Reduced load-dependent default mode network deactivation across executive tasks in schizophrenia spectrum disorders

Area of Science:

• Neuroscience
• Cognitive Science
• Psychiatry

Background:

• Schizophrenia is characterized by cognitive deficits and disrupted brain connectivity.
• Altered activation in large-scale brain networks, including the task-positive network (TPN) and default mode network (DMN), is observed in schizophrenia during cognitive tasks.
• The interplay between TPN and DMN dysfunction and their dependence on cognitive state in schizophrenia require further investigation.

Purpose of the Study:

• To investigate the recruitment of the TPN and DMN in patients with schizophrenia spectrum disorders compared to healthy controls during executive tasks.
• To determine if TPN and DMN dysfunction share common mechanisms or operate independently.
• To examine the relationship between network activation and task performance.

Main Methods:

• Independent component analysis was used to examine TPN and DMN activity.
• Participants included 29 patients with schizophrenia spectrum disorders and 21 healthy controls.
• Two executive tasks assessing planning/problem-solving and spatial working memory were employed.

Main Results:

• Patients showed reduced load-dependent DMN deactivation compared to controls across tasks.
• Moderate associations between TPN and DMN activation suggest partly independent network mechanisms.
• TPN activation correlated with task performance, while DMN activation did not.

Conclusions:

• A general, load-dependent DMN dysfunction is present in schizophrenia spectrum disorder across demanding executive tasks.
• This DMN dysfunction is not merely a byproduct of overall cognitive impairment.
• Findings highlight specific network alterations contributing to cognitive deficits in schizophrenia.