Dear SPM users!
I am analyzing fMRI data from an experiment including self-control decisions. Based on the results of research with the readiness potential and the impact of endogenous reward system fluctuations on decision making (e.g. Soon, C. S., Brass, M., Heinze, H. J., & Haynes, J. D. (2008). Unconscious determinants of free decisions in the human brain. Nature neuroscience, 11(5), 543-545.; Chew, B., Hauser, T. U., Papoutsi, M., Magerkurth, J., Dolan, R. J., & Rutledge, R. B. (2019). Endogenous fluctuations in the dopaminergic midbrain drive behavioral choice variability. Proceedings of the National Academy of Sciences, 116(37), 18732-18737. ), I want to check whether the activity of the striatum (directly releted to decision making process) preceding the decision may affect the probability of self-control success.
The first idea is to model the pre-decision period (e.g. 3 seconds) as two separate conditions in GLM, depending on whether the decision was self-control success or failure. And the results are promising, however the HRF used in GLM is slow and I am afraid that such defined conditions may also capture the BOLD signal related to the neural activity during and even after the decisions, so it limits the interpretation that it is the "pre-tiral brain acitivy".
Do you think my concerns are justified and if so, what solution would you suggest?
Thank you
Jakub
|