The notion of using magnetic waves to stimulate biological tissues in attempt to treat diseases can be traced back to over 100 years. However, because of the lack of technical advances, these magnetic waves lacked strength and accuracy and therefore effectiveness and scientific backing.
In 1985, Anthony Barker and colleagues introduced the first modern transcranial magnetic stimulation (TMS) system. This system was based upon physic and technological advances from the 1900s. The physics underling TMS was discovered by Michael Faraday in 1881. He was able to create a magnetic field by running electricity through a coil. Alternating the magnetic field can influence conductors which are close by such as metal or in the case of human tissues, neurons in the brain.
In TMS, when applying the magnetic generated by a coil to the head, the brain will be permeated quite by the Magnetic Field and will affect the neurons. When the magnetic field intensified or changed quick enough, it affects the neurons by depolarizing them and making them release the neurotransmitters that regulate brain functions.