Neurostimulation

Neurostimulation is the purposeful modulation of the nervous system's activity using invasive (e.g. microelectrodes) or non-invasive means (e.g. transcranial magnetic stimulation or transcranial electric stimulation, tES, such as tDCS or transcranial alternating current stimulation, tACS). Neurostimulation usually refers to the electromagnetic approaches to neuromodulation. Neurostimulation technology can improve the life quality of those who are severely paralyzed or have profound losses to various sense organs, as well as for permanent reduction of severe, chronic pain which would otherwise require constant (around-the-clock), high-dose opioid therapy (such as neuropathic pain and spinal-cord injury). It serves as the key part of neural prosthetics for hearing aids, artificial vision, artificial limbs, and brain-machine interfaces. In the case of neural stimulation, mostly an electrical stimulation is utilized and charge-balanced biphasic constant current waveforms or capacitively coupled charge injection approaches are adopted. Alternatively, transcranial magnetic stimulation and transcranial electric stimulation have been proposed as non-invasive methods in which either a magnetic field or transcranially applied electric currents cause neurostimulation. Brain stimulation has potentials to treat some disorders such as epilepsy. In this method, scheduled stimulation is applied to specific cortical or subcortical targets. There are available commercial devices that can deliver an electrical pulse at scheduled time intervals. Scheduled stimulation is hypothesized to alter the intrinsic neurophysiologic properties of epileptic networks. The most explored targets for scheduled stimulation are the anterior nucleus of the thalamus and the hippocampus. The anterior nucleus of the thalamus has been studied, which has shown a significant seizure reduction with the stimulator on versus off during several months after stimulator implantation. Moreover, the cluster headache (CH) can be treated by using a temporary stimulating electrode at sphenopalatine ganglion (SPG).