Following sensory impairments occur in extensive damage to somatosensory area of cerebral coex. EXCEPT-
Damage to the sensory coex results in decreased sensory thresholds, an inability to discriminate the propeies of tactile stimuli or to identify objects by touch. The secondary somatosensory coex (SII; area 40) is in the lower parietal lobe Somatosensory Coex Primary somatosensory coex (SI; areas 3,1,2) is located in the post central gyrus. This receives somatotopic input from the VPL and VPM of the thalamus. Histologically, this area would consist of granular coex. The sensory homunculus includes coical representation of the body based on the degree of sensory innervation. There are actually four submaps, one each in area 3a, 3b, 1 and 2. Very sensitive areas such as the lips and the fingeips have a huge representation. Neurons within each coical site (paicularly layer IV) are arranged in columns representing specific body regions. If a region is amputated (such as a finger) there is reorganization with neurons responding to stimulation of adjacent body pas. This can also happen as the result of increased use of a body pa. Damage to the sensory coex results in decreased sensory thresholds, an inability to discriminate the propeies of tactile stimuli or to identify objects by touch.but the pain sensation is less effected . The secondary somatosensory coex (SII; area 40) is in the lower parietal lobe. This receives connections from the primary sensory coex and also less specific thalamic nuclei. This responds to sensory stimuli bilaterally, although with much less precision than the primary coex. Nonetheless, lesions to this area may impair some elements of sensory discrimination. The somatosensory association coex (areas 5 and 7) is directly posterior to the sensory coex in the superior parietal lobes. This receives synthesized connections from the primary and secondary sensory coices. These neurons respond to several types of inputs and are involved in complex associations. Damage can affect the ability to recognize objects even though the objects can be felt (tactile agnosia). Coical damage, paicularly in the area of coex where the posterior parietal lobe meets the anterior occipital and the posterior, superior temporal lobe, can cause neglect of the contralateral side of the world. This typically happens with nondominant hemisphere lesions since this hemisphere appears necessary to distribute attention to both sides of the body. The dominant hemisphere appears to only "pay attention" to the associated (usually right) side of the world. Therefore, neglect usually involves the left side and can be so severe that the individual even denies that their left side belongs to them. Ref Harrison20th edition pg 2456
Pressure
Sensory localization
Exact weight determination
Pain
C.N.S