Interactive Brain

Understanding Brain Injuries

What is TBI

TBI stands for traumatic brain injury. A traumatic brain injury, more commonly known as a TBI, occurs when an external force comes in contact with the head. The most common TBI injuries are from a car or motorcycle accident, a fall from a roof or ladder, or a jolt in sports.

When there is a direct blow to the head, a bruising of the brain and damage to the internal tissue and blood vessels occurs due to a mechanism called coup-contrecoup. A bruise directly related to trauma at the site of impact is called a coup lesion pronounced, “Coo”. When the brain jolts backwards, it hits the skull on the opposite side and forms a bruise called a contrecoup lesion.

Side View

Broca's Area

Cerebellum

Cerebrum

Frontal Lobe

Occipital Lobe

Olfactory System

Parietal Lobe

Temporal Lobe

Wernicke's Area

Broca's Area

Frontal Lobe Cerebrum Parietal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

Broca’s Area

Description
Named after 19th-century physician Paul Broca, Broca's area is a section of the brain located in the frontal lobe of the cortex. It is important in the production of written and spoken language.

Function
Broca's area is involved in both written and spoken language processing. It is critical in the complicated task of understandably combining words and grammar. Patients with this condition often do not have a problem with understanding language but have difficulty finding the words or grammar necessary to communicate fluently.

Result of Injury
Injury to this area can cause a condition called Broca's aphasia, also referred to as expressive aphasia, motor aphasia, or non-fluent aphasia. People with this condition are not able to create complex sentences and have difficulty finding the correct word. Patients struggle to form sentences. Their speech is often described as telegraphic, with short sentences containing only keywords. Patients are usually aware that they cannot speak properly.

Example of speech affected by Broca's aphasia: "Ah… Friday… ah, Mom and Steve and Mom… hospital. Two… ah, doctors… and ah… thirty minutes … and yes … ah … hospital. And, er, Wednesday … nine o'clock. And er Thursday, ten o'clock… doctors. Two doctors… and ah… teeth. Yeah, … fine."

Cerebellum

Frontal Lobe Cerebrum Parietal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

Cerebellum

Description
The word cerebellum means "little brain." The cerebellum is located at the base of the brain and is involved with the coordination of movement. It makes up approximately 10 percent of the brain's volume and contains at least half of the brain's neurons. It is divided into two hemispheres that are covered by a thin layer of gray matter known as the cortex.

Function
The cerebellum receives input from other areas of the brain and spinal cord, along with information about the position and movement of the body's limbs and joints. It uses all of this information to control equilibrium and to provide precise coordination of movements.

Result of Injury
A patient may experience problems with one or more of the following:

Gait, where the manner of standing or walking is not normal.
Ataxia, which is unsteadiness or lack of coordination of the limbs, posture, and gait.
Hypotonia, which is decreased muscle tone.
Tremor, where parts of the body can tremble uncontrollably, especially with any purposeful movement such as trying to pick up or point at an object.
Abnormal eye movement, such as impaired tracking, fixation, and an involuntary, constant, twitching of the eye called nystagmus.

Cerebrum

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

Cerebrum

Description
The cerebrum forms what most people think of as the "brain." It lies on top of the brainstem and is the largest area of the brain. It is divided into two halves — the right hemisphere, which controls the left side of the body, and the left hemisphere, which controls the right side of the body.

Function
The cerebrum's main functions include consciousness, thought, reason, memory, vision, hearing, touch, motor control, coordination, and emotions. The specific functional areas of the cerebrum are divided into four lobes: the frontal, parietal, temporal, and occipital lobes.

Result of Injury
The effect of injury to the cerebrum depends on the specific part of the brain that is injured. In general, injury to the left half of the brain can cause problems on the right side of the body, and damage to the right side of the brain can cause problems on the left side of the body. The results of damage to specific areas of the brain are discussed in the sections for the individual lobes.

Frontal Lobe

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Occipital Lobe Broca's Area Olfactory System Temporal Lobe Cerebellum

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Frontal Lobe

Description
The frontal lobes are located at the front of the cerebrum. They are the part of the brain that regulates and mediates the higher intellectual functions known as executive functions. They play an important role in the control of social behaviors.

