The cerebral cortex
The cerebral cortex is the outer layer of the brain, a thin layer of connecting nerve cells that serves as the information processing center of the brain. This part of the brain is divided into two parts, each playing an important role in different functions. The cerebral cortex covers a larger area in humans than in other animals, enabling us to develop higher cognitive abilities. As mammals evolved, their cortex expanded, allowing for greater flexibility and adaptability in learning and behavior. In humans, much of what defines our unique cognitive abilities comes from the activities of the cerebral cortex.
By the end of this section, you should know about:
- Planning
- The Role of the Cerebral Cortex in Higher Functions
- Right-Left Differences in the Intact Brain
- A study of left-handedness
Let’s Take a closer look at them.
Test Your Knowledge
At the end of this section, take a fast and free pop quiz to see how much you know about The Cerebral Cortex.
Planning
If you examine a human brain, you will find a wrinkled face like a walnut pattern. This fold increases the surface area of the cortex, creating more neural and synaptic connections—about 20 to 23 billion neurons, 300 billion synapses and the cortex is divided into four major layers.
The Cerebral Cortex: Motor Functions and the Motor Cortex
In the 19th century, scientists discovered that specific parts of the nervous system are involved in body functions. For example, the motor cortex, located behind the frontal lobe, controls voluntary body movements. Stimulation of parts of this region produces movements of specific body parts, the left hemisphere dominating the right hemisphere, and vice versa Over time, Wilder Penfield and other scientists applied electrical stimulation to patients dreams were used to map the motor cortex in areas requiring fine motor control , of the cell.
The Cerebral Cortex: Brain-Computer Interfaces and Their Applications
One interesting application of motor cortex research is the development of brain-computer interfaces. By closely monitoring brain activity, scientists have been able to use their theory to help individuals control devices such as robotic arms and computers. This technology has the potential to help paralyzed or disabled individuals by translating neurological activity into work in the 19th century. U.S. The military is investing in this technology, hoping to develop systems that allow soldiers to control devices with their minds.
The Cerebral Cortex: Sensory Functions and the Somatosensory Cortex
In addition to physical function, the cerebral cortex also processes emotional information. The somatosensory cortex, located anterior to the parietal lobe, receives signals from cutaneous sensations and motor organs. Highly sensitive areas of the body, such as the lips, have large corresponding areas in the somatosensory cortex. Other specialized sensory areas in the cortex process information from the visual and auditory systems. The optic nerve in the dorsal cortex processes visual information, while the auditory nerve processes visual sounds. These spaces help us see and understand the world around us.
The Role of the Cerebral Cortex in Higher Functions
In addition to physical and sensory function, the cerebral cortex is important for more advanced cognitive abilities, such as language, memory, and reasoning. Every part of the cortex plays a role in these complex processes. For example, the frontal lobes are involved in decision making, problem solving, and planning. Time is needed to process auditory and speech information. The dorsal horn helps integrate sensory information with spatial perception. The occipital lobes primarily process visual information. These areas work together to enable humans to think, speak, and navigate the world with sophistication and precision.
The Association Areas: Higher Mental Functions
The human cerebral cortex is divided into regions that specialize in generating sensory input or transmitting mechanical commands. However, these areas comprise only one-fourth of the cortex, leaving a large portion devoted to higher cognitive functions known as the association area. While not directly responsible for simple physical actions or emotional reception, they play an important role in connecting complex processes such as thought, memory and decision-making, and so enable more sophisticated cognitive functions to work. Despite their importance, the association areas do not respond detectably to electrical stimulation, creating the illusion that the brain is only using 10 percent of its capacity.
The prefrontal cortex, located in the frontal lobes, is especially important for planning, judgment, and processing new memories. Damage to this region can impair a person’s ability to plan ahead, even while their memory and intelligence remain intact. It can also lead to personality changes, as seen in the famous case of Phineas Gage, whose frontal lobe injury altered his personality and social behavior. The parietal lobes are involved in mathematical and spatial reasoning, while areas in the temporal lobes help with facial recognition. Damage to the latter can impair the ability to recognize familiar faces, despite the ability to describe facial features.
Brain Plasticity: Adaptation After Injury
One of the most remarkable aspects of the brain is its plasticity or ability to reorganize itself in response to damage or experience. Although the brain and spinal cord are generally not as regenerative as other body tissues (such as the skin), they exhibit the ability to form new neural pathways. Medical care such as trauma victims or brain-damaged children Forced use of damaged limbs can help restore lost abilities. Which in turn retrain the brain to regain physical strength.
In addition, brain plasticity benefits individuals who are blind or deaf. When a person loses one sense, unused areas of the brain can be repurposed. For example, blind people tend to have an expansion of the area of the brain devoted to their sense of touch as it compensates for vision loss. Allowing them to read Braille better. Similarly, deaf people can have improved vision, especially to detect motion. That the brain adapts to the absence of auditory input. This plasticity highlights the unique ability of the brain to adapt to new challenges and experiences. Contributing to recovery and acquisition of new skills even after severe damage.
