Hello,
I am working on a project that assesses the relationship between diet and memory-related brain activity (brain activity is a within-subjects variable). I previously used 3dDeconvolve to create functional maps of remembered and forgotten words, which I then used to compare to diet using 3dLME. However, some diet variables may have a quadratic relationship (i.e., u-shaped curve) with brain activity. For example, both too much and too little dietary iron is bad for you. Are there any analyses in AFNI that can assess this quadratic relationship between diet and brain activity? The closest I have come to is using a nonparametric test (3dWilcoxon), which looks at non-linear relationships between functional maps, but I would not be able to look at diet in this analysis.
Thank you for your help,
Cameryn Eickstead
AFNI version info (afni -23.0.1_with_r.sif):