Frequency-dependent alterations in regional homogeneity in major depression

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Resting-state functional magnetic resonance imaging (fMRI) studies indicate abnormal spontaneous neural activity in major depressive disorder (MDD).
• The frequency-dependent characteristics of this neural activity in MDD remain largely unexplored.

Purpose of the Study:

• To investigate frequency-dependent spontaneous neural activity using regional homogeneity (ReHo) in MDD patients.
• To identify specific brain regions and frequency bands associated with neural abnormalities in MDD.

Main Methods:

• Utilized resting-state fMRI to analyze spontaneous neural activity in 31 MDD patients and 31 healthy controls.
• Examined ReHo in three frequency bands: typical (0.01–0.08 Hz), slow-4 (0.027–0.073 Hz), and slow-5 (0.010–0.027 Hz).

Main Results:

• MDD patients showed altered ReHo in the middle frontal gyrus (MFG), fusiform, and postcentral gyrus in the typical band.
• Significant differences in ReHo were observed in the slow-4 band (increased in middle occipital gyrus (MOG), decreased in anterior cingulate cortex (ACC), inferior frontal gyrus (IFG), superior frontal gyrus (SFG), and bilateral thalamus).
• Increased ReHo in the medial prefrontal cortex (mPFC) was found in the slow-5 band for MDD patients.

Conclusions:

• Abnormalities in ReHo in MDD are frequency-band specific.
• Future research on spontaneous neural activity in MDD should consider the influence of different frequency bands.