Frontal Lobe Anatomy And Function
The brain has two hemispheres, the left and the right, which are further divided into three sections: the forebrain, the midbrain, and the hindbrain. Differentiation of these separate parts occurs during fetal development. Each has specific functions:
- The hindbrain controls respiration and heart rate
- The midbrain controls reflex actions such as eye movement
- The forebrain controls emotional perceptions and responses, involuntary movements, sleep patterns, memory, and organizational ability
The forebrain eventually develops into the cerebrum, the outer layer of which is called the cerebral cortex. The frontal lobe is one of the four lobes of the cerebral cortex, which also includes the temporal lobe, the parietal lobe, and the occipital lobe.
Each of these regions carries out specific functions, and damage to any of these lobes results in corresponding impairment.
The frontal lobes are relatively large compared to other regions of the brain, and the extensive functions controlled by the frontal lobe is reflected in its proportional size.
Middle Cerebral Artery Syndrome
Middle cerebral artery syndrome occurs when blood flow within the maintrunk of one of the middle cerebral arteries is interrupted. These arteries supply large parts of the lateral surfaces of the temporal and parietallobes.
Because the lateral surface of the postcentral gyrus in the parietal lobe provides motor input to the contralateral upper extremities and face, ischemic damage to this structure frequently results in contralateral hemiplegia of these body parts.
The lateral surface of the precentralgyrus in the frontal lobe interprets sensory information from the contralateral upper extremities and face. If this part of the cortex is damaged, an affected individual will typically present with contralateral loss of sensation in those same regions.
Because the speechcenters are also located on the lateral surface of the left hemisphere, they can be damaged in middle cerebral artery syndrome as well. Their involvement can result in aphasia, which can present as varying difficulties with reading, writing, and speech.
Posterior Cerebral Artery Syndrome
Posterior cerebral artery syndrome occurs when there is obstruction of the blood flow through the calcarinebranch of the posterior cerebral artery. The calcarine branch supplies the visual cortex in the occipitallobe, the part of the brain necessary for sight.
Ischemic damage to this region can lead to a condition called contralateral homonymous hemianopia , which is the loss of vision in the contralateral visual field. For example, if calcarine branch of the left posterior cerebral artery is occluded, an affected individual will typically experience vision loss in the right visual field of each eye. In cases of temporal lobe ischemia, amnesia may result.
The presence of dual blood supply to parts of the occipital lobe means that certain regions of the visual field may be spared from damage when the posterior cerebral artery is occluded: this typically presents as macular sparing, or sparing of the central visual field.
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Brain Structure And Function
The brain has two halves or hemispheres: right and left. The right hemisphere controls the left side of the body, and the left hemisphere controls the right side. In most people, the left hemisphere regulates language and speech, and the right hemisphere controls nonverbal, spatial skills. If the right side of the brain is damaged, movement of the left arm and leg, vision on the left, and/or hearing in the left ear may be affected. Injury to the left side of the brain affects speech and movement on the right side of the body. Each half of the brain is divided into main functional sections, called lobes. There are four lobes in each half of the brain: the Frontal Lobe, Temporal Lobe, Parietal Lobe, and Occipital Lobe. Other important sections of the brain are the Cerebellum and the Brain Stem. Although not usually divided into lobes, the cerebellum and brain stem both have different parts. Each of the brain hemispheres and lobes, cerebellum, and brain stem has specific functions, and they all work together:
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Frontal Lobe: most anterior, right under the forehead the frontal lobe controls intellectual activities, such as the ability to organize, as well as personality, behavior, and emotional control.
Parietal Lobe: near the back and top of the head above the ears the parietal lobe controls the ability to read, write, and understand spatial relationships.
Lobes Of The Brain And What They Control
Each brain hemisphere has four sections, called lobes: frontal, parietal, temporal and occipital. Each lobe controls specific functions.
