Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
, 29 (16), 5202-6

Polarity-sensitive Modulation of Cortical Neurotransmitters by Transcranial Stimulation

Affiliations
Comparative Study

Polarity-sensitive Modulation of Cortical Neurotransmitters by Transcranial Stimulation

Charlotte J Stagg et al. J Neurosci.

Abstract

Transcranial direct current stimulation (tDCS) modulates cortical excitability and is being used for human studies more frequently. Here we probe the underlying neuronal mechanisms by measuring polarity-specific changes in neurotransmitter concentrations using magnetic resonance spectroscopy (MRS). MRS provides evidence that excitatory (anodal) tDCS causes locally reduced GABA while inhibitory (cathodal) stimulation causes reduced glutamatergic neuronal activity with a highly correlated reduction in GABA, presumably due to the close biochemical relationship between the two neurotransmitters.

Figures

Figure 1.
Figure 1.
A, Typical placement of the 2 × 2 × 2 cm voxel within the left sensorimotor cortex. B, GABA optimized 3 T spectrum, showing resonances from NAA, GABA, and Glx. C, Changes in neurotransmitter-to-NAA ratios, given as percentage change from baseline values (mean ± SD). *p < 0.05, **p < 0.01. D, No change in absolute NAA quantification is seen in any stimulus condition. E, F, The decreases seen in both GABA (E) and Glx (F) following stimulation were sustained over the 20 min scanning period.
Figure 2.
Figure 2.
A, Typical 7 T spectrum, showing creatine (Cr), NAA, glutamate (Glu), and glutamine (Gln) resonances. B, Glutamate-to-creatine ratios within the sensorimotor cortex in individual subjects. *p < 0.05.

Similar articles

See all similar articles

Cited by 222 articles

See all "Cited by" articles

Publication types

Substances

Feedback