Resting-state modulation of α rhythms by interference with angular gyrus activity

Area of Science:

• Neuroscience
• Cognitive Neuroscience

Background:

• The default mode network (DMN) is active during rest and suppressed during goal-directed tasks.
• The angular gyrus (AG) is a core region within the DMN, involved in spontaneous neural activity.

Purpose of the Study:

• To investigate if inhibitory magnetic stimulation of the angular gyrus (AG) enhances resting-state electroencephalography (EEG) alpha rhythms.
• To determine the causal role of the AG in modulating alpha rhythms during restful wakefulness.

Main Methods:

• Low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) was applied to the left and right AG in 15 healthy adults.
• EEG alpha power density and coherence were measured during resting-state conditions, comparing AG stimulation with sham stimulation.
• Control stimulation sites included the frontal eye fields (FEF) and intraparietal sulcus (IPS).

Main Results:

• rTMS over the AG significantly enhanced dominant alpha power density (8-10 Hz) in the occipitoparietal cortex compared to sham stimulation.
• Right AG-rTMS also increased intrahemispheric alpha coherence (8-10 Hz).
• Stimulation over FEF or IPS did not produce similar enhancements in alpha rhythms.

Conclusions:

• The angular gyrus (AG) plays a causal role in the modulation of dominant low-frequency alpha rhythms during resting-state conditions.
• Targeted inhibition of AG activity can enhance spontaneous alpha oscillations, providing insights into DMN function.