Pain
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Spinothalamic tract cells in anesthetized monkeys were found to respond to noxious cold stimuli (18/19 cells tested), as well as to noxious heat and noxious mechanical stimuli. Responses to repetition of the noxious cold stimuli after a series of noxious heat stimuli were enhanced. ⋯ Thus, damage to a region of skin can result in enhanced responsiveness of spinothalamic cells to stimuli applied in an undamaged region of the receptive field. The possible relationship between these observations and cutaneous hyperalgesia is discussed.