Not tDCS but these are certainly exciting times. Some breakthroughs heading our way.  Paper: Oscillatory dynamics coordinating human frontal networks in support of goal maintenance [Paywall]

The anterior (blue) and posterior (orange) regions of the prefrontal cortex sync up to communicate cognitive goals to one another. (Image courtesy of Bradley Voytek)

Voytek and fellow researchers at UC Berkeley’s Helen Wills Neuroscience Institute measured electrical activity in the brains of cognitively healthy epilepsy patients. They found that, as the mental exercises became more demanding, theta waves at 4-8 Hertz or cycles per second synchronized within the brain’s frontal lobe, enabling it to connect with other brain regions, such as the motor cortex.
“In these brief moments of synchronization, quick communication occurs as the neurons between brain regions lock into these frequencies, and this measure is critical in a variety of disorders,” said Voytek, an assistant professor of cognitive science at UC San Diego who conducted the study as a postdoctoral fellow in neuroscience at UC Berkeley.

Source: It don’t mean a thing if the brain ain’t got that swing | UC Berkeley News
See Also: voyteklab.com