Which area receives sensory information from the skin at the site of the stimulus from the opposite side of the body?

• A. Somatosensory association area
• B. Auditory association area
• C. Primary somatosensory cortex
• D. Wernicke's area

Answer: (C)

Contralateral processing of skin sensation is key: the brain receives touch, temperature, and proprioceptive input from one side of the body and sends it to the opposite hemisphere for initial processing. The primary somatosensory cortex, located in the postcentral gyrus of the parietal lobe, is the first cortical area to receive this input. It holds a somatotopic map of the body, so each region of the skin corresponds to a specific area on this cortex. Because the sensory pathways cross to the opposite side before reaching cortex, sensory information from the left side of the body is processed in the right primary somatosensory cortex, and vice versa. The other areas serve different roles—somatosensory association area interprets input, auditory association area handles hearing, and Wernicke's area is for language—so the primary somatosensory cortex is the one that first receives contralateral skin sensation.