script by Alice Van Audenhaege and Remi Gau
Jan 2022
Categories of stimuli = 3 (words, houses and faces); 24 exemplars per category (tot = 72).
There are 30 blocks : 10 for each condition.
This localizer should be ran only once (1 run).
In each block all the 12 stimuli from a category are presented in random order.
750 msec for each image + 250 msec ISI (=central fixation cross).
In each block there are either 0, 1 or 2 (this is randomly decided) target stimuli: a target is the repetition of the previous stimulus (N-back task).
The participant has to press when he/she sees a target.
Each block has a duration of 12, 13 or 14 s (depending if 0, 1 or 2 targets).
3 categories with 12 stimulus each;
trial duration= 750msec stimulus + 250 msec ISI = 1s;
block duration = 1 category in each block + 0/1/2 targets = 12/13/14s
1 pause of 8 s at the beginning of the run
30 pauses of 6s = 180s
30 blocks per run : minimum 360s / maximum 420s (according to 0, 1 or 2 targets)
MINIMUM DURATION = 548s (9min08sec) / MAXIMUM DURATION = 608s (10min08sec)
Fixation cross to fill the time difference to get to 488s anyway.
TWO SET OF STIMULI (order of pres. counterbalanced accross partic.) : Set A Set B
To be used with a folder named stimuli containing the following files stored
on OSF in VOTC-loc_stimuli.zip:
https://osf.io/2xtsn/?view_only=22f09bb4dc5f4a11823103141ca2f735
The only variable you need to manually change is Cfg.device at the beginning of the script. Put either 'PC' or 'Scanner'.
Once you will Run the script you will be asked to select some variables:
- Group (TO DEFINE): ctrl is defined as default
- SubID
- Run Number : 1st or 2nd run
- Stimuli ID: 'setA' or 'setB' (it is important to spell correctly this variable because these labels are used to select the correct stimuli folder in the script. In case this input is not given or it is mispelled. it will automatically pick the set A.)