Transcranial Magnetic Stimulation
A technique that uses rapidly changing magnetic fields to excite neurons in the biont brain. Weak electric currents are induced in the brain or other nervous tissue to trigger brain activity and transfer data. This allows non-invasive interfacing between the subject's brain and external processing devices.
Non-invasive neural interfacing using magnetic fields
Transcranial stimulation was developed as a medical treatment for various neurological ailments in the Information Age, but was adapted for use as a non-invasive neural interface soon after. TMS was used to control external devices, access data, and to induce auditory and visual stimuli. The rapidly changing magnetic fields required for this technology were at first produced by quite bulky helmets, but modern TMS equipment is inconspicuous and generally hidden in a headband, stylish hat, or sometimes a wig (often deliberately outlandish in style). Certain styles of cosmetic TMS equipment can be applied to the skin externally, and may or may not be detectable.
TMS and other non-invasive technologies are today popular among modosophonts who prefer not to allow extraneous devices to enter their bodies; some cultures actively encourage non-invasive technology. Coupled with Superconducting Quantum Interference Devices (or more advanced remote sensing devices) to detect changes in neural states non-intrusively, TMS allows a two way flow of information to and from a biont brain and nervous system. The rate of data transfer is not as rapid as that allowed by Direct Neural Interfacing or Direct Cranial interfacing, but can be perfectly adequate for many applications.
One early application was as part of total-immersion gear to enable humans access to virtual reality environments, long before the first successful uploading technology was available. The first TMS helmets capable of high-resolution immersion were invented in the 150s AT and the technology was continously developed until 910, with the production of the G-Interface Mark 5, developed by Deimos Cybersystems. In the present era, these early TMS helmets are extremely rare and prized antiquities, although modern nanocopies are almost completely indistinguishable from the originals.
TMS techniques are sometimes used remotely to stimulate the nervous systems of subjects without their knowledge, however this process is difficult to achieve due to limits on the controllability of magnetic fields at a distance.