Table 4.
Changes in the brain networks by anodal tDCS.
| Study | Subject (n) | Stimulation intensity (mA) | Stimulation duration (min) | Stimulation site | Pharmacological intervention | Results |
|---|---|---|---|---|---|---|
| Clark et al. (2011) | Healthy subjects (7) | 2 | 30 | Right parietal lobe | None | Increased glutamic acid concentrations under anode electrodes. |
| Polanía et al. (2011) | Healthy subjects (13) | 1 | 10 | Left primary motor cortex | None | Reduced direct functional connectivity to gray matter away from the left somatomotor cortex (SM1). Enhanced functional connectivity between the premotor area and the parietal lobe via the left SM1. Enhanced functional connectivity between the left posterior cingulate cortex and the right DLPFC. |
| Stagg et al. (2014) | Healthy subjects (10) | 1 | 10 | Left primary motor cortex | None | Negative correlation between GABA concentrations and functional connectivity of the resting motor network. Decreased GABA concentrations. Enhanced the functional connectivity of the resting motor network. |
| Hunter et al. (2015) | Healthy subjects (9) | 2 | 30 | Right parietal lobe | None | Increased glutamic acid concentrations under anode electrodes. Enhanced the functional connectivity of the superior parietal-inferior parietal-left frontal parietal-cerebellum. Suppressed the functional connectivity of the anterior cingulate-basal ganglia. |
| Bachtiar et al. (2015) | Healthy subjects (12) | 1 | 20 | Left primary motor cortex | None | Decreased GABA concentrations. Enhanced the functional connectivity of the resting motor network. Decreased GABA concentrations and enhanced functional connectivity of motor networks by different mechanisms. |
| Fonteneau et al. (2018) | Healthy subjects (32) | 2 | 20 | Both dorsolateral prefrontal cortex (DLPFC) | None | Increased dopamine release in the striatum. |
| Wörsching et al. (2018) | Healthy subjects (28) | 2 | 20 | Right DLPFC | None | Decreased resting-state fMRI connectivity in a medial part of the left prefrontal cortex. Decreased regional brain activity during a delayed-response working-memory (DWM) retrieval. Faster responses to the DWM task. |
| Fukai et al. (2019) | Healthy subjects (20) | 2 | 26 | Left DLPFC | None | Increased dopamine release in the right ventral striatum. |
| Bulubas et al. (2019) | Patients with major depression (52) | 2 | 30 (22 sessions) | Left DLPFC | Escitalopram 20 mg/day |
Association between larger gray matter volumes and depression improvement assessed over a treatment period of 10 weeks. |