Transcranial Direct Current Stimulation over the Temporoparietal Junction Modulates Posture Control in Unfamiliar...

Area of Science:

• Neuroscience
• Human Motor Control
• Sensory Integration

Background:

• The temporoparietal junction (TPJ) integrates multisensory information (visual, somatosensory, vestibular) crucial for constructing body schema.
• Accurate body schema is essential for maintaining balance, particularly during tasks requiring sensory reweighting, such as standing on unstable surfaces with eyes closed.
• Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can modulate cortical excitability and influence neural processing.

Purpose of the Study:

• To investigate whether transcranial direct current stimulation (tDCS) applied to the temporoparietal junction (TPJ) can modulate dynamic postural control.
• To determine the effects of anodal and cathodal tDCS over the right TPJ on postural control under conditions demanding body schema updates (unstable surface, eyes closed).
• To assess the impact of tDCS on postural control in a condition with intact visual and somatosensory input (stable surface, eyes open).

Main Methods:

• Sixteen healthy participants underwent three sessions of tDCS over the right TPJ: anodal, cathodal, and sham (control), with the order counterbalanced.
• Dynamic postural control was assessed using a stable surface with eyes open and an unstable surface with eyes closed.
• Postural control was evaluated during and after tDCS application.

Main Results:

• Anodal tDCS significantly enhanced postural control on the unstable surface with eyes closed, both during and after stimulation.
• Cathodal tDCS significantly impaired postural control on the unstable surface with eyes closed during stimulation.
• Neither anodal nor cathodal tDCS affected postural control on the stable surface with eyes open.

Conclusions:

• Anodal tDCS over the TPJ may improve postural control by enhancing the integration of non-visual and altered tactile sensory information for body schema updating.
• Cathodal tDCS over the TPJ appears to disrupt the neural processes involved in postural control under challenging sensory conditions.
• tDCS targeting the TPJ holds potential for developing new strategies to improve balance and prevent falls by facilitating adaptive body schema mechanisms.