Diversity and task-dependence of task representations in V1 during freely-moving decisions

Abstract

Neurons in primary visual cortex (area V1) are strongly driven by both sensory stimuli and non-sensory events. However, although the representation of sensory stimuli has been well characterized, much less is known about the representation of non-sensory events. Here, we characterize the specificity and organization of non-sensory representations in rat V1 during a freely-moving visual decision task. We find that single neurons encode diverse combinations of task features simultaneously and across task epochs. Despite heterogeneity at the level of single neuron response patterns, both visual and non-visual task variables could be reliably decoded from small neural populations (5-40 units) throughout a trial. Interestingly, in animals trained to make an auditory decision following passive observation of a visual stimulus, some but not all task features could also be decoded from V1 activity. Our results support the view that even in V1 - the earliest stage of the cortical hierarchy - bottom-up sensory information is combined with top-down non-sensory information in a task-dependent manner.