A detailed explanation of Brain structure The brain consists of two hemispheres, the left hemisphere and the right hemisphere, and the endplate connecting the middle part of the two hemispheres, that is, the front end of the third ventricle. The cerebral hemisphere is covered with gray matter, called cerebral cortex, and its deep side is white matter, called medulla. The gray matter nuclei in medulla are basal ganglia. Between the two hemispheres of the brain by giant bundle fibers? Connect.
The specific content includes five parts: cerebral lobes, functional orientation of cerebral cortex, deep structure of cerebral hemisphere, white matter in cerebral hemisphere, olfactory brain and limbic system.
The position, structure and main functions of each leaf are as follows:
1, frontal lobe: also called frontal lobe. Located in front of the central sulcus. Between the central sulcus and the central anterior sulcus is the central anterior gyrus. There are superior frontal sulcus and inferior hungry sulcus in front of it, and the superior frontal gyrus, middle frontal gyrus and inferior frontal gyrus are separated by the two sulcus. There are lateral fissure ascending branches and horizontal branches in the posterior part of inferior frontal gyrus, which are divided into orbit, triangle and lid. The front of the frontal lobe is the frontal pole. There are straight gyrus and orbital gyrus bounded by orbital sulcus at the bottom of frontal lobe, and the innermost deep sulcus is olfactory tract sulcus, which contains olfactory tract and olfactory bulb. The olfactory tract is divided into medial and lateral olfactory stria, and the triangular area bounded by its bifurcation is called olfactory triangle, also known as anterior penetrating substance, from which many perforating vessels of the anterior basilar artery ring enter the brain. On the medial side of the frontal lobe, the part of the anterior and posterior central gyrus is called paracentral lobule. Responsible for thinking and planning, related to individual needs and emotions.
2. Parietal lobe: located behind the central sulcus, and the parietal occipital fissure is before the connecting line of the anterior occipital notch. Between the central sulcus and the central posterior sulcus is the central posterior gyrus. The transverse interparietal sulcus divides the rest of the parietal lobe into superior parietal lobule and inferior parietal lobule. The inferior parietal lobule includes superior marginal gyrus and angular gyrus. In response to feelings of pain, touch, taste, temperature and pressure, this area is also related to mathematics and logic.
3. Temporal lobe: Located below the lateral fissure, it is divided into superior temporal gyrus, middle temporal gyrus and inferior temporal gyrus by three sulcus. Hidden in the lateral fissure is the transverse temporal gyrus. On the side and bottom of the temporal lobe, between the infratemporal sulcus and the lateral accessory fissure is the fusiform gyrus, and between the lateral accessory fissure and the hippocampal fissure is the hippocampal gyrus, and the hooked part around the front end of the hippocampal fissure is called the hippocampal uncinate gyrus. Responsible for processing auditory information, but also related to memory and emotion.
4. Occipital lobe: located behind the connecting line between occipital parietal fissure and anterior occipital notch. On the medial side, there is a wedge between the talus fissure and the occipital fissure, and a lingual gyrus between the talus fissure and the lateral accessory fissure. Responsible for processing visual information.
5. Island leaf: located in the deep side of the lateral fissure, the oblique central hook on its surface is divided into long loop and short loop.
6. Marginal system: related to memory, and related to emotion in behavior.
Summary of the brain The cerebral cortex is the highest center of the central nervous system, and the functions of each cortex are complex, which are not only related to various senses and movements of the body, but also closely related to language and writing. According to the characteristics of cell composition, arrangement and construction of cerebral cortex, the cortex is divided into several regions.
Now, according to Brodmann's functional area positioning, it is briefly described as follows:
? Cortical motor area: Located in the anterior central gyrus (area 4), it is the center of voluntary movement. It mainly receives proprioception impulses from the contralateral skeletal muscle, tendons and joints to feel the position, posture and motion of the body, and sends out fibers, namely pyramidal tract, to control the voluntary movement of contralateral skeletal muscle. The premotor area of returning cortex: located in front of the anterior central gyrus (area 6), it is the extrapyramidal cortex area. It sends fibers to thalamus, basal ganglia, red nucleus and substantia nigra. It is related to the coordination of joint movement and posture and movement, and also has some functions of autonomic cortex center.
