Intrinsic-signal optical imaging reveals crypticocular dominance columns in primary visual cortex of New World owl monkeys
- Department of Psychology, Vanderbilt University, Nashville TN, USA
A significant concept in neuroscience is that sensory areas of the neocortex have evolved the remarkable ability to represent a number of stimulus features within the confines of a global map of the sensory periphery. Modularity, the term often used to describe the inhomogeneous nature of the neocortex, is without a doubt an important organizational principle of early sensory areas, such as the primary visual cortex (V1). Ocular dominance columns, one type of module in V1, are found in many primate species as well as in carnivores. Yet, their variable presence in some New World monkey species and complete absence in other species has been enigmatic. Here, we demonstrate that optical imaging reveals the presence of ocular dominance columns in the superficial layers of V1 of owl monkeys (Aotus trivirgatus), even though the geniculate inputs related to each eye are highly overlapping in layer 4. The ocular dominance columns in owl monkeys revealed by optical imaging are circular in appearance. The distance between left eye centers and right eye centers is approximately 650 μm. We find no relationship between ocular dominance centers and other modular organizational features such as orientation pinwheels or the centers of the cytochrome oxidase blobs. These results are significant because they suggest that functional columns may exist in the absence of obvious differences in the distributions of activating inputs and ocular dominance columns may be more widely distributed across mammalian taxa than commonly suggested.
V1, Ocular dominance, Owl monkey, Visual cortex, Evolution
Peter M. Kaskan, Haidong D. Lu, Barbara C. Dillenburger, Anna W. Roe and Jon H. Kaas (2007). Intrinsic-signal optical imaging reveals crypticocular dominance columns in primary visual cortex of New World owl monkeys. Front. Neurosci. 1:1. 67-75. doi: 10.3389/neuro.01/1.1.005.2007
Received: 15 August 2007;
Paper pending published: 01 September 2007;
Accepted: 01 September 2007;
Published online: 15 October 2007.
Idan Segev, Hebrew University, Israel
Daniel TsÃ‚Â’o, SUNY Upstate Medical University, USA
Roni Azouz, Ben Gurion University, Israel
© 2007 Kaskan, Lu, Dillenburger, Roe and Kaas. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
John H. Kaas, Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA. e-mail: email@example.com