title: Dysfunctional prefrontal gamma-band oscillations reflect working memory and other cognitive deficits in schizophrenia.
abstract: Impairments in working memory (WM) and other cognitive functions are cardinal neuropsychological symptoms in schizophrenia (ScZ). The prefrontal cortex (PFC) is important for mediating and executing these functions. Functional neuroimaging and molecular studies have consistently shown PFC abnormalities in ScZ. In addition, recent studies have suggested that impairments in oscillatory activity, especially in the gamma band (approximately 30-80 Hz), reflect disturbed cortical information processing in this patient group. Here we review evidence that dysfunctional gamma-band responses (GBR) in the PFC could be a factor contributing to WM and other cognitive deficits in ScZ. We provide an overview of noninvasive electrophysiological studies reporting frontal GBR abnormalities in ScZ patients during WM and other cognitive tasks. In agreement with the often-reported hypofrontality in functional neuroimaging studies, the majority of reviewed studies revealed reduced amplitudes or reduced phase locking of GBR over frontal areas in this patient group. Clinical implications derived from these findings and possibilities to foster future studies on GBR abnormalities in ScZ patients, are discussed. Since oscillatory activity in the gamma band has previously been linked to a variety of neurotransmitters, such as the gamma-aminobutyric acid-ergic system, the study of prefrontal GBR could also have implications for pharmacologic approaches in the treatment of WM and other cognitive deficits in ScZ.
authors.affiliation: Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin. Electronic address: daniel.senkowski@charite.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Senkowski
authors.affiliation: Department for Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Geermany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gallinat
mesh_terms: D000818:Animals; D065818:Gamma Rhythm; D006801:Humans; D008569:Memory Disorders / Q000209:etiology / Q000503:physiopathology; D008570:Memory, Short-Term / Q000502:physiology; D017397:Prefrontal Cortex / Q000503:physiopathology*; D012559:Schizophrenia / Q000150:complications / Q000503:physiopathology*; D012565:Schizophrenic Psychology
keywords: Electroencephalography; Gamma-aminobutyric acid; Magnetoencephalography; Oscillatory activity; Prefrontal cortex; Schizophrenia