Decision-making requires the flexibility to make different behavioural responses to the same sensory stimulus depending on the context. We identified cortical areas and neural activity patterns that mediate this flexibility during navigation using a delayed match-to-sample task in virtual reality. An optogenetics screen identified mouse V1, posterior parietal cortex (PPC), and retrosplenial cortex (RSC) as necessary for accurate decision-making. Calcium imaging revealed that navigation goals were encoded by neurons that nonlinearly mix specific combinations of contextual information from short-term memory and visual information. These neurons formed efficient, easy-to-decode population codes that appeared to govern accurate decision-making because they were informative before correct choices but degenerated during errors. These cells were distributed across posterior cortex, even V1, and surprisingly were densest in RSC and sparsest in PPC. We propose the flexibility of navigation decisions arises from distributed neurons that mix context and visual information within a visual-parietal-retrosplenial network, centered in RSC.
Shin Kira is a postdoctoral fellow in the Harvey Lab at Harvard Medical School. He received his MD from Tokyo Medical and Dental University in Japan, and completed his PhD in the Shadlen lab at the University of Washington and Columbia University. For his thesis projects, he studied decision-making in monkeys and humans by using electrophysiology, psychophysics, and computational modeling. Now as a postdoctoral fellow in the Harvey lab, he studies flexible decision-making in mice by using calcium imaging and optogenetics. His primary interest is in how the brain forms generalisations of past experiences to make rational and flexible decisions in novel situations. He envisions to investigate neural circuit mechanisms underlying generalisable intelligence and its recovery from impairment by advanced neural recording and manipulation techniques in mice.
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