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Efferent projections of the main and the accessory olfactory bulb in the tree shrew (Tupaia glis).

Publication ,  Journal Article
Skeen, LC; Hall, WC
Published in: J Comp Neurol
March 1, 1977

The projections of the main and the accessory olfactory bulb in the tree shrew (Tupaia glis) have been analyzed with anterograde degeneration and autoradiographic methods for identifying axonal projections, and with the horseradish peroxidase method for identifying the distribution of neurons from which these projections originate. The cytoarchitectonic features of the paleocortical areas which receive projections from the main and the accessory olfactory bulb have also been described. The efferent projections of the accessory olfactory bulb are distributed to the bed nucleus of the accessory olfactory tract, the medial amygdaloid area, the posteromedial cortical amygdaloid area, and to the caudal portion of the bed nucleus of the stria terminalis. In contrast, the efferent projections of the main olfactory bulb are distributed to the anterior olfactory nucleus, the tenia tecta, the olfactory tubercle, the pyriform cortex, the anterior cortical amygdaloid area, the posterolateral cortical amygdaloid area, and to the lateral entorhinal cortex. These observations are consistent with the notion that the olfactory system can be divided into at least two major subsystems: one related to the vomeronasal organ and accessory olfactory bulb, and another related to the main olfactory organ and main olfactory bulb. The paleocortical areas receiving olfactory projections have three basic layers: a superficially positioned plexiform layer (layer I), a pyramidal cell layer (layer II), and a polymorphic cell layer (layer III). The projections of both the main and the accessory olfactory bulb terminate in the outer portion of the plexiform layer (sublamina Ia). Sublamina Ia contains the distal segments of dendrites which originate from a heterogeneous population of neurons located in layer II and, to a lesser extent, layer III. Although the efferent projections of the main and the accessory olfactory bulb are segregated, evidence for a more refined topographical organization within these projections was not obtained. However, the distribution of retrogradely labeled neurons in the main olfactory bulb, following injections of horseradish peroxidase into its various paleocortical targets, indicates that the olfactory projections to these areas may not all originate from the same population of cells.

Duke Scholars

Published In

J Comp Neurol

DOI

ISSN

0021-9967

Publication Date

March 1, 1977

Volume

172

Issue

1

Start / End Page

1 / 35

Location

United States

Related Subject Headings

  • Shrews
  • Proline
  • Olfactory Pathways
  • Olfactory Bulb
  • Neurology & Neurosurgery
  • Nerve Degeneration
  • Leucine
  • Efferent Pathways
  • Cerebral Cortex
  • Axonal Transport
 

Citation

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ICMJE
MLA
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Skeen, L. C., & Hall, W. C. (1977). Efferent projections of the main and the accessory olfactory bulb in the tree shrew (Tupaia glis). J Comp Neurol, 172(1), 1–35. https://doi.org/10.1002/cne.901720102
Skeen, L. C., and W. C. Hall. “Efferent projections of the main and the accessory olfactory bulb in the tree shrew (Tupaia glis).J Comp Neurol 172, no. 1 (March 1, 1977): 1–35. https://doi.org/10.1002/cne.901720102.
Skeen, L. C., and W. C. Hall. “Efferent projections of the main and the accessory olfactory bulb in the tree shrew (Tupaia glis).J Comp Neurol, vol. 172, no. 1, Mar. 1977, pp. 1–35. Pubmed, doi:10.1002/cne.901720102.
Journal cover image

Published In

J Comp Neurol

DOI

ISSN

0021-9967

Publication Date

March 1, 1977

Volume

172

Issue

1

Start / End Page

1 / 35

Location

United States

Related Subject Headings

  • Shrews
  • Proline
  • Olfactory Pathways
  • Olfactory Bulb
  • Neurology & Neurosurgery
  • Nerve Degeneration
  • Leucine
  • Efferent Pathways
  • Cerebral Cortex
  • Axonal Transport