Understanding Brain Damage

• Brain tumours are a mass of cells that grow independently from the rest of the body.  More cases of brain tumours are detected now due to sophisticated techniques. The growth of cancerous cells puts pressure onto the brain, which can cause a blood clot or directly cause brain damage due to the pressure of the tumour.
  
• Cerebrovascular disorders Include bleeding in the brain or a disruption of supply to the brain.  Lack of blood to the brain can cause problems for the cells that are associated with the brain. Humans can survive for around four minutes without oxygen, before the brain damage becomes severe, leaving little realistic chance of survival.  A stroke can lead to a blood shortage to the brain, which is caused by a blood clot.
  
• Closed head injuries are injuries which do not penetrate the skull.
• Contusions cause bleeding and are generally caused by the brain slamming against the skull.  A sufficient blow to the head can supersede the skull’s defences (particularly at the temple) and can therefore allow structural damage to occur.
  
• Infections of the brain An invasion of the brain by micro-organism is a brain infection, and resulting inflammation is encephalitis. There are two common types of brain infection: bacterial infections and viral infections.    
  
• Neurotoxins The nervous system can be damaged by exposure to any one of a variety of toxic chemicals, mercury and lead can accumulate in the brain and permanently damage it producing a toxic psychosis.
  
• Genetic factors such as chromosomal anomalies, abnormal recessive genes or faulty dominant genes can lead to a range of disorders such as
• Down’s syndrome, Huntington’s disease and phenylketonuria.  A dysfunctional hereditary gene could be passed on to offspring preventing the brain from fully developing.
  

Outlined below are some summaries of what each part of the brain is reponsible for. Injuries to these parts of the brain will in turn give rise to an associated physical or mental symptom.

Frontal Lobe
The frontal lobe is the front part of the brain and is involved in organizing, planning, problem solving, personality and higher cognitive functions such as emotion and behaviour.  The anterior or front portion of the frontal lobe is called the prefrontal cortex. It is important for higher cognitive functions and determining personality. The posterior or back of the frontal lobe consists of premotor and motor areas, where the nerve cells that produce movement are located.  The premotor area modifies movements.

The frontal lobe is the area of the brain that is responsible for:

• Monitoring a person's behaviour.
  
• Providing feedback about that behaviour.
  
• Allowing us to modify behaviour to make it more effective and appropriate.
  

The frontal lobes assess behaviour against two sources of feedback, external and internal.

External feedback allows us to adjust both actions and speech to the surrounding environment.

Internal feedback allows us to line up our own words and actions against internal standards, including beliefs, ideals and values that matter to us personally.

The frontal lobes also help to organise behaviour in sequences (for example, formulating plans), and in making the choice of what to do when confronted by alternatives. They have many intricate connections to deeper parts of the brain, including the limbic system which is largely responsible for emotions and in turn is closely connected with memory areas of the brain.

One of the specific behaviour deficits following frontal lobe damage is attention disorder, patients showing distractibility and poor attention. They present with poor memory, sometimes referred to as "forgetting to remember." The thinking of patients with frontal lobe injury tends to be concrete, and they may show perseveration and stereotypy of their responses. The perseveration, with inability to switch from one line of thinking to another, leads to difficulties with arithmetic calculations, such as serial sevens or carryover subtraction.

Other features of frontal lobe syndromes include reduced activity, particularly a diminution of spontaneous activity, lack of drive, inability to plan ahead, and lack of concern. Sometimes associated with this are bouts of restless, aimless uncoordinated behaviour. Affect may be disturbed with apathy, emotional blunting, and the patient showing an indifference to the world around him. In contrast, on other occasions, euphoria and disinhibition (loss on inhibition) are described. The euphoria is not that of a manic condition, having an empty quality to it. The disinhibition can lead to marked abnormalities of behaviour, sometimes associated with outbursts of irritability and aggression.

Brainstem
Neurological functions are located in the brain stem, such as breathing, digestion, heart rate, blood pressure and arousal (being awake and alert). Damage to this area can affect any of these functions.  The brainstem is also the pathway for the nerves going up and down the spinal cord to the highest part of the brain.

Cerebellum
This portion of the brain helps to coordinate movement (balance and muscle coordination). Damage can result in ataxia (a problem with muscle coordination), affecting ability to talk, walk, eat and self-care.

Occipital Lobe
This region of the brain processes visual information. It is responsible for visual recognition and contains the areas that help the recognition of shapes and colours. Damage to this area can cause visual deficits.

Parietal lobes
Damage to the right parietal lobe area can cause visuo-spatial deficits, such as having difficulty finding your way around new places or even familiar places.  Damage to the left lobe can disrupt a patient’s ability to understand spoken or written language.  The lobes also contain the primary sensory cortex, which control sensation (touch, pressure).  Behind the primary sensory cortex is an association area that controls fine sensation (judgement of weight, size, shape and texture).

Temporal Lobes
There are two temporal lobes, one on each side of the brain. The lobes allow us to distinguish smells and sounds. They also help us to sort new information and are thought to be responsible for the short term memory. The right lobe is thought to be involved in visual memory (faces, pictures), whilst the left lobe is mainly involved in verbal memory (words, names).

