Spatial and temporal integration of signals in foveal line orientation

被引:20
作者
Westheimer, G
Ley, EJ
机构
[1] Division of Neurobiology, University of California, Berkeley
[2] Division of Neurobiology, University of California, Berkeley, CA 94720-3200
关键词
PRIMARY VISUAL-CORTEX; STRIATE CORTEX; MAGNIFICATION FACTOR; FIELD SIZE; MONKEY; CAT; CELLS; PARALLEL; NEURONS;
D O I
10.1152/jn.1997.77.5.2677
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
The discrimination of the orientation of a line improves with line length, reaching an optimum when a foveal line is similar to 0.5 degrees long. We studied the effect of eliminating sections of the line, of displacing them out of alignment, and of delaying them. Orientation discrimination thresholds are only a little elevated when a 25-arcmin line is replaced by three equally spaced collinear 5-arcmin segments. Two collinear 5-arcmin segments show better thresholds than a single one when they are separated by as much as 20 arcmin. But thresholds are impaired by bringing line segments out of collinearity by as little as 1 arcmin. Asynchrony of up to 50 ms can be tolerated, but when the middle segment of a three-line pattern is delayed by similar to 100 ms there is active inhibition, thresholds being now higher than when the middle segment is absent. It is concluded that for signals to address the orientation discrimination mechanism optimally, they have to be contained inside a narrow spatial corridor and be presented within a time window of similar to 50 ms, but that some spatial summation can take place over a length of >0.5 degrees in the fovea. Because short lines made of black and white collinear segments do not have good orientation thresholds, whereas longer and interrupted lines do, it is concluded that what is involved is potentiating interaction between collinearly arranged neurons with identical orientation selectivity rather than summation of signals within the receptive fields of single neurons.
引用
收藏
页码:2677 / 2684
页数:8
相关论文
共 24 条
[11]   SIZE, SHAPE, AND CONTRAST IN DETECTION OF TARGETS BY DAYLIGHT VISION .1. DATA AND ANALYTICAL DESCRIPTION [J].
LAMAR, ES ;
HECHT, S ;
SHLAER, S ;
HENDLEY, CD .
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA, 1947, 37 (07) :531-545
[12]   LONG AXONS WITHIN THE STRIATE CORTEX - THEIR DISTRIBUTION, ORIENTATION, AND PATTERNS OF CONNECTION [J].
MITCHISON, G ;
CRICK, F .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES, 1982, 79 (11) :3661-3665
[13]   PERCEIVED DIAGONALS IN GRIDS AND LATTICES [J].
MORGAN, MJ ;
HOTOPF, WHN .
VISION RESEARCH, 1989, 29 (08) :1005-+
[14]  
NELSON JI, 1985, EXP BRAIN RES, V61, P54
[15]  
POLAT U, 1994, VISION RES, V34, P115
[16]  
TOMAS JP, 1978, VISION RES, V18, P1023
[17]  
VOGELS R, 1990, J NEUROSCI, V10, P3543
[18]   PERCEPTUAL DISTORTION OF AN OBLIQUE LINE IN PRESENCE OF AN ABUTTING VERTICAL LINE [J].
WENDEROTH, P ;
BEH, H ;
WHITE, D .
VISION RESEARCH, 1978, 18 (08) :923-930
[19]   CONTRAST AND DURATION OF EXPOSURE DIFFERENTIALLY AFFECT VERNIER AND STEREOSCOPIC ACUITY [J].
WESTHEIMER, G ;
PETTET, MW .
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 1990, 241 (1300) :42-46
[20]   Classifying illusory contours: Edges defined by ''pacman'' and monocular tokens [J].
Westheimer, G ;
Li, W .
JOURNAL OF NEUROPHYSIOLOGY, 1997, 77 (02) :731-736