Adjusting brain dynamics in schizophrenia by means of perceptual and cognitive training

Abstract

Examined whether training effects on M50 ratio and task performance are mediated by changes in brain oscillatory activity in schizophrenia. Participants included 36 schizophrenic adults (mean age 30 years) and 15 healthy controls (mean age 29 years). Patients completed German versions of the California Verbal Learning Test (CVLT) and Global Assessment of Functioning Scale (GAF) before and after a 4-week training consisting of either specific cognitive exercises (CE) or standard cognitive training (CP). In addition, time-locked and non-time-locked oscillatory activity was measured in patients and controls together with M50 ratio in a paired-click design using MEG before and after training or after a 4-week period (controls). Results showed a stronger time-locked gamma band response and more non-time-locked alpha band desynchronization in patients after 4 weeks, more so after CE than after CP. Only after CE increased alpha desynchronization was associated with normalized M50 ratio and with improved verbal memory performance. Thus, both types of cognitive training normalized gamma activity, associated with improved stimulus encoding. More targeted training of auditory-verbal discrimination and memory additionally normalized alpha desynchronization, associated with improved elaborative processing. The latter is suggested to contribute to improved auditory gating and cognitive function. It is concluded that dysfunctional interplay of oscillatory activity that may contribute to auditory processing disruption in schizophrenia may be modified by targeted training.