EXPERIMENTAL, DIAGNOSTIC, AND THERAPEUTIC APPLICATION OF REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION (RTMS) WITH A FOCUS ON MOTOR CORTEX STIMULATION

Repetitive transcranial magnetic stimulation (rTMS) of the brain is a new tool with an expanding range of applications, In this overview, st imulation of the motor cortex is used as a model for an analysis of th e transcranially activated cortical mechanisms. The following motor ef fects of rTMS are analyzed: increment of stimulation effects, afterdis charges of emg-responses, flip-flop of excitatory and inhibitory stimu lation effects, cortical stimulus spread. Long term depression (LTD) a nd long term potentiation (LTP) of cortical excitability may be associ ated with probable therapeutic effects of rTMS in epilepsy or Parkinso n's disease while the basis of beneficial effects in depression is sti ll unknown. The observed changes of cerebral perfusion are associated with neuronal activation. The interference of rTMS with complex brain functions such as speech may be used to detect the speech-competent he misphere. To elicit an epiletic fit is considered to be the main risk of rTMS, It can be reduced by choosing combinations of stimulus parame ters (frequency, intensity, train duration, inter-train-interval, numb er of trains) within defined limits.