This time I had a "brain pacemaker" installed, which uses wires and a battery source to stimulate deep parts of the brain with electric currents.

CNN: 'I had brain surgery while I was awake'

An epilepsy patient could have a pacemaker for the brain: An electrode array like Donoghue's could pick up signals that lead to a seizure, and a stimulator could fire and reset the brain before the seizure takes hold.

FORBES: Technology

Unlike stimulation for treatment of Parkinson's or other issues, in which the brain is stimulated continuously or repeatedly with an implanted pacemaker-like device, memory in the latest study was improved by a single burst of current when administered in the right location as memories were being formed, according to Dr. Fried.

WSJ: Memory Gets Jolt in Brain Research