Neural rhythms of dissociative state

Dissociation is an altered behavioural state in which sensory experiences are disrupted and separated from affective responses. It can occur with trauma, epilepsy or under the influence of psychedelic drugs. This paper models human behavioural dissociation in mice induced by ketamine or phencyclidine. The dissociative state was associated with, and could be induced by, low frequency rhythmic activity in retrosplenial cortex layer-5 neurons and certain patterns of coupling with other brain areas. In a patient with epilepsy, there was a similar rhythm at the time of self-reported dissociation around seizures. Furthermore, brief electrical stimulation of the right or left deep posteromedial cortex also elicited dissociative experiences. These results identify molecular, cellular and physiological properties of a cortical rhythm underlying states of dissociation.