@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 {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} }