Distinct roles of visual, parietal, and frontal motor cortices in memory-guided sensorimotor decisions

TLDR

Mapping specific sensory features to future motor actions is a crucial capability of mammalian nervous systems. The study examined how visual (V1), posterior parietal (PPC), and frontal motor (fMC) cortices contribute to sensorimotor mapping in mice performing a memory‑guided visual discrimination task. Large‑scale calcium imaging and optogenetic inhibition were employed to record neuronal activity and test causal involvement across these regions during the task. Neuronal recordings revealed heterogeneous responses across all task epochs, with V1 encoding stimulus identity, fMC encoding choice even early, and PPC multiplexing both; population analyses showed distinct encoding patterns, and optogenetic inhibition demonstrated that all regions are required during the stimulus epoch, but only fMC is necessary during the delay and response epochs, indicating that stimulus identity is rapidly transformed into choice by V1, PPC, and fMC, while only fMC sustains the choice in memory before execution.

Abstract

Mapping specific sensory features to future motor actions is a crucial capability of mammalian nervous systems. We investigated the role of visual (V1), posterior parietal (PPC), and frontal motor (fMC) cortices for sensorimotor mapping in mice during performance of a memory-guided visual discrimination task. Large-scale calcium imaging revealed that V1, PPC, and fMC neurons exhibited heterogeneous responses spanning all task epochs (stimulus, delay, response). Population analyses demonstrated unique encoding of stimulus identity and behavioral choice information across regions, with V1 encoding stimulus, fMC encoding choice even early in the trial, and PPC multiplexing the two variables. Optogenetic inhibition during behavior revealed that all regions were necessary during the stimulus epoch, but only fMC was required during the delay and response epochs. Stimulus identity can thus be rapidly transformed into behavioral choice, requiring V1, PPC, and fMC during the transformation period, but only fMC for maintaining the choice in memory prior to execution.