Dysfunctional Long-Range Coordination of Neural Activity during Gestalt Perception in Schizophrenia

Abstract

Recent theoretical and empirical research on schizophrenia converges on the notion that core aspects of the pathophysiology of the disorder may arise from a dysfunction in the coordination of distributed neural activity. Synchronization of neural responses in the ␤-band (15-30 Hz) and ␥-band range (30 -80 Hz) has been implicated as a possible neural substrate for dysfunctional coordination in schizophrenia. To test this hypothesis, we examined the electroencephalography (EEG) activity in 19 patients with a Diagnostic and Statistical Manual of Mental Disorder, edition IV criteria, diagnosis of schizophrenia and 19 healthy control subjects during a Gestalt perception task. EEG data were analyzed for phase synchrony and induced spectral power as an index of neural synchronization. Schizophrenia patients were impaired significantly in the detection of images that required the grouping of stimulus elements into coherent object representations. This deficit was accompanied by longer reaction times in schizophrenia patients. Deficits in Gestalt perception in schizophrenia patients were associated with reduced phase synchrony in the ␤-band (20 -30 Hz), whereas induced spectral power in the ␥-band (40 -70 Hz) was mainly intact. Our findings suggest that schizophrenia patients are impaired in the long-range synchronization of neural responses, which may reflect a core deficit in the coordination of neural activity and underlie the specific cognitive dysfunctions associated with the disorder.

Gamma Oscillatory Power is Impaired During Cognitive Control Independent of Medication Status in First-Episode Schizophrenia

“…Gamma activity has also been studied in schizophrenia using tasks with more complex processing demands. These studies have found schizophrenia patients to exhibit relatively lower frequency (Spencer et al, 2004) and decreased synchrony (Spencer et al, 2003) of an oscillation that is phase-locked to motor response in a Gestalt perception task, although others have found preserved gamma power in a different Gestalt perception task (Uhlhaas et al, 2006). Task demands with a stronger PFC-dependence have also revealed gamma deficits in schizophrenia patients, including impaired frontal gamma power (measured by magnetoencephalography) during mental arithmetic performance (Kissler et al, 2000) and an inability to mount increased delay-period gamma power in response to increasing working memory load during the N-Back (Basar-Eroglu et al, 2007).…”

The development of neural synchrony reflects late maturation and restructuring of functional networks in humans

“…1 A and B) (12) and were analyzed for spectral power as well as for phase synchronization of induced oscillations. Mooney faces were chosen as stimuli because their perception is associated with increased synchronization of oscillatory activity in the beta and gamma band and with the coherent activation of extended functional networks (13,14). Therefore, we expected to find developmental changes in the topology of interareal synchronization and perhaps also in the frequency of the bands in which this synchronization occurs.…”

Deep Brain Stimulation in Schizophrenia

“…Moreover, an association of neural oscillations with symptom dimensions has been demonstrated. Deficits in beta/gamma bands may contribute to perceptual impairments, and neural synchronization has been found correlated with positive and negative symptom dimensions of schizophrenia (Spencer et al, 2004;Uhlhaas et al, 2008;Uhlhaas et al, 2006). Changes in alpha synchronization during a memory task have been found to be correlated with task performance (Haenschel et al, 2010).…”

“…Some investigations have found correlations of neural synchronization with memory performance and sensory processing, respectively (Spencer et al, 2004;Uhlhaas et al, 2008;Uhlhaas et al, 2006;Haenschel et al, 2010). Reduced synchronization, for instance, has been demonstrated in the anterior cingulate cortex (ACC) during an auditory discrimination task (Gallinat et al, 2002).…”