- Frontal lobe. The largest lobe of the brain, located in the front of the head, the frontal lobe is involved in personality characteristics, decision-making and movement. Recognition of smell usually involves parts of the frontal lobe. The frontal lobe contains Brocas area, which is associated with speech ability.
- Parietal lobe. The middle part of the brain, the parietal lobe helps a person identify objects and understand spatial relationships . The parietal lobe is also involved in interpreting pain and touch in the body. The parietal lobe houses Wernickes area, which helps the brain understand spoken language.
- Occipital lobe. The occipital lobe is the back part of the brain that is involved with vision.
- Temporal lobe. The sides of the brain, temporal lobes are involved in short-term memory, speech, musical rhythm and some degree of smell recognition.
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Diseases And Conditions Related To The Frontal Brain Lobe
One of the first conditions we will address is depression. Today, we know with certainty that one of the main characteristics of virtually all depressed persons – regardless of the underlying cause of depression – is a significant decrease in blood flow to the frontal lobe and its impaired activity.
This reduced activity is found in the most prominent part of the frontal lobe. It is called the “prefrontal cortex“. It is the part of the brain that truly represents the control center of the brain.
However, it is much more than that. We know that the prefrontal cortex is responsible for behavioral planning, decision making, emotional control, self-awareness, and independence from other people.
Depression can be caused by a stroke in the medial part of the frontal lobe. The consequences of these strokes include emotional instability. Generally speaking, depression is not caused by strokes in other parts of the brain.
Moreover, frontal brain lobe damage can result from surgical removal, injury, or stroke. It can also be a consequence of Alzheimer’s disease. Regardless of the process that damages the frontal lobe, the consequences are generally the same.
Patients suffering from Alzheimer’s disease who had frontal lobe damage were significantly more depressed. They were also much more likely to have other behavioral problems such as anxiety, self-delusions, and lack of self-discipline.
Damage to the inferolateral area causes motor aphasia .
How Does The Parietal Lobe Interact With Other Areas Of The Body
It is a myth that any single brain region controls any function. Rather, each region of the brain works in conjunction with the body. Without the environment, the brain could do little or nothing, and the parietal lobe is no exception. Its role in sensory processing means that the parietal lobe depends on a cascade of sensory input from all over the body, including the eyes, hands, tongue, and skin. These disparate regions cannot function without the input of the parietal lobe, which assigns meaning to the sensory input you encounter each day.
The parietal lobe also sends signals to and receives signals from other brain regions, most notably the occipital lobe. The occipital lobe aids the parietal lobe in visual perception and processing, as well as spatial navigation and reasoning.
Though each brain region has a specific set of functions, many of these functions are interchangeable and cross brain regions. Every brain region, for instance, is vital for language processing. Some research has also found that, when there is damage to one region of the brain, nearby regions may compensate, particularly if an injured person receives immediate and comprehensive occupational and physical therapy.
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Frontal Lobe : Anatomy Location & Function
Frontal Lobe: The frontal lobe is the largest of the four major lobes of the cerebral cortex in the brain. The frontal lobe, located at the front of the brain, of each cerebral hemisphere in front of the temporal lobe and the parietal lobe. The frontal lobe is separated from the parietal lobe by a groove in tissues called the central sulcus, and of the temporal lobe by a deeper groove named the lateral sulcus. The most anterior rounded portion of the frontal lobe is identified as the frontal pole, one of the three poles of the cerebrum.
The precentral gyrus, a part of the frontal lobe immediately anterior to the central sulcus, holds the primary motor cortex, that controls voluntary actions of particular body parts.
The frontal lobe comprises the maximum of the dopamine-sensitive neurons in the cerebral cortex. The dopaminergic system is linked with reward, attention, short-term memory tasks, planning, and motivation. Dopamine serves to limit and pick sensory information reaching from the thalamus to the forebrain.
Parietal Lobe: Function Location And Structure
The parietal lobe receives and manages sensory input and is located just under the parietal bone of the skull.