? Cortical eye movement area: located in the 8-axis of frontal lobe and occipital lobe 19 area, it is the gaze center of eye movement in the same direction, which manages the simultaneous gaze of two eyeballs to the opposite side. General sensory area of cortex: located in the central posterior gyrus (1, 2, 3), which receives the pain, temperature, touch and proprioception impulses of the opposite side of the body and forms corresponding feelings. The parietal lobules (5, 7) are cortical areas for fine tactile and solid perception.
? Frontal junction area: it is the 9, 10, 1 1 area in front of the frontal lobe, which is closely related to intellectual and mental activities.
? Visual cortex area: the adjacent area between the upper and lower lip of the occipital lobe and the cuneiform lobe and lingual gyrus (17 area). The cortex of each side receives the visual impulse from the opposite visual field of both eyes and forms vision.
? Auditory cortex: located in the middle of transverse temporal gyrus (4 1 42), also known as Heschl's gyrus. Each cortex produces hearing according to auditory impulses from both ears.
? Olfactory cortex area: located in the olfactory area, the anterior part of the uncinate gyrus and the hippocampus (most of areas 25, 28, 34 and 35). Each cortex receives impulses from bilateral olfactory nerves.
? Visceral cortex area: this area is not concentrated, mainly distributed in the anterior cingulate gyrus, anterior temporal lobe, posterior orbital gyrus, insula, hippocampus and uncinate gyrus of hippocampus.
? Language use center: Special activities such as human language and using tools also have a relatively concentrated representative area (dominant hemisphere) on one side of the cortex, also known as the language use center.
They are:
① Motor language center: located in the posterior part of inferior frontal gyrus (areas 44 and 45, also called Broca area).
② Auditory language center: located in the cortex of the 42 nd and 22 nd regions of the superior temporal gyrus, which has the function of hearing sounds and understanding a series of processes of idioms. ③ Visual language center: located in the angular gyrus of the inferior parietal lobule, namely area 39. This area has the function of understanding the meaning of symbols and words you see.
④ Application center: located in the superior marginal gyrus of the inferior parietal lobule, that is, area 40. This area is in charge of fine coordination functions.
⑤ Writing center: It is located in areas 8 and 6 at the back of the middle frontal gyrus, that is, in front of the central anterior gyrus.
Deep structure of cerebral hemisphere? Basal ganglion: Basal ganglion is a group of nerve nuclei under the cerebral cortex, which includes striatum, amygdala and lamina cribrosa (banded nucleus).
The striatum consists of caudate nucleus and lenticular nucleus. The striatum is one of the heavy meridian structures of the extrapyramidal system of thalamus and a part of the motor integration center. It mainly receives afferent impulses from cerebral cortex, thalamus, subthalamic nucleus and substantia nigra, and forms extensive connections with red nucleus and reticular structure to maintain the coordination of muscle tension and muscle activity.
? Internal capsule: The internal capsule is located between lentiform nucleus, caudate nucleus and thalamus, which is the only way for the important nerve bundle connecting the cerebral cortex with the lower center, and looks like a broad white matter fiber belt. The internal capsule can be divided into three parts, the forehead is called forelimb, the occipital part is called hind limb, and the confluence area of the two parts is knee.
cerebrum
Telencephalon, also known as telencephalon, is the main part of the higher nervous system of vertebrate brain, which is composed of the left and right hemispheres. It is the largest part of the brain in humans and is the higher nerve center that controls movement, produces feelings and realizes higher brain functions. In vertebrates, telencephalon is a bulging part of the thin wall at the head of the neural tube in embryo, and then it develops into two hemispheres, mainly including cerebral cortex and basal nucleus. The cerebral cortex is gray matter covered on the surface of telencephalon, which is mainly composed of cell bodies of neurons. The deep cortex consists of medulla or white matter formed by nerve fibers. There is also a gray mass in the medulla, that is, the basal nucleus, and the striatum is the main part. The brain in a broad sense refers to all brain structures above the tentorium cerebelli, namely telencephalon, diencephalon and part of midbrain (see central nervous system).
