Originally Posted by Bobby Jr
I feel like you missed out an introduction of what this is all about in your post.
Care to explain the significance of the colours and what they mean? Do red, blue, purple have obvious meaning in terms of activity or something? What about green or white?
As said, the test was likely an fMRI as a CAT scan isn't really applicable here. The colors show changes in blood flow to a particular area which is correlated to neuronal activity. In short, whenever an area becomes active, it requires glucose. Oxygenated blood carries glucose to the area a few seconds after the deoxygenated blood has gone. Oxygenated and deoxygenated blood respond very differently to magnetic fields, so it is this change that the machine is picking up. The colors themselves aren't particularly relevant as long as you specify the levels yourself. The greater the change in oxygenated blood flow to an area, the more neurons are firing in that area, in short.