Functional asymmetry of the cerebral hemispheres

The two hemispheres are not exactly the same in terms of the functions they perform. Each hemisphere and, in particular, its associative zones have a specific functional specialization, which is expressed in the implementation of a function, the neural mechanism of which is located mainly in it. This determines the existence of the so-called functional asymmetry of the cerebral hemispheres.
Functional asymmetry of the cerebral hemispheres is also called lateralization of brain functions. The left hemisphere specializes in speech, mathematical operations, and logical tasks, while the right hemisphere specializes in spatial perception and orientation, face recognition and complex visual images, tactile object recognition, and understanding and interpreting music. The proof of this specialization is the dichotomous listening tests. They send different sound signals to both ears, and establish what the subject hears. In a test with linguistic material, most people hear the text presented in the right ear, because through it the material directly reaches the areas of speech in the left hemisphere. When listening to music, the result is the opposite - the left ear is preferable, which delivers information directly to the right hemisphere, which is dominant in terms of musical abilities. The results are similar when presenting visual stimuli with a tachystoscope in only one half of the visual field. Verbal stimuli (words) are better recognized when they are presented in the left half of the visual field.
The main difference between the two hemispheres is the way information is processed. The left hemisphere specializes in analytical information processing, while the right hemisphere specializes in synthetic processing. This means that the left hemisphere breaks down the analyzed object or event into small elements, while the right hemisphere ignores the details and pays attention to the object or event as a whole. Figuratively speaking, the left hemisphere sees individual trees, and the right hemisphere sees a forest. However, this specialization of the two areas cannot be separated in the brain due to the constant interhemispheric exchange of information through the corpus callosum and the anterior commissure.
The role of information transmission between the two hemispheres through the corpus callosum is best manifested in its congenital absence (agenesis) or after surgery in the treatment of severe forms of epilepsy. When patients with corneal body surgery have objects placed in the left side of their visual field for a very short time, it is difficult for them to tell what they are seeing. At the same time, patients can point to the observed object among other objects, hold it with their left hand, or draw. This indicates that they can see the object, but since visual information does not reach the center of speech in the left hemisphere, they cannot name it. If such patients look at hybrid figures in which the left half of the face is a woman and the right half is a man, they will say that the image is a man, since the visualization reaches the left hemisphere, where the center of speech is. However, if they are forced to pay attention to a face, they point to an image of a woman, as the right hemisphere is the dominant one for face recognition. These corpus callosum effects only occur in laboratory conditions when images are presented for a very short time. In natural conditions, when eye movements are performed, information from a large part of the space reaches each hemisphere, so patients with an operated corneal body do not experience difficulties in their daily activities. They only find it difficult to perform tasks that require very good coordination with both hands (playing musical instruments, some sports).
Methods for studying brain asymmetry.
The simplest clinical test for determining the dominant speech hemisphere is the Wada test. In this test, a fast-acting anesthetic is injected into only one carotid artery, which briefly "anesthetizes" only one hemisphere. The subject is instructed to speak before and during anesthesia. If the left hemisphere is "anesthetized" and the patient stops speaking and cannot continue the command, it means that it is dominant in terms of the patient's speech. An interesting observation when performing this test is that, in addition to speech, it also affects mood. An injection of anesthetic on the left causes short-term depression, and an injection on the right causes euphoria.
Modern methods of studying the functional asymmetry of the cerebral hemispheres include the use of positron emission tomography, functional magnetic resonance imaging, magnetoencephalography, and event-related potentials. Using such methods, it was found that in speech tests, most people activate certain areas in the left hemisphere, while lateralization is less pronounced in women than in men. Жители Нижнекамска чаще всего решают melbet скачать казино , а затем настраивают уведомления по избранным лигам. Служба поддержки: +7 (800) 706-12-99.