Dr Shankar Sachidhanandam, Switzerland : "Neural dynamics of sensory perception and decision making in the mouse posterior parietal cortex"

Speaker :

Dr Shankar Sachidhanandam

Sensory Perception Group, Department of Physiology, University of Bern, Switzerland

Title: "Neural dynamics of sensory perception and decision making in the mouse posterior parietal cortex"

Abstract: Higher order sensory cortices, such as the posterior parietal cortex (PPC) have been implicated in a range of cognitive behaviors, ranging from navigation to multisensory integration and perceptual decision making. Only recently we have begun to explore the neural circuit dynamics in PPC during such complex behaviors, over a large population of neurons and at single-cell resolution. Here we trained mice to perform a whisker-based texture discrimination task and report their decision by licking. Using genetically encoded calcium indicators (GECIs) and chronic cranial windows, we recorded the neural responses from excitatory neurons in layer 2/3 of the PPC of well trained mice during goal directed behavior. We observed that some neurons displayed sensory evoked responses whereas others had task-outcome related activity that was present before behavioral report by licking. Another subset of neurons showed enhanced activity upon the omission of the texture stimulus, with all other cues present. Moreover, these neurons displayed minimal overlap in activity, suggesting the presence of discrete neuronal classes with temporally diverse activity dynamics. Finally, optogenetic inhibition of the PPC during the task led to a decrease in performance. These findings demonstrate that neural activity in the PPC can influence task outcome, hence contributing to perceptual decision making.