The largest part of the brain is the cerebrum – a structure with a surface made of furrows and ridges — a pattern that is unique in each person.
The cerebrum is the part of the brain responsible for creating our understanding of the world that surrounds us by taking in the environmental stimuli, giving them a meaning after translating them into concepts and feelings. In this way, it supports the initiation and coordination of movement, touch, hearing, temperature regulation, vision, reasoning, problem-solving, emotions, and learning.
How Is the Cerebrum Anatomically Divided?
The cerebrum is composed of two cerebral hemispheres, located on the cerebral cortex’s left and right side. The characteristic structure of its folded and wrinkled surface consists of gyri and sulci.
Each cerebral hemisphere is composed of 5 lobes:
Furthermore, the cerebrum’s hemispheres are separated by a deep fissure that contains the Corpus Callosum and is protected by the thin membranes labeled as meninges. One of the meninges is the location of the subarachnoid space filled with cerebrospinal fluid.
Cerebral Cortex
The cerebral cortex is the outer cover of the cerebrum, i.e., the largest part of the brain with connections to all aspects of the body. Its folded and wrinkled surface forms the lobes of the cerebral cortex.
The characteristic folded surface of the brain, which is created by the gyri and sulci, increases the cerebral cortex’s body, increasing the number of cortical neurons that transfer the sensory information to the corresponding centers of the brain.
This rain structure has a vitally important function since it’s responsible for both the regulation and control of the most complex mental processes: language and the processing of information.
Frontal Lobe
The frontal lobe is the so-called “center of intelligence” or a “control panel” of our personality because it regulates and controls all intellectual processes, movement, speech, and some aspects of our nature. This area of the cerebral cortex also plays a vital role in memory, attention, motivation, speech production, and visual attention.
This lobe consists of several wider regions (including the corresponding Brodmann areas). Those brain regions are responsible for processing the information received through the neural paths of the brain.
While the left frontal lobe is in charge of the brain’s cognitive processes, the right frontal lobe governs our non-verbal abilities. Namely, the nerve cells from the left side of the body transmit their information to the nerve cells of the cerebral cortex’s right side, and vice versa. In a way, they’re responsible for the brain mapping out the corresponding parts of the body.
Parietal Lobe
The parietal lobe houses the primary sensory cortex that processes the sensory stimuli of touch and pressure. There’s a larger cortical area behind the primary sensory area dedicated to the regulation and control of the weight, size, shape, and texture of the perceived objects.
Temporal Lobe
The temporal lobe processes and regulates the recognition of sounds, as well as their tones and loudness. The auditory cortex, the main area responsible for the processing and translation of auditory stimuli, is located within the temporal lobe.
This part of the brain also helps us understand speech, language, and retain visual memories. It also plays a significant role in the process of generating and storing long-term memories, in translation, and in remembering emotions. Besides, it also aids in the process of facial recognition.
Occipital Lobe
The occipital lobe is one of the four major lobes located in the cerebral cortex, but it’s smallest in size. This lobe mainly analyzes and interprets visual information from sensory nerve signals sent by the eyes. It is responsible for receiving, selecting, organizing, processing, and integrating the visual signals received through the eye’s retina.
The processes that take place within the occipital lobe include assessing distance, depth, and size of both the visual field and the objects within the area, transferring visual information to other parts of the brain, identifying visual stimuli and signals, and recognizing people/faces, etc.
Insular Lobe
The insular lobe processes some of the most vital cognitive functions and social emotions in the human brain, such as disgust, pride, humiliation, guilt, atonement. By doing this, it predicts the internal condition of the most vital systems of the body.
Probably the most notable function of the insula is the assignment of emotional meaning to the physiological sensations and events. For example, if we feel any kind of physical pain, the insula would recognize it as a negative feeling. This function makes the insula of great importance for psychopathology.
The mind and body are both controlled by the insular lobe. If this part of the brain becomes dysfunctional, the body will suffer too. Such is the case with anorexia nervosa, in which the patients lose their weight up to a critical condition due to brain lesions or damage.
