Present address: Yale University School of Medicine, Section in Neurobiology, 333 Cedar Street, SHM-I412, New Haven, CT 06510, USA.
Anatomy and physiology of a neural mechanism defining depth order and contrast polarity at illusory contours
Article first published online: 9 OCT 2008
European Journal of Neuroscience
Volume 12, Issue 11, pages 4117–4130, November 2000
How to Cite
Heider, B., Meskenaite, V. and Peterhans, E. (2000), Anatomy and physiology of a neural mechanism defining depth order and contrast polarity at illusory contours. European Journal of Neuroscience, 12: 4117–4130. doi: 10.1046/j.1460-9568.2000.00293.x
- Issue published online: 9 OCT 2008
- Article first published online: 9 OCT 2008
- Received 10 December 1999, revised 20 July 2000, accepted 24 August 2000
- aler monkey;
- figureground segregation;
- occlusion cues;
- visual contour processing;
- V1 and V2
We studied the anatomy and physiology of neurons in monkey visual cortex, which contribute to mechanisms segregating figure and ground at contours based on information provided by occlusion cues. First, we defined the location of neurons sensitive to occluding (illusory) contours. These neurons were found most frequently in the pale cytochrome oxidase stripes of area V2 but rarely in V1. In area V2, they were found in all laminae and with similar frequencies. The few neurons recorded in area V1 concentrated in the upper laminae. Second, we studied the properties and anatomical location of neurons sensitive to occlusion cues (dark and light line-ends, corners). These neurons had end-stopped receptive fields and were found with similar frequencies in both areas. In area V1, they concentrated in the upper laminae. In area V2, they were found in all laminae and cytochrome oxidase stripes. These neurons responded to short stimuli of optimal length (bars, edges) and to stimuli terminating in their receptive field (line-ends, corners). Overall, about half of these neurons detected the direction of such terminations and about 60% were selective for certain types of termination. In summary, our results suggest that in monkey visual cortex, occlusion cues are represented in areas V1 and V2, whereas grouping mechanisms detecting occluding contours concentrate in area V2.