Journal of Neurophysiology, Vol 68, Issue 1 164-181, Copyright © 1992 by APS

ARTICLES

Neural responses to visual texture patterns in middle temporal area of the macaque monkey

J. F. Olavarria, E. A. DeYoe, J. J. Knierim, J. M. Fox and D. C. van Essen
Division of Biology 216-76, California Institute of Technology, Pasadena 91125.

1. We studied how neurons in the middle temporal visual area (MT) of anesthetized macaque monkeys responded to textured and nontextured visual stimuli. Stimuli contained a central rectangular "figure" that was either uniform in luminance or consisted of an array of oriented line segments. The figure moved at constant velocity in one of four orthogonal directions. The region surrounding the figure was either uniform in luminance or contained a texture array (whose elements were identical or orthogonal in orientation to those of the figure), and it either was stationary or moved along with the figure. 2. A textured figure moving across a stationary textured background ("texture bar" stimulus) often elicited vigorous neural responses, but, on average, the responses to texture bars were significantly smaller than to solid (uniform luminance) bars. 3. Many cells showed direction selectivity that was similar for both texture bars and solid bars. However, on average, the direction selectivity measured when texture bars were used was significantly smaller than that for solid bars, and many cells lost significant direction selectivity altogether. The reduction in direction selectivity for texture bars generally reflected a combination of decreased responsiveness in the preferred direction and increased responsiveness in the null (opposite to preferred) direction. 4. Responses to a texture bar in the absence of a texture background ("texture bar alone") were very similar to the responses to solid bars both in the magnitude of response and in the degree of direction selectivity. Conversely, adding a static texture surround to a moving solid bar reduced direction selectivity on average without a reduction in response magnitude. These results indicate that the static surround is largely responsible for the differences in direction selectivity for texture bars versus solid bars. 5. In the majority of MT cells studied, responses to a moving texture bar were largely independent of whether the elements in the bar were of the same orientation as the background elements or of the orthogonal orientation. Thus, for the class of stimuli we used, orientation contrast does not markedly affect the responses of MT neurons to moving texture patterns. 6. The optimum figure length and the shapes of the length tuning curves determined with the use of solid bars and texture bars differed significantly in most of the cells examined. Thus neurons in MT are not simply selective for a particular figure shape independent of whatever cues are used to delineate the figure.

This article has been cited by other articles:

				S. G. Mysore, R. Vogels, S. E. Raiguel, and G. A. Orban Shape Selectivity for Camouflage-Breaking Dynamic Stimuli in Dorsal V4 Neurons Cereb Cortex, June 1, 2008; 18(6): 1429 - 1443. [Abstract] [Full Text] [PDF]

				L. L. Lui, J. A. Bourne, and M. G. P. Rosa Spatial Summation, End Inhibition and Side Inhibition in the Middle Temporal Visual Area (MT) J Neurophysiol, February 1, 2007; 97(2): 1135 - 1148. [Abstract] [Full Text] [PDF]

				J. Larsson, M. S. Landy, and D. J. Heeger Orientation-Selective Adaptation to First- and Second-Order Patterns in Human Visual Cortex J Neurophysiol, February 1, 2006; 95(2): 862 - 881. [Abstract] [Full Text] [PDF]

				J. Hegde and D. C. Van Essen Stimulus Dependence of Disparity Coding in Primate Visual Area V4 J Neurophysiol, January 1, 2005; 93(1): 620 - 626. [Abstract] [Full Text] [PDF]

				J. D. Schall, T. R. Sato, K. G. Thompson, A. A. Vaughn, and C.-H. Juan Effects of Search Efficiency on Surround Suppression During Visual Selection in Frontal Eye Field J Neurophysiol, June 1, 2004; 91(6): 2765 - 2769. [Abstract] [Full Text] [PDF]

				A. E. Seiffert, D. C. Somers, A. M. Dale, and R. B.H. Tootell Functional MRI Studies of Human Visual Motion Perception: Texture, Luminance, Attention and After-effects Cereb Cortex, April 1, 2003; 13(4): 340 - 349. [Abstract] [Full Text] [PDF]

				J. A. Bourne, R. Tweedale, and M. G.P. Rosa Physiological Responses of New World Monkey V1 Neurons to Stimuli Defined by Coherent Motion Cereb Cortex, November 1, 2002; 12(11): 1132 - 1145. [Abstract] [Full Text] [PDF]

				S. Eifuku and R. H. Wurtz Response to Motion in Extrastriate Area MSTl: Center-Surround Interactions J Neurophysiol, July 1, 1998; 80(1): 282 - 296. [Abstract] [Full Text] [PDF]

				K. Mulligan, J.-N. Kim, and H. Sherk Simulated Optic Flow and Extrastriate Cortex. II. Responses to Bar Versus Large-Field Stimuli J Neurophysiol, February 1, 1997; 77(2): 562 - 570. [Abstract] [Full Text] [PDF]

				G Sary, R Vogels, and G. Orban Cue-invariant shape selectivity of macaque inferior temporal neurons Science, May 14, 1993; 260(5110): 995 - 997. [Abstract] [PDF]

				J. Gallant, J Braun, and D. Van Essen Selectivity for polar, hyperbolic, and Cartesian gratings in macaque visual cortex Science, January 1, 1993; 259(5091): 100 - 103. [Abstract] [PDF]