Figure 2.3 Tagging the Brain In these images from live persons, a radioactively labeled sugar is used to detect differences between the brain activity of a depressed person (A) and that of a person who is not depressed (B). The more active a brain region is, the more sugar it takes up (shown as orange areas). The brain of the depressed person (left) shows less activity than the brain of the person who is not depressed.