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Persistent encoding of sound categories during task engagement in Auditory Cortex

Dr. Rupesh Kumar,  a joint postdoctoral fellow under Prof. Shihab Shamma (Labaratoire des System Perceptifs) and Dr. Srdjan Ostojic (Group for Neural Theory) at Ecole Normale Superieure, Paris gave a talk on  Persistent encoding of sound categories during task engagement in Auditory Cortex on 20 July.

Categorizing sensory stimuli into task relevant classes is a key cognitive process for assigning proper goal-directed behavioral responses. Sensory areas, such as primary auditory cortex (A1) plays a highly flexible role in processing incoming stimuli and implements a first step in encoding behavioral meaning of the stimuli at the population level during task engagement. It is still not clear how auditory cortex flexibly assigns sensory stimuli to task-relevant categories, and how the representation of these categories is sustained after stimulus presentation. For this, Dr. Kumar and his team trained ferrets to classify click trains in Go/No-Go categories (low and high rates) during an appetitive choice task and recorded from A1 while ferrets were either passively listening or actively discriminating stimuli. In his talk, Dr. Kumar showed that task-engagement enhanced target category at the population level and induced persistent representation during the delay period preceding the response window. Encoding scheme of categories evolves dynamically between the different trial epochs and depends on stimuli attributes. These results suggest that training over a categorization task can form behavior-dependent long-term encoding of stimulus behavioral meaning in A1. Furthermore, the dynamic evolution of category representation within trials possibly reflects feed-forward and feedback-driven representations of sounds in A1 during task-engagement.

Dr. Kumar completed his M.Sc in Physics from JNU and later joined as SRF in Sleep research laboratory of Prof. B N Mallick. His PhD was on understanding neural circuitry for sleep wake regulation and EEG dynamics. He is currently a joint postdoctoral fellow under Prof. Shihab Shamma (Labaratoire des System Perceptifs) and Dr. Srdjan Ostojic (Group for Neural Theory) at Ecole Normale Superieure, Paris.