Regulates the Autonomic Nervous System (heart rate, blood pressure, body temperature) and the endocrine system (hormone release). Involved in hunger, thirst, sex drive, and the body's response to stress.
Involved in emotion formation, pain processing, learning, and linking behavioral outcomes to motivation.
📍 Location and Context
The limbic system structures are located on the border ("limbus" is Latin for border) between the older, subcortical areas (like the brainstem) and the newer, sophisticated cerebral cortex.4
It is considered an evolutionarily ancient part of the brain, involved in the basic instincts necessary for survival.5 It works in conjunction with other parts of the brain, particularly the prefrontal cortex, which provides the executive control necessary to regulate and modulate the emotional impulses generated by the limbic system.
OTHER SOURCES
The brain parts that you do not often see in drawings is found deep within the brain. This brain part is called the limbic system and is involved in emotions and basic drives. Some refer to the limbic system as the lower brain, not only because of where it is located, but because it handles the things about us that are a bit less civilized.
For example, the amygdala and nucleus accumbens are important for processing fear and reward. They are also involved in drug, alcohol and other addictions. The cingulate gyrus runs the day to day activities of the body that we do not directly control, like heart rate and blood pressure.
One interesting part of the limbic system that actually resides in the parietal cortex is called the hippocampus. The hippocampus is the brain part that forms memories. You have one of these on each side of the brain.
If one hippocampus is injured, say by a stroke, the other one will still allow your brain to make memories. However, if both hippocampi are removed, as was once done through surgery, then you cannot form new memories!
This horrible thing happened to a person that underwent surgery to prevent almost continuous, life-ruining seizures.
After the surgery, it was found that the person could only remember things that happened prior to the surgery and could not make new memories.
Each day, in fact each new moment was a confusing, perpetual question of How did I get here?
Needless to say this surgery never happens anymore but this terribly unfortunate occurrence demonstrates the importance of the hippocampus in memory.
The human brain is divided into several major regions, each responsible for specific functions. One of these important regions is the Cerebellum, located at the lower back part of the brain, just beneath the Occipital Lobe and behind the Brainstem.
The Cerebellum is often referred to as the “little brain” because of its rounded, wrinkled structure that resembles a smaller version of the main brain. It plays a vital role in movement coordination, balance, posture, and motor learning.
Tip: The temporal lobe sits below the parietal and frontal lobes, near your ears, which is why it’s heavily involved in hearing.
Temporal Lobe - There are two temporal lobes, one on each side of the brain located at about the level of the ears. These lobes allow a person to tell one smell from another and one sound from another. They also help in sorting new information and are believed to be responsible for short-term memory.
Tip: On an actual brain, the central sulcus separates the frontal lobe (motor functions) from the parietal lobe (sensory functions).
Parietal Lobe - One of the two parietal lobes of the brain located behind the frontal lobe at the top of the brain.
Parietal Lobe, Right - Damage to this area can cause visuo-spatial deficits (e.g., the patient may have difficulty finding their way around new, or even familiar, places).
Parietal Lobe, Left - Damage to this area may disrupt a patient's ability to understand spoken and/or written language.
The parietal lobes contain the primary sensory cortex which controls sensation (touch, pressure). Behind the primary sensory cortex is a large association area that controls fine sensation (judgment of texture, weight, size, shape)
The occipital lobe is the smallest of the four lobes of the brain, located at the back of the skull, and is primarily responsible for visual processing. It receives visual information from the eyes and processes it to allow us to see, recognize objects, and understand spatial relationships.
Key Functions of the Occipital Lobe:
Visual Processing:
The occipital lobe is the main area for visual processing, including color, form, and motion.
Visual Perception:
It allows us to perceive and interpret what we see, including recognizing objects, faces, and places.
Spatial Awareness:
It helps us understand the location of objects in our environment and our own position in space.
Coordination with other lobes:
The occipital lobe works with other brain areas, like the parietal and temporal lobes, to enhance visual experiences and integrate visual information with other senses.
Memory and Learning:
It plays a role in visual memory and learning, including recognizing familiar objects and scenes.
Potential Issues from Occipital Lobe Damage:
Visual Deficits: Damage can lead to various visual impairments, such as blurred vision, color blindness, and difficulty recognizing objects or faces.
The occipital lobe contains the primary visual cortex (V1), which receives initial visual input, and secondary visual areas, which further process visual information.
