Premium
Impact of transcranial direct current stimulation on structural plasticity of the somatosensory system
Author(s) -
Hirtz Raphael,
Weiss Thomas,
Huonker Ralph,
Witte Otto W.
Publication year - 2018
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.24258
Subject(s) - transcranial direct current stimulation , somatosensory system , neuroscience , precuneus , psychology , fractional anisotropy , white matter , diffusion mri , neuroplasticity , corpus callosum , somatosensory evoked potential , middle frontal gyrus , stimulation , medicine , functional magnetic resonance imaging , magnetic resonance imaging , radiology
Abstract While there is a growing body of evidence regarding the behavioral and neurofunctional changes in response to the longitudinal delivery of transcranial direct current stimulation (tDCS), there is limited evidence regarding its structural effects. Therefore, the present study was intended to investigate the effect of repeatedly applied anodal tDCS over the primary somatosensory cortex on the gray matter (GM) and white matter (WM) compartment of the brain. Structural tDCS effects were, moreover, related to effects evidenced by functional imaging and behavioral assessment. tDCS was applied over the course of 5 days in 25 subjects with concomitant assessment of tactile acuity of the right and left index finger as well as imaging at baseline, after the last delivery of tDCS and at follow‐up 4 weeks thereafter. Irrespective of the stimulation condition (anodal vs. sham), voxel‐based morphometry revealed a behaviorally relevant decrease of GM in the precuneus co‐localized with a functional change of its activity. Moreover, there was a decrease in GM of the bilateral lingual gyrus and the right cerebellum. Diffusion tensor imaging analysis showed an increase of fractional anisotropy exclusively in the tDCS anodal condition in the left frontal cortex affecting the final stretch of a somatosensory decision making network comprising the middle and superior frontal gyrus as well as regions adjacent to the genu of the corpus callosum. Thus, this is the first study in humans to identify structural plasticity in the GM compartment and tDCS‐specific changes in the WM compartment in response to somatosensory learning.