A thalamic nucleus specific for pain and temperature sensation.
The existence of a posterolateral thalamic relay nucleus for pain and temperature sensation was postulated in 1911, on the basis of the stroke-induced analgesia and thermanaesthesia found paradoxically in patients with thalamic pain syndrome. Pain or temperature sensations can be evoked in humans by electrical stimulation in a vaguely defined region of the posterolateral thalamus. Here we use anterograde tracing and single unit recordings to demonstrate that there is a distinct nucleus in the posterior thalamus of the macaque monkey that receives a dense, topographic input from spinothalamic lamina I neurons and in which almost all neurons are nociceptive- or thermoreceptive-specific. Immunohistochemical staining showed that this nucleus is defined by a dense calbindin-positive fibre plexus in the macaque, so we applied the same staining method to sections of human thalamus. We found a nearly identical fibre plexus localized within a distinct nucleus that is cytoarchitectonically homologous to the lamina I relay nucleus in the macaque thalamus. The stereotaxic coordinates of this nucleus and its location relative to the main somatosensory representation fit clinical descriptions of the pain-producing region in humans. We conclude that this is a specific thalamic nucleus for pain and temperature sensation in both monkey and human.
Craig
A D
AD
Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013.
Bushnell
M C
MC
Zhang
E T
ET
Blomqvist
A
A
D000818:Animals; D001931:Brain Mapping; D064026:Calbindins; D006801:Humans; D008252:Macaca fascicularis; D009474:Neurons / Q000502:physiology; D010146:Pain; D010465:Perception / Q000502:physiology*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013133:Spinothalamic Tracts / Q000502:physiology; D013787:Thalamic Nuclei / Q000502:physiology*; D013697:Thermosensing / Q000502:physiology*
D064026:Calbindins; D064030:S100 Calcium Binding Protein G