Less than 15% of the spinothalamic fibers originate from neurons in lamina I in cat.
Lamina I neurons sending their axons into the spinothalamic tract are thought to play a crucial role in nociception, but many spinothalamic fibers do not originate from lamina I neurons. In cat, no consensus exists about what percentage of the spinothalamic tract cells are located in lamina I. After wheat germ agglutinin-conjugated horseradish peroxidase injections that covered large parts of the thalamus, retrogradely labeled cells were plotted and counted in all segments of the spinal cord. Results show that, averaged over all spinal segments, the percentage of labeled lamina I neurons was 4.9-14.2%. These results demonstrate that, in contrast to what is concluded in several previous studies, lamina I in the cat provides only a limited part of the total spinal input to the thalamus.
Klop
E M
EM
Department of Anatomy and Embryology, Faculty of Medical Sciences, Rijksuniversiteit Groningen, Antonius Deusinglaan 1, bldg 3215, P.O. Box 196, 9700 AD Groningen, The Netherlands.
Mouton
L J
LJ
Holstege
G
G
D000818:Animals; D001370:Axonal Transport; D002415:Cats; D002452:Cell Count / Q000379:methods; D005260:Female; D007839:Functional Laterality; D009474:Neurons / Q000502:physiology*; D010146:Pain / Q000473:pathology; D013116:Spinal Cord / Q000166:cytology* / Q000502:physiology; D013133:Spinothalamic Tracts / Q000166:cytology* / Q000502:physiology; D013997:Time Factors; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate / Q000378:metabolism
D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate