As in explained in the books and courses, comprehension is a function of consciousness (essence).
Naturally, while we are in the body, the consciousness perceives through our three brains, thus when the consciousness comprehends, there can be a response in the three brains. Nevertheless, the comprehension itself occurs in the consciousness itself.
This distinction is important, in order that we learn how to access and use the consciousness, rather than remaining attached to the functions of the three brains.
“Nothing is easier than self-deceit. For what each man wishes, that he also believes.” —Demosthenes
"Do not worry; cultivate the habit of being happy." —Samael Aun Weor