Schizophrenia is characterized by dysfunction in basic auditory processing, as well as higher-order operations of verbal learning and executive functions. We investigated whether targeted cognitive training of auditory processing improves neural responses to speech stimuli, and how these changes relate to higher-order cognitive functions. Patients with schizophrenia performed an auditory syllable identification task during magnetoencephalography before and after 50 hours of either targeted cognitive training or a computer games control. Healthy comparison subjects were assessed at baseline and after a 10 week no-contact interval. Prior to training, patients (N = 34) showed reduced M100 response in primary auditory cortex relative to healthy participants (N = 13). At reassessment, only the targeted cognitive training patient group (N = 18) exhibited increased M100 responses. Additionally, this group showed increased induced high gamma band activity within left dorsolateral prefrontal cortex immediately after stimulus presentation, and later in bilateral temporal cortices. Training-related changes in neural activity correlated with changes in executive function scores but not verbal learning and memory. These data suggest that computerized cognitive training that targets auditory and verbal learning operations enhances both sensory responses in auditory cortex as well as engagement of prefrontal regions, as indexed during an auditory processing task with low demands on working memory. This neural circuit enhancement is in turn associated with better executive function but not verbal memory.
Bibliographical noteFunding Information:
Supplementary material is available at http://schizophreniabulletin. oxfordjournals.org. National Institutes of Health (R01DC004855, R01DC010145, R21NS076171, R01MH068725); Howard Hughes Medical Institute Research Fellowship program (to E. G. B.); San Francisco Department of Veterans'' Affairs Medical Center. The cognitive training software used in this study was supplied to the senior author free of charge by Posit Science Corporation. We thank Greg Simpson and Tracy Luks for insights on study design, and Mary Vertinski and Alex Genevsky for assistance with data collection. Dr Vinogradov is a paid consultant to Posit Science Corporation and Forum Pharmaceuticals. Drs Dale, Brown, Fisher, Herman, Hinkley, Subramaniam, Nagarajan, and Mrs Dowling report no competing interests.