Stimulus timing and task design schematic. Note: The figure illustrates the timing and task design of the two saccade task conditions. Stimulation of the fixation, delay, response and ITI period was identical for both conditions (a, b). In the visually-guided saccade task (a) the direction of the saccade was indicated by an exogenous cue, a white circle in the target placeholder (Cue). In the simple internally-guided saccade task (b) the direction of the upcoming saccade was indicated by an endogenous arrow-like symbol pointing towards the left or right placeholder (Cue). ITI, inter-trial interval