Effects of magnetic stimulation of cervical spinal cord on main cerebral arterial blood flow

Magnetic stimulation is a non-invasive method for stimulation of nervous tissue, including cerebral cortex, spinal roots, and peripheral nerves. Neural tissue can easily be stimulated through skin by a stimulator coil. To find a new, noninvasive method alternative to the epidural electrical stimulation, the effect of magnetic stimulation of cervical spinal cord on blood flow in main cerebral artery is investigated. Cervical spinal cord at C2 and C7 levels were stimulated magnetically in healthy male volunteers, age between 17-40, for once, consecutively twice, and consecutively thrice, and blood flow in right middle cerebral artery was measured by transcranial Doppler ultrasonography during and after magnetic stimulation. Mean flow velocity in right middle cerebral artery decreased after magnetic stimulation of high cervical spinal cord, and this change appeared early and was prolonged as number of magnetic stimulation increased. Our results show that magnetic stimulation of high cervical spinal cord increases cerebral blood flow.