First level design files

First level design files describe the experimental setup within one session in a simple txt format. They specify onset times and duration of the various experimental events. They can be used as input into single-subject LISA (LISA single subject analysis using precoloring (vlisa_precoloring) , LISA single subject analysis using prewhitening (vlisa_prewhitening))

The design specification of first level designs must be given as a text file in the following format. Each line of the file corresponds to one trial. Each line must have 4 entries: 1. event type specified by an integer, 2. onset time in seconds, 3. trial duration in seconds, 4. amplitude. Comment lines begin with one of the following characters ‘%’, ‘#’, ‘/’. Here are some examples:

% Example 1
% event     onset      duration   amplitude
    1       18.00        3.00        1.00
    1      150.00        3.00        1.00
    1      168.00        2.00        1.00
    2       24.00        1.00        1.00
    2       90.00        1.00        1.00

This design file describes two event types where event 1 occurs at 18,150 and 168 sec., and event 2 occurs at 24 and 90 sec. The trial lengths of event ‘1’ are 2 or 3 seconds. Trials of event ‘2’ have a duration of only one second. Both events have a standard amplitude of 1.

% Example 2
% event     onset      duration   amplitude
    1       18.00        3.00        1.00
    1      150.00        3.00        1.00
    1      168.00        2.00        1.00
    2       24.00        1.00        1.00
    2       90.00        1.00        1.00
    3       24.00        1.00        5.80
    3       90.00        1.00        7.26

This is essentially the same design as in example 1. However, event 2 has an additional parametric component which is specified as event ‘3’. Note that the event therefore occurs twice, once without and once with the additional parameter.