4 Visual Processing in the Primate Brain
Published Online: 26 SEP 2012
Copyright © 2013 John Wiley & Sons, Inc. All rights reserved.
Handbook of Psychology, Second Edition
How to Cite
Baker, C. I. 2012. Visual Processing in the Primate Brain. Handbook of Psychology, Second Edition. 3:4.
- Published Online: 26 SEP 2012
Vision begins with patterns on light landing on the retina of the eye and ends with complex behaviors requiring detailed information about the external world. From the retina onwards, the neural machinery of visual processing is highly specialized with the continuous divergence and convergence of multiple processing streams. By the time signals leave the eye in the optic nerve there are already numerous distinct populations of retinal ganglion cells sending information in parallel to the brain. In the thalamus, the different layers of the lateral geniculate nucleus contain magnocellular, parvocellular, and koniocellular neurons with distinct functional properties that appear to form three parallel pathways. Finally, in the cerebral cortex, the dorsal and ventral processing streams emerging from primary visual cortex project into parietal and temporal cortex conveying spatial and object information, respectively. At the ends of these cortical visual streams, highly complex properties are observed with, for example, regions selectively responding to the sight of specific visual stimuli, such as faces, and single neurons whose properties correlate very closely with perceptual judgments. Ultimately, the information in parallel pathways must be integrated to provide a unified percept, and at all stages of visual processing the segregation of different processing streams is rarely complete with much mixing of signals from different parallel streams. This chapter will follow the visual processing stream in human and nonhuman primates from the retina to high-level cortex highlighting the general principles of organization at anatomical and functional levels.
- parallel processing;
- dorsal stream;
- ventral stream