Beta or concentration values?
I've noticed that in the fNIRS literature, one can either use HRF concentration or beta values for stats. Is one measure preferable over the other? In which circumstance would you use HRF concentration or beta values?
Also, just a really simple question: I noticed that my group average HRFs peak around 4-5 seconds. Is this normal?? Since my stimulus lasts for 4 seconds with a jittered ISI (mean: 8 s), can I take the concentration values between 1-5 seconds for my stats?