Whisking up a change in state

In mammals, quiet wakefulness and active behaviour are associated with synchronized and desynchronized patterns, respectively, of spontaneous cortical activity (termed cortical states). The mechanisms controlling cortical states are poorly understood. Poulet et al. showed that active whisking behaviour in mice, which is associated with a desynchronized state in the barrel cortex, is linked to increased thalamic activity, and that thalamic inactivation blocks the desynchronized state during whisking. In animals in quiet wakefulness, optogenetic-stimulated thalamic firing could induce a desynchronized cortical state in the barrel cortex. These findings suggest that thalamic activity may drive cortical desynchronization.