The response characteristics of neurons at the origin of the postsynaptic dorsal column (PSDC) pathway were determined in unanesthetized, decerebrated, spinalized rats. Sixty-four percent of PSDC neurons responded only to innocuous mechanical stimuli. Thirty-six percent responded to innocuous stimuli but were more powerfully activated by noxious pinch, Ninety-three percent of the tested PSDC neurons were not activated by any of several intensities of sustained, repeated noxious heating of their receptive fields. The failure of pinch-responssive PSDC cells to respond to thermal stimulation, even in sensitized skin, suggests that they do not receive a functionally significant input from C polymodal nociceptors, heat nociceptors, or mechanical-heat nociceptors. We conclude, therefore that the postsynaptic dorsal column pathway is not importantly involved in nociception in the rat.
- nociceptor input
- postsynaptic dorsal column pathway
- thermal stimulation