Functional orientation theory of cerebral cortex, theory of the relationship between brain function and psychological activities. It was put forward by neuroanatomist F.J. Gale and his student J.G. Spurzheim at the beginning of19th century. They believe that the cerebral cortex is divided into many independent functional areas, which divide various psychological abilities. They put forward in the six-volume Anatomy and Physiology of Nervous System: ① The brain is the only psychological organ; ② People's basic personality and various intellectual characteristics are determined by nature; ③ There must be cortical regions with different developmental levels in the brain, which are responsible for different abilities, that is, different functions lead to different control structures. They also believe that the shape of the skull is consistent with the outline of the cerebral cortex, so we can judge the development of the cerebral cortex from the shape characteristics of a certain part of the skull, so as to judge the individual's ability in a certain aspect. They listed a lot of independent psychological abilities, which belonged to the functions of different parts of the brain, and called these parts corresponding organs. For example, the brain region in the posterior lower corner of the parietal bone is an aggressive organ; The cortical area under the posterior superior skull is the organ of self-esteem; The cortical area under the posterior upper part of the head may be a cautious organ; The cerebellum is an organ of lust and so on. This view was called phrenology after 18 15 years. At that time, it aroused the interest of ordinary people, but it was strongly opposed by serious scientists. One of the most famous opponents is M.-J.-P. Florence (see functional equivalence theory of cerebral cortex). Florence thinks that the research of Gal and Spoor Zheim is not rigorous in methodology, so their theories have no reliable factual basis. About 50 years later, due to the accumulation of clinical observation and animal experimental materials, the concept of cortical functional localization has revived.
Page (abbreviation of page) broca, a French neurologist, found in 186 1 that the brain tissues in the posterior part of the second and third frontal gyrus of the left hemisphere and the anterior part of Sylvia's fissure were softened or damaged, and the patient lost the ability to speak. This area is called broca District from now on. Three years later, J.H. Jackson, a British clinical neurologist, noticed the relationship between speech loss and right hemichorea, and pointed out that in addition to the tongue motor area discovered by broca, there is also a certain cerebral gyrus that manages the fine hand movements directly controlled by psychology. In 1870, German psychiatrists G. Fritsch and E. Hietzig pioneered the method of electrically stimulating different regions of animal brain hemisphere. By stimulating the first half of the cerebral hemisphere, they obtained the contraction movement of the muscles of the contralateral body and found five different movement points. But it is impossible to get muscle movement by stimulating the second half of the hemisphere. This experimental result proves that there is a certain degree of specialized motor center in the brain. Since then, British neuroscientist D. Frerier published the results of repeated electrical stimulation experiments by Fritsch and Hietzig in the brains of monkeys, dogs and other animals in 1876, and established the positioning principle of brain sensory and motor functions.
But these locatable functions are relatively simple functions of action and feeling. If we admit that the brain is an organ of psychology, according to Gal and Spurzheim, do other psychological abilities that make up a person's personality also have a definite position? Ferrier himself avoids making any speculation on this issue without definite factual basis.
1874, an American brain surgeon, R. Bacelo, conducted an electrical stimulation test on the cerebral cortex of a patient with a festering skull and exposed meninges. It was found that ① when he stimulated the cerebral cortex of a conscious patient with weak current, he could not feel pain, while strong current could cause painful facial expressions, shouting, hand stretching and contralateral arm spasm, blindness, dilated pupils, purple lips and white vomit. ② Stimulating individual areas with weak current can cause individual muscle contraction; ③ Stimulation is often accompanied by subjective feelings. For example, when stimulating the back of the left hemisphere, it can cause the muscles of the right upper limb to contract, and then the muscles of the right lower limb to contract. At the same time, the patient reported that his right arm and right leg felt irritable and uncomfortable.
Later, in 109, H. Cushing of the United States used the same electrical stimulation method to find areas in the cerebral cortex of a boy aged 15 and a 44-year-old adult man that can produce pure sensory experience without exercise. Since then, the exploration of sensory functional areas has begun. Mainly depends on the patient's introspection report made under electrical stimulation.
