Nociceptive and thermoreceptive lamina I neurons are anatomically distinct.
Pain and temperature stimuli activate neurons of lamina I within the dorsal horn of the spinal cord, and although these neurons can be classified into three basic morphological types and three major physiological classes, earlier studies did not establish a structure/function correlation between their morphology and their physiological responses. We recorded and intracellularly labeled 38 cat lamina I neurons. All 12 fusiform cells were nociceptive-specific, responsive only to pinch and/or heat. All 11 pyramidal cells were thermoreceptive-specific, responsive only to innocuous cooling. Of ten multipolar cells, six were polymodal, responsive to heat, pinch and cold, and four were nociceptive-specific. Five unclassified cells had features consistent with this pattern. These results support the view that central pain and temperature pathways contain anatomically discrete sets of modality-selective neurons.
Han
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ZS
Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013, USA.
Zhang
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ET
Craig
A D
AD
D000818:Animals; D002415:Cats; D003080:Cold Temperature; D004594:Electrophysiology; D005260:Female; D006358:Hot Temperature; D008297:Male; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D010812:Physical Stimulation; D017966:Pyramidal Cells / Q000502:physiology; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D013823:Thermoreceptors / Q000502:physiology*