Gating of the vertex somatosensory and auditory evoked potential P50 and the correlation to skin conductance orienting response in healthy men

A defect in auditory evoked potential (AEP) P50 gating supports the theory of information-processing deficits in schizophrenia. The relationship betwe en gating of the mid-latency evoked potentials (EP) in the somatosensory an d the auditory modalities has not been studied together before. In schizoph renia, we might expect the processing deficits to act on multiple modalitie s. We have examined the gating of median nerve somatosensory EP (SEP) follo wing paired stimulation identical to the AEP P50 gating paradigm using inte rstimulus intervals (ISI) of 500, 750 and 1000 ms and the correlation of ga ting to the skin conductance orienting response (SCOR) in 20 healthy men. W e measured mid-latency vertex components (SEP: P50, N65, P85 and N100; AEP: P30, N45, P50 and N80). The gating was most pronounced at ISI 500 ms where the SEP P50 and N100 gating were 0.59 and 0.37, respectively, as compared to a gating of 0.61 in P30, 0.33 in P50 and 0.45 in N80 in the AEP. Repetit ion effects in the two modalities were not correlated. AEP P50 gating was c orrelated to skin conductance level (SCL). The combination of recording rep etition effects on the mid-latency EP in two modalities could provide a met hod for investigating if deficits of information processing in schizophreni a are cross-modal. (C) 2001 Elsevier Science Ireland Ltd. All rights reserv ed.