If you want to learn more about how the brain and nervous system interract with each other and the human body, you may be interested in the following ACS courses:
Biopsychology I
Biopsychology II
Neuropsychology

Talk to us - get in touch by using our FREE COUNSELLING SERVICE.

• Brain tumours are a mass of cells that grow independently from the rest of the body.  More cases of brain tumours are detected now due to sophisticated techniques. The growth of cancerous cells puts pressure onto the brain, which can cause a blood clot or directly cause brain damage due to the pressure of the tumour.
• Cerebrovascular disorders Include bleeding in the brain or a disruption of supply to the brain.  Lack of blood to the brain can cause problems for the cells that are associated with the brain. Humans can survive for around four minutes without oxygen, before the brain damage becomes severe, leaving little realistic chance of survival.  A stroke can lead to a blood shortage to the brain, which is caused by a blood clot.
• Closed head injuries are injuries which do not penetrate the skull. Contusions cause bleeding and are generally caused by the brain slamming against the skull.  A sufficient blow to the head can supersede the skull’s defences (particularly at the temple) and can therefore allow structural damage to occur.
  Infections of the brain An invasion of the brain by micro-organism is a brain infection, and resulting inflammation is encephalitis. There are two common types of brain infection: bacterial infections and viral infections.    
• Neurotoxins The nervous system can be damaged by exposure to any one of a variety of toxic chemicals, mercury and lead can accumulate in the brain and permanently damage it producing a toxic psychosis.
• Genetic factors such as chromosomal anomalies, abnormal recessive genes or faulty dominant genes can lead to a range of disorders such as Down’s syndrome, Huntington’s disease and phenylketonuria.  A dysfunctional hereditary gene could be passed on to offspring preventing the brain from fully developing. 

Frontal Lobe
The frontal lobe is the front part of the brain and is involved in organizing, planning, problem solving, personality and higher cognitive functions such as emotion and behaviour.  The anterior or front portion of the frontal lobe is called the prefrontal cortex. It is important for higher cognitive functions and determining personality. The posterior or back of the frontal lobe consists of premotor and motor areas, where the nerve cells that produce movement are located.  The premotor area modifies movements

• Monitoring a person's behaviour
• Providing feedback about that behaviour
• Allowing us to modify behaviour to make it more effective and appropriate.

The frontal lobes assess behaviour against two sources of feedback, external and internal.
External feedback allows us to adjust both actions and speech to the surrounding environment.
Internal feedback allows us to line up our own words and actions against internal standards, including beliefs, ideals and values that matter to us personally.
The frontal lobes also help to organise behaviour in sequences (for example, formulating plans), and in making the choice of what to do when confronted by alternatives. They have many intricate connections to deeper parts of the brain, including the limbic system which is largely responsible for emotions and in turn is closely connected with memory areas of the brain.
One of the specific behaviour deficits following frontal lobe damage is attention disorder, patients showing distractibility and poor attention. They present with poor memory, sometimes referred to as "forgetting to remember." The thinking of patients with frontal lobe injury tends to be concrete, and they may show perseveration and stereotypy of their responses. The perseveration, with inability to switch from one line of thinking to another, leads to difficulties with arithmetic calculations, such as serial sevens or carryover subtraction.

Other features of frontal lobe syndromes include reduced activity, particularly a diminution of spontaneous activity, lack of drive, inability to plan ahead, and lack of concern. Sometimes associated with this are bouts of restless, aimless uncoordinated behaviour. Affect may be disturbed with apathy, emotional blunting, and the patient showing an indifference to the world around him. In contrast, on other occasions, euphoria and disinhibition (loss on inhibition) are described. The euphoria is not that of a manic condition, having an empty quality to it. The disinhibition can lead to marked abnormalities of behaviour, sometimes associated with outbursts of irritability and aggression.

Brainstem
Neurological functions are located in the brain stem, such as breathing, digestion, heart rate, blood pressure and arousal (being awake and alert). Damage to this area can affect any of these functions.  The brainstem is also the pathway for the nerves going up and down the spinal cord to the highest part of the brain.

Cerebellum
This portion of the brain helps to coordinate movement (balance and muscle coordination). Damage can result in ataxia (a problem with muscle coordination), affecting ability to talk, walk, eat and self-care.

Occipital Lobe
This region of the brain processes visual information. It is responsible for visual recognition and contains the areas that help the recognition of shapes and colours. Damage to this area can cause visual deficits.

Parietal lobes
Damage to the right parietal lobe area can cause visuo-spatial deficits, such as having difficulty finding your way around new places or even familiar places.  Damage to the left lobe can disrupt a patient’s ability to understand spoken or written language.  The lobes also contain the primary sensory cortex, which control sensation (touch, pressure).  Behind the primary sensory cortex is an association area that controls fine sensation (judgement of weight, size, shape and texture).

[16/04/2024 19:40:03]

More from ACS

The Brain and Behaviour

Working with People

Biopsychology I