Figure 1: a. Schematic view of the motion stimulus. The psychophysical learning task consisted of discriminating opposite motion directions in a two frame stochastic random dot cinematogram displayed in a circular aperture 10° in diameter. 20% of the dots provided directional motion signal while the remaining 80% of the dots were reploted in the second frame at random locations within the stimulus aperture providing masking motion noise. A square fixation mark, 0.5° in diameter, was placed in the center of the display and subjects were asked to fixate it throughout a trial. The static control condition consisted of a random dot display with the same statistics as the motion display. Here the square fixation mark transiently (for 30 msec) turned into a T or an L, and subjects were asked to perform a letter discrimination. b. The figure shows averaged data of the psychophysical performance of the left-right motion discrimination runs from four subjects. Each data point corresponds to approximately 100 trials obtained during a motion run (120sec). The abscisa refers to the block number and the ordinate refers to the proportion correct responses. c. The figure shows subjects’performance on one block of the up-down direction dsicrimination (untrained direction).