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Sharma, A. K.

Publications and source records attributed to Sharma, A. K..

3 recordsLinked to original sources

Predicting natural behavior from whole-brain neural dynamics

The activity of an animals brain contains information about that animals actions and movements. We investigated the neural representation of locomotion in the nematode C. elegans by recording population calcium activity during unrestrained movement. We report that a neural population more accurately decodes locomotion than any single neuron. Relevant signals are distributed across neurons with diverse tunings to locomotion. Two distinct subpopulations are informative for decoding velocity and body curvature, and different neurons activities contribute features relevant for different instances of behavioral motifs. We labeled neurons AVAL and AVAR and found their activity was highly correlated with one another. They exhibited expected transients during backward locomotion, although they were not always the most informative neurons for decoding velocity. Finally, we compared population neural activity during movement and immobilization. Immobilization alters the correlation structure of neural activity and its dynamics. Some neurons previously correlated with AVA become anti-correlated and vice versa. The activity of an animals brain contains information about that animals actions and movements. We investigated the neural representation of locomotion in the nematode C. elegans by recording brain-wide neural dynamics in freely moving animals. We report that a population of neurons more accurately decodes the animals locomotion than any single neuron. Neural signals are distributed across neurons in the population with a diversity of tuning to locomotion. Two distinct subpopulations are most informative for decoding velocity and body curvature, and different neurons activities contribute features relevant for different instances of behavioral motifs within these subpopulations. We additionally labeled the AVA neurons within our population recordings. AVAL and AVAR exhibit activity that is highly correlated with one another, and they exhibit the expected responses to locomotion, although we find that AVA is not always the most informative neuron for decoding velocity. Finally, we compared brain-wide neural activity during movement and immobilization and observe that immobilization alters the correlation structure of neural activity and its dynamics. Some neurons that were previously correlated with AVA become anti-correlated and vice versa during immobilization. We conclude that neural population codes are important for understanding neural dynamics of behavior in moving animals.

neuroscience

Genome Sequence of Indian Peacock Reveals the Peculiar Case of a Glittering Bird

The unique ornamental features and extreme sexual traits of Peacock have always intrigued the scientists. However, the genomic evidence to explain its phenotype are yet unknown. Thus, we report the first genome sequence and comparative analysis of peacock with the available high-quality genomes of chicken, turkey, duck, flycatcher and zebra finch. The candidate genes involved in early developmental pathways including TGF-{beta}, BMP, and Wnt signaling pathway, which are also involved in feather patterning, bone morphogenesis, and skeletal muscle development, showed signs of adaptive evolution and provided useful clues on the phenotype of peacock. The innate and adaptive immune components such as complement system and T-cell response also showed signs of adaptive evolution in peacock suggesting their possible role in building a robust immune system which is consistent with the between species predictions of Hamilton-Zuk hypothesis. This study provides novel genomic and evolutionary insights into the molecular understanding towards the phenotypic evolution of Indian peacock.

genomics

SCGN Administration prevents Insulin Resistance and Diabetic Complications in High-Fat Diet Fed Animals

Secretagogin (SCGN) is poorly-studied secretory/cytosolic CaBP enriched in pancreatic {beta}-cells. Recent studies implicated SCGN in diabetes; however, its function and therapeutic prospect remain uncharted. Based on the apparent synchrony of SCGN and insulin secretion (and its disruption in HFD-fed animals) and considering SCGN downregulation in Type 2 diabetes, we hypothesized that SCGN is a key regulator of insulin response. To test this, we administered rSCGN to HFD-fed animals. We here report that a novel SCGN-insulin interaction stabilizes insulin and potentiates insulin action. Moreover, a chronic rSCGN administration improves insulin response and alleviates obesity associated risk factors such as weight gain, liver steatosis and cholesterol imbalance in DIO animals. Beside the anti-diabetic effects, prolonged rSCGN treatment also induces {beta}-cell regeneration. These effects seem to originate from SCGN mediated regulation of insulin concentration & function as validated in insulin-deficient STZ animals. Our results demonstrate the prospects of the therapeutic potential of SCGN against diabetes.

physiology