iTBS over the left hV6A enhances PPC-PPC functional connectivity during reaching tasks: an EEG study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• The posterior parietal cortex-primary motor cortex (PPC-M1) network is crucial for goal-directed actions and visuomotor integration.
• Human area V6A (hV6A), within the medial PPC, plays a key role in targeting during reaching movements.
• Understanding the modulation of PPC-M1 functional connectivity is vital for advancing motor control research.

Purpose of the Study:

• To investigate the effects of intermittent theta burst stimulation (iTBS) on functional connectivity and network efficiency in the PPC.
• To explore the role of left hV6A in modulating visuomotor transformations during reaching tasks.
• To assess changes in brain network dynamics following targeted neuromodulation.

Main Methods:

• Utilized Electroencephalography (EEG) to record brain activity during right-hand reaching tasks.
• Applied real or sham iTBS to the left hV6A based on individual MRI neural navigation.
• Measured resting-state and task-based EEG, alongside a Stroop test for attention assessment, before and after stimulation.

Main Results:

• Real iTBS of the left hV6A significantly increased interhemispheric functional connectivity in the medial PPC within the alpha band during reaching.
• Alpha and beta band small-worldness significantly increased during reaching tasks post-iTBS, indicating enhanced network efficiency.
• Sham iTBS did not produce significant changes in functional connectivity or network efficiency.

Conclusions:

• Left hV6A stimulation via iTBS enhances functional connectivity and network efficiency in the bilateral PPC during reaching.
• These findings highlight the left hV6A as a potential neuromodulatory target for improving spatial orienting and motor functions.
• Targeted modulation of hV6A may offer therapeutic benefits for individuals with motor control deficits.