Transcranial cerebellar direct current stimulation: Effects on brain resting state oscillatory and network activity

Area of Science:

• Neuroscience
• Neurophysiology
• Brain Stimulation

Background:

• The cerebellum's role extends beyond motor control, interacting with cortical networks.
• Non-invasive brain stimulation techniques like transcranial cerebellar direct current stimulation (tcDCS) offer a method to probe these interactions.
• Understanding cerebellar-cortical interplay is crucial for neurological disorder research.

Purpose of the Study:

• To investigate the effects of unilateral tcDCS on electroencephalographic (EEG) oscillatory activity and cortical network organization.
• To differentiate the impact of anodal versus cathodal tcDCS on resting-state brain function.
• To explore the functional connectivity changes between cerebellar and cerebral networks.

Main Methods:

• Utilized unilateral tcDCS with the active electrode over the right cerebellar hemisphere.
• Recorded electroencephalographic (EEG) data at resting state under anodal, cathodal, and sham stimulation conditions.
• Analyzed spectral (de)synchronization and functional connectivity in various frequency bands.

Main Results:

• Anodal tcDCS induced a lateralized gamma band synchronization over the sensorimotor area.
• Increased network segregation in sensory-motor rhythms and enhanced interhemispheric communication in the gamma band were observed post-anodal stimulation.
• Cathodal tcDCS did not produce significant changes in EEG oscillatory activity or network organization compared to sham stimulation.

Conclusions:

• Anodal tcDCS can modulate cortical network organization and functional connectivity, particularly in sensorimotor areas and gamma band activity.
• The findings highlight the specific influence of anodal stimulation on cerebellar-cortical interactions.
• Cathodal tcDCS appears to have a negligible effect on these measures under the tested conditions, suggesting polarity-dependent neuromodulation.