How does the brain determine the location of touch sensations?

The brain determines the location of touch sensations by interpreting signals from different parts of the body mapped in the somatosensory cortex. The somatosensory cortex is a specific area located in the parietal lobe of the brain that is responsible for processing sensory information from the body, including touch, temperature, pain, and proprioception (the sense of body position).

This area contains a topographical map known as the somatotopic map, where different regions correspond to sensations from different parts of the body. When sensory receptors in the skin and other tissues are activated, they send signals through sensory nerve pathways to the somatosensory cortex. The brain then analyzes these signals based on their pathways and the location of the activated receptors on the body, allowing a person to perceive where the touch sensation occurred. This mapping is crucial for spatial awareness and motor response to stimuli.

The other choices refer to different sensory modalities; the auditory cortex is focused on sound, the visual cortex on sight, and the olfactory bulb on smell—none of which are involved in processing touch sensations directly.