Distributed context-dependent choice information in mouse dorsal-parietal cortex

Abstract

Choice information appears in the brain as distributed signals with top-down and bottom-up components that together support decision-making computations. In sensory and associative cortical regions, the presence of choice signals, their strength, and area specificity are known to be elusive and changeable, limiting a cohesive understanding of their computational significance. In this study, examining the mesoscale activity in mouse posterior cortex during a complex visual discrimination task, we found that broadly distributed choice signals defined a decision variable in a low-dimensional embedding space of multi-area activations, particularly along the ventral visual stream. The subspace they defined was near-orthogonal to concurrently represented sensory and motor-related activations, and it was modulated by task difficulty and contextually by the attention state of the animals. To mechanistically relate choice representations to decision-making computations, we trained recurrent neural networks with the choices of the animals and found an equivalent decision variable whose context-dependent dynamics agreed with that of the neural data. In conclusion, our results demonstrated an independent decision variable broadly represented in the posterior cortex, controlled by task features and cognitive demands. Its dynamics reflected decision computations, possibly linked to context-dependent feedback signals used for probabilistic-inference computations in variable animal-environment interactions.

Synaptic wiring motifs in posterior parietal cortex support decision-making

“…We sought to understand relationships between trial-type selective neuron activity and synaptic connectivity in PPC. Although selective activity in PPC has been reported in many previous studies 4–11 , accompanying connectivity data has not been previously available. Here, we used automated serial-section transmission EM 17 to image a volume in PPC with synapse resolution.…”

“…Experiments with primates have revealed the importance of the neocortex for perceptual decision-making, including the posterior parietal cortex (PPC), where neuronal activity is predictive of upcoming behavioral choices [1][2][3] . Such choice-selective activity has also been found in rodent PPC [4][5][6][7][8][9][10][11][12] , but it remains unclear how this selective neuronal activity arises and to what extent it is generated from local synaptic connectivity.…”