The Claustrum Coordinates Cortical Slow-Wave Activity
During sleep and awake rest, the neocortex generates large-scale slow-wave activity. Here we report that the claustrum, a poorly understood subcortical neural structure, coordinates neocortical slow-wave generation. We established a transgenic mouse line allowing genetic and electrophysiological interrogation of a subpopulation of claustral glutamatergic neurons. These claustral excitatory neurons received inputs from glutamatergic neurons in a large neocortical network. Optogenetic activation of claustral neurons in vitro induced excitatory post-synaptic responses in most neocortical neurons, but elicited action potentials primarily in inhibitory interneurons. Optogenetic activation of claustral neurons in vivo induced a Down-state featuring a prolonged silencing of neural acticity in all layers of many cortical areas, followed by a globally synchronized Down-to-Up state transition. These results demonstrate a crucial role of the claustrum in synchronizing inhibitory interneurons across the neocortex for spatiotemporal coordination of brain state. Thus, the claustrum is a major subcortical hub for the synchronization of neocortical slow-wave activity.