GABAergic interneurons are positioned to powerfully influence the dynamics of neural activity, yet the interneuron mediated circuit mechanisms that control spontaneous and evoked neocortical activity remains elusive. Vasoactive intestinal peptide (VIP+) interneurons are a specialized cell class which synapse specifically on other interneurons, potentially serving to facilitate increases in cortical activity. Here, using in vivo Ca2+ imaging, we describe the interaction between local network activity and VIP+ cells and determine their role in modulating neocortical activity in mouse visual cortex. VIP+ cells were active across brain states including locomotion, non-locomotion, visual stimulation, and under anesthesia. VIP+ activity correlated most clearly with the mean level of population activity of nearby excitatory neurons during all brain states, suggesting VIP+ cells enable high excitability states in the cortex. The pharmacogenetic blockade of VIP+ cell output reduced network activity during locomotion, non-locomotion, under anesthesia, and visual stimulation, suggesting VIP+ cells exert a state independent facilitation of neural activity in the cortex. Collectively, our findings demonstrate that VIP+ neurons have a generalizable disinhibitory role in the generation of high activity regimes during spontaneous and stimulus evoked neocortical activity.
- spontaneous activity
- Copyright © 2015, Journal of Neurophysiology