What is the primary function of the primary somatosensory cortex (S1)?

The primary somatosensory cortex (S1) has a crucial role in processing sensory information from various body parts. Located in the postcentral gyrus of the parietal lobe, it receives afferent signals from the thalamus about tactile stimuli, proprioception, and pain, allowing it to decode various aspects of touch, temperature, pressure, and pain sensation.

This area of the brain is organized in a way that maps sensory inputs from the body—often described as a homunculus—where different regions correspond to different body parts based on their sensory input. For example, the hands and face have larger representations in this cortex due to the high density of sensory receptors in these areas, reflecting their significance in tactile processing.

By integrating these diverse sensory inputs, S1 enables the perception and interpretation of sensory information, allowing for proper responses and interactions with the environment. This function is fundamental for tasks that require fine motor skills, as well as for spatial awareness and body image representation.