The somatosensory cortex is the part of your brain that processes information from your body’s senses—like touch, pressure, temperature, and pain. It also helps with proprioception, which is your awareness of body position and movement.
It receives messages from your skin, muscles, and joints, then interprets them so you can react, like pulling your hand away from something hot.
Key Takeaways
- The somatosensory cortex processes touch, pain, temperature, pressure, and body position.
- It’s located in the parietal lobe and organized as a “body map” called the sensory homunculus.
- Primary and secondary somatosensory areas each handle different aspects of sensation.
- Damage to this area can cause numbness, tactile agnosia, or phantom limb pain—but the brain can adapt.
- This brain region helps us not only feel the world, but also make sense of it through memory and emotion.
Where is the somatosensory cortex located?
The somatosensory cortex is located in the parietal lobe of the brain, specifically in a ridge of the cerebral cortex called the postcentral gyrus, which lies directly behind the central sulcus (a deep fissure) and the primary motor cortex.
Both hemispheres of the brain contain a somatosensory cortex, with each side processing sensory information from the opposite side of the body.
Somatosensory cortex functions
The somatosensory cortex handles many sensory tasks, including:
- Detecting touch, pressure, pain, and temperature
- Judging weight and force
- Identifying objects through touch (even with your eyes closed)
- Recognizing textures
- Knowing where your limbs are in space (proprioception)
- Storing sensory memories (e.g., the feel of velvet)
It doesn’t just register sensations—it interprets them based on past experiences and emotional context by connecting to areas like the hippocampus and amygdala.
Areas of the somatosensory cortex
The somatosensory cortex is divided into two main regions: the primary and secondary somatosensory cortex.
- Primary Somatosensory Cortex (S1): Located in the postcentral gyrus, this area includes Brodmann areas 1, 2, 3a, and 3b. Each area handles different types of sensory input:
- 3b: basic touch
- 3a: body position
- 1: texture
- 2: shape and size
- Secondary Somatosensory Cortex (S2): Found deeper in the lateral sulcus, S2 receives input from both S1 and the thalamus. It’s involved in recognizing objects by touch, storing sensory memories, and processing the emotional meaning of sensations.
The primary and secondary somatosensory cortices process information from the opposite side of the body, meaning the left hemisphere processes sensations from the right side of the body and vice versa.
This arrangement, known as contralateral processing, is fundamental to how the somatosensory cortex operates.
The Sensory Homunculus: A Map of Your Body in the Brain
Inside the somatosensory cortex, your body is mapped out in a layout called the “sensory homunculus.”
Areas like the hands, lips, and face take up more space because they’re more sensitive and packed with nerve endings. Less sensitive areas, like your back or thighs, occupy less cortical space.
This map is distorted compared to your actual body—more important sensory regions get more brain real estate.
For example, your fingertips are small, but they take up a large portion of the somatosensory cortex because they’re so sensitive.
How Sensory Information Gets to the Brain
Touch and other sensations travel through a three-neuron pathway:
- Primary neurons in the skin and muscles detect stimuli (like heat or pressure).
- Secondary neurons in the spinal cord and brainstem relay this information to the brain.
- Tertiary neurons in the thalamus send it to the somatosensory cortex, where it’s interpreted.
This system helps form the sensory homunculus and allows precise awareness of where and how you’re being touched.
What Happens If the Somatosensory Cortex Is Damaged?
Damage can result from stroke, traumatic brain injury, or diseases like multiple sclerosis. Depending on the area affected, symptoms may include:
- Numbness: Loss of sensation, often in the hands or face
- Impaired temperature detection: Not recognizing when something is too hot or cold
- Tactile agnosia: Inability to identify objects by touch alone
- Poor pressure judgment: Not knowing how hard something is pressing on your skin
- Phantom limb pain: Feeling pain in an amputated limb, linked to changes in the sensory map
In some cases, the brain can reorganize and reassign sensory functions—a process called neuroplasticity. For example, after losing a limb, nearby brain areas may expand to take over that unused space.
Why the Somatosensory Cortex Matters
Understanding this brain region helps explain how we connect to the physical world. It’s not just about feeling things—it’s about making sense of them.
Whether you’re typing on a keyboard, recognizing the softness of a pet’s fur, or avoiding a hot stove, the somatosensory cortex is constantly working behind the scenes.
Research into this area also helps clinicians treat sensory disorders, pain conditions, and even phantom limb syndrome.
As scientists learn more, therapies can be designed to retrain the brain’s sensory map and improve quality of life.
References
Coghill, R. R. (2009). Pain: Neuroimaging. Encyclopedia of Neuroscience, 409-414.
Flor, H. (2003). Remapping somatosensory cortex after injury. Advances in neurology, 93, 195-204.
Neuroscientifically Challenged. (2016, March 10). Know your brain: Primary somatosensory cortex . https://www.neuroscientificallychallenged.com/blog/know-your-brain-primary-somatosensory-cortex
Purves, D., Augustine, G., Fitzpatrick, D., Katz, L., LaMantia, A., McNamara, J., & Williams, S. (2001). Neuroscience 2nd edition. sunderland (ma) sinauer associates. Types of Eye Movements and Their Functions.
Raju, H., & Tadi, P. (2020). Neuroanatomy, Somatosensory Cortex. StatPearls [Internet].
The Human Memory. (2020, November, 25). Somatosensory Cortex . https://human-memory.net/somatosensory-cortex/
