Deficits in high- (>60 Hz) gamma-band oscillations during visual processing in schizophrenia

Abstract

Current theories of the pathophysiology of schizophrenia have focused on abnormal temporal coordination of neural activity. Oscillations in the gamma-band range (>25 Hz) are of particular interest as they establish synchronization with great precision in local cortical networks. However, the contribution of high gamma (>60 Hz) oscillations toward the pathophysiology is less established. To address this issue, we recorded magnetoencephalographic (MEG) data from 16 medicated patients with chronic schizophrenia and 16 controls during the perception of Mooney faces. MEG data were analysed in the 25–150 Hz frequency range. Patients showed elevated reaction times and reduced detection rates during the perception of upright Mooney faces while responses to inverted stimuli were intact. Impaired processing of Mooney faces in schizophrenia patients was accompanied by a pronounced reduction in spectral power between 60–120 Hz (effect size: d = 1.26) which was correlated with disorganized symptoms (r = −0.72). Our findings demonstrate that deficits in high gamma-band oscillations as measured by MEG are a sensitive marker for aberrant cortical functioning in schizophrenia, suggesting an important aspect of the pathophysiology of the disorder.

Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

“…This finding is not directly relevant to the main question addressed in this study but it is interesting because it contrasts with previous studies in patients with established schizophrenia who show reduced ability to spontaneously disambiguate two-tone images of faces without prior knowledge (46,47). This previous effect is most likely related to well-established schizophrenic deficits in early and midlevel vision that affect perceptual organization, context processing and integration (37,38,(48)(49)(50)(51)(52)(53) rather than to top-down influences from high-level visual cognition as in the current study.…”

Interactions between visual and semantic processing during object recognition revealed by modulatory effects of age of acquisition

“…2A and B) which may represent a response to the offset of the visual stimulus which occurred at 200 ms (cf. Grützner et al, 2013;N'Diaye et al, 2004). A reduction in oscillatory power relative to baseline began in the 10-25 Hz band at around 200 ms, between the two evoked responses, and then continued to around 600 ms at 5-10 Hz ( Fig.…”

A new Mooney test

“…The Mooney test remains of interest and continues to be used in visual perception research (especially on face processing), in clinical research, and in studies using brain imaging (Carbon, Grüter, & Grüter, 2013;Grützner et al, 2013;Rivolta et al, 2014;Rossion et al, 2011;Towler, Gosling, Duchaine, & Eimer, 2014). In combination with other measures, and across different populations-both clinical and nonclinical-the quick, reliable, and standardized new Mooney-Verhallen Test might give further insights into the still mysterious nature of closure and its relationship to different genotypes, phenotypes, and behaviors.…”