Systems and methods are disclosed to stimulate brain tissue to treat medical conditions such as movement disorders, pain and epilepsy. The disclosed invention uses electrical stimulation of the brain tissue, where vibrational energy from a source is received by an implanted device and converted to electrical energy and the converted electrical energy is used by implanted electrodes to stimulate the pre-determined brain site. The vibrational energy is generated by a controller-transmitter, which could be either implanted or located externally. The vibrational energy is received by a receiver-stimulator, which could be located under the skull, within the brain, on the dura, or in the cranial space close to the brain. As a therapeutic treatment, the implantable receiver-stimulator stimulates the brain sites that are effective in altering brain activity.