Relationship between P50 suppression and the cortical silent period.

Deficient inhibitory neurotransmission has been demonstrated in schizophrenia through electroencephalography (e.g. P50 suppression) and transcranial magnetic stimulation (e.g. short-interval cortical inhibition and the cortical silent period). It is not known whether these inhibitory paradigms are related despite evidence suggesting that both are coordinated through gamma-aminobutyric acid inhibitory neurotransmission. We explored the relationship between P50 suppression, short-interval cortical inhibition and the cortical silent period in 21 healthy participants using previously published methods. P50 suppression was significantly correlated with cortical silent period (r=-0.49, P=0.02) but not with short-interval cortical inhibition. As both P50 suppression and the cortical silent period have been linked to gamma-aminobutyric acidB receptor-mediated inhibitory neurotransmission, these data highlight the importance of this receptor subtype in the pathophysiology of schizophrenia.