Receptive Fields for the Somatosensory System
S1 (somatosensory - touch) Somatosensory Area 1, or S1, is for touch and proprioception in the somatosensory system.
The somatosensory system feeds the Brodmann Areas 3, 1 and 2 of the primary somatosensory cortex.
But there are also pathways for proprioception (via the cerebellum), and motor control (via Brodmann area 4).
The primary somatosensory cortex
The primary somatosensory area is located in the postcentral gyrus in the cerebral cortex (Parietal Lobe). It is the main sensory receptive area for the sense of touch. Brodmann areas 3, 1 and 2, in the parietal lobe, has the pattern of a homunculus. The sensory homunculus is at the somatosensory map of sensory space and it is called a homunculus in this location.
The various aspects of touch are all categorized as somatic senses: touch or pressure, temperature (warm or cold)/ thermoception, pain (including itch and tickle), and the sensations of muscle movement and joint position including posture, movement, and facial expression (collectively also called proprioception). “Touch” is usually replaced with somatic senses as coetaneous (skin), kinaesthesia (movement) and visceral (internal) senses, of which the first two are better known.
Visceral senses operate with sensory information from within the body, such as stomach aches.
The inability to feel anything or almost anything is called anaesthesia.
Paraesthesia is a sensation of tingling, pricking, or numbness of a person's skin with no apparent long term physical effect.
Somatosensory agnosia, or Astereognosia, related to tactile sense.
Pain is registered in the anterior cingulate gyrus of the brain.