Greater individual variability in functional brain activity during working memory performance in Schizophrenia...

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Schizophrenia Spectrum Disorders (SSD) present significant heterogeneity, complicating traditional case-control research.
• Variability in functional brain activity is a key challenge in understanding SSD neurobiology.
• Working memory (WM) deficits are common in SSD.

Purpose of the Study:

• To investigate individual variability in functional brain activity during a working memory task in SSD compared to typically developing controls (TDC).
• To explore how individual differences in brain activity relate to cognitive performance and age in SSD.
• To re-evaluate group differences in SSD by considering individual variability.

Main Methods:

• Utilized neuroimaging (fMRI) and behavioral data from 34 TDC and 56 individuals with SSD (N=90).
• Examined functional brain activity during an N-Back working memory task (3-Back vs 1-Back).
• Quantified individual variability using a 'variability score' based on correlational distance of fMRI activity maps.

Main Results:

• Individuals with SSD demonstrated significantly greater functional brain activity variability compared to TDC (p=0.00090).
• Case-control analysis revealed reduced activity in task-related networks in SSD.
• Subgroup analysis showed that low-variability SSD individuals did not differ from TDC, while high-variability individuals had minimal group-level activity.

Conclusions:

• Individual variability in functional brain activity is a crucial factor in understanding SSD, potentially explaining previous inconsistent findings.
• High variability in SSD may reflect idiosyncratic neural patterns rather than specific task-related impairments.
• Variability is linked to cognitive performance and age in SSD, suggesting its relevance to disease mechanisms and progression.