Stimulus-response profile during single-pulse transcranial magnetic stimulation to the primary motor cortex

Takashi Hanakawa, Tatsuya Mima, Riki Matsumoto, Mitsunari Abe, Morito Inouchi, Shin Ichi Urayama, Kimitaka Anami, Manabu Honda, Hidenao Fukuyama

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


We examined the stimulus-response profile during single-pulse transcranial magnetic stimulation (TMS) by measuring motor-evoked potentials (MEPs) with electromyographic monitoring and hemodynamic responses with functional magnetic resonance imaging (fMRI) at 3 Tesla. In 16 healthy subjects, single TMS pulses were irregularly delivered to the left primary motor cortex at a mean frequency of 0.15 Hz with a wide range of stimulus intensities. The measurement of MEP proved a typical relationship between stimulus intensity and MEP amplitude in the concurrent TMS-fMRI environment. In the population-level analysis of the suprathreshold stimulation conditions, significant increases in hemodynamic responses were detected in the motor/somatosensory network, reflecting both direct and remote effects of TMS, and also the auditory/cognitive areas, perhaps related to detection of clicks. The stimulus-response profile showed both linear and nonlinear components in the direct and remote motor/somatosensory network. A detailed analysis suggested that the nonlinear components of the motor/somatosensory network activity might be induced by nonlinear recruitment of neurons in addition to sensory afferents resulting from movement. These findings expand our basic knowledge of the quantitative relationship between TMS-induced neural activations and hemodynamic signals measured by neuroimaging techniques.

Original languageEnglish
Pages (from-to)2605-2615
Number of pages11
JournalCerebral Cortex
Issue number11
Publication statusPublished - 2009 Nov
Externally publishedYes


  • Functional MRI
  • Functional connectivity
  • Motor-evoked potentials
  • Multidisciplinary brain mapping
  • Transcranial magnetic stimulation

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience


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