The Role of Oscillations and Synchrony in Cortical Networks and Their Putative Relevance for the Pathophysiology of Schizophrenia

Abstract

Neural oscillations and their synchronization may represent a versatile signal to realize flexible communication within and between cortical areas. By now, there is extensive evidence to suggest that cognitive functions depending on coordination of distributed neural responses, such as perceptual grouping, attention-dependent stimulus selection, subsystem integration, working memory, and consciousness, are associated with synchronized oscillatory activity in the theta-, alpha-, beta-, and gamma-band, suggesting a functional mechanism of neural oscillations in cortical networks. In addition to their role in normal brain functioning, there is increasing evidence that altered oscillatory activity may be associated with certain neuropsychiatric disorders, such as schizophrenia, that involve dysfunctional cognition and behavior. In the following article, we aim to summarize the evidence on the role of neural oscillations during normal brain functioning and their relationship to cognitive processes. In the second part, we review research that has examined oscillatory activity during cognitive and behavioral tasks in schizophrenia. These studies suggest that schizophrenia involves abnormal oscillations and synchrony that are related to cognitive dysfunctions and some of the symptoms of the disorder. Perspectives for future research will be discussed in relationship to methodological issues, the utility of neural oscillations as a biomarker, and the neurodevelopmental hypothesis of schizophrenia.

Differences of temporal dynamics and signal complexity of gamma band oscillations in first-episode psychosis during a working memory task

“…These impaired interactions between brain regions support the notion of a disconnectivity syndrome in schizophrenia, which suggests dysfunctional coordination or synchronization of neuronal oscillations in large-scale networks (Uhlhaas 2013). Alterations of neuronal synchrony parameters of these brain regions have also been demonstrated to be implicated in the pathophysiological processes of the disorder (Uhlhaas et al 2008;Roach et al 2013;Skåtun et al 2016). …”

Does schizophrenia arise from oxidative dysregulation of parvalbumin-interneurons in the developing cortex?

“…In particular, synaptic inhibition from PVinterneurons controls the firing rates of pyramidal neurons, synchronizes spikes within populations of neurons, and participates in the development of executive functions associated with prefrontal brain regions (Kawaguchi and Kubota, 1993;Goldman-Rakic, 1999;Markram et al, 2004). PV-interneurons are a part of the network that generates oscillatory activity in the gamma range (Sohal et al, 2009;Cardin et al, 2009), suggesting that their dysfunction may account for the disruption in evoked gamma-frequency oscillations and as well as the cognitive deficits observed in schizophrenia (GonzalezBurgos and Lewis, 2008;Roopun et al, 2008;Uhlhaas et al, 2008).…”

Relating Intrinsic Low-Frequency BOLD Cortical Oscillations to Cognition in Schizophrenia

“…In contrast to interregional-phase synchronization, in this study we focus on amplitude measures of LFO activity that can be construed as a measure of local activity synchronization (Roach and Mathalon, 2008;Uhlhaas et al, 2008). It has been shown in a primate model that modulations of local field potential-recorded band-limited power in higher frequencies (particularly gamma-band) fluctuate with the same low-frequency periodicity as BOLD signals (Leopold et al, 2003).…”