somatosensory cortex

The somatosensory cortex is the part of the brain that receives the body's sense of touch and position — the warmth of a mug, the pressure on your fingertips, where your limbs are even with your eyes closed. It sits as a band right behind the motor strip, so movement commands and touch sensations are neighbors.

Like the motor cortex, it carries a body map: each patch listens to signals from a particular part of the skin, with sensitive regions like the fingertips claiming extra room. When you touch something, the matching patch of this cortex becomes active.

For BCIs, this is the place to write information back in, not just read it out. By gently stimulating the right spot with tiny electrical pulses, researchers can make a person feel touch on a hand that isn't theirs — giving a robotic prosthetic hand an artificial sense of touch so its user can feel contact and grip, not just see it.