title: Direct and indirect activation of human corticospinal neurons by transcranial magnetic and electrical stimulation.
abstract: Corticospinal volleys and surface electromyographic (EMG) responses evoked by magnetic and electrical transcranial stimulation were recorded simultaneously in three conscious human subjects. For magnetic stimulation, the figure-of-eight coil was held on the hand motor area either with the induced current through the brain flowing in a postero-anterior direction (P-A stimulation) or in a latero-medial direction (L-M stimulation). For electrical stimulation, the anode was placed 7 cm lateral to the vertex and cathode at the vertex (anodal stimulation). The P-A stimulation that was generally used preferentially evoked I waves, whereas the L-M and anodal stimulation preferentially evoked D wave. The results suggested that the mode of activation by transcranial magnetic stimulation altered, depending on its current direction, and the difference between P-M magnetic and electrical stimulation can be explained by the context of the D and I hypothesis.
authors: Department of Orthopedic Surgery, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
authors: H
authors: H
authors: Nakamura
authors: H
authors: H
authors: Kitagawa
authors: Y
authors: Y
authors: Kawaguchi
authors: H
authors: H
authors: Tsuji
mesh_terms: D000368:Aged; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D011712:Pyramidal Tracts / Q000166:cytology*