Altered transient brain dynamics in multiple sclerosis: Treatment or pathology?

Area of Science:

• Neuroscience
• Neurology
• Brain Network Dynamics

Background:

• Multiple sclerosis (MS) is a neuroinflammatory and neurodegenerative disease impacting brain function via atrophy and reduced connectivity.
• The effects of MS on the fast temporal dynamics of large-scale brain network activation and deactivation remain largely unknown.
• Benzodiazepines (BZDs) are commonly used to manage MS symptoms like insomnia and anxiety, potentially influencing brain activity.

Purpose of the Study:

• To investigate alterations in fast temporal brain network dynamics in multiple sclerosis patients.
• To determine if observed changes are due to MS pathology or BZD treatment.
• To characterize the impact of MS and BZDs on brain dynamics in a spatially, temporally, and spectrally defined manner.

Main Methods:

• Employed a novel method to detect fast temporal dynamics of brain networks.
• Studied 90 MS patients and 46 healthy controls.
• Analyzed gender-specific differences and the influence of BZD usage on brain dynamics and spectral power (theta and beta bands).

Main Results:

• Male MS patients exhibited a less dynamic frontal default mode network (DMN).
• Female MS patients showed reduced activation of the frontal DMN, independent of BZD use.
• BZDs significantly altered brain dynamics, increasing time in sensorimotor deactivation and occipital activation states, and modifying theta and beta band power.

Conclusions:

• Multiple sclerosis induces gender-dependent changes in the temporal dynamics of the frontal DMN.
• Benzodiazepine treatment significantly impacts brain network dynamics and spectral power in MS patients.
• This study provides the first in vivo characterization of MS and BZD effects on brain dynamics across spatial, temporal, and spectral domains.