Corpus Callosum
This cerebrum structure is both the most important and the largest C-shaped white matter structure of the brain. Namely, it allows the communication of both sides of the brain, i.e., it enables the relay of information among the most important brain processing centers. Similar areas of this brain structure are connected by neuron fibers that branch out to them from different corpus callosum areas.
By supporting the transmission of information to the hemispheres, corpus callosum aids the functional coordination of the areas dedicated to the processing of perception, attention, language, memory, thinking, and consciousness, by supporting them to work together.
Meninges of the Brain
The Dura mater (closest to the bone), Arachnoid mater (around the brain), and Pia mater (closely attached to the brain and the surface of the spinal cord) are the meninges of the brain, i.e., three-layer membranes that protect the central nervous system against trauma.
Cerebrospinal Fluid
The choroid plexus is a brain structure responsible for the production of cerebrospinal fluid. This secretory tissue made up of a capillary network produces the cerebrospinal fluid and transports it within the cranial cavity, i.e., the skull.
The cerebrospinal fluid protects and nourishes the brain and spinal cord while it flows around them. It carries the proteins and glucose that provide energy for the proper function of the brain cells. It also contains lymphocytes that guard the brain structures against infection.
The Gyri and Sulci of the Brain
The cerebral cortex follows the folds and furrows of the cerebrum to cover its entire surface. The gyri (sg. gyrus) is the raised surface (or ridges) of the brain that gives it its familiar folded structure, while the sulci (sg. sulcus) are the furrows that run between them.
These rain structures divide each hemisphere of the cerebral cortex into five regions called lobes, i.e., centers of regulation of specific brain functions.
What Structures Comprise the Cerebrum?
The subcortical structures of the cerebrum include the hippocampus, basal ganglia, and the olfactory bulb.
Hippocampus
Located in the temporal lobe, the hippocampus (along with the entorhinal cortex and perirhinal cortex), is the place where the declarative (explicit) memories are processed, encoded, translated, recorded, and consolidated in the brain so that they can be retrieved at some point in the future.
The hippocampus also supports the translation of emotions and their association with the previously stored information of an emotion-evoking event.
Basal Ganglia
Because of their appearance, the basal ganglia are also called “islands” of gray matter, located deep in the cerebrum. These groups of neurons and the cerebral cortex are composed mainly of the cell bodies and projections (dendrites) of neurons involved in the interactions between the cognitive and motor processes.
The basal ganglia are one of the most fundamental processing units of the brain, responsible for a broad spectrum of functions, including the control of voluntary motor movements, procedural and habit learning, movements of the eyes, cognition, as well as emotion.
Olfactory Bulb
The olfactory bulb filters the background odors to support the transmission of a few selected odors. They also aid the other brain areas in modulating the detection or the filtering of odors.
This cortical structure comprises of 2 types of neuronal cells:
- Projection neurons
- Interneurons
These cells send their fibers to the primary olfactory cortex. They are the only sensory connections that do not pass through the thalamus before connecting to the brain’s critical structures.
Fun Facts
Did you know?
- The corpus callosum is the most massive white matter structure, comprising over 200 million axonal projections.
- The occipital lobe helps us understand what we have seen by linking the visual information we get through our eyes with the images stored in our memory.
- When you look at a lemon and recognize it by its yellow color, this is due to the occipital plane’s function in your brain.
- How many times have you stubbed your little toe on the coffee table or the door? It hurts, right? Well, the insula is the part of the brain that supports this sensory perception and helps you realize that the impact you feel is pain.
- The cerebrum is the Latin word for “brain.”
- All forms of vocalization, such as reciting, singing, even humming, can be healing. The pleasant sound activates the dedicated centers in the temporal lobe of the cerebral cortex, making us feel more alive and more present at the moment.
- In the case of inflicted damage to the hippocampus, we might lose our memory, leading to the need to learn how to read, write, or speak anew.
- The volume of the basal ganglia can be increased through cardiovascular exercises, which can improve its function.
- The human brain comprises about 1000 billion neurons.
- The furrows of the cerebrum can be complete or incomplete. On the other hand, the folds increase the gray matter, which in turn increases the quantity of information processed in the brain.