The nervous system is important to control and coordinate all the actions of an organism and transmit signals between different parts of the body via specialized cells called neurons. Moreover, the complexity of the nervous system increases with the complexity of the body of organisms. Most primitive animals like sponges and flatworms have a very simple nervous system while advanced animals like vertebrates have a highly complex nervous system with larger brains. The brain is one of the largest and most amazing organs in humans that can be categorized under the central nervous system. The human brain can be divided into three categories as forebrain, midbrain, and hindbrain. Both cerebrum and cerebral cortex belong to the forebrain.
1. Overview and Key Difference
2. What is Cerebrum
3. What is Cerebral Cortex
4. Similarities Between Cerebrum and Cerebral Cortex
5. Side by Side Comparison – Cerebrum vs Cerebral Cortex in Tabular Form
What is Cerebrum?
Cerebrum is the largest and most prominent part of the human brain. It appears to envelop the rest of the brain as it constitutes 4/5 of its weight. It is split longitudinally into two large, prominent hemispheres – left and right, by the deep median fissure called ‘cerebral fissure’. A horizontal sheet of nerve fibers known as corpus callosum connects these two hemispheres. Each hemisphere has different parts as frontal, parietal, temporal, and occipital lobes. The three deep fissures, central, parieto-occipital and Sylvian fissure, divide each hemisphere into the above lobes.
Furthermore, each hemisphere receives sensory input from the contralateral side of the body and exerts motor control over that side. The basic function of the cerebrum is to control voluntary functions and seat of intelligence, will power, memory, reasoning, thinking, learning, emotions, speech, etc.
What is Cerebral Cortex?
Cerebral cortex is the 2 to 4 mm thick layer of gray matter on the outer surface of the cerebrum. In humans, the cerebral cortex is densely packed, with over 10 billion nerve cells (about 10% of all the neurons in the brain). Therefore, most of the neural activities of the cerebrum take place within this layer. Furthermore, the outer surface of the cerebral cortex is highly convoluted, and this convoluted surface increases the surface area of the cerebral cortex. Gyri are the ridges of these convolutions while sulci are the depressions between them. Each region is responsible for a particular function. According to the function or activity, the regions of the cerebral cortex can be divided into three general categories as motor, sensory, and associative.
The motor cortex is associated with the movement of body parts while the sensory cortex (auditory cortex, visual cortex etc.,) is associated with sensory organs. There is a portion of the cerebral cortex which is not occupied by motor and sensory cortices, known as the ‘association cortex’. This region is responsible for higher mental activities; in higher primates, especially in humans, it covers 95% of the total cerebral cortex surface.
What are the Similarities Between Cerebrum and Cerebral Cortex?
- Cerebrum and cerebral cortex are components of the forebrain.
- Specifically, cerebral cortex is the outer layer of the gray matter of cerebrum. Hence, the cerebral cortex is a part of the cerebrum.
- Thus, both are located in the uppermost region of the central nervous system.
- Furthermore, they are important in the coordination of functions of the body.
What is the Difference Between Cerebrum and Cerebral Cortex?
Cerebrum is the largest and most prominent part of the brain whereas cerebral cortex is the outer layer of the cerebrum. So, this is the key difference between cerebrum and cerebral cortex. Moreover, cerebrum has both gray and white matter while the gray part of it is the cerebral cortex. Thus, this is also a difference between cerebrum and cerebral cortex.
Besides, a further difference between cerebrum and cerebral cortex is that the human cerebrum has both cell bodies and nerve fibers while cerebral cortex contains approximately 10 billion nerve cell bodies and their dendrites. Furthermore, a significant difference between cerebrum and cerebral cortex is that the cerebrum has two hemispheres while cerebral cortex has four lobes.
The below infographic summarizes the difference between cerebrum and cerebral cortex, comparatively.
Summary – Cerebrum vs Cerebral Cortex
In summarizing the difference between cerebrum and cerebral cortex, the cerebrum is the largest and prominent part of the brain, whereas the cerebral cortex is a part of the cerebrum. In fact, it is the outer layer of the gray matter of the cerebrum. Moreover, the cerebrum consists of two hemispheres while cerebral cortex consists of four lobes. Furthermore, cerebrum has cell bodies and nerve fibers while cerebral cortex has cell bodies and dendrites.
1. “Lobes of the brain NL” By Henry Vandyke Carter – Modifications: vectorization (CorelDraw). Original: Gray728.png. Modifications made by Mysid (Public Domain) via Commons Wikimedia
2. “Brainmaps-macaque-hippocampus” By brainmaps.org (CC BY 3.0) via Commons Wikimedia