Brain structure
The brain mainly includes the left and right hemispheres, which is the highest part of the central nervous system. The human brain is an organ of thinking and consciousness developed in the process of long-term evolution. The shape of the cerebral hemisphere is divided into leaves. The left and right cerebral hemispheres are connected by the corpus callosum. The cavities in the hemisphere are called lateral ventricles, which communicate with the third ventricle through the interventricular foramen. Each hemisphere has three sides, namely, the bulging back outer side, the vertical inner side and the uneven bottom. The outer side and the inner side of the back are bounded by the upper edge, and the outer side and the bottom are bounded by the lower edge. The surface of the hemisphere is uneven, covered with grooves and fissures of different depths, and the uplift between the grooves and fissures is called the cerebral gyrus. The main fissures in the dorsal lateral surface are as follows: the central sulcus inclines from the upper edge near the midpoint to the lower front; The lateral fissure of the brain starts from the bottom of the hemisphere and turns to the lateral surface from the lower front to the upper back. On the inner side of the hemisphere, there is a parietal occipital fissure inclined from the upper back to the lower front; The taloid fissure connects the occipital fissure from the back to the front and reaches the occipital pole backwards. These fissures divide the cerebral hemisphere into five lobes: the frontal lobe before the central sulcus and above the lateral fissure; Temporal lobe below lateral fissure; The occipital lobe behind the occipital fissure and the parietal lobe above the lateral fissure and between the central sulcus and the occipital fissure; And the insula deep in the lateral fissure. In addition, with the central sulcus as the boundary, the central anterior gyrus is between the central sulcus and the central anterior sulcus; The central posterior gyrus is located between the central sulcus and the central posterior sulcus.
Internal structure of the cerebral hemisphere 1. Gray matter: A layer of gray matter covering the surface of the cerebral hemisphere is called cerebral cortex, which is the place where neurons are concentrated. The distribution of these neurons in the cortex has a strict hierarchy, and the differentiation of the ancient cortex on the inner side of the cerebral hemisphere is relatively simple, generally only three layers: ① molecular layer; ② pyramidal cell layer; ③ Polymorphic cell layer. The neocortex on the lateral side of the cerebral hemisphere has a high degree of differentiation, and there are six layers: ① molecular layer (also called banded layer); ② outer granular layer; ③ outer pyramidal cell layer; ④ Inner granular layer; ⑤ Inner pyramidal cell layer (also called ganglion cell layer); ⑥ Polymorphic cell layer.
2. The deep surface of the cortex is white matter, and there are gray matter nuclei in the white matter, which are close to the brain base and called basal ganglia. The basal nucleus is mainly striatum. The striatum consists of caudate nucleus and lenticular nucleus. The caudate nucleus is thick at the front end and thin at the tail end, bending and surrounding the thalamus; The lenticular nucleus is located on the lateral side of caudate nucleus and thalamus, and is divided into globus pallidus and putamen. The caudate nucleus and putamen appear later in phylogeny (that is, animal evolution), which is called new striatum, while globus pallidus appears earlier in phylogeny, which is called old striatum. The main function of striatum is to coordinate the movement of muscles and maintain a certain posture of the body.
left brain
Broca's brain division experiment: It took 200 years to understand the seemingly simple problem of functional differences between the left and right hemispheres of his brain. Before19th century, we knew almost nothing about the differences between the left and right brains. Human beings have experienced a long and painful process in understanding this self. 18 16, a French doctor, broca, happened to meet an aphasic patient. It turned out that he could speak, but he couldn't express his thoughts in words after his illness. But the examination showed that his hearing organs and pronunciation organs were intact. When the patient's body was dissected, broca found that the patient's left frontal lobe tissue had serious lesions, and he wrote a paper that caused a sensation in the scientific community? People speak with their left brain. The study of aphasia makes people finally realize the left brain and the right brain, which is the famous broca's experiment of brain division.
