Somatosensory Function and the Parietal Lobe

The parietal lobe is the middle lobe of the cerebrum and is found on the lateral surface of the hemisphere; it consists of the postcentral gyrus and superior and inferior parietal lobules. In this region of the cerebrum, one finds major functional differences between the left hemisphere, which is dominant for language, and the right hemisphere, which is important for body imagery. The pain pathway has been discussed in Chapters 3 (spinal cord), 4 (brain stem), and 6 (diencephalon). In this chapter we will cover the pathways subserving tactile information for (1) the extremities, thorax, and abdomen, the posterior columns and (2) the trigeminal systems subserving tactile information from the head. The importance of these pathways is apparent when one walks in the dark or drinks or eats.