Which region tags pain according to severity?

• A. Anterior cingulate cortex
• B. Hippocampus
• C. Thalamus
• D. Cerebellum

Answer: (A)

Pain has both a sensory-discriminative aspect (where and how intense it is) and an affective-motivational aspect (how unpleasant and significant it feels). The anterior cingulate cortex is key for the affective side, and its activity tracks how severe or bothersome the pain is. In other words, the ACC encodes the unpleasantness and motivational significance of pain, and its response scales with the perceived intensity.

The other regions play different roles: the hippocampus is mainly about memory, the thalamus serves as a relay for sensory information to the cortex, and the cerebellum deals with coordination and, to some extent, modulation, but not primarily with tagging pain by severity.