Cerebrum

The cerebrum is part of the brain in humans and other animals. In humans, the cerebrum is the largest part of the brain. It is made up of two hemispheres. The cerebrum includes many lobes, which are different parts that usually help the brain perform specific tasks. The cerebrum is important because it helps people perform many common tasks, such as seeing, hearing, and orienting oneself. People who have damage to the cerebrum can experience a number of different effects, such as an inability to write, changes in vision, and an inability to recognize common objects.

Background

The brain is an important organ because it helps control many other organs in the body. Brains allow humans to move, reason, and feel emotion. The brain is extremely complex. Doctors and researchers continue to learn more about the brain all the time, but science has a great deal to learn about this important organ. The brain is part of the central nervous system, which also includes the spinal cord and nerves. The human brain usually weighs about three pounds. A human brain includes approximately 86 billion nerve cells. These nerve cells are called neurons. They allow the brain to function. The neurons collect signals through dendrites that are sent along nerve fibers called axons. The brain has a number of different parts that help it function. The main parts of the brain are the brainstem, the cerebellum, the cerebrum, and the hypothalamus. The brain is protected by a bone called the cranium. The meninges, tissue that protects the brain and spinal cord, separate the cranium from the brain.

Overview

The cerebrum is one of the major parts of the brain. It is also the largest part of the brain. It consists of two hemispheres: the left and the right. The two hemispheres are separated by a large groove called the great longitudinal fissure. The two pieces are joined at the bottom with a piece called the corpus callosum. The corpus callosum not only joins the hemispheres but also helps relay messages between the two sides.

The surface of the cerebrum is called the cerebral cortex. The cerebral cortex is the outer part of the brain, and it is often known as gray matter. It is packed with neurons. In 2025, scientists reported progress in creating a highly detailed map of a small region of the mouse cerebral cortex, showing how tens of thousands of neurons connect to one another. The cerebral cortex is wrinkled and folded in many places. These wrinkles and folds are important because they give the brain more surface area. The larger the surface area of the brain, the more neurons the brain has. Therefore, the wrinkles in the brain actually allow humans to have larger, more powerful brains. Some congenital abnormalities and illnesses cause brains to have fewer wrinkles and bumps. For example, some babies born to mothers infected with the Zika virus have fewer wrinkles in their brains. Babies born with fewer wrinkles often have many cognitive disabilities, in part because the wrinkles allow for more neurons in the brain.

Below the cerebral cortex is the white matter. It contains fibers that connect neurons. Humans are born with many more neurons than they have as adults. However, these neurons that are present in a young human brain are inexperienced. As people use their brains over many years, the brain creates networks of neurons. These networks become entrenched since they are used frequently. Other brain cells, called astrocytes, also help the brain process and support communication between neurons. Other neurons die, but the neurons in the networks become stronger.

The cerebrum is separated into four major lobes: the frontal lobe, the parietal lobe, the occipital lobe, and the temporal lobe. Each lobe is separated by fissures and wrinkles in the brain. These different parts play different roles in the brain. Each lobe is responsible for some individualized tasks. However, different brain parts can learn to play different roles. Therefore, if one part of the brain is injured, sometimes other parts of the brain can take over, completing tasks normally done by the damaged part of the brain. However, this does not happen all the time and is most common in babies and very young children. New tools, such as Neuropixels probes, allow scientists to record signals from thousands of neurons across multiple brain regions at the same time, helping them understand how different parts of the cerebrum (including the lobes) work together.

The frontal lobe is part of the cerebrum. This part of the cerebrum is located near the front of the skull. It plays an important role in speaking, solving problems, planning, controlling emotions, and making decisions. This area, called Broca’s area, is very important for translating human emotions into words. Because of this, the frontal lobe plays an important part in preventing people from having emotional outbursts. Damage to the frontal lobe may result in an inability to control regular emotions in a typical way. The frontal lobe also includes the motor cortex, which manages voluntary skeletal muscle movements.

The parietal lobe is located in the upper middle of the cerebrum. The parietal lobe is important for sending and receiving information about touch, heat, and pain. The parietal lobe includes the sensory cortex. The sensory cortex receives information that is sent from the spinal cord. It helps people understand where their body parts are and helps them move the body. Damage to the parietal lobe may cause people to have difficulty understanding direction or understanding written language. Damage to the parietal lobe could result in an inability to write or an inability to orient oneself.

The occipital lobe is located at the back of the skull. It helps process visual information. This part of the brain also helps people recognize shapes and colors. Damage to the occipital lobe could result in a loss of vision or other visual abnormalities, such as seeing flashing lights or stars.

The temporal lobe has two parts. One is located on the right side of the brain, and the other is located on the left side. This part of the brain is responsible for processing short-term memories. It also helps people differentiate between different sounds and different smells. The right temporal lobe is mostly responsible for visual memory, including faces and images. The left temporal lobe is mostly responsible for verbal memory, including words and names. Damage to the temporal lobes could result in hearing problems or irritability.

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