Blake Russell

Title:

Signatures of Perception in Neuronal Signals Propagating Through Cortex and Subcortex

Abstract:

Perception is inherently variable; the same external stimulus might be detected or missed in different instances. Previous studies have shown that as neuronal signals propagate from primary sensory cortices to higher cortical regions, they better reflect the trial-by-trial percept. In addition to sending projections to higher cortical areas, primary sensory regions also form substantial subcortical projections, for example to the thalamus or striatum. However, it remains unknown how the structure and timing of population codes underlying perception change as neuronal signals propagate from cortex to subcortical regions. To address this question, we recorded electrophysiological neuronal activity in a somatosensory optogenetic detection task. In this task, mice report optogenetic stimulation of primary somatosensory cortical neurons (S1), delivered using an LED through a cranial window, by turning a wheel to receive a water reward. Using Neuropixels probes, we have acquired high-temporal resolution neuronal data simultaneously from key S1 outputs, including secondary somatosensory cortex (S2), thalamus (ventral posteromedial nucleus, medial posterior nucleus) and dorsolateral striatum (DLS). Our results indicate that cortical and subcortical regions receiving signals from S1 exhibit differential timing and neural codes underlying perception.