Retinotopic axis specificity and selective clustering of feedback projections from V2 to V1 in the Owl monkey

Amir Shmuel, Maria Korman, Anna Sterkin, Michal Harel, Shimon Ullman, Rafael Malach, Amiram Grinvald

Research output: Contribution to journalArticlepeer-review


Cortical maps and feedback connections are ubiquitous features of the visual cerebral cortex. The role of the feedback connections, however, is unclear. This study was aimed at revealing possible organizational relationships between the feedback projections from area V2 and the functional maps of orientation and retinotopy in area V1. Optical imaging of intrinsic signals was combined with cytochrome oxidase histochemistry and connectional anatomy in owl monkeys. Tracer injections were administered at orientation-selective domains in regions of pale and thick cytochrome oxidase stripes adjacent to the border between these stripes. The feedback projections from V2 were found to be more diffuse than the intrinsic horizontal connections within V1, but they nevertheless demonstrated clustering. The clusters of feedback axons projected preferentially to interblob cytochrome oxidase regions. The distribution of preferred orientations of the recipient domains in V1 was broad but appeared biased toward values similar to the preferred orientation of the projecting cells in V2. The global spatial distribution of the feedback projections in V1 was anisotropic. The major axis of anisotropy was systematically parallel to a retinotopic axis in V1 corresponding to the preferred orientation of the cells of origin in V2. We conclude that the feedback connections from V2 to V1 might play a role in enhancing the response in V1 to collinear contour elements.

Original languageEnglish
Pages (from-to)2117-2131
Number of pages15
JournalJournal of Neuroscience
Issue number8
StatePublished - 23 Feb 2005
Externally publishedYes


  • Cerebral cortex
  • Cortex
  • Cortical maps
  • Cytochrome oxidase
  • Feedback connections
  • Monkey
  • Orientation
  • Orientation map
  • Retinotopic map
  • Retinotopy
  • Striate cortex
  • V1
  • V2
  • Vision
  • Visual cortex

ASJC Scopus subject areas

  • General Neuroscience


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