Asymmetry in hemispheric function is an important feature of human brain structure and cognitive function, also known as hemispheric dominance or hemispheric lateralization. In other words, the left and right hemispheres play different roles in generating behaviors, higher mental activities, and cognitive functions. There are also asymmetries in the use of human hands, mainly in the form of differences in preference and differences in skill and technique. The right-handedness is clearly dominant in the human population, accounting for about 90%. The majority of right-handed and partially left-handed people have their language centers in the left hemisphere, and only some left-handed people have their language centers in the right hemisphere, which is usually referred to as the left hemisphere of dominance. Modern neurophysiology believes that the left hemisphere plays a decisive role in language function, logical thinking, analytical ability, application skills and computation; the right hemisphere has a significant role in spatial function, shape recognition, music, art, general ability and short term visual memory. However, there are also symmetrical parts of hemispheric functions, and limited lesions in various parts of the cerebral cortex and its associated white matter can produce a number of clinical signs and syndromes, for example, lesions in the anterior central sulcus, which performs motor functions, can lead to paralysis in the corresponding areas, and lesions in the posterior central sulcus, which performs somatosensory afferent functions, can lead to sensory impairment in the corresponding areas.