DIAGRAM OF BRAIN
The occipital lobe is the smallest of the four brain lobes, situated at the rear of the skull, and is chiefly responsible for visual processing. It receives visual data from the eyes and processes it, enabling us to see, identify objects, and comprehend spatial relationships.
Key Functions of the Occipital Lobe:
Visual Processing:
The occipital lobe serves as the primary region for visual processing, encompassing color, shape, and movement.
Visual Perception:
It enables us to perceive and interpret visual stimuli, including the recognition of objects, faces, and locations.
Spatial Awareness:
It assists in understanding the positioning of objects within our surroundings and our own location in space.
The occipital lobe collaborates with other brain regions, such as the parietal and temporal lobes, to enhance visual experiences and integrate visual data with other sensory inputs.
Memory and Learning:
It contributes to visual memory and learning, including the recognition of familiar objects and scenes.
Potential Issues from Occipital Lobe Damage:
Visual Deficits: Damage may result in various visual impairments, including blurred vision, color blindness, and challenges in recognizing objects or faces.
Spatial Disorientation: Difficulty in locating objects or navigating through the environment.
Reading and Writing Problems: Inability to recognize or process written text.
Visual Hallucinations: Experiencing visual sensations that do not actually exist.
Epilepsy: Seizures may originate in the occipital lobe.
Location and Structure:
The occipital lobe is positioned at the back of the head, beneath the parietal and temporal lobes.
It is separated from the parietal lobe by the parietooccipital sulcus.
The occipital lobe houses the primary visual cortex (V1), which receives the initial visual input, along with secondary visual areas that further process visual information.
Comprehensive Functions and Anatomy of the Frontal Lobe
The Frontal Lobe is the largest and most anterior region of the cerebral cortex, often described as the brain's executive control center. It integrates complex cognitive processes and coordinates our actions with our intentions.
1. Motor Control Centers
The back strip of the frontal lobe, located just in front of the central sulcus, is dedicated to controlling voluntary movement.
Primary Motor Cortex (M1): Located in the Precentral Gyrus, this area is the source of the main motor commands that travel down to the spinal cord (via the corticospinal tract). It is organized somatotopically, meaning there is a complete but distorted map of the body (the motor homunculus) where different body parts are controlled by specific cortical areas.
Premotor Cortex (PMC): Involved in the planning and orientation of movement, especially movements guided by external stimuli. It helps select appropriate movements based on visual or sensory information.
Supplementary Motor Area (SMA): Critical for planning sequences of movements (like playing a musical instrument) and coordinating movements that involve both sides of the body (e.g., clapping). It is crucial for movements initiated internally, based on an individual's will.
2. Executive Functions and Cognition
The anterior portion of the frontal lobe is known as the Prefrontal Cortex (PFC), responsible for higher-order cognitive abilities that govern behavior.
Function
Description
Planning & Goal-Setting
Formulating strategies, anticipating consequences, and creating step-by-step plans to achieve a goal.
The ability to switch between different concepts, tasks, or rules based on context.
Attention & Concentration
Maintaining focus on a task and filtering out distractions.
3. Language Production
Broca's Area: Located in the lower portion of the left frontal lobe (for most people), this region is essential for the production of speech. Damage to this area results in expressive aphasia, where a person knows what they want to say but struggles to form words and sentences.
4. Personality, Emotion, and Judgment
The frontal lobe is instrumental in shaping personality and regulating emotional and social behavior.
Personality: It integrates information to determine our unique temperament, disposition, and emotional stability.
Social and Moral Reasoning: It allows us to understand social rules, make ethical judgments, and monitor the appropriateness of our own behavior in a social context.
In summary, the frontal lobe functions as the brain's conductor, coordinating a vast orchestra of thoughts, emotions, and movements to execute complex, intentional, and socially appropriate behavior.
The frontal lobe, positioned at the forefront of the brain just behind the forehead, is the largest among the four brain lobes and is integral to numerous higher-level cognitive functions, personality traits, and voluntary movements. It is frequently regarded as the brain's command center for behavior and emotions.
Key Functions of the Frontal Lobe:
Cognitive Functions:
The frontal lobe is crucial for activities such as working memory, reasoning, judgment, planning, and problem-solving.
Movement:
It governs voluntary movements through the primary motor cortex and also contributes to the planning and coordination of movements via the premotor cortex.
