Anne Churchland: Decisions, movements and brains

University of California Los Angeles (UCLA)

Understanding how cortical circuits generate complex behavior requires investigating how neurons within those circuits are modulated. Most efforts to understand neural activity during well-learned tasks focus on cognitive computations and task-related movements. We wondered whether mice making decisions explore a broader movement landscape, and how this impacts neural activity. We characterized movements using video and other sensors and measured neural activity using widefield and two-photon imaging. Cortex-wide activity was dominated by movements, especially uninstructed movements not required for the task. Next, we evaluated how the encoding of movement and task parameters varied across pyramidal neuron (PyN) types. Functional differences across PyN types have been observed within cortical areas, but it is not known whether these local differences extend throughout the cortex, nor whether additional differences emerge when larger-scale dynamics are considered. We used genetic and retrograde labeling to target pyramidal tract (PT), intratelencephalic (IT) and corticostriatal projection neurons and measured their cortex-wide activity. Each PyN type drove unique neural dynamics, both at the local and cortex-wide scale. Cortical activity and optogenetic inactivation during an auditory decision task also revealed distinct functional roles: all PyNs in parietal cortex were recruited during perception of the auditory stimulus, but, surprisingly, PT neurons had the largest causal role. In frontal cortex, all PyNs were required for accurate choices but showed distinct choice-tuning. Our results reveal that movements dominate neural activity in diverse PyN types, and that rich, cell-type-specific cortical dynamics shape perceptual decisions.

 

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Organized by

Henning Sprekeler / Margret Franke