Imaging human intra-cerebral connectivity by PET during TMS

Peter Fox, Roger Ingham, Mark S. George, Helen Mayberg, Janis Ingham, John Roby, Charles Martin, Paul Jerabek

Research output: Contribution to journalArticlepeer-review

364 Scopus citations


NON-INVASIVE imaging of human inter-regional neural connectivity by positron emission tomography (PET) during transcranial magnetic stimulation (TMS) was performed. The hand area of primary motor cortex (M1) in the left cerebral hemisphere was stimulated with TMS while local and remote effects were recorded with PET. At the stimulated site, TMS increased blood flow (12- 20%) in a highly focal manner, without an inhibitory surround. Remote covariances, an index of connectivity with M1, were also focal. Connectivity patterns established in non-human species were generally confirmed. Excitatory connectivity (positive covariance) was observed in ipsilateral primary and secondary somatosensory areas (S1 and S2), in ipsilateral ventral, lateral premotor cortex (M2) and in contralateral supplementary motor area (SMA). Inhibitory connectivity (negative covariance) was observed in contralateral M1.

Original languageEnglish
Pages (from-to)2787-2791
Number of pages5
Issue number12
StatePublished - 1997
Externally publishedYes


  • Connectivity
  • Human
  • M2
  • Positron emission tomography (PET)
  • Primary motor cortex (M1)
  • S1
  • S2
  • SMA
  • Transcranial magnetic stimulation (TMS)


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