How TMS works

One of the great success strategies of neuroscience has been to correlate mental illness with altered brain activities. In depressed patients for example, the left dorso-lateral pre-frontal cortex (a region of the brain corresponding to the top of the forehead) has lowered metabolic activity. It is known that this region is linked strongly to the deeper-lying limbic system that regulates mood and emotion.

Neuroscientists now believe that the magnetic stimulation of the left side pre-frontal cortex enhances its activity, and increases blood flow to the stimulated area. These effects in turn boost the activity of the limbic system and lift mood: the changes are not instantaneous – typically five TMS treatments a week over several weeks are needed to effect a sustained change in mood and mental disposition.

TMS research done on animals suggests that considerably more than blood flow stimulation and enhanced cortical electrical activity is induced by TMS treatments. Some neuroscientists suggest that the changes brought about by TMS are caused by alterations in neurotransmitter activity, alteration of behavior at the synaptic level and even by switching on gene activity. The growth of nerve cells and the secretion of neuro-protective molecules boosted by TMS treatments may also enhance recovery from pathological states.