The morphological basis for binocular and ON/OFF convergence in tree shrew striate cortex.
Journal Article (Journal Article)
We used retrograde and anterograde transport methods and single-cell reconstructions to examine the projection from layer IV to supragranular layers in the tree shrew's striate cortex. We found that neurons in the ON and OFF subdivisions of layer IV (IVa and IVb, respectively) have overlapping terminal fields throughout layers II and III. Despite their overlap, these projections are organized in a highly stratified, mirror-symmetric fashion that respects the vertical position of neurons within each sublayer. Neurons in the middle of layer IV (lower IVa and upper IVb) project to layers IIIa/b, II, and I; neurons located at the edges of layer IV (upper IVa and lower IVb) project to the lower half of layer IIIc; and neurons in the middle of IVa and the middle of IVb project to upper IIIc. The stratified nature of the projections from layer IV to layer III is reminiscent of the pattern of ipsilateral and contralateral eye inputs to layer IV. Inputs from the ipsilateral eye are limited to the edges of layer IV (upper IVa and lower IVb), while those from the contralateral eye terminate throughout the depth of IVa and IVb. Thus, cells near the edges of layer IV should receive strong input from both eyes, while those in the middle of layer IV should receive mostly contralateral input. Taken together, these results suggest that the projections from layer IV to layer III bring together the information conveyed by the ON and OFF pathways, but do so in a way that matches the ocular dominance characteristics for each pathway.
Full Text
Duke Authors
Cited Authors
- Muly, EC; Fitzpatrick, D
Published Date
- April 1992
Published In
Volume / Issue
- 12 / 4
Start / End Page
- 1319 - 1334
PubMed ID
- 1313492
Pubmed Central ID
- PMC6575789
International Standard Serial Number (ISSN)
- 0270-6474
Digital Object Identifier (DOI)
- 10.1523/JNEUROSCI.12-04-01319.1992
Language
- eng
Conference Location
- United States