Description of Paradigm and visual Stimulation in
Heinzle et al. (in preparation)
“Visuo-motor functional network topology predicts upcoming tasks”
The flexible visuo-motor task required subjects to respond to
a visual stimulus (go-signal) presented in their left or right visual hemifield
with either the ipsilateral or the contralateral hand. The stimulus-response mapping varied between
trials: In pro-trials (called ‘II), the response had to be given with the hand
on the side of the visual go-signal, in anti-trials (called ‘X-trials’) with
the hand opposite to the go-signal. The task condition was indicated by
a cue at the beginning of each trial (‘II’ or ‘X’, 3s). After a pause of 2s,
subjects were presented two clock-like shapes, in the left and right visual
field, with eight clock hands each (Fig. 1B) rotating at different velocities.
Specifically, all eight hands of each clock rotated in the same direction with
their rotational velocities normally distributed around a mean of m=50°/s with standard
deviation s=30°/s. Negative speeds were
inverted so that all clock hands turned into the same direction. At the
go-signal, all speeds were set to m=50°/s.
Short explanation of trials
in the Stimulus Video:
The stimulus video (Heinzleetal_Stimulus.avi) shows three
consecutive, illustrative trials of the paradigm.
Trial 1 is a X-trial, with a delay period of 14 seconds. The
go-signal (synchronization of clock hands) is shown on the left and the subject
responds correctly with a right finger press. The black bar shown after the
button press indicates reaction time and was used to motivate subjects to
respond as quickly as possible.
Trial 2 is a X-trial, with a delay period of 10 seconds. The
go-signal is shown on the right and the subject makes an error by responding
with a finger press on the right. This error is indicated to the subject:
Falsche Seite! (Wrong side!).
Trial 3 is a II-trial with a delay period of 4 seconds, i.e.
a catch trial. The go-signal is shown on the left and the subject responds
correctly with a left finger press.