This research was supported by NINCDS Grant NS-09623 to Duke University.
The medial geniculate body of the tree shrew, Tupaia glis II. Connections with the neocortex†
Article first published online: 9 OCT 2004
Copyright © 1978 The Wistar Institute of Anatomy and Biology
Journal of Comparative Neurology
Volume 182, Issue 3, pages 459–493, 1 December 1978
How to Cite
Oliver, D. L. and Hall, W. C. (1978), The medial geniculate body of the tree shrew, Tupaia glis II. Connections with the neocortex. J. Comp. Neurol., 182: 459–493. doi: 10.1002/cne.901820306
D. L. Oliver was supported by NIMH Fellowship 5F01-MH58175 and NIMH Training Grant 5T01-MH08394.
William C. Hall holds an NIMH Research Scientist Career Development Award MH-25734.
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
In this study the temporal cortex of the tree shrew was subdivided on the basis of cytoarchitectonic criteria, and the connections of each subdivision with the thalamus and midbrain were analyzed with retrograde and anterograde techniques.
The results indicate that, with one exception, each subdivision of the medial geniculate body projects to a separate cortical area. The primary auditory cortex receives projections from the ventral nucleus. Surrounding the primary cortex are at least five additional cytoarchitectonically distinct areas which receive projections from the remaining medial geniculate subdivisions. The evidence suggests that there is very little overlap in the projections from each of these geniculate subdivisions. An exception is the projection of the caudal nucleus of the medial division. This subdivision apparently projects to most, if not all, of the cortical target of the medial geniculate body. Although the cortical projections of the caudal nucleus overlap those of the other medial geniculate subdivisions, the laminar distribution of its terminationsin cortex is different. The caudal nucleus projects primarily to layer VI whereas the other subdivisions of the medial geniculate body project primarily to layer IV and the adjacent part of layer III.
Anterograde techniques were also used to study the projections from the cortex back to the thalamus and to the midbrain. The projections to the thalamus precisely reciprocate the thalamocortical connections. The projections to the midbrain are to the same areas which the preceding study (Oliver and Hall, '78) showed give rise to ascending projections to the medial geniculate body. An exception is the central nucleus of the inferior colliculus which apparently does not receive a projection from the temporal cortex.