The Cerebral Cortex: Brain restructuring and neurotransmission
The brain displays remarkable resilience in its ability to regenerate, especially after injury or illness. When a particular part of the brain becomes damaged or incapacitated, nearby or distant areas can also take over. This phenomenon manifests itself in various circumstances. For example, when a tumor blocks speech function on the left side, the right hemisphere compensates and begins processing certain speech functions Similarly, when a person loses a finger, the part of the brain that gives finger sensation will begin to “borrow.” ” areas responsible for close fingers Unexpected experiences can happen.”
In addition to restructuring, the brain also has the ability to activate neurons—creating new neurons to replace damaged ones. This phenomenon, once thought to occur in only a few brains, is now routinely observed in adults, especially in areas like the hippocampus, which is important for the memory that scientists are able to use with radioactive carbon isotopes from the Cold War nuclear experiments confirmed new tissue formation. These studies have shown that about 700 new neurons are made in the hippocampus every day. Arthritis can be helped through activities such as exercise, sleep, and stimulating environments.
The Cerebral Cortex: Brain restructuring and neurotransmission
The brain displays remarkable resilience in its ability to regenerate, especially after injury or illness. When a particular part of the brain becomes damaged or incapacitated, nearby or distant areas can also take over. This phenomenon manifests itself in various circumstances. For example, when a tumor blocks speech function on the left side, the right hemisphere compensates and begins processing certain speech functions. Similarly, when a person loses a finger, the part of the brain that gives finger sensation will begin to “borrow.” ” areas responsible for close fingers Unexpected experiences can happen.” For example, the patient who lost a leg reported feeling sexual sensations in his strange legs. Which now had increased sensitivity due to the “availability” of formerly adjacent brain areas. for another project
In addition to restructuring, the brain also has the ability to activate neurons—creating new neurons to replace damaged ones. This phenomenon, once thought to occur in only a few brains, is now routinely observed in adults, especially in areas like the hippocampus, which is important for the memory that scientists are able to use with radioactive carbon isotopes from the Cold War nuclear experiments confirmed new tissue formation. These studies have shown that about 700 new neurons are made in the hippocampus every day. Arthritis can be helped through activities such as exercise, sleep, and stimulating environments. Research is ongoing to understand whether stem cells could potentially be used to repair damaged brain areas in the future, offering hope for conditions like brain injury or neurodegenerative diseases.
The Split Brain: Understanding Hemispheric Function
The brain is divided into two parts, each of which performs different functions. For example, the left hemisphere typically processes language, while the right hemisphere is involved in spatial reasoning, facial recognition, etc. Damage to these areas can lead to impairment of related functions greater than. However, this division of labor is not as rigid as is sometimes thought.
In the 1960s, researchers began studying split-brain patients—who underwent surgery to cut the corpus callosum, a group of nerve fibers that connected the two hemispheres’ researchers could study each hemisphere at independently by presenting stimuli on only one side of the eye
In one famous experiment, patients were shown the word “HE·ART” divided into their vision. The “HE” component was shown in the left visual field (processed by the right hemisphere). And the “ART” component was shown in the right visual field (processed by the left hemisphere). However, when the patients were asked to indicate when they saw it. They pointed to “HE” with their left hand, which was dominated by the right hemisphere. This meant that each part of the earth had free access to information and different levels of responsiveness.
The Cerebral Cortex: Other experiments
Other experiments showed that the right hemisphere, although often seen as “small”, has important abilities. Such as recognizing objects and understanding emotions even if the left is not expressed even by patients whose brains split can have conditions in which their two hands worked independently, as if each piece of land made its decisions
Studies of split brains have shown that the two brain hemispheres have different functions, but function less smoothly when the corpus callosum is connected and even if it is severed, each hemisphere can function independently. Leading to interesting and sometimes bizarre reactions. The left hemisphere controlling language often tries to explain actions initiated by the right hemisphere (which lacks language control) by formulating a logical explanation. Even if it does not make sense to the person.This observation occurs the tendency of the brain to organize even coherent information when working with automation.
Cerebral [seh-REE-bruhl] cortex the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control and information-processing center.
Frontal lobes portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.
Parietal [puh-RYE-uh-tuhl] lobes portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.
Occipital [ahk-SIP-uh-tuhl] lobes portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields.
Temporal lobes portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear.
Motor cortex an area at the rear of the frontal lobes that controls voluntary movements.
Somatosensory cortex area at the front of the parietal lobes that registers and processes body touch and movement sensations.
Right-Left Differences in the Intact Brain
In split-brain individuals, the two hemispheres contribute to different activities, although they generally work together seamlessly. Studies of brain function have shown that particular tasks tend to activate one hemisphere more than the other. For example, the right hemisphere is generally more involved in tasks requiring spatial awareness, facial recognition, and reasoning. On the other hand, the left hemisphere is dominant in tasks such as language production and logical processing, such as language and arithmetic.
