The onset mark demarcates the beginning of each trial.
A cue presented at the beginning of each trial would indicate the type of the upcoming trial.
The beginning of each trial was preceded by three visually presented warning signals (Attention! Set! Go!).
At the beginning of each trial, subjects were asked to close their eyes.
At the beginning of each trial, a fixation cross was projected into the central visual field.
At the beginning of each trial, a fixation cross was presented for 1 s.
At the beginning of each trial, the subject placed his or her right index finger on the starting position.
At the beginning of each trial, a single beetle was placed at the down-wind end of the Y-tube.
The first onset was set to the presentation of the 'agency cues' (Fig. 1) at the beginning of each trial.
The trials were paced by the computer software which displayed a fresh writing area in the beginning of each trial.
At the beginning of each trial, a 5.5 deg white ring was placed in the center of the display.
