Fig. 1.
Orientation discrimination test and training procedures. (A) Orientation discrimination test procedure. Subjects gazed upon a small green dot on the center of the screen from the fixation to an orientation stimulus. After the signal orientation stimulus disappeared, the color of the fixation dot changed from green to red. As soon as it changed color, subjects had 1500 ms to respond with a key-press regarding which of the 135°, 75°, or 15° orientations was presented. (B) Subjects performed a go/no-go task by choosing between pressing (go) and not pressing (no-go) a button, in response to orientation stimuli. The chance of getting a drop of water (~1 ml of water over 300ms) varied depending on the presented orientation stimulus.