In Helen's accident she sustained injuries to every part of her brain. The big questions were what did this mean and how could she be affected?
What parts of the brain do what?
The Cerebral Cortex
The cerebral cortex is the largest part of the brain and is the area that is responsible for all our thinking activities. It is divided into two connected halves – the left and right cerebral hemispheres.
The left hemisphere controls the right side of the body and the right hemisphere controls the left. For example, if a person sustains a brain injury, such as a stroke, to the left hemisphere in the area of the cerebral cortex that controls movement, this may result in weakness or even paralysis of the right arm and leg.
In most people, the left hemisphere primarily controls verbal functions such as speech and language while the right hemisphere primarily controls visual spatial (non-verbal) functions such as those involved in drawing, rhythm or finding one’s way in unfamiliar surroundings. The hemispheres are known to process material in different ways with the left cerebral hemisphere specialising in processing material in a sequential and logical manner and the right cerebral hemisphere processing information in a holistic and intuitive way.
The cerebral cortex is further divided into four areas, or lobes:
1. The Frontal Lobes
2. The Temporal Lobe
3. The Parietal Lobe
4. The Occipital Lobe
Each lobe of the brain controls specific functions and skills.
The Frontal Lobes
The frontal lobes have been termed the “executive” of the brain. This is where all of our higher-level thinking goes on. They allow us to:
- Reason logically
- Make decisions
- Plan and organise
- Problem-solve
- Exercise good judgement
- Monitor or manage our actions
It is considered to be the home of our personality and the control centre for our emotions and behaviour. The frontal lobes allow us to apply our knowledge and adapt our behaviour so that it is appropriate to the situation we are in. The frontal lobes also contain the motor cortex, a vital part of the brain system controlling movement.
The frontal lobes are extremely vulnerable to injury due to their position at the front of the skull. Studies have found that the frontal area is the most common region of injury, even following mild brain injury. Damage to this area can cause myriad cognitive problems and can dramatically change social behaviour and personality. Physical problems can include the loss of fine movements, lack of strength in the arms, hands and fingers, little spontaneous facial expression or difficulty in speaking.
Temporal Lobe
The temporal lobe lies just behind our ears and contains the auditory cortex. This allows us to interpret sound. The temporal lobe stores most of our memories and is involved in aspects of language, including our ability to use language and understand what we hear.
Like the frontal lobes, the temporal lobe is involved in regulating certain aspects of personality. Deep inside the temporal lobe are the structures of the hypothalamus and limbic system. The hypothalamus is involved in instinctual behaviours such as aggression, sexual arousal, appetite, thirst and temperature control. The limbic system is in control of emotional reactions.
Damage to these areas can severely disrupt our emotions resulting in sudden and dramatic mood swings; and can also lead to inappropriate social behaviour such as hyper-sexuality and impulsiveness.
Parietal Lobe
The parietal lobe contains the somatosensory cortex which receives and analyses information from the skin concerning touch, pressure, temperature and some aspects of pain.
The parietal lobe is vital to our spatial understanding of the world. For example, it enables us to understand where we are in relation to our surroundings and where our body parts are in relation to each other, as well as the spatial relationships between the things we perceive in our environment.
Damage to the parietal lobe can impair reading, writing and mathematical abilities, drawing and constructional tasks, as well as self-care abilities such as washing and dressing.
Occipital Lobe
The occipital lobe analyses what we see and is, therefore, responsible for sight. If it is damaged, blindness or partial blindness can result.
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| The brain |
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| Fractured Base of Skull |