Left-dominant temporal-frontal hypercoupling in schizophrenia patients with hallucinations during speech perception

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Previous neuroimaging studies on schizophrenia and hallucinations yielded inconsistent results regarding speech-related brain activity.
• Task selection in functional neuroimaging may influence the detection of hyperactivity in schizophrenia.

Purpose of the Study:

• To investigate functional brain connectivity during tasks manipulating control over verbal material in schizophrenia patients and controls.
• To explore the relationship between brain activity, hallucination status, and task demands.

Main Methods:

• Compared brain activity in 23 schizophrenia patients (10 hallucinators, 13 nonhallucinators), 22 bipolar patients, and 27 healthy controls.
• Utilized a task with two conditions: inner verbal thought (requiring control) and speech perception (SP; not requiring control).
• Employed functional connectivity analysis to examine network coupling.

Main Results:

• A left-dominant temporal-frontal network, including speech-related regions, exhibited hypercoupling in hallucinating schizophrenia patients during SP.
• This hypercoupling was observed only during SP, where control over verbal material was not required.
• Hyperconnectivity correlated with recent hallucination severity in schizophrenia patients during SP.

Conclusions:

• Findings suggest that speech-related network hypercoupling in schizophrenia is task-dependent, specifically occurring during passive speech perception.
• Hyperconnectivity during SP, not inner thought, is linked to hallucination severity.
• Practicing control over inner verbal thought processes may be a potential strategy to mitigate hallucinations in schizophrenia.