Ke. Schmidt et al., THE PERCEPTUAL GROUPING CRITERION OF COLINEARITY IS REFLECTED BY ANISOTROPIES OF CONNECTIONS IN THE PRIMARY VISUAL-CORTEX, European journal of neuroscience, 9(5), 1997, pp. 1083-1089
An important step in the processing of visual patterns is the segmenta
tion of the retinal image. Neuronal responses evoked by the contours o
f individual objects need to be identified and associated for further
joint processing. These grouping operations are based on a number of G
estalt criteria. Here we report that connections in the visual cortex
of the cat exhibit a highly significant anisotropy, preferentially lin
king neurons activated by contours that have similar orientation and a
re aligned colinearly. These anatomical data suggest a close relation
between the perceptual grouping criterion of colinearity and the topol
ogy of tangential intracortical connections. We propose that tangentia
l intracortical connections support perceptual grouping by modulating
the saliency of distributed cortical responses in a context-dependent
way. The present data are compatible with the hypothesis that the crit
eria for this grouping operation are determined by the architecture of
the tangential connections.