Functional MRI Evaluation of Multiple Neural Networks Underlying Auditory Verbal Hallucinations in Schizophrenia Spectrum Disorders

• Published in: Frontiers in psychiatry 2016-03, Vol.7, p.39-39
• Main Authors: Thoma, Robert J, Chaze, Charlotte, Lewine, Jeffrey David, Calhoun, Vince D, Clark, Vincent P, Bustillo, Juan, Houck, Jon, Ford, Judith, Bigelow, Rose, Wilhelmi, Corbin, Stephen, Julia M, Turner, Jessica A
• Format: Article
• Language: English
• Subjects: Auditory verbal hallucinations; functional magnetic resonance imaging; general linear model; Independent Component Analysis; Psychiatry; Schizophrenia
• ISSN: 1664-0640; 1664-0640
• DOI: 10.3389/fpsyt.2016.00039

Functional MRI studies have identified a distributed set of brain activations to be associated with auditory verbal hallucinations (AVH). However, very little is known about how activated brain regions may be linked together into AVH-generating networks. Fifteen volunteers with schizophrenia or schizoaffective disorder pressed buttons to indicate onset and offset of AVH during fMRI scanning. When a general linear model was used to compare blood oxygenation level dependence signals during periods in which subjects indicated that they were versus were not experiencing AVH ("AVH-on" versus "AVH-off"), it revealed AVH-related activity in bilateral inferior frontal and superior temporal regions; the right middle temporal gyrus; and the left insula, supramarginal gyrus, inferior parietal lobule, and extranuclear white matter. In an effort to identify AVH-related networks, the raw data were also processed using independent component analyses (ICAs). Four ICA components were spatially consistent with an a priori network framework based upon published meta-analyses of imaging correlates of AVH. Of these four components, only a network involving bilateral auditory cortices and posterior receptive language areas was significantly and positively correlated to the pattern of AVH-on versus AVH-off. The ICA also identified two additional networks (occipital-temporal and medial prefrontal), not fully matching the meta-analysis framework, but nevertheless containing nodes reported as active in some studies of AVH. Both networks showed significant AVH-related profiles, but both were most active during AVH-off periods. Overall, the data suggest that AVH generation requires specific and selective activation of auditory cortical and posterior language regions, perhaps coupled to a release of indirect influence by occipital and medial frontal structures.