Neural Signatures Of Alpha 2-Adrenergic Agonist-Induced Unconsciousness And Awakening By Antagonist

How the brain dynamics change during anesthetic-induced altered states of consciousness is not completely understood. The alpha 2-adrenergic agonists are unique. They generate unconsciousness selectively through alpha 2-adrenergic receptors and related circuits. We studied intracortical neuronal dynamics during transitions of loss of consciousness (LOC) with the alpha 2-adrenergic agonist dexmedetomidine and return of consciousness (ROC) in a functionally interconnecting somatosensory and ventral premotor network in non-human primates. LOC, ROC and full task performance recovery were all associated with distinct neural changes. The early recovery demonstrated characteristic intermediate dynamics distinguished by sustained high spindle activities. Awakening by the alpha 2-adrenergic antagonist completely eliminated this intermediate state and instantaneously restored awake dynamics and the top task performance while the anesthetic was still being infused. The results suggest that instantaneous functional recovery is possible following anesthetic-induced unconsciousness and the intermediate recovery state is not a necessary path for the brain recovery.