The postcentral region occupies the postcentral gyrus and stretches from the superomedial border to the adjoining part of the paracentral lobule. There is the typical sensory cortex with all well developed six layers. The postcentral region is the sensory receptive area. It receives information from the nuclei ventralis posterolateralis and posteromedialis of the lateral nuclear mass of the thalamus. These relay impulses from the spinothalamic tracts, medial lemnisci, and secondary trigeminal tracts, and traverse the posterior limb of the internal capsule. The functions of the parietal lobe are analysis, synthesis, integration, interpretation, and elaboration of the primary sensory impulses that are received from the thalamus. The sensory cortex is somatotopically organized too. Destruction of this area results in contralateral hemihypestesia and astereognosis. Stimulation of this area by either artificial excitation or disease processes produces paresthesias on the opposite side of the body (sensory jacksonian epilepsy).
The superior parietal lobule. Destruction of this lobule results in contralateral astereognosis and sensory neglect.
The angular and supramarginal gyri of the dominant hemisphere are important in relation to language and related functions, and lesions in these areas may be responsible for various types of receptive aphasia, alexia, acalculia, and sensory apraxia. Destruction of nondominant hemisphere result in autotopagnosia or somatotopagnosia (the loss of power to orient the body or the relation of its individual parts; there may be loss of identification of one limb or one part of the body), anosognosia (the ignorance of the existence of disease), pseudomelia (a sensation of presence or absence of additional extremities).