Language:
It contains Broca's area, which is essential for the production of speech.
Social and Emotional Behavior:
The frontal lobe plays a role in the regulation of emotions, social interactions, and decision-making. It aids in impulse control, managing social behavior, and comprehending the consequences of actions.
Personality:
Injury to the frontal lobe can result in notable alterations in personality, including apathy, impulsivity, and diminished social skills.
Location:
The frontal lobe is located at the front of the brain, directly behind the forehead. It is separated from the parietal lobe by the central sulcus and from the temporal lobe by the lateral sulcus.
Injury to the frontal lobe can lead to various cognitive and behavioral deficits, collectively referred to as frontal lobe syndrome. Symptoms may encompass apathy, impulsivity, impaired judgment, and personality changes.
Headaches in the forehead or temple area can sometimes be linked to frontal lobe problems, although numerous other causes may exist.
In conclusion, the frontal lobe is a crucial brain region responsible for a broad spectrum of higher-level cognitive, behavioral, and motor functions. Damage to this area can result in significant impairments in these areas.
Frontal Lobe - Front part of the brain; involved in planning, organizing, problem solving, selective attention, personality and a variety of "higher cognitive functions" including behavior and emotions.
The anterior (front) portion of the frontal lobe is called the prefrontal cortex. It is very important for the "higher cognitive functions" and the determination of the personality.
The posterior (back) of the frontal lobe consists of the premotor and motor areas. Nerve cells that produce movement are located in the motor areas. The premotor areas serve to modify movements.
The frontal lobe is divided from the parietal lobe by the central culcus. Diagram of Brain.
The brain controls movement through a complex, hierarchical system involving multiple regions thatThe brain controls voluntary movement through a precisely organized, hierarchical system that begins with intent and ends with the contraction of specific muscles.This is primarily executed via the motor pathways (descending tracts) involving several key brain regions.
🧠 Key Brain Regions for Movement
Movement is not controlled by a single area, but by a network of structures that coordinate planning, initiation, execution, and correction.
Premotor Cortex and Supplementary Motor Area: These areas in the frontal lobe are involved in the planning and sequencing of complex movements (e.g., deciding the steps to pick up a cup).
Primary Motor Cortex (M1): Located in the frontal lobe's precentral gyrus, this is where the final, specific commands to initiate a voluntary movement are generated. It operates a motor homunculus, a map where different parts of the cortex control specific body parts (the hands and face take up the most space).
The cerebellum is essential for coordination, balance, and fine-tuning movement. It constantly compares the intended movement from the cortex with the actual movement reported by the body's sensory feedback, correcting any errors in real-time.
A group of deep structures that act as a gate, regulating the initiation and suppression of movements. They select the appropriate motor program and inhibit unwanted movements, which is why damage here (as in Parkinson's disease) leads to tremors and difficulty initiating movement.
⚡ The Motor Pathway (The Command Line)
The signal to move travels from the cortex down the primary descending pathway, the Corticospinal Tract, using two main types of neurons:
1. Upper Motor Neuron (UMN)
Origin: The cell body of the UMN is located in the Primary Motor Cortex.
Decussation (The Crossover): The axon of the UMN travels down through the brainstem.In the medulla oblongata, the majority of the fibers cross over (decussate) to the opposite side of the central nervous system.
Descent: The pathway continues down the spinal cord on the side opposite to its origin (the contralateral side). This is why the left side of your brain controls the right side of your body, and vice-versa.
2. Lower Motor Neuron (LMN)
Synapse: The UMN axon synapses with the LMN cell body in the ventral horn of the spinal cord (or in the brainstem for face/neck movements).
The area of the brain that controls movement is in a very narrow strip that goes from near the top of the head right down along where your ear is located.
It's called the motor strip. If I injure that area, I'll have problems controlling half of my body. If I have a stroke in the left hemisphere of my brain, the right side of the body will stop working.
If I have an injury to my right hemisphere in this area, the left side of my body stops working (remember, we have two brains). This is why one half of the face may droop when a person has had a stroke.
Diagram of Brain
Brain tumors are broadly classified based on where they originate (primary or metastatic) and the type of cell they arise from.1The World Health Organization (WHO) also assigns a grade from I to IV based on how aggressive the cells are.2
Here is an overview of the types of brain cancer and tumors:
1. Primary Brain Tumors3
These tumors originate within the brain or spinal cord tissue.4They are often named after the cells they resemble.5
A. Gliomas (The Most Common Type)
Gliomas arise from glial cells, the supportive cells of the brain.6They are categorized by the specific type of glial cell they develop from:7
A rare, aggressive cancer of the immune cells that starts in the brain or spinal cord.