Function
The frontal lobes contribute to the regulation of emotions, cognition, error detection, volition, a sense of self, and more. The executive functions of the frontal lobes involve the ability to recognize future consequences resulting from current actions, to choose between good and bad actions, override and suppress unacceptable social responses, and determine similarities and differences between things or events. The frontal lobes also play an important part in retaining longer-term memories, which are often derived from input from the limbic system or emotional brain. The frontal lobe modifies those emotions to generally fit socially acceptable norms.

Result of Injury
Damage to the frontal lobes can lead to a wide variety of symptoms, including the loss of inhibitions and impaired mental flexibility. It may be difficult to prioritize tasks and motivation may diminish. Talking may increase or decrease dramatically. Perceptions about taking risks and following rules can be impaired and socialization can diminish or increase. Damage to some areas of the frontal lobe can affect sexual interest and habits.

Occipital Lobe

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

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Occipital Lobe

Description
The occipital lobes are located in the back of the brain and are the smallest of the four lobes. They are the visual center and are the primary portion of the brain responsible for receiving input from the eyes.

Function
The occipital lobes receive and process all input from the eyes. Area A is the primary visual cortex and the recipient of visual input from the eyes. Area A performs the initial processing of the information, for example combining input from the two eyes, and beginning to analyze depth. This information is then passed on to Areas B and C. Areas B and C are the associative visual cortex, where motion, color, and other parameters are interpreted to provide meaning.

Result of the Injury
Damage to the right occipital lobe can result in loss of the left visual field of both eyes, and damage to the left occipital lobe results in loss of the right visual field of both eyes. Damage to both the left and right occipital lobes can result in blindness, even though the eyes themselves may be functioning normally. This condition is called cortical blindness. If the front part of the occipital lobe is damaged, people have difficulty recognizing familiar objects and faces and accurately interpreting what they see.

Olfactory System

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

Olfactory System

Description
The olfactory system includes the olfactory epithelium, which is located inside the nose, the olfactory bulb, which is located just above the olfactory epithelium, and the olfactory cortex, which is on the surface of the temporal lobe. The olfactory system is responsible for the sensing, processing, and identifying of smells.

Function
The olfactory system is responsible for the sense of smell. In addition, it combines with taste information in the brain to create the sensation of flavor. Many people with a lost sense of smell retain the ability to detect salty, sweet, and bitter tastes but complain that food tastes bland. The sense of smell is strongly associated with memory. As a result, smells are often powerful triggers for specific memories, both good and bad. Because the sense of smell is also closely associated with the limbic system or emotional brain, the smell is known to provoke strong emotional responses.

Result of Injury
Damage to the olfactory system can cause impairment or loss of the sense of smell and the sense of taste. Much of what we attribute to our sense of taste actually depends on the aromas of what we eat and drink.

Parietal Lobe

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

Parietal Lobe

Description
The parietal lobes are positioned above the temporal lobes and between the frontal and occipital lobes. They contain the part of the brain primarily responsible for movement and the sense of touch. They also play a very important role in integrating sensory information, particularly determining spatial sense and navigation.

Function
The parietal lobes contain the portion of the brain primarily responsible for movement. This area is called the motor cortex. Located next to the motor cortex is the area of the brain primarily responsible for the sense of touch. This area is known as the somatosensory cortex. A large portion of the parietal lobe acts as an interchange for information for most of the other senses. These interconnections contribute a great deal to the ability to interpret people, places, and things around us. In essence, the parietal lobes "pull it all together."

Result of Injury
Damage to the parietal lobes can result in conditions known as agnosia and apraxia. Agnosia is the inability to recognize an object using a specific sense, even though that sense is basically intact. For example, someone might not be able to recognize an orange by sight, although they could identify the orange by touch or smell.

Apraxia is the inability to perform a specific movement, although all of the muscles are intact and able to perform that task under different circumstances. For example, someone may be unable to touch their nose on command but would be perfectly able to do so if their nose itched.

Damage to the parietal lobe can also cause word blindness, known as alexia, with writing impairments, called agraphia. Damage to the right parietal lobe can impair skills such as dressing and washing, and can also cause difficulty in making things, denial of deficits, and loss of drawing ability. Damage can also cause a person to neglect the opposite side of their body, even to the point of not recognizing their own limbs.

Temporal Lobe

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

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Temporal Lobe

Description
The temporal lobes are the part of the cerebrum that is involved in speech, memory, and hearing. They are located on both sides of the brain, below the parietal lobes and in front of the occipital lobes.

