Increased excitability of the human corticospinal system with hyperventilation

Masud Seyal, Brendan Mull, Blondell Gage

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Objectives: Hyperventilation is effective in inducing generalized spike-wave discharges in patients with absence seizures and improves visual function and normalizes visual function in patients with multiple sclerosis. Hyperventilation increases the excitability of cutaneous and motor axons. In experimental animals, hyperventilation increases excitability of hippocampal neurons. There is however no direct evidence of a hyperventilation-induced increase in neuronal excitability within the central nervous system in humans. In this study we determined the effects of hyperventilation on the human corticospinal system. Methods: We studied the effects of hyperventilation on (1) motor evoked potentials (MEPs) induced by transcranial magnetic pulse stimulation of the motor cortex and (2) F-wave responses. Six subjects were studied. Results: Hyperventilation resulting in an end-tidal pCO2 of 15 mm Hg or less enhanced the amplitude of the MEP and resulted in a shortened onset latency. F-wave amplitudes were enhanced without any change in onset latency. Conclusions: These findings indicate that hyperventilation increases the excitability of the human corticospinal system. A hyperventilation-induced increase in excitability within the central nervous system may account for clinical phenomena such as facilitation of spike-wave discharges. Copyright (C) 1998 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)263-267
Number of pages5
JournalElectroencephalography and Clinical Neurophysiology - Electromyography and Motor Control
Issue number3
StatePublished - Jun 1998


  • Corticospinal excitability
  • F-waves
  • Hyperventilation
  • Transcranial magnetic stimulation

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)


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