The establishment of the concept of division of labor between left and right brain: The new concept of division of labor between left and right brain was really established in 1950s. We can't help mentioning one person here, that is, sperry, a famous biologist and a professor at California Institute of Technology. He and his students began to conduct experimental research on splitting brains in animals, and found that when all the connections between the left and right brains of cats (followed by monkeys) were cut off, these animals still lived normally. What's more exciting is that they can train two hemispheres to accomplish the same task in opposite ways. Later, they conducted an experimental study on schizencephaly, that is, cut off the neural connection between the two hemispheres for patients with severe epilepsy, making them relatively independent hemispheres. The results show that each independent hemisphere has its own stream of consciousness, and two independent consciousness exist in parallel in the same mind, and they have their own feelings, perceptions, cognition, learning and memory. In other words, the left brain also has the function of the right brain, and the right brain also has the function of the left brain, but each has its own division of labor and emphasis.
If depicted vividly, the left brain is like an orator, good at language and logical analysis; Like a scientist, he is good at abstract thinking and complex calculation, but rigid, lacking humor and rich emotions. Like an artist, the right brain is good at nonverbal thinking in images and intuition, and has an extraordinary perception of artistic activities such as music, art and dance, and a strong spatial imagination. Not good at words, but full of passion and creativity, emotional, humorous and human.
The corpus callosum composed of 300 million active nerve cells in the left and right brain is connected into a whole, which constantly smoothes the information input from the outside and connects abstract and whole images with concrete logical information.
Another view about the left and right brain can be regarded as a supplement to sperry's brain science achievements, that is, the information stored in the left brain is generally obtained after we are born, and the information repeatedly strengthened in the left brain eventually turns into our right brain, which inherits the genetic factors of our ancestors and is the spokesman of their wisdom.
right brain
There are 200 billion brain cells in the human brain, which can store 1 100 billion messages. The mind travels more than 300 miles per hour, has more than 1 100 megabytes of interlaced circuits, and produces 4,000 thoughts every 24 hours on average. It is the most sophisticated and sensitive organ in the world. It is found that there are countless resources to be developed in the brain, and the average person uses less than 5% of the brain power. The remaining part to be developed is the key to the performance of brain power and potential.
The human brain structure is divided into brain, cerebellum and brain stem. The brain consists of cerebral cortex (neocortex), limbic lobe (old cortex), brain stem and brain beam. The cerebral cortex can be divided into frontal lobe, nie lobe and occipital lobe.
In addition, the brain is divided into left and right halves. The right hemisphere is the "right brain" and the left hemisphere is the "left brain". And the left and right brains divide all the structures of the brain equally. The left brain and the right brain have the same shape, but their functions are quite different. Left brain language, that is, using language to process information, converts the information that enters the brain to see, hear, touch, smell and taste (the five senses of the left brain) into language to convey, which is quite time-consuming. The left brain mainly controls knowledge, judgment, thinking and so on, which is closely related to conscious consciousness.
The five senses of the right brain are hidden in the bottom of the right brain, which can be called "instinctive five senses". They control autonomic nerves and cosmic fluctuations, and are related to the subconscious mind. The right brain processes the received information with images, which can be processed instantly, so it can process a lot of information at the same time (mental arithmetic, speed reading, etc. are the manifestations of the right brain processing information). Most people's five senses in the right brain are controlled and suppressed by the rationality of the left brain, so it is difficult to play the existing potential instinct. However, people who know how to use their right brain flexibly can distinguish colors by listening to sounds, or emerge images and smell. Psychologists call this situation "sensation", which is the potential of the right brain.
If the right brain is given a lot of memory, the right brain will automatically process these messages and derive creative messages. In other words, the right brain has autonomy, can exert its own imagination, think and visualize creativity, and has the excellent function as a storyteller. If it is a left brain, no matter how hard you rack your brains, it has its limits. However, as long as the memory of the right brain is combined with the thinking ability, it can be connected with the pre-linguistic pure thinking and image thinking without language, and the original idea will be magically triggered.
function
In 1981, Roger, winner of the Nobel Prize in Medical Physiology? Professor Shi Beni classified the functional differences between the left and right brain as follows:
Right brain (instinctive brain? Subconscious brain)
1. Visualization function (planning, creativity, imagination)
2. The function of * * * vibrating with the universe (sixth sense, reading ability, penetrating vision, intuition, inspiration, dreams, etc.)
