Anodal transcranial direct current stimulation does not alter GABA concentration or functional connectivity in the...

Area of Science:

• Neuroscience
• Neuroimaging
• Rehabilitation Science

Background:

• Anodal direct current stimulation (a-tDCS) is a potential therapy for vision disorders like amblyopia.
• The neural mechanisms of a-tDCS on the visual cortex are not well understood.
• In the motor cortex, a-tDCS reduces gamma-aminobutyric acid (GABA), influencing neuroplasticity.

Purpose of the Study:

• To investigate if a-tDCS applied to the visual cortex alters local GABA concentration.
• To assess the impact of a-tDCS on visual cortex resting-state functional connectivity.
• To explore the relationship between visual cortex GABA and binocular rivalry dynamics.

Main Methods:

• Fourteen participants with normal vision underwent two sessions of real or sham a-tDCS.
• Magnetic resonance spectroscopy (MRS) measured GABA and glutamate-glutamine (Glx) concentrations.
• Task-free functional MRI (fMRI) assessed resting-state functional connectivity.

Main Results:

• No significant changes in GABA or Glx concentrations were observed between sessions.
• Resting-state functional connectivity in the visual cortex remained unaffected by a-tDCS.
• No clear association was found between binocular rivalry dynamics and GABA levels.

Conclusions:

• a-tDCS applied to the visual cortex does not appear to modulate GABA concentration.
• The findings suggest that a-tDCS mechanisms in the visual cortex may differ from those in the motor cortex.
• Further research is needed to elucidate the specific neural effects of a-tDCS on visual processing.