Canadian neurologist and neurosurgeon W.G. Penfield explored electrical stimulation of cerebral cortex of about 400 patients undergoing brain surgery from 1928 to 1950. 1950, he and T. Rasmussen co-authored the book "Human Cerebral Cortex", describing their research results, that is, the anterior central gyrus is the area that controls voluntary movement, called the motor area. The relationship between this area and the limbs it controls is reversed, that is, the upper part controls the lower limbs and the lower part controls the upper limbs. The area of each part is directly proportional to the importance of the functions of the controlled motor organs. Electrical stimulation of the central posterior gyrus does not produce movement, but produces somatic sensation, so it is determined as the somatosensory area. The relationship between various parts of this area and the body is also reversed. The area occupied by each part of the body in this area is directly proportional to the sensitivity of this part. Stimulating the posterior occipital lobe, patients often report feeling of light, color or shadow. Stimulating the cortex between the middle temporal gyrus, the inferior temporal gyrus and the occipital lobe, as well as the temporal cortex and the parietal cortex, patients often report that they seem to have heard the voices of acquaintances a few years ago, or that acquaintances appear in front of them, and even reproduce a scene they have experienced in the past. Stimulating the Bullokar area in the frontal lobe of the left hemisphere often stops the patient from speaking (see figure).
Looking at the above research results, it seems that the functional orientation of the cerebral cortex has such a clear outline: ① The function of directly controlling voluntary movement is in the anterior central gyrus, which is called the first-order motor area; ② Somatosensory function is in the posterior central gyrus; ③ The visual function is around the rectangular fissure of occipital pole or occipital lobe; ④ The auditory function is in the transverse temporal gyrus, and these areas are called the first-order sensory areas. There is also a secondary area on the periphery of the primary sensory area for advanced processing of various senses; ⑤ It is generally believed that visceral sensory function lies in insular lobe; 6. Olfactory processing is in the lateral lobe; ⑦ The motor function of organizing speech is in the left hemisphere Bullokar area of most right-handed people; To understand the function of language, most people are also in the superior marginal gyrus and angular gyrus behind the lateral fissure of the left hemisphere, that is, Wernicke's area.
The meaning of these functions is relatively simple, and the positioning is relatively clear. In addition, most functions of cortex are considered to be complex or comprehensive, and their location is not clear. People generally attribute the functions of judgment, planning and decision-making to the frontal lobe, and even think that the functional organization of the frontal lobe determines a person's personality characteristics; As for synthesizing all kinds of feelings, knowing one's spatial state is considered as the function of the parietal lobe; Dreaming and memory are mostly functions of temporal lobe; Emotion and emotion are mainly the functions of the limbic system, and are also closely related to the anterior temporal lobe.
In the 1960s, R.W. sperry, M.S. gazzaniga, W. Geschwind and others studied the patients with brain anatomy, and obtained conclusive materials to prove the functional asymmetry of the two hemispheres of the brain. Researchers have realized that speech ability is in the left hemisphere of most right-handed people, and the hemisphere with speech function is called the dominant hemisphere. This hemisphere not only has the ability to analyze and process languages, but also has advantages in analyzing the subtle structure and abstract features of things (such as the rhythm and frequency of sounds, mathematical concepts and logical reasoning, etc.). ); The right hemisphere is good at understanding the overall nature and spatial relationship of things (such as recognizing various images and spatial structures). In this way, in addition to the functional orientation of the cortex, the functional division of the two hemispheres is also proposed.
Now neuroanatomists, neurophysiologists and neuropathologists generally recognize the above-mentioned cortical functional orientation. But this is not only different from the functional orientation proposed by Gal at the beginning, but also different in concept. Gail tried to arrange many independent mental abilities he imagined in different parts of the cerebral hemisphere, and the cerebral hemisphere seemed to hold these different mental abilities independently. Today, only the cortex around the anterior central gyrus, posterior central gyrus, transverse temporal gyrus, occipital pole and medial rectangular fissure has a strict correspondence with the peripheral organs it controls and undertakes. As for the joint area and limbic system, which occupy the largest part of the cortex, most of them accept information from various channels, so they can only admit that they have different effects on different psychological processes and States (such as sensory processing, learning and memory, emotions and emotions, etc.). ), but we can't think that these psychological processes are independent of each other, let alone believe that these processes will be carried out in some limited parts. Even though the two hemispheres of the cerebral cortex have a division of labor in function, in normal people, their work is unified.
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