Resting state brain dynamics and its transients: a combined TMS-EEG study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Dynamics

Background:

• The brain's resting state exhibits complex spatio-temporal dynamics.
• These dynamics are hypothesized to persist during tasks but alter in disease.
• Current rest-state paradigms often fail to directly probe these mechanisms.

Purpose of the Study:

• To investigate the brain's relaxation dynamics following perturbation.
• To compare the effects of stimulating different brain networks on resting state activity.
• To elucidate the role of specific brain regions in maintaining rest state function.

Main Methods:

• Combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG).
• Targeted stimulation of the medial prefrontal cortex (MPFC) within the Default Mode Network (DMN) and the superior parietal lobule (SPL) of the Dorsal Attention Network.
• TMS was triggered by increased occipital alpha rhythm power.

Main Results:

• TMS at MPFC enhanced occipital alpha rhythm (Event Related Synchronisation) more than TMS at SPL.
• MPFC stimulation resulted in a longer transient lifetime and higher amplitude of alpha rhythm.
• Demonstrated a strong coupling between MPFC activity and occipital alpha power.

Conclusions:

• The Default Mode Network (DMN), particularly the MPFC, plays a crucial role in organizing brain rest.
• Resting brain dynamics show significant coupling with specific network activities.
• This study provides insights into the mechanisms governing the brain's transition to and maintenance of rest.