title: Electrophysiological evidence for reduced latent inhibition in schizophrenic patients.
abstract: The present study examined latent inhibition (LI) effects in 17 acute and 16 partially remitted schizophrenic patients, and in 20 healthy controls, by measuring manual response latencies and event-related potentials (ERPs) during an association learning task. ERPs were recorded to elucidate the role of attention in the LI effect. Subjects performed a go/no-go task with an auditory conditional stimulus predicting a visual go command. Half of the subjects in each diagnostic group were pre-exposed to the conditional stimulus which had been used as an irrelevant distractor in a preceding discrimination task. Independent of diagnostic group membership, pre-exposed subjects showed slower manual responses to go stimuli than non-pre-exposed subjects, reflecting a robust LI effect. The N100 wave after the conditional stimuli, however, showed a differential pattern: pre-exposure increased N100 amplitudes in acute schizophrenics, whereas pre-exposed control subjects showed a trend for decreased N100. The amplitude of the contingent negative variation (CNV) was unaffected by pre-exposure. The ERP results suggest that acute schizophrenics have a deficit in learned inattention to irrelevant stimuli. However, the intact LI effect in schizophrenics at the motor speed level shows that human LI is a complex phenomenon depending on the tasks and measures used.
authors.affiliation: Department of Psychiatry, Ludwig-Maximilians-Universität München, Nussbaumstrasse 7, 80336, Munich, Germany. nk@psy.med.uni-muenchen.de
authors.forename: N
authors.initials: N
authors.lastname: Kathmann
authors.forename: S
authors.initials: S
authors.lastname: von Recum
authors.forename: C
authors.initials: C
authors.lastname: Haag
authors.forename: R R
authors.initials: RR
authors.lastname: Engel
mesh_terms: D000208:Acute Disease; D000328:Adult; D001245:Association Learning / Q000502:physiology; D001288:Attention / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D011897:Random Allocation; D011930:Reaction Time; D012559:Schizophrenia