Functional magnetic resonance imaging of motor activation in the human cervical spinal cord.

Functional magnetic resonance imaging (fMRI) at 1.5 T of a 30-mm segment of the human spinal cord, centered at the seventh cervical cord segment, showed mean blood-oxygenation-dependent contrast changes in image intensity of 4.8% associated with a unilateral hand-closing task in normal human volunteers. The observed locale of activation in the ipsilateral intermediate and ventral gray matter of the cervical cord contains motoneurons, corticospinal axonal terminations from the hand area of the brain motor cortex, and capillaries supplying the spinal neurons. This noninvasive observation of focal activation within the human spinal cord is consistent with neuronal cooperation over more than one cord segment and suggests that fMRI of the human central nervous system may have wider clinical applications outside of the brain.