A neuroimaging study typically follows specific steps. First one sets up the experiment itself, using various software detailed elsewhere in this handbook. Then pre- and pilot testing is followed by the actual data acquisition and finishing with the analysis.
Experiment Setup
While setting up an experiment one must decide which software to use for stimulus presentation. At UiO researchers are presented with the choice between three different options: E-prime, MATLAB/Psychtoolbox and Python/PsychoPy (although some may prefer Presentation, it is less commonly used). The following table gives a short overview of the three most frequently used programs.
Pre-tests
Pre-tests are preliminary tests of sequences, equipment and stimuli scripts performed at the scanner prior to actual pilot testing
Pilot tests
Before collecting data for the experiment, it is essential to discuss the experiment design with colleagues and have them perform the task to provide feedback on its design. Pilot test your experiment behaviorally to make sure you can obtain the predicted behavioral effect before proceeding to collect brain data.
After testing the experiment behaviorally, data from 2-5 subjects are usually collected and analyzed, including the analysis corresponding to the main hypotheses.
Pilot tests may be performed on a phantom or healthy volunteer at the scanner, depending on what the study entails. Volunteers for pilots must go through the same screening and consent process as regular participants. In addition to fulfilling the need for informed consent, we also must ensure that pilot participants do not have any health conditions or prosthetics that contraindicate MRI scanning. Pilot tests should not only include the testing of scanning sequences, tasks and stimuli, but also tests of the pre-processing and analysis pipelines should be performed at this stage. After the analysis of these datasets, flaws, suboptimal design features, extraneous conditions or the need for additional conditions may be found.
Pilot datasets can be used for the final analyses if the following criteria are met:
- The procedure/design is satisfactory.
- The experiment will not be changed after the pilot.
- The pilot participants fulfill the study's inclusion criteria.