[Cerebral evoked potentials in comatose states of various etiology]

The authors studied the evoked potentials (EPs) of the brain cortex in patients in comatose states of various etiology as well as the EPs of the brain cortical and subcortical structures of the animals during simulation of the conditions studied in clinical practice. A sharp drop in the amplitude of early waves and an increase in the amplitude and latency of late EP waves in all the cerebral structures irrespective of the coma genesis were disclosed. The changes were of a simultaneous and generalized character with a greater similarity between the EPs of the cortical zones but an increase of their difference from the subcortical structures. These facts are explained by the deprivation of the nonspecific systems of both cortical and local inhibitory influence which leads to the late activation of the brain specific systems. It is assumed that the space-time dissociation in the action of various cerebral systems is, regardless of the coma genesis, one of the principal mechanisms giving rise to disorders of information perception, analysis and processing.