Function
The temporal lobe is involved in hearing and understanding what is heard and is home to the primary auditory cortex. It is also responsible for the formation and retrieval of long-term memories. The temporal lobe also plays a role in vision, sexual behavior, and personality.

Result of Injury
Individuals with temporal lobe damage have difficulty placing words or pictures into categories. Language skills can also be impaired by temporal lobe damage. The impairment or loss of long-term memory can result from injury to the temporal lobes. Specifically, damage to the right side of the temporal lobes can result in the inability to recall non-verbal material, such as music and drawings. It can also cause a loss of inhibition when talking. Left temporal lobe damage can impair the ability to recognize words and can result in impaired memory for verbal material.

Wernicke's Area

Cerebrum Parietal Lobe Frontal Lobe Wernicke's Area Broca's Area Olfactory System Temporal Lobe Cerebellum Occipital Lobe

Wernicke’s Area

Description
Wernicke's area is located in the left temporal lobe. It plays a role in the understanding of language and is named after Carl Wernicke, a German neurologist, and psychiatrist. In 1874, Wernicke discovered that damage to this area could cause a type of speech disorder that is now called Wernicke's aphasia.

Function
Wernicke's area plays an important role in the processing and comprehension of language. Proper function of Wernicke's area is required for patients to form coherent sentences and to understand the speech of others.

Result of Injury
Damage to Wernicke's area can cause a condition called Wernicke's aphasia or receptive aphasia. This condition affects a person's ability to understand the language when listening, the ability to read, and the ability to speak with meaning. Speech often sounds like a babble, fluent and grammatical, though totally nonsensical. Wernicke's aphasics have severe difficulties with comprehension but are often unaware of it. They may become annoyed or frustrated when others can't seem to understand them.

Example of speech affected by Wernicke's aphasia: "I can't tell you what that is, but I know what it is, but I don't know where it is. But I don't know what's under. I know it's you couldn't say it's… I couldn't say what it is. I couldn't say what that is. This shu… that should be right in here. That's very bad in there. Anyway, this one here, and that, and that's it. This is the getting in here and that's the getting around here, and that, and that's it. This is getting in here and that's the getting around here, this one and one with this one. And this one, and that's it, isn't it? I don't know what else you'd want."

Inside View

Brain Stem

Cerebellum

Frontal Lobe

Hypothalamus

Limbic System

Occipital Lobe

Olfactory System

Parietal Lobe

Septal (Corpus Collosum)

Temporal Lobe

Brain Stem

Brain Stem Cerebellum Frontal Lobe Hypothalamus Limbic System Occipital Lobe Olfactory System Parietal Lobe Septal (Corpus Collosum) Temporal Lobe

Brain Stem

Description
The brain stem is a part of the brain located beneath the cerebrum and in front of the cerebellum. It connects the spinal cord to the rest of the brain and is responsible for regulating many of the body's basic functions. It is sometimes referred to as the most primitive portion of the brain.

Function
Neurological functions located in the brainstem include those necessary for survival such as breathing, digestion, heart rate, and blood pressure, and for being awake and alert. It plays an important role in basic attention, arousal, and consciousness. One key part of the brain stem is called the reticular activating system, which works as the "on/off switch," in terms of sleeping, waking up, and motivation.

The brain stem serves as a conduit, with information to and from other parts of the body passing through the brain stem on the way to or from the brain.

Many of the cranial nerves originate in or pass through the brain stem. These nerves are responsible for things such as vision, hearing, taste, smell, the control of eye movements, and movement and sensation of the face.

Result of Injury
The brain stem is vital to proper body functions and can cause severe disabilities if it is damaged. In fact, because the brain stem controls such basic functions as breathing and heartbeat, damage to the brain stem can result in death. Brain stem injury is also a cause for persistent coma. Brain stem injury can also result in memory problems, difficulty concentrating, difficulty staying focused, and physical problems including the inability to walk, remain balanced, and a loss of strength. Problems with vision, such as impaired eye movement, can also be caused by injury to the brain stem. Paralysis may also occur when the brain stem is damaged since it is directly linked to the spinal cord.

Cerebellum

Brain Stem Cerebellum Frontal Lobe Hypothalamus Limbic System Occipital Lobe Olfactory System Parietal Lobe Septal (Corpus Collosum) Temporal Lobe