Aberrant prefrontal activity and arousal level correlate with action initiation and response vigor

Orchestrating learned Stimulus-Response (S-R) mappings has been suggested as one of the central functions of the prefrontal cortex (PFC). While S-R selective activity has been demonstrated, it remains unclear whether the strength of such activity is related to the vigor of the subsequent response. Here, we trained male rats to perform a Go/NoGo response task while head-fixed on a treadmill. This allowed us to record PFC (cingulate, area 24) single unit spiking, as well as running speed as a proxy for response vigor. We show that aberrant activation of the "wrong" S-R mapping is correlated with initiation of the incorrect response. The vigor of the incorrect response was directly related to the strength of the aberrant stimulus-evoked activity. A similar relationship was observed for pre-trial arousal state and response vigor. Our findings confirm the long-standing concept, established in psychology and cognitive neuroscience, that S-R mappings are directly related to response vigor. Moreover, we provide evidence for the often suggested but rarely tested relationship between arousal and response vigor and a potential underlying neuronal mechanism involving neuromodulation of S-R mapping activity. Significance statementThe concept of stimulus-response (S-R) mappings is fundamental in psychology and has been widely documented as a key function of the prefrontal cortex. Here, the authors directly link prefrontal single neuron mapping-selective activity to the vigor of responses. Moreover, they link a physiological measure of arousal to response vigor and suggest that neuromodulatory systems invigorate responses by potentially modulating PFC S-R mapping-selective activity.