Dynamical structure of cortical taste responses revealed by precisely-timed optogenetic perturbation

The purpose of perception is driving action. During tasting, for instance, every stimulus must be either swallowed or rejected (the latter via a behavior known as “gaping”). Taste responses in the rodent primary gustatory cortex (GC) span this sensorimotor divide, progressing through a series of firing epochs that culminate in the emergence of action-related firing. Population analyses reveal this emergence to be a sudden, coherent ensemble transition that, despite varying in latency between trials, precedes gaping onset by 0.2-0.3s. Here, we tested whether this transition drives gaping, delivering 0.5s GC perturbations at various time-points in tasting trials. Perturbations significantly delayed gaping, but only when they preceded the action-related transition - thus, the same perturbation might have an impact or not, depending on the transition latency in that particular trial. Our results suggest a distributed attractor network model of taste processing, and a dynamical role for cortex in driving motor behavior.