What Are the Different Areas of the Somatosensory Cortex?

The somatosensory cortex is located in the postcentral gyrus, which is found in the human brain's parietal lobe. The postcentral gyrus can be divided into sections called Brodmann areas 1, 2, and 3. These three areas make up the primary somatosensory cortex, which is responsible for processing certain types of sensory information, primarily touch, which are collected from sensory neurons located throughout the body. Brodmann area 3 receives the majority of sensory information.

The cerebral cortex, also called the cerebrum, is the outer part of the human brain. Its surface is made up of many convolutions, or ridges, called gyri and fissures, or depressions, called sulci. It's divided into two large sections called hemispheres by a long depression called the great longitudinal fissure. Both hemispheres are sectioned into lobes. The frontal lobe is at the front of the head, the parietal lobe is on the top and upper sides of the head, the temporal lobe is on the lower sides of the head, and the occipital lobe is located at the back of the head.

Within the parietal lobe is a convolution called the postcentral gyrus, which is found on the top of the parietal lobe and extends down to the upper side of the brain. The postcentral gyrus crosses the great longitudinal fissure and exists in both brain hemispheres. Anatomical landmarks that surround the postcentral gyrus are the central sulcus in front, the postcentral sulcus behind, and the lateral sulcus underneath. The lateral sulcus is located on the side of the cerebral cortex, and it separates the frontal and parietal lobes from the temporal lobe below them.

Located within the postcentral gyrus is the somatosensory cortex, which is also called the primary somatosensory cortex, and it's the main processing center for the somatosensory system. Responsible for processing information related to temperature, touch, pain, and the position of the body, the somatosensory system is spread throughout all the major areas of the body and contains sensory receptors that detect sensory stimuli, which are sent to the central nervous system for processing. The primary somatosensory cortex is divided into three sections known as Brodmann areas, which are collectively equivalent to brain region S1 and run the entire length of the postcentral gyrus.

Brodmann area 3 is closest to the central sulcus, Brodmann area 1 is closest to the postcentral sulcus, and Brodmann area 2 sits between the other two Brodmann areas. Some scientists believe that only Brodmann area 3 should be referred to as the primary somatosensory cortex because it receives the greatest amount of sensory information. Brodmann area 3 is further subdivided into areas 3a and 3b.