The organization of lateral ventromedial thalamic connections in the rat: a link for the distribution of nociceptive signals to widespread cortical regions.

Abstract:

:We have used several anatomical tracing techniques to study the organization of the lateral ventromedial thalamic nucleus in the rat, a region that is selectively activated by cutaneous nociceptive inputs from any part of the body. The lateral ventromedial thalamic projections are organized as a widespread dense band covering mainly layer I of the dorsolateral anterior-most aspect of the cortex. This band diminishes progressively as one moves caudally, disappearing completely at 1mm caudal to bregma level. These widespread projections contrast with the circumscribed projections to the deep layers of the primary somatosensory and insular cortices from the adjacent ventral posteromedial and ventroposterior parvicellular thalamic regions, respectively. Injections into the lateral part of the ventromedial thalamic nucleus of an anterograde/retrograde tracer showed that the cortical layer I areas showing the densest projections from this thalamic region also contain the greatest number of retrogradely labeled cells in cortical layers V and VI. The same injections retrogradely labeled numerous cells which were confined to the dorsal subnucleus reticularis dorsalis in an area that contains a concentration of neurons with widespread nociceptive convergence. Finally, the lateral part of the ventromedial thalamic nucleus was also differentially labeled following a topical application of tetramethylrhodamine-labeled dextran on the dorsolateral anterior cortex. These findings suggest that lateral ventromedial thalamic neurons could be part of a spino-reticulo-thalamo-cortical network that allows signals of pain from any part of the body surface to spread across widespread cortical areas.

journal_name

Neuroscience

journal_title

Neuroscience

authors

Desbois C,Villanueva L

doi

10.1016/s0306-4522(00)00537-6

keywords:

subject

Has Abstract

pub_date

2001-01-01 00:00:00

pages

885-98

issue

4

eissn

0306-4522

issn

1873-7544

pii

S0306-4522(00)00537-6

journal_volume

102

pub_type

杂志文章