Journal of neurophysiology
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Extracellular recordings were made from 81 primate spinothalamic (STT) neurons in the L7-S1 segments of the spinal cord. The majority of the sample was recorded from within laminae IV-V. The temporal features of the responses to noxious thermal stimulation of glabrous and hairy skin were studied in an attempt to determine whether natural groupings of STT neurons could be identified on the basis of response time course alone and whether these groups were skin type dependent. ⋯ With one exception, no dependence upon the type of skin that was stimulated was found in the latencies of either the LP2 class or the shorter latency SP2 class. Prior conditioning of the skin with a 30-s thermal pulse of 51-55 degrees C led to a suppression of the early response phase and an enhancement of the late phase in nearly all cases examined (n = 11). This pattern was independent of skin type.(ABSTRACT TRUNCATED AT 400 WORDS)
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Extracellular recordings were made from 81 primate spinothalamic (STT) neurons in the L7-S1 segments of the spinal cord. The majority of the sample was recorded from within laminae IV-V. The responses of STT neurons to noxious thermal stimulation of glabrous and hairy skin were studied in an attempt to identify a neural substrate for the differences in thermal sensation evoked by noxious stimulation of these two types of skin. ⋯ These alterations in population behavior may underly the alterations in sensory quality in humans that occur in these temperature ranges when stimulating hairy and glabrous skin. The possible roles of the thermally and mechanically based classes in thermal intensity and quality coding were examined. Within the lower intensity ranges (less than 49-51 degrees C), the Cmnr and Dmnr classes appeared to be best suited to intensity coding.(ABSTRACT TRUNCATED AT 400 WORDS)