Reduced auditory evoked gamma band response and cognitive processing deficits in first episode schizophrenia. (18th August 2015)

• Record Type: Journal Article
• Authors: Leicht, Gregor; Andreou, Christina; Polomac, Nenad; Lanig, Clarissa; Schöttle, Daniel; Lambert, Martin; Mulert, Christoph
• Is Part Of: World journal of biological psychiatry. Volume 16:Number 6(2015)
• Page Start: 387
• Page End: 397
• Publication Date: 2015-08-18
• Subjects: schizophrenia -- EEG -- gamma -- first episode -- auditory; Biological psychiatry -- Periodicals; Biological Psychiatry -- Periodicals; 616.89
• DOI: 10.3109/15622975.2015.1017605
• Languages: English
• ISSNs: 1562-2975

Abstract

Abstract: Objectives. Gamma-band oscillations (e.g., the early auditory evoked gamma-band response, aeGBR) have been suggested to mediate cognitive and perceptual processes by driving the synchronization of local neuronal populations. Reduced aeGBR is a consistent finding in patients with schizophrenia and high-risk subjects, and has been proposed to represent an endophenotype for the illness. However, it is still unclear whether this reduction represents a deficit in sensory or cognitive processes, or a combination of the two. The present study investigated this question by manipulating the difficulty of an auditory reaction task in patients with first-episode schizophrenia and healthy controls. Methods. A 64-channel EEG was recorded in 23 patients with first-episode schizophrenia and 22 healthy controls during two conditions of an auditory reaction task: an easy condition that merely required low-level vigilance, and a difficult condition that placed significant demands on attention and working memory. Results . In contrast to healthy controls, patients failed to increase aeGBR power and phase-locking in the difficult condition. In patients, aeGBR power and phase-locking indices were associated with working memory deficits. Conclusions . The observed results confirm the applicability of aeGBR disturbances as a stable endophenotype of schizophrenia, and suggest a cognitive, rather than sensory, deficit at their origin.