3. Ultra-high-speed automatic calculus function (mental arithmetic, mathematics)
4. Ultra-high-speed mass memory (speed reading, memory)? Intellectual? Knowledge? Understand? Thinking? Judge? Reasoning? Language? restrain
Left brain (conscious brain)
? Five senses (sight, hearing, smell, touch and taste)
People's right brain has intuitive overall grasping ability, thinking ability in images, originality and so on, so the development of the right brain is indispensable for personal success. In modern society, the importance of right brain development is particularly prominent, and everyone who wants to succeed must pay attention to it.
telencephalon
Telencephalon consists of left and right hemispheres and basal nucleus, and the corpus callosum connects the two hemispheres.
(A) the shape of the cerebral hemisphere
1. Three faces
Each cerebral hemisphere can be divided into upper lateral surface, inner lateral surface and lower surface.
2. Three interlobar sulcus
Central sulcus, lateral sulcus and occipital sulcus.
3. Five leaves
Frontal lobe, parietal lobe, occipital lobe, temporal lobe, insular lobe.
4. Main sulcus
(1) Frontal lobe: anterior central sulcus, superior frontal sulcus, inferior frontal sulcus, anterior central gyrus, superior frontal gyrus, middle frontal gyrus and inferior frontal gyrus.
(2) Parietal lobe: central posterior sulcus, central posterior gyrus, angular gyrus, supramarginal gyrus, etc.
(3) Temporal lobe: superior temporal sulcus, inferior temporal sulcus, superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus and transverse temporal gyrus.
(4) Medial surface: cingulate sulcus, taloid sulcus, lateral accessory sulcus, cingulate gyrus, central accessory lobule, parahippocampal gyrus, etc.
(5) Below: olfactory bulb, olfactory bundle, etc.
(2) the internal structure of the cerebral hemisphere
1. Functional area of cerebral cortex
(1) Somatosensory areas: the posterior central gyrus and the posterior central lobule.
(2) Body motor area: anterior central gyrus and anterior central lobule.
(3) Visual area: cortex on both sides of taloid sulcus.
(4) Auditory area: transverse temporal gyrus.
(5) Language center
? Auditory language center: superior marginal gyrus.
? Visual language center: angular gyrus.
? Writing center: posterior part of middle frontal gyrus.
? Motor language center: posterior part of inferior frontal gyrus.
2.basal nucleus
It is a gray mass embedded in the medulla of the brain, located at the base of the brain. It mainly includes cribriform nucleus, caudate nucleus, lentiform nucleus, amygdala and so on.
Striatum: caudate nucleus and lenticular nucleus are collectively called striatum. Its main function is to maintain the tension of skeletal muscle and coordinate the movement of muscle groups.
basal nuclei
Basal nucleus, pea-shaped amygdala buried in the brain floor
Tail beans are collectively called striatum coordination movement and tension.
3. Brain medulla
(1) Connecting fibers: connecting ipsilateral cerebral hemispheres.
(2) Conjunctive fiber: the corpus callosum.
(3) Projecting fibers: mainly internal capsule.
Internal capsule: located between dorsal thalamus, caudate nucleus and lenticular nucleus, it consists of ascending sensory fibers and descending motor fibers. On the horizontal section of the brain? > < ? It is divided into three parts: anterior limb of internal capsule, knee of internal capsule and hind limb of internal capsule.
(1) Anterior limb of internal capsule: located between dorsal thalamus and head of caudate nucleus.
(2) Posterior limb of internal capsule: located between dorsal thalamus and lenticular nucleus. There are mainly fiber bundles such as corticospinal tract, spinal thalamic tract and visual radiation.
(3) Knee of internal capsule: located at the intersection of anterior limb and posterior limb of internal capsule, with part of the cortex passing through.
Damage to one internal capsule can cause sensory loss of the contralateral limb and paralysis of skeletal muscle.