MRI study of human brain exposed to weak direct current stimulation of the frontal cortex
M A Nitsche1, L Niehaus, K T Hoffmann
1Department of Clinical Neurophysiology, Georg-August-University, Robert-Koch-Str. 40, 37075 Goettingen, Germany. mnitsch1@gwdg.de
Objective:
To determine whether weak transcranial direct current stimulation (tDCS), which is an interesting new tool inducing prolonged cortical excitability shifts in humans, induces brain edema, disturbance of the blood-brain barrier or structural alterations of the brain detectable by magnetic resonance imaging (MRI).
Methods:
In 10 healthy individuals, tDCS, which is known to alter cortical excitability for about 1 h, was applied over motor and pre-frontal cortices. contrast-enhanced t1-, t2-, and diffusion-weighted mri was performed immediately before, 30 and 60 min after tdcs.
Results:
MRI performed 30 and 60 min after tDCS did not show pathological signal alterations in pre- and post-contrast-enhanced T1-weighted and diffusion-weighted MR sequences.
Conclusions:
tDCS protocols which are known to result in cortical excitability changes persisting for an hour after stimulation do not induce brain edema or alterations of the blood-brain barrier or cerebral tissue detectable by MRI.
Significance:
These results deliver further evidence for the safety of the currently applied tDCS protocols in humans.
