QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, July 15, 2009, 29(28):9050-9058; doi:10.1523/JNEUROSCI.1760-09.2009

This Article Full Text Full Text (PDF) Supplemental Data Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Schira, M. M. Articles by Spehar, B. PubMed PubMed Citation Articles by Schira, M. M. Articles by Spehar, B.

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
The Foveal Confluence in Human Visual Cortex

Mark M. Schira,^1,2,3 Christopher W. Tyler,⁴ Michael Breakspear,^2,3,5 and Branka Spehar¹

Schools of ¹Psychology and ²Psychiatry, University of New South Wales, Sydney, New South Wales 2052, Australia, ³The Black Dog Institute, Prince of Wales Hospital, Randwick, New South Wales 2031, Australia, ⁴The Smith-Kettlewell Eye Research Institute, San Francisco, California 94115, and ⁵Queensland Institute of Medical Research and the Royal Brisbane and Woman's Hospital, Herston, Queensland 4006, Australia

Correspondence should be addressed to Mark M. Schira, School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia. Email: mschira{at}science.unsw.edu.au

The human visual system devotes a significant proportion of its resources to a very small part of the visual field, the fovea. Foveal vision is crucial for natural behavior and many tasks in daily life such as reading or fine motor control. Despite its significant size, this part of cortex is rarely investigated and the limited data have resulted in competing models of the layout of the foveal confluence in primate species. Specifically, how V2 and V3 converge at the central fovea is the subject of debate in primates and has remained "terra incognita" in humans. Using high-resolution fMRI (1.2 x 1.2 x 1.2 mm³) and carefully designed visual stimuli, we sought to accurately map the human foveal confluence and hence disambiguate the competing theories. We find that V1, V2, and V3 are separable right into the center of the foveal confluence, and V1 ends as a rounded wedge with an affine mapping of the foveal singularity. The adjacent V2 and, in contrast to current concepts from macaque monkey, also V3 maps form continuous bands (5 mm wide) around the tip of V1. This mapping results in a highly anisotropic representation of the visual field in these areas. Unexpectedly, for the centermost 0.75°, the cortical representations for both V2 and V3 are larger than that of V1, indicating that more neuronal processing power is dedicated to second-level analysis in this small but important part of the visual field.

---

Received April 12, 2009; accepted May 14, 2009.

Correspondence should be addressed to Mark M. Schira, School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia. Email: mschira{at}science.unsw.edu.au

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help