When performing working memory processing tasks, the anterior cingulate cortex lights up. It does not during memory recall (the medial temporal lobes do, which sort of makes sense as the medial temporal lobe is the location of the hippocampus). The ACC also responds to pain, fear, and other unpleasant “avoidance” sensations.

Maybe there’s a physiological basis for the avoidance people display to challenging mental tasks? Can it be that the body interprets it as another form of pain?

Edit: Ooh, it increases with task difficulty too.