical left fronto-temporal regions, the two languages evoked similar activity. Therefore, it is the lack of proficiency rather than secondary acquisition order that determines the recruitment of non-classical areas for word processing.

}, keywords = {Adult, Brain Mapping, Female, Humans, Language, Language Development, Magnetic Resonance Imaging, Magnetoencephalography, Male, Multilingualism, Young Adult}, issn = {1932-6203}, doi = {10.1371/journal.pone.0018240}, author = {Leonard, Matthew K and Torres, Christina and Travis, Katherine E and Brown, Timothy T and Hagler, Donald J and Dale, Anders M and Elman, Jeffrey L and Halgren, Eric} } @article {206, title = {Spatiotemporal neural dynamics of word understanding in 12- to 18-month-old-infants.}, journal = {Cereb Cortex}, volume = {21}, year = {2011}, month = {2011 Aug}, pages = {1832-9}, abstract = {

Learning words is central in human development. However, lacking clear evidence for how or where language is processed in the developing brain, it is unknown whether these processes are similar in infants and adults. Here, we use magnetoencephalography in combination with high-resolution structural magnetic resonance imaging to noninvasively estimate the spatiotemporal distribution of word-selective brain activity in 12- to 18-month-old infants. Infants watched pictures of common objects and listened to words that they understood. A subset of these infants also listened to familiar words compared with sensory control sounds. In both experiments, words evoked a characteristic event-related brain response peaking \~{}400 ms after word onset, which localized to left frontotemporal cortices. In adults, this activity, termed the N400m, is associated with lexico-semantic encoding. Like adults, we find that the amplitude of the infant N400m is also modulated by semantic priming, being reduced to words preceded by a semantically related picture. These findings suggest that similar left frontotemporal areas are used for encoding lexico-semantic information throughout the life span, from the earliest stages of word learning. Furthermore, this ontogenetic consistency implies that the neurophysiological processes underlying the N400m may be important both for understanding already known words and for learning new words.

}, keywords = {Adult, Brain Mapping, Cerebral Cortex, Evoked Potentials, Auditory, Female, Humans, Infant, Language Tests, Learning, Magnetic Resonance Imaging, Magnetoencephalography, Male, Neurons, Speech Perception, Vocabulary}, issn = {1460-2199}, doi = {10.1093/cercor/bhq259}, author = {Travis, Katherine E and Leonard, Matthew K and Brown, Timothy T and Hagler, Donald J and Curran, Megan and Dale, Anders M and Elman, Jeffrey L and Halgren, Eric} } @article {211, title = {Accumulation of neural activity in the posterior insula encodes the passage of time.}, journal = {Neuropsychologia}, volume = {48}, year = {2010}, month = {2010 Aug}, pages = {3110-20}, abstract = {

A number of studies have examined the perception of time with durations ranging from milliseconds to a few seconds, however the neural basis of these processes are still poorly understood and the neural substrates underlying the perception of multiple-second intervals are unknown. Here we present evidence of neural systems activity in circumscribed areas of the human brain involved in the encoding of intervals with durations of 9 and 18s in a temporal reproduction task using event-related functional magnetic resonance imaging (fMRI). During the encoding there was greater activation in more posterior parts of the medial frontal and insular cortex whereas the reproduction phase involved more anterior parts of these brain structures. Intriguingly, activation curves over time show an accumulating pattern of neural activity, which peaks at the end of the interval within bilateral posterior insula and superior temporal cortex when individuals are presented with 9- and 18-s tone intervals. This is consistent with an accumulator-type activity, which encodes duration in the multiple seconds range. Given the close connection between the dorsal posterior insula and ascending internal body signals, we suggest that the accumulation of physiological changes in body states constitutes our experience of time. This is the first time that an accumulation function in the posterior insula is detected that might be correlated with the encoding of time intervals.

}, keywords = {Adult, Analysis of Variance, Brain Mapping, Cerebral Cortex, Factor Analysis, Statistical, Female, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Male, Neuropsychological Tests, Oxygen, Reaction Time, Time Factors, Time Perception, Young Adult}, issn = {1873-3514}, doi = {10.1016/j.neuropsychologia.2010.06.023}, author = {Wittmann, Marc and Simmons, Alan N and Aron, Jennifer L and Paulus, Martin P} } @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} } @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} }