BASELINE ACTIVITY OF V1 INTERNEURONS CONNECTS PUPIL-LINKED AROUSAL TO ENGAGED BEHAVIORAL STATE

Humans and rodents alternate between discrete, persistent behavioral states during perceptual decision-making. For example, using a GLM-HMM, trials can be clustered into states of engaged, disengaged, and biased decision-making strategies. In mice, the probability of being in an engaged state exhibits an inverted-U relationship with baseline pupil-linked arousal, consistent with the Yerkes-Dodson Law. The neural basis of this relationship is not known.

Here, we examined whether baseline spiking activity in primary visual cortex (V1) statistically mediates the relationship between arousal and choice behavior. We applied GLM-HMMs to session-wise time courses of choice behavior of mice and humans performing challenging perceptual decision-making tasks. We simultaneously recorded pupil size in both species, and extra-cellular electrophysiology in primary visual cortex of mice.

We replicated the inverted-U relationship between baseline pupil size and engaged state probability in mice (N=11; audio-visual change detection task) and showed that it generalizes to humans (N=69; auditory detection task). A nonlinear mediation model revealed that baseline activity of putative fast-spiking interneurons, but not putative pyramidal neurons, made a significant statistical contribution to the inverted-U shaped relationship between pupil-linked arousal and engaged-state probability.

Our findings are consistent with the idea that arousal may shape behavioral states by modulating baseline inhibitory activity within a primary sensory region.