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Distributed Hierarchical Processing in the Primate Cerebral Cortex

Felleman, Daniel J. and Van Essen, David C. (1991) Distributed Hierarchical Processing in the Primate Cerebral Cortex. Cerebral Cortex, 1 (1). pp. 1-47. ISSN 1047-3211. doi:10.1093/cercor/1.1.1.

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In recent years, many new cortical areas have been identified in the macaque monkey. The number of identified connections between areas has increased even more dramatically. We report here on (1) a summary of the layout of cortical areas associated with vision and with other modalities, (2) a computerized database for storing and representing large amounts of information on connectivity patterns, and (3) the application of these data to the analysis of hierarchical organization of the cerebral cortex. Our analysis concentrates on the visual system, which includes 25 neocortical areas that are predominantly or exclusively visual in function, plus an additional 7 areas that we regard as visual-association areas on the basis of their extensive visual inputs. A total of 305 connections among these 32 visual and visual-association areas have been reported. This represents 31% of the possible number of pathways it each area were connected with all others. The actual degree of connectivity is likely to be closer to 40%. The great majority of pathways involve reciprocal connections between areas. There are also extensive connections with cortical areas outside the visual system proper, including the somatosensory cortex, as well as neocortical, transitional, and archicortical regions in the temporal and frontal lobes. In the somatosensory/motor system, there are 62 identified pathways linking 13 cortical areas, suggesting an overall connectivity of about 40%. Based on the laminar patterns of connections between areas, we propose a hierarchy of visual areas and of somato sensory/motor areas that is more comprehensive than those suggested in other recent studies. The current version of the visual hierarchy includes 10 levels of cortical processing. Altogether, it contains 14 levels if one includes the retina and lateral geniculate nucleus at the bottom as well as the entorhinal cortex and hippocampus at the top. Within this hierarchy, there are multiple, intertwined processing streams, which, at a low level, are related to the compartmental organization of areas V1 and V2 and, at a high level, are related to the distinction between processing centers in the temporal and parietal lobes. However, there are some pathways and relationships (about 10% of the total) whose descriptions do not fit cleanly into this hierarchical scheme for one reason or another. In most instances, though, it is unclear whether these represent genuine exceptions to a strict hierarchy rather than inaccuracies or uncertainties in the reported assignment.

Item Type:Article
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Van Essen, David C.0000-0001-7044-4721
Additional Information:© 1991 Oxford University Press. We thank R. Andersen and L. Ungerleider for providing preprints of their work, T. Morales-Oblon for typing, K. Tazumi and S. Kallenbach for assistance, and numerous colleagues for valuable discussions and suggestions. We also thank J. Whitehead and K. Tazumi for the fabrication of the physical brain models that were used for analyzing the location of cortical areas. This work was supported by NIH Grant EY02091 and ONR Grant N00014-89-1192 to D.V.E. and by an Alfred P. Sloan research fellowship and a Whitehall Foundation Grant to D.J.F. Readers interested in acquiring copies of the EXCEL database or of the CANVAS cortical hierarchy should communicate with D.J.F.
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-89-1192
Alfred P. Sloan FoundationUNSPECIFIED
Whitehall FoundationUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20120419-132810904
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:30205
Deposited By: Tony Diaz
Deposited On:23 Apr 2012 21:49
Last Modified:28 Sep 2022 21:52

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