HRF mean units
Can someone explain the discrepancy between these two values? I am attempting to analyze mean HRF amplitude differences between groups and am working through some of the training datasets. In the screenshot of the Homer GUI, I am looking at the subject HRF for the channel between source 3 and detector 1, which seems to be around 100-110 uM mm. When I export the HRF mean into a .txt file and look at the same channel, the value is quite different: 3.72231e-05 (please note that I will attach the other screenshot to a comment on this post). Why is this? If I am unknowingly comparing two different things can you please also explain my misconception (if it's clear to you)? thank you in advance.
Here is a screenshot of the txt file that I get when I export the subject's mean HRF
I suspect the units in the exported text file are Molar (M) with some pathlength factor applied to get M instead of M mm units.If the GUI is giving you around 100 uM mm and you divide that by 3mm, then you get close to what you get in the text file. Although I am not sure why the pathlength factor would be set to 3 mm.
It would be great if someone can dig through the code and figure this out for us.