- Parietal Lobe
Neuroscientists have long divided the brain into four distinct lobes. Originally this division was based solely on the location of the lobes within the skull, but we now know that each lobe carries out a number of highly specialized functions. The parietal lobe is located just under the parietal bone of the skull. This important brain lobe helps integrate sensory input and process language.
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What Is The Gray Matter And White Matter
Gray and white matter are two different regions of the central nervous system. In the brain, gray matter refers to the darker, outer portion, while white matter describes the lighter, inner section underneath. In the spinal cord, this order is reversed: The white matter is on the outside, and the gray matter sits within.
Gray matter is primarily composed of neuron somas , and white matter is mostly made of axons wrapped in myelin . The different composition of neuron parts is why the two appear as separate shades on certain scans.
Each region serves a different role. Gray matter is primarily responsible for processing and interpreting information, while white matter transmits that information to other parts of the nervous system.
Frontal Lobe Damage Symptoms
Symptoms of damage to the frontal lobe can vary because there are so many functions carried out by the frontal lobes. These symptoms may include one or more of the following:
- Weakness on one side of the body or one side of the face
- Inability to problem solve or organize tasks
- Reduced creativity
- Reduced sense of taste or smell
- Low attention span, easily distractedï»¿ï»¿
- Reduced or increased sexual interest or peculiar sexual habits
- Impulsive or risky behavior
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Prefrontal Cortex Of The Front Lobe
The prefrontal cortex is located in the front part of the frontal lobe. It is considered the ultimate expression of human brain development. It is responsible for cognition, behavior and emotional activity. Prefrontal cortex receives information from the limbic system and acts as a mediator between cognition and feelings through executive functions. Executive functions are a set of cognitive skills necessary for controlling and self-regulating your behavior. Within the prefrontal cortex, three areas or circuits are important: dorsolateral, anterior and orbital cingulum.
Dorsolateral area of the frontal lobe
It is one of the most recently evolved parts of the human brain. It establishes connections with the other three brain areas and transforms the information into thoughts, decisions, plans, and actions. It is in charge of superior cognitive abilities such as:
- Attention: Focus, inhibition, and divided attention.
- Working memory: maintenance and manipulation of the information.
- Prospective memory: programming upcoming actions.
- Hypothesis generator: analysis of the possible outcomes.
- Metacognition: self-analysis of cognitive activity and continuous performance.
- Problem Resolution: analysis of the situation and development of an action plan.
- Shifting: the ability to adapt to new situations.
- Planning:organizing behavior towards a new objective.
Anterior cingulum of the frontal lobe
Orbital area of the frontal lobe
How Does The Frontal Lobe Interact With Other Areas Of The Body
Though the frontal lobe is often deemed the seat of consciousness, it cannot think or feel alone. No single brain region can fully control any other region or function without heavy input from the body, other parts of the brain, and the outside world. The frontal lobe is no exception, and works alongside all other brain lobes to coordinate consciousness.
The frontal lobe, like all brain regions, connects with the limbic lobe, which houses brain structures associated with the limbic system. The limbic system controls automatic and primitive reactions, but these reactions are heavily dependent upon emotion and experience. Because the frontal lobe is home to much consciousness, its input into the limbic lobe is vital. For instance, an emotional reaction to a traumatic experience can affect limbic functioning forever, and the memories housed in the frontal lobe may strengthen limbic system reactions over time.
Because the frontal lobe is home to many higher functions, it is especially dependent upon experiences and memories. That means that social interactions, education, and similar experiences heavily affect the functioning of this important brain region. Sensory input also plays a key role, since the frontal lobe relies on memory, previous experience, and information about the surrounding world to judge the potential effects of future actions.
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Position Of The Frontal Brain Lobe
First of all, the frontal brain lobe is the largest part of our brain. Secondly, as its name implies, it is positioned in the front of the head. More importantly, the frontal lobe is positioned in both hemispheres.
Its anatomical position implies that it spreads from central sulcus to the front pole. This brain part contains four frontal curves. Those are:
- Precentral curve,
- Lower curve .