A striking example of hemispheric specialization can be found in the process of brain surgery. Surgeons sometimes inject sedatives into the jugular artery to pump blood into one side to temporarily “block” that side to identify areas of importance in speech. As drugs provide a person calmly enters the left hemisphere (which controls speech in most people). The patient will lose speech and the right arm will limp The left arm will touch, but the patient will lie down only able to speak. This shows how in most people the left hemisphere is such a major factor in speech production.
Language processing in both hemispheres: Interestingly, both left and right hemispheres contribute to language processing, albeit with different functions While the left hemisphere processes the language of most individuals, deaf and hard of hearing process their speech in the manner of speaking or touching in the left hemisphere It can interfere, as it will affect speech in individuals who hear the story
The Cerebral Cortex: Key activity in each category
Left Hemisphere: Known for its ability to process language realistically and quickly, the left hemisphere excels at tasks such as reading, writing, speaking, and math, and is particularly adept at rapid and direct word processing.
The Right Wing Right specializes more in the interpretation of nuances and ideas behind language. For example, when given a word like “boot,” followed by “summer” and “earth,” the right hemisphere can make an associative leap to “camp,” understanding the context in general later on. or lack of understanding for subtle reasons.
The Cerebral Cortex: The right hemisphere also excels at tasks like:
Copying drawings
It is better than the left hemisphere at spatial tasks, such as copying complex images or recognizing faces.
Emotional processing
It is more attuned to recognizing and expressing emotions, particularly through the left side of the face (which is controlled by the right hemisphere). Damage to the right hemisphere can impair these abilities.
Speech modulation
The right hemisphere helps us modulate speech in ways that make our meaning clearer. For example, it allows us to ask, “What’s that in the road ahead?” instead of the confusing, “What’s that in the road, a head?”
Self-awareness
Damage to the right hemisphere can lead to bizarre effects on self-awareness, such as the denial of a paralyzed limb, a condition called anosognosia. People with right hemisphere damage may refuse to acknowledge their paralysis or impairment.
Together, these findings confirm that while the two hemispheres of the brain look nearly identical, they are far from redundant. Each hemisphere plays a unique role, contributing to the harmonious functioning of the whole brain. This understanding not only sheds light on the specialized functions of the brain but also illustrates the complexity of our neural processes.
Association areas: areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.
Plasticity the brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.
Neurogenesis the formation of new neurons. corpus callosum [KOR-pus kah-LOWsum] the large band of neural fibers connecting the two brain hemispheres and carrying messages between them.
Split brain a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.
A study of left-handedness
Although left-handedness is not as common as right-handedness, it is an interesting study. About 90% of the population is right-handed, which means they primarily use their right hand for tasks such as writing and taxes. In contrast, about 10% of the population is left-handed, with a slight preponderance of men. Some individuals are bipedal, which means they can perform different tasks with both hands, although this is rare.
Handedness and brain function: The cerebral cortex plays an important role in handedness. Nearly all right-handers (96%) process language predominantly in the left hemisphere, which tends to be slightly dominant. However, left-handed individuals vary widely in how they process language: about 70% use the left hemisphere, the remainder may use the right hemisphere or both. This variation of how individuals process language with the left is an interesting aspect of how brain functions can vary between people.
Is handedness inherent? A genetic effect of alcohol exposure is likely to be prenatal, although research suggests that genetics is not the sole determinant. Studies in twins and fetuses suggest a genetic influence on whether one is left- or right-handed. Interestingly, right-handedness is also present in apes and other primates, suggesting that this trait is deeply rooted in evolutionary history.
Cultural and social attitudes toward lefties: Culturally, being a leftist has historically been viewed negatively, often associated with shyness or inferiority Terms such as “gauche” (French in for “left”) carries negative connotations, while “right-handed” is generally associated with “right-handed” or “righteous.” That too by left-handed individuals Helped greatly in various industries.
The Cerebral Cortex: Benefits of left-handed work
In sports: Left-handed players can have a tactical advantage. For example, in a sport like soccer, left-footed players are valuable on the left side of the field. Left-handed baseball players can also cause challenges for opponents, although left-handed hitters are historically under-represented in golf.
Academic Achievement: Interestingly, studies have shown that in some cases, left-handed people perform better than right-handed people. For example, left-handed students outperformed right-handed students in university exams in Iran (Noroozian et al., 2003).
Left-handedness and entrepreneurship: Left-handedness is common in some industries, especially in areas that require creativity or complex problem solving. Left-handed individuals are often found in greater numbers than expected among musicians, artists, architects, and mathematicians.
Challenges for left-handed individuals: Despite the advantages, left-handed individuals often face practical challenges. They struggle with everyday objects designed for right-handed people, such as tables, spoons, or kitchen utensils. But where their natural left-handedness gives them an advantage, these problems don’t seem to deter them.