Which of the following manifestation occur secondary to ablation of the 'somatosensory area I' of the cerebral coex?
Widespread bilateral excision of somatosensory area I result in person being unable to localize discretely the different sensations in the different pas of the body. Somatosensory area 1 is located in the posterior bank of the central sulcus and on the crown of postcentral sulcus. This area corresponds to Brodmann's area 3a, 3b, 1 and 2. Neurons in area 1 and 3b are responsive to cutaneous inputs both rapidly and slowly adapting. Area 2 and 3a respond to deep stimuli, with area 3a responsive to muscle afferents and area 2 to joints. Area 3b is critical for the performance of tactile discrimination based on shape or texture of a stimulus. Inactivation of this area leads to lack of appreciation of the quality or existence of tactile stimuli. Lesion of area 1 disrupt performance based on texture but leaves intact performance based on stimulus size, whereas lesion in area 2 produces opposite effect. Ref: Guyton and Hall - Textbook of Medical Physiology, 10th Edition, Page 546; Ganong's Review of Medical Physiology, 22nd Edition, Pages 139-40; Fundamental Neuroscience, Volume 1 By Larry R. Squire, 2nd Edition, Page 689