Comparison of human transcallosal responses evoked by magnetic coil and electrical stimulation

doi:10.1016/0168-5597(89)90030-0

Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section

Volume 74, Issue 6, November–December 1989, Pages 417-424

https://doi.org/10.1016/0168-5597(89)90030-0 Get rights and content

Abstract

Human transcallosal responses (TCRs) were elicited by focal magnetic oil (MC) stimulation of homologous sites in contralateral frontal cortex and compared with those to focal anodic stimulation. With MC stimulation, the TCR consisted of an initially positive wave with an onset latency of 8.8–12.2 msec, a duration of 7–15 msec, and an amplitude which reached up to 20 μV, sometimes followed by a broad low amplitude negative wave. With anodic stimulation, a similar response was obtained in which the positive wave was similar in latency and maximum amplitude, but had a greater duration. With anodic stimulation, not only was the TCR threshold below that for contralateral movement, but it reached substantial size at intensities below motor threshold. With MC stimulation, contralateral arm movement and scalp corticomotor potentials were observed when the MC was displaced posteriorly towards the central sulcus. Unlike with anodic stimulation, the MC evoked TCR was usually not preceded by a prominent EMG potential from temporalis muscle and was not associated with subject discomfort.

The TCR provides unique information concerning the functional integrity of callosal projection neurons, their axons and transsynaptic processes in recipient cortex. This information may prove useful in the evaluation of intrinsic cerebral mechanisms and in establishing cortical viability.

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Comparison of human transcallosal responses evoked by magnetic coil and electrical stimulation

Abstract

Electroenceph. clin. Neurophysiol.

Brain Res.

The spread of activity in the cerebral cortex

J. Physiol. (Lond.)

Cerebral cortical responses to contralateral transcranial stimulation in humans

J. Physiol. (Lond.)

Human cerebral cortical responses to contralateral transcranial stimulation

Neurosurgery

Focal cerebral and peripheral nerve stimulation in man with the magnetic coil

J. Physiol. (Lond.)

Transcallosal responses elicited by focal magnetic coil stimulation of human frontal cortex

J. Physiol. (Lond.)

Hemispheric asymmetries in the visual cortical evoked potential as a function of stimulus location

Psychophysiology

Magnetic stimulation of the human brain

J. Physiol. (Lond.)

Transcranial magnetic stimulation of the human brain: responses in muscles supplied by cranial nerves

Exp. Brain Res.

Cortical response to activity of callosal neurons

J. Neurophysiol.

Somatomotor and somatosensory evoked responses: median nerve stimulation in man

Arch. Neurol.