Figure 1.

Electrolytic and demyelinating lesions of the ventrolateral spinal white matter. a, A representative Nissl-stained section illustrating the focal gliosis induced 3 d after an electrolytic lesion of the ventrolateral spinal white matter (eSTTx), the region of the spinothalamic tract, at the T8 or T9 vertebral level. Drawings of the injury sites in 15 rats used for pain behavior assessment, as assessed post hoc at 31 d postlesion. Animals in which the lesion site extended beyond the ventrolateral quadrant white matter were not analyzed. b, Visualization of LPC-induced demyelination in ventrolateral spinal cord with myelin staining 14 d after injection (left). Immunostaining with an antibody against neurofilament protein 200 in an adjacent section, showing that the LPC injection does not damage spinothalamic tract axons (right).