The effect of tourniquet-induced ischemia on somatically evoked cerebral magnetic fields in man

We recorded somatically evoked magnetic fields (SEFs) during tourniquet-induced ischemia in healthy humans. The subjective intensities of the stimuli decreased earlier and more clearly than the amplitudes of the SEF deflections peaking at 60-80 ms. Mixed nerve and sensory nerve responses behaved differently during ischemia. The results indicate that these SEF deflections are transmitted through thick myelinated fibers. Muscle afferents might contribute considerably to mixed nerve SEFs.