2. Metastatic (Secondary) Brain Tumors8
These are cancers that start in another part of the body (e.g., lung, breast, skin/melanoma, colon) and spread to the brain.9
Key Fact: Metastatic tumors are far more common than primary brain tumors.10
The tumor is named and treated according to the tissue of origin (e.g., metastatic lung cancer to the brain).11
The WHO Brain Tumor Grading System
The World Health Organization (WHO) classifies brain tumors into four grades based on how the cells look under a microscope (histology) and their likely behavior:12
WHO Grade
Classification
Characteristics
Grade I
Benign / Low-Grade
Slowest growing; least malignant; often curable with surgery alone.
Grade II
Low-Grade
Grow slowly but may spread into nearby tissue; can potentially recur as a higher grade.
Grade III
Malignant / High-Grade
Faster growing; cells are abnormal (anaplastic); likely to recur.
Grade IV
Malignant / High-Grade
Fastest growing; most aggressive and invasive (e.g., Glioblastoma).
There are over 100 types of cancer that can affect the central nervous system (CNS).16 As mentioned previously, cancers that arise in other locations (breast, lung, etc.) and spread (metastasize) to the brain are not considered brain cancer. They are still treated as the cancers of the original site. Here, we will only discuss primary brain cancers (those that originate in the brain).
Gliomas
Malignant gliomas are the most common and deadly brain cancers. They originate in the glial cells of the central nervous system (CNS). Gliomas can be divided into 3 main types:
astrocytomas,
oligodendrogliomas, and
ependymomas.
The median survival of patients with glioma has improved over the past few years but is still only 15 months, with few patients living more than two years.Research indicates that this type of brain cancer may resist treatment because it contains stem cells that are responsible for driving the formation of blood vessels (angiogenesis), spread of the tumor (metastasis), and resistance to treatments.
Astrocytomas:
Astrocytomas are tumors that develop in astrocytes and are found in the cerebrum and the cerebellum. Astrocytomas make up approximately 50% of all primary brain tumors. Glioblastoma multiforme, an astryocytoma subtype, is the most aggressive form of brain cancer and is associated with poor prognosis.
Oligodendrogliomas:
Oligodendrogliomas are tumors that develop in oligodendrocytes, and more often in the oligodendrocytes that are found in the cerebral hemispheres. Oligodendrocytes are glial cells that produce myelin, a component of the brain that increases impulse speed. Oligodendrogliomas make up approximately 4% of primary brain tumors. Approximately 55% of all cases of oligodendrogliomas appear in people between the ages of 40 and 64.
Ependymomas:
Ependymomas are tumors that develop in the ependymal cells. Ependymal cells are the cells in the brain and where ceribrospinal fluid (CSF) is created and stored. 24Ependymomas account for only 2% to 3% of all primary brain tumors but account for 8% to 10% of brain tumors in children. Ependymoma tumors are usually found in ventricle linings, the spinal cord, or the regions near the cerebellum.
Nongliomas are tumors that do not arise from glial cells. More prevalent examples of nongliomas include meningiomas and medulloblastomas. Less prevalent examples include medullpituitary adenomas, primary CNS lymphomas, and CNS germ cell tumors.
Meningiomas:
Meningiomas are tumors that develop in the meninges, membranes covering the brain and spinal cord. Meningioma tumors are frequently formed from arachnoid cells. These cells are responsible for the absorption of the cerebrospinal fluid (CSF). Meningioma tumors are responsible for 13% to 30% of all tumors arising within the cranium - the bony case surrounding the brain. Tumor arising within the cranium are also called intracranial tumors. Most meningiomas are benign. Malignant meningiomas are extremely rare, with an incidence rate of approximately two out of every million people, per year. The risk for developing meningiomas increases with age and is more prevalent in women.
Medulloblastomas:
Medulloblastomas are the most common brain malignancies in children. These cancers arise in the posterior fossa - a specific region of the space inside the skull (intracranial cavity) that contains the brainstem and the cerebellum. The fourth ventricle region is involved in the development of approximately 80% of childhood cases.
