Auditory Steady-State Responses Probe GABA-Related Oscillatory Cortical Circuits and Their Relation to Neurodevelopmental Mental Disorders

Larsen discusses the study by Mancini et al on the use of 22q11DS as a genetic model for schizophrenia and on the developmental patterns of gamma band oscillations. They report findings from 40-Hz auditory steady-state responses (ASSRs). ASSRs can be evoked by brief tones or clicks and provide a noninvasive means of the ability to generate neural synchrony in the gamma range in the auditory system. The oscillatory activity evoked by these 40-Hz responses relies on the fast-spiking paralbumin positive GABAergic interneurons by exerting a finely tuned inhibition onto the pyramidal cells as well as other inhibitory interneurons. These oscillations are therefore considered to be an electrophysiological reflection of the excitation-inhibition balance, providing an insight into the underlying circuit dysfunction and thereby pathophysiology of schizophrenia.