Experiments were performed in two rhesus monkeys, B and E. Each monkey made a combination of slow and fast eye-movements following a visual target. The target was stationary at first and then either abruptly started moving (at a speed of 10°/s) in a certain direction (Ramp paradigm) or made a Step before starting the motion (Step-Ramp paradigm). By using a specific Step size and Step direction the initial saccade was eliminated in the Step-Ramp paradigm. The direction of the stimulus motion was predominantly horizontal with a smaller vertical component that was systematically varied between 0° and +-20°. We investigated how precisely the monkeys can follow this vertical component of the stimulus motion. The files: There are separate files for each monkey (B and E) and paradigm (Ramp and Step_Ramp). The files are MATLAB data files. Ramp: Each file consists of three variables – ‘alldatx’, ‘alldaty’, and ‘init’. ‘alldatx’ and ‘alldaty’ are cell arrays in which each cell represents one vertical component of the stimulus: 1=20° up, 2=10° up, 3=5° up, 4=2° up, 5=0° , 6=2° down, 7=5° down, 8=10° down, 9=20° down. Each cell contains a matrix of n x 2001 elements. Each row represents the eye velocities during one individual trial between 1000 ms before and 1000 ms after the start of stimulus motion with a sampling rate of 1000 Hz. ‘init’ is a cell array in which each cell represents one vertical component of the stimulus (s. above). Each cell contains a structure array which shows the approximate properties of the initial saccade in each trial: ‘init.t’: Start end end time of the saccade (in ms) after the start of stimulus motion. ‘init.amp’: Amplitude of the initial saccade in deg ‘init.startpos’, ‘init.endpos’: start- and end-position (x, y) of the saccade Step_Ramp: Each file consists of two variables – ‘alldatx’, ‘alldaty’. Description is the same as for Ramp.

This research was supported by: DFG - SFB/TRR 135/A1