Disrupted cognitive network revealed by task-induced brain entropy in schizophrenia

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Psychiatry

Background:

• Brain entropy (BEN) quantifies information in brain activity, offering insights into brain function.
• Resting-state fMRI studies show altered BEN in schizophrenia (SCZ).
• Task-dependent BEN in SCZ remains under-investigated, especially concerning cognitive deficits.

Purpose of the Study:

• To investigate dynamic changes in task-evoked brain entropy (BEN) during cognitive tasks in schizophrenia (SCZ).
• To explore the association between task BEN, working memory (WM) capacity, and clinical symptoms in SCZ.
• To determine if task BEN can serve as a neuroimaging marker for cognitive deficits in SCZ.

Main Methods:

• Analyzed fMRI data from 15 SCZ patients and 15 healthy controls (HC) during an N-back task.
• Calculated task BEN and examined correlations with 2-back task performance, clinical symptoms, and neuropsychological scores.
• Compared task BEN values between SCZ and HC groups across various brain regions.

Main Results:

• SCZ patients showed significantly reduced task BEN in the cerebellum, hippocampus, parahippocampal gyrus, thalamus, middle frontal gyrus (MFG), and superior frontal gyrus (SFG) compared to HC.
• In HC, task BEN positively correlated with 2-back accuracy in MFG and SFG; these correlations were absent in SCZ.
• Task BEN negatively associated with positive and negative symptoms in SCZ, particularly in the parahippocampal gyrus.

Conclusions:

• Reduced task BEN in prefrontal and hippocampal regions during high cognitive demand tasks is linked to cognitive deficits in SCZ.
• Task BEN alterations may represent a neuroimaging biomarker for schizophrenia-related cognitive impairments.
• This study highlights the utility of task-evoked BEN in understanding cognitive dysfunction in SCZ.