Similarity and Diversity in Visual Cortex: Is There a Unifying Theory of Cortical Computation?

Duke University Medical Center, Durham, North Carolina

^* To whom correspondence should be addressed. E-mail: vanhooser{at}neuro.duke.edu.

	Abstract

The cerebral cortex, with its conserved 6-layer structure, has inspired many unifying models of function. However, recent comparative studies of primary visual cortex have revealed considerable structural diversity, raising doubts about the possibility of an all-encompassing theory. This review examines similarities and differences in V1 across mammals. Gross laminar interconnections are relatively conserved. Major functional response classes are found universally or nearly universally. Orientation and spatial frequency tuning bandwidths are quite similar despite an enormous range of visual resolution across species, and orientation tuning is contrast-invariant. Nevertheless, there is considerable diversity in the abundance of different cell classes, laminar organization, functional architecture, and functional connectivity. Orientation-selective responses arise in different layers in different species. Some mammals have elaborate columnar architecture like orientation maps and ocular dominance bands, but others lack this organization with no apparent impact on single cell properties. Finally, local functional connectivity varies according to map structure: similar cells are connected in smooth map regions but dissimilar cells are linked in animals without maps. If there is a single structure/function relation for cortex, it must accommodate significant variations in cortical circuitry. Alternatively, natural selection may craft unique circuits that function differently in each species. DOI: 10.1177/1073858407306597

First published on October 2, 2007, doi:10.1177/1073858407306597

The Neuroscientist 2007;13:639.

A more recent version of this article appeared on December 1, 2007


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				A. Watakabe, Y. Komatsu, O. Sadakane, S. Shimegi, T. Takahata, N. Higo, S. Tochitani, T. Hashikawa, T. Naito, H. Osaki, et al. Enriched Expression of Serotonin 1B and 2A Receptor Genes in Macaque Visual Cortex and their Bidirectional Modulatory Effects on Neuronal Responses Cereb Cortex, August 1, 2009; 19(8): 1915 - 1928. [Abstract] [Full Text] [PDF]