Final answer:
The primary somatosensory cortex consists of the postcentral gyrus and the posterior bank of the central sulcus, including the Brodmann's areas 1, 2, 3a, and 3b, which process various tactile and proprioceptive sensations.
Step-by-step explanation:
The primary somatosensory cortex (S1) comprises the postcentral gyrus plus the posterior bank of the central sulcus. It is divided into four subregions: 3a, 3b, 1, and 2. These areas are assigned Brodmann numbers and relate to processing various somatosensations such as touch, pressure, pain, and proprioception. The first three areas listed are located in the postcentral gyrus and represent Brodmann's areas 1, 2, and 3. These subregions are each responsible for specific aspects of somatosensory processing, with finer separations based on the sensory homunculus and submodalities of sensation.