Behavioral state and stimulus strength regulate the role of somatostatin interneurons in stabilizing network activity

We investigated the role of somatostatin-expressing (SST) interneurons in inhibition stabilization within mouse primary visual cortex. By selectively blocking glutamatergic inputs to SST cells, we observed paradoxical facilitation of SST activity with increasing stimulus contrast and arousal—a hallmark of inhibition stabilization. Our computational modeling revealed that higher sensory input and arousal drive the network toward regimes where other interneuron classes cannot maintain stability alone. We demonstrate that SST cells' contribution to cortical processing is state-dependent, becoming increasingly critical as input strength and behavioral arousal increase, thereby enabling stable sensory encoding across diverse contexts.