Evidence for abnormal cortical functional connectivity during working memory in schizophrenia

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Schizophrenia lacks clear regional pathology, suggesting disturbed neuronal interactions.
• Theoretical, neurochemical, and neuroanatomical data support aberrant brain connectivity in schizophrenia.

Purpose of the Study:

• To apply a novel functional neuroimaging analysis to characterize systems-level cooperative brain activity in schizophrenia.
• To identify potential trait markers for schizophrenia using functional connectivity patterns.

Main Methods:

• Positron emission tomography (PET) was used to scan 13 medication-free patients with schizophrenia and 13 healthy controls.
• Subjects performed a working memory (n-back) task and a sensorimotor baseline task.
• Canonical variates analysis extracted functional connectivity patterns differentiating the groups.

Main Results:

• A primary connectivity pattern, with distinct loadings for patients (inferotemporal, hippocampal, cerebellar) and controls (prefrontal cortex, anterior cingulate), perfectly separated the groups.
• This pattern demonstrated high diagnostic potential and was prospectively validated.
• A secondary pattern related to working memory task activation showed greater variability in patients, suggesting impaired neural network sustainability.

Conclusions:

• Significant disruptions in distributed cooperative brain activity were observed in schizophrenia.
• A frontotemporal interaction pattern shows promise as a schizophrenia trait marker for future research.