Extinction and Precipitation of Cutaneous Sensations

It is generally assumed that the cutaneous modalities of one side of the body are represented in the opposite side of the brain. Conventionally, a lesion in the right parietal lobe causes a decrease in sensation on the left side of the body. However, there is also clinical and physiologic evidence indicating that certain parts of the body are bilaterally represented in the parietal cortex. Foerster1electrically stimulated the sensory cortical area in man, with the result that the patient complained of bilateral paresthesias. Dusser de Barenne2reported that painting a small part of the arm area in one parietal cortex with strychnine produced hypersensitivity in both arms in the monkey. Other than these investigations, there are relatively few studies demonstrating a functional relationship between the sensations of the two halves of the body, such as stimulation of the skin on one side influencing the cutaneous sensation on