Most noteworthy, this brain part contains the Broca’s fields. This segment of the frontal brain lobe represents the primary motor cortex. Besides, they contain the Motor Speech Component. The frontal lobe also houses a center for controlling the willing horizontal orientation of a look to the opposite side.
A very important part of the frontal lobe is the prefrontal cortex. It has a role in planning and executing motor activities, taking initiative, motivation, control of emotions, and behavior. The cortical urinary center is located in this lobe. The inflow of blood into the frontal lobe is made possible by the anterior and middle cerebral arteries.
Ventricles And Cerebrospinal Fluid
Deep in the brain are four open areas with passageways between them. They also open into the central spinal canal and the area beneath arachnoid layer of the meninges.
The ventricles manufacture cerebrospinal fluid, or CSF, a watery fluid that circulates in and around the ventricles and the spinal cord, and between the meninges. CSF surrounds and cushions the spinal cord and brain, washes out waste and impurities, and delivers nutrients.
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What Are Some Important Structures In The Parietal Lobe
In addition to being divided into left and right hemispheres, the parietal lobe has a number of distinct structures, each with its own unique contribution to brain functioning. Those structures include:
- Postcentral gyrus: This region is the brain’s primary somatosensory cortex, and maps sensory information onto what is known as a sensory homonculus. Some researchers also refer to this region as Brodmann area 3.
- Posterior parietal cortex: This region is thought to play a vital role in coordinating movement and spatial reasoning. It also plays a role in attention, particularly attention driven by new stimuli, such as when an animal jumps into the road while you are driving.
- Superior parietal lobule: This region helps you determine your own orientation in space, as well as the orientation of other objects. It also receives significant input from the hand, suggesting that it helps coordinate fine motor skills and sensory input from the hands.
- Inferior parietal lobule: Sometimes called Gerschwind’s territory, this region aids in assessing facial expressions for emotional content. Some research suggests it plays a role in other functions, including language processing, basic mathematical operations, and even body image. It contains a number of sub-regions, including the angular and supramarginal gyrus.
Where Is The Frontal Lobe Located
Neuroscientists have traditionally divided the brain’s cerebrum into four lobes: the frontal, parietal, occipital, and temporal. The cerebrum is the newest part of the brain to have evolved, and houses most higher functions, such as conscious thought, morality, memory, and the ability to learn through memorization, deduction, and other complex processes. The frontal lobe plays a key role in this complex set of cognitive functions.
Named for its location, the frontal lobe is situated toward the front of the cerebrum, just behind the forehead and under the frontal skull bones. It sits atop the temporal lobe, in front of the parietal lobe, and apart from the occipital lobe, with portions of the limbic systemsometimes called the limbic lobe crossing all four brain lobes, including the frontal lobe.
The central sulcus separates the frontal and parietal lobes, with the lateral sulcus separating the frontal and temporal lobes.
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Clinical Relevance: Cerebrovascular Accident
A cerebrovascular accident is defined clinically as “an abrupt loss of focal brain function lasting more than 24 hours due to either spontaneous haemorrhage into brain substance or inadequate blood supply to part of the brain i.e. ischaemia “.
Damage to the cerebrum in this matter can give rise to a range of clinical signs. The exact nature of the functional deficit that arises depends on the specific lobe that has been affected:
- Frontal lobe – a diverse range of presentations, often personality and behavioural changes occur and an inability to solve problems develops.
- Parietal lobe – typically presents with attention deficits e.g. contralateral hemispatial neglect syndrome: where the patient does not pay attention to the side of the body opposite to the lesion.
- Temporal lobe – presents with recognition deficits e.g. auditory agnosia: patient cannot recognise basic sounds, prosopagnosia: failure to recognise faces.
- Occipital lobe – visual field defects: contralateral hemianopia or quadrantanopia with macular sparing.
- Global lesions – severe cognitive deficits , patients cannot answer simple questions such as their name, today’s date, where they are etc.