Functional magnetic resonance imaging of the human cervical spinal cord with stimulation of different sensory dermatomes

Functional MR imaging (fMRI) of the cervical spinal cord was carried out in 13 healthy volunteers. A cold stimulus was applied, at different times, to three different sensory dermatome regions overlying the right hand and forearm: the thumb side of the palm, the little finger side of the palm, and the forearm below the elbow. Stimulation of these areas is expected to involve the 6th, 8th, and 5th cervical spinal cord segments respectively. Whereas true activations are expected to correspond to the region being stimulated, false activations such as arising from noise and motion, are not. The results demonstrate that clustering of active pixels into groups based on their intensity time courses discriminates false activations from true activations. Following clustering, the distribution of activity observed with fMRI matched the expected regions of neuronal activation with the different areas of stimulation on the hand and forearm.