A method for capturing dynamic spectral coupling in resting fMRI reveals domain-specific patterns in schizophrenia

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Resting-state functional magnetic resonance imaging (rs-fMRI) is crucial for assessing brain connectivity.
• Prior research primarily evaluated connectivity through time-series correlations, potentially overlooking dynamic spectral changes.
• Schizophrenia is associated with altered brain activity, but the precise nature of spectral connectivity differences remains unclear.

Purpose of the Study:

• To introduce and validate a novel framework for assessing time-resolved spectral coupling (trSC) in brain networks.
• To investigate group differences in trSC between individuals with schizophrenia (SZ) and healthy controls (HC), and between males and females.
• To explore potential spectral connectivity underpinnings of visual processing impairments in schizophrenia.

Main Methods:

• rs-fMRI data from 151 SZ and 163 HC were analyzed using independent component analysis (ICA) to identify brain circuits.
• Time-resolved spectral coupling (trSC) was calculated by correlating power spectra of windowed time courses between brain components.
• Connectivity maps were subgrouped into quartiles, and differences in cluster counts and sizes were analyzed using regression.

Main Results:

• Individuals with schizophrenia exhibited significantly different and more modular spectral coupling patterns across multiple brain networks compared to controls.
• Healthy controls and males showed higher spectral coupling in the visual network, particularly in the highest quartile, indicating increased trSC.
• Schizophrenia patients displayed less spectrally consistent visual networks, with reduced short-timescale spectral correlation with other functional domains.

Conclusions:

• The trSC approach reveals significant, distinct differences in time-varying spectral coupling between schizophrenia patients and controls, and between sexes.
• Elevated trSC in the visual network of controls suggests greater spectral synchrony, which is diminished in schizophrenia.
• trSC offers a valuable tool for investigating the neural mechanisms underlying cognitive and sensory processing deficits in psychiatric disorders like schizophrenia.