Attending to one direction may increase the performance in the opposite direction

DÉCIMA, A.; BARRAZA J.F.; BALDASSI, S.

Tolouse

Congreso; 33th European Conference on Visual Perception; 2011

Previous studies (Martinez-Trujillo and Treue, 2004 Current Biology 14 744?451) showed that direction selective responses are modulated by the degree of similarity between the attended direction and the cell´s direction selectivity rather than the match between attended direction and target?s direction. We sought perceptual correlates of this phenomenon by performing an experiment in which three patches of random dots were displayed. One of the patches summoned attention -by containing a hue change to be reported- and moved either coherently in direction θ or randomly. One of the other two patches had a variable proportion of dots moving coherently in the direction opposite to θ, while the other had no coherent movement at all. Observers had to decide which patch had coherent movement. We used a masking technique to psychophysically desensitize the channels tuned to −θ in order to relatively increase the response of channels tuned to +θ. Results show that, instead of what the feature-matching hypothesis would predict, performance improves in the presence of coherent motion in the attended patch, which suggests that attention would modulate the performance of the "selected channel", independently of the stimulus direction. We are currently investigating the spatial and decisional regimes that determine this behavior.