Figure 6.

A memory-based smooth-pursuit task and representative eye movements of a macaque monkey. (A) Schematic illustration of the task. A red stationary spot appeared at the screen center and the monkeys were required to fixate it (1. fixation). Cue 1 consisted of a random-dot pattern of 10° diameter. All 150 dots moved along one of eight directions at 10°/s for 0.5 s [2. cue 1, 100% correlation of Newsome and Pare (1988)]. Visual motion-direction was randomly presented. The monkeys were required to remember both the color of the dots and their movement direction while fixating the stationary spot. After a delay (3. delay 1), a stationary random-dot pattern was presented as the 2nd cue for 0.5 s (4. cue 2). If the color of the stationary cue 2 dots was the same as the cue 1 color, it instructed the monkeys to prepare to pursue a spot that would move in the direction instructed by cue 1 (i.e., go). If the color of cue 2 differed from cue 1, it instructed the monkeys not to pursue (i.e., no-go) but to maintain fixation of a stationary spot which required remembering the no-go instruction during the 2nd delay (5. delay 2). Go/no-go cue was randomly presented. After the delay, the monkeys were required to execute the correct action by selecting one of three spots and either pursuing the correct spot in the correct direction or maintaining fixation (6. action). For this, the stationary spot remained centered, but spawned two identical spots; one that moved in the direction instructed by cue 1 and the other moved in the opposite direction at 10°/s. For correct performance, the monkeys were rewarded. For analysis, all trials were sorted by cue 1, cue 2 direction/instructions. (B) eye movement records during early and late training when cue 1 was rightward and cue 2 was go. Pos and vel indicate position and velocity. For further explanation, see text. Modified from Fukushima et al. (2008, 2011a) and Shichinohe et al. (2009).