%0 Journal Article
%T Two-dimensional map of direction selectivity in cortical visual area MT of Cebus monkey
%A DIOGO ANTONIA CINIRA M.
%A SOARES JULIANA G. M.
%A ALBRIGHT THOMAS D.
%A GATTASS RICARDO
%J Anais da Academia Brasileira de Ci¨ºncias
%D 2002
%I Academia Brasileira de Ci¨ºncias
%X We studied the spatial organization of direction of motion in visual area MT of the Cebus apella monkey. We used arrays of 6 (700 ¦̀m apart) parallel electrodes in penetrations tangential to the cortical layers to record multi-unit responses to moving bars, at 200 ¦̀m steps. We determined the direction selectivity at each recording site. The data from single penetrations showed cyclic and gradual changes in the direction selectivity of clusters of cells, intermixed with abrupt 180o discontinuities along the electrode track. In order to obtain maps of direction of motion selectivity, we examined the spatial distribution of direction of motion in MT and we applied a method to determine the location of the centers of radial arrangements of direction selectivity. This tangential organization is characterized by slow continuous changes in direction of motion, interrupted by discontinuities. The changes in direction selectivity are organized radially in a pinwheel fashion and in slabs of linear variation. The pinwheel arrangements have 800-1400 ¦̀m in diameter. The size of the radial arrangement is comparable to the point image size in area MT at each eccentricity.
%K extrastriate cortex
%K visual system
%K primates
%K direction of motion
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000300009