Direct demonstration of the effects of repetitive transcranial magnetic stimulation on the excitability of the human motor cortex.
The effects of repetitive transcranial magnetic stimulation (rTMS; 20 stimuli at 5 Hz at 120% resting motor threshold intensity using a biphasic stimulus pulse) on the excitability of human motor cortex were investigated in two patients who had an electrode implanted into the cervical epidural space. The corticospinal D wave increased in amplitude with successive stimuli, and reached a maximum after three or five pulses. At this stage, the amplitude of the I waves was unchanged, but after a further 10 stimuli an additional I wave was recruited. Both effects were still evident 2 min after the end of the rTMS. The effects are compatible with a short-term increase in cortical excitability during suprathreshold rTMS.
Di Lazzaro
V
V
Institute of Neurology, Università Cattolica, L.go A. Gemelli 8, 00168 Rome, Italy. vdilazzaro@rm.unicatt.it
Oliviero
A
A
Berardelli
A
A
Mazzone
P
P
Insola
A
A
Pilato
F
F
Saturno
E
E
Dileone
M
M
Tonali
P A
PA
Rothwell
J C
JC
D000368:Aged; D004558:Electric Stimulation / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation