Lateral differences in the default mode network in healthy controls and patients with schizophrenia

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Psychiatry

Background:

• Schizophrenia is associated with altered brain lateralization.
• The default mode network (DMN) plays a crucial role in intrinsic brain activity.
• Previous studies suggest DMN abnormalities in schizophrenia, particularly during cognitive tasks.

Purpose of the Study:

• To investigate lateral differences in DMN intrinsic fluctuations in healthy controls (HCs) and schizophrenia (SZ) patients.
• To compare DMN asymmetry between HCs and SZ during rest and an auditory oddball (AOD) task.
• To determine if DMN abnormalities in SZ are present during resting states and task conditions.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan 28 HCs and 28 SZ patients.
• Resting-state fMRI and fMRI during an AOD task were acquired.
• Analysis focused on lateral differences and functional asymmetries within the DMN.

Main Results:

• Significant lateral fluctuations were observed in both HCs and SZ during rest and AOD.
• HCs showed maximal asymmetry in the inferior parietal lobule during rest; SZ showed it in the posterior cingulate gyrus.
• Significant group differences (HC > SZ) in asymmetry were found in the inferior parietal lobule and posterior cingulate during rest and/or AOD.
• Reduced activity in language-related areas was noted in SZ compared to HCs during rest.

Conclusions:

• Schizophrenia is characterized by abnormal hemispheric asymmetry within the DMN.
• DMN disruptions in SZ are detectable during resting conditions, not just during tasks.
• Findings suggest potential neurological markers for schizophrenia detectable via DMN asymmetry.