Gender-specific Modulation of Short-Term Neuroplasticity in the Visual Cortex Induced by Transcranial Direct Current Stimulation

Vis Neurosci. Jan-Feb 2008;25(1):77-81. doi: 10.1017/S0952523808080097.

Abstract

Transcranial direct current stimulation (tDCS) is a non-invasive method of modulating levels of cortical excitability. In this study, data gathered over a number of previously conducted experiments before and after tDCS, has been re-analyzed to investigate correlations between sex differences with respect to neuroplastic effects. Visual evoked potentials (VEPs), phosphene thresholds (PTs), and contrast sensitivity measurements (CSs) are used as indicators of the excitability of the primary visual cortex. The data revealed that cathodally induced excitability effects 10 min post stimulation with tDCS, showed no significant difference between genders. However, stimulation in the anodal direction revealed sex-specific effects: in women, anodal stimulation heightened cortical excitability significantly when compared to the age-matched male subject group. There was no significant difference between male and female subjects immediately after stimulation. These results indicate that sex differences exist within the visual cortex of humans, and may be subject to the influences of modulatory neurotransmitters or gonadal hormones which mirror short-term neuroplastic effects.

MeSH terms

  • Adult
  • Analysis of Variance
  • Contrast Sensitivity / radiation effects*
  • Electric Stimulation / methods*
  • Evoked Potentials, Visual / radiation effects
  • Female
  • Humans
  • Male
  • Neuronal Plasticity / radiation effects*
  • Phosphenes / radiation effects
  • Photic Stimulation / methods
  • Sex Characteristics*
  • Time Factors
  • Visual Cortex / radiation effects*