Cerebellar Transcranial Direct Current Stimulation Reconfigures Brain Networks Involved in Motor Execution and Mental...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuromodulation

Background:

• Transcranial direct current stimulation (tDCS) is increasingly used to modulate cerebellar activity.
• tDCS effects are polarity-specific and mediated via the dentato-thalamo-cortical pathway.
• Previous research indicates tDCS of the cerebellum dynamically affects resting-state networks.

Purpose of the Study:

• To test the hypothesis that tDCS reconfigurates brain networks involved in motor execution (ME) and motor mental imagery (MMI).
• To investigate tDCS-induced reconfiguration of ME- and MMI-related networks using fMRI.
• To explore the role of the cerebellum in modulating cognitive networks.

Main Methods:

• A randomized, sham-controlled design involving 21 healthy volunteers.
• Application of real anodal tDCS (1.5 mA, 20 min) or sham tDCS over the right cerebellum.
• Simultaneous fMRI recording during overt motor execution (drawing circles) and motor mental imagery.

Main Results:

• Real tDCS, compared to sham, reconfigured functional links between intrinsic networks, notably the central executive network and salience network, in relation to cerebellar lobule VII.
• The right cerebellum influenced prefrontal and anterior cingulate areas during both ME and MMI, enhancing overt motor performance.
• During MMI, cerebellar tDCS modulated the default-mode network and associative visual areas.

Conclusions:

• Cerebellar tDCS is a novel tool for modulating cognitive brain networks controlling motor execution and mental imagery.
• This neuromodulation technique tunes the activity of remote cortical regions.
• The findings open new possibilities for non-invasive neuromodulation in disorders affecting cerebello-thalamo-cortical pathways.