RT Journal Article
SR Electronic
T1 Analysis of discontinuity in visual contours in area 19 of the cat
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 1131
OP 1143
DO 10.1523/JNEUROSCI.08-04-01131.1988
VO 8
IS 4
A1 H Saito
A1 K Tanaka
A1 Y Fukada
A1 H Oyamada
YR 1988
UL http://www.jneurosci.org/content/8/4/1131.abstract
AB Previous ablation studies have suggested that area 19 of the cat plays an important role in pattern discrimination. To clarify the functional roles unique to area 19, we studied the receptive-field properties of cells in area 19 and compared them with those of cells in area 17. Recordings were made of anesthetized and immobilized animals. The majority (72%) of the cells in area 17 responded maximally to an elongated bar at a particular orientation, while they responded only weakly or not at all to a small spot (elongation-requiring cells). In contrast, more than half (63%) of the cells in area 19 showed a good response to a nonoriented small stimulus moving in any direction (dot- responsive cells). Two-thirds of the dot-responsive cells in area 19 failed to respond when the moving slit was elongated to more than some length in any orientation. These dot-responsive cells of the “inhibited- by-length” type responded strongly to the end of a long bar, and many of them also responded strongly to a break point in the middle of a long bar. We suggest that these dot-responsive cells of the “inhibited- by-length” type detect discontinuities in contours. Though they are in the minority, elongation-requiring cells constitute a considerable population (37%) in area 19, and dot-responsive and elongation- requiring cells from columnar patches in the same area. We conclude that, in contrast to area 17, whose main role is the decomposition of patterns into oriented contours, area 19 analyzes both orientation and discontinuities, with a strong bias towards the latter.