Me & U-First!
Module 3 – Intellectual
The Brain and Behaviour
When the brain is damaged due to a disease process such as Alzheimer's disease,
behaviours may change, one may lose control of emotions, and physical abilities can
become impaired.
Dementia involves the entire central nervous system (CNS) including neurons, glial
cells, and neurotransmitters. Different types of dementia may affect different areas of
the brain. The areas affected define the symptoms
Alzheimer Disease is identified by neurofibrillary tangles & plaques and shrinkage of the
brain. Brain cells shrink or disappear and are replaced by dense, irregular-shaped spots
or plaques. Thread like tangles appear within existing brain cells, choking healthy cells.
A person with AD has less brain tissue with continual shrinkage over time –
www.alzheimer.ca.)
Each hemisphere or side of the brain contains four lobes. The four lobes, frontal,
parietal, occipital and temporal each have different functions, Other parts important to
function are the cerebellum, brainstem and hippocampus, at the base of the brain. In
order to understand behaviour we will look at areas of the brain affected by Alzheimer
Disease and other dementias and the function of these areas
The National Brain Tumor Foundation has a diagram of the brain at
http://www.braintumor.org/anatomy/ . When you move the cursor over each part of the
brain, a box appears indicating for which functions that part of the brain is responsible.
Neurotransmitter changes are responsible in part for some of the changes in behaviour
of a person with Alzheimer's disease. People with Alzheimer’s disease have low levels
of acetylcholine, impairing communication between cells. In addition to reduced
acetylcholine, there are a number of other neurotransmitters that affect behaviour:
norepinephrine, dopamine, serotonin, and glutamate (see attachment on acetylcholine).
Alzheimer’s disease is thought to start in the limbic system and progress through the
parietal and temporal lobes. Up to this point, the person may display deficits in skills and
require help with complex tasks. Damage to other areas of the brain is associated with
more moderately severe Alzheimer’s disease. It is believed that skills are lost in the
same order that they are developed.
Limbic System
Deep within the brain, the limbic system is a group of interconnected structures that
mediate emotions, learning and memory.
The limbic system connects the frontal and temporal lobes and connects behaviour
with memories. Misinterpretations of words and events can occur, resulting in anger,
suspiciousness and blaming others, for example, believing that objects are being
stolen. This can be challenging for all concerned.
The hippocampus, which is vital to memory, is one of the first areas affected by
Alzheimer’s disease.
- Control of sexuality is thought to be in the limbic system.
- Damage in the limbic system can result in emotions that are extreme and changing
rapidly. Conversely, the person may appear uninterested or unaffected emotionally
by events around them. Any number of emotions can be present, causing the
person to become irritable, depressed or anxious.
- The limbic system also controls daily functions such as sleeping and appetite, so
the person may lose track of when they would normally be awake or sleeping. This
may result in the person being awake through the night.
- The limbic system includes the hypothalamus, which is responsible for control of
body temperature, thirst and appetite. A person with damage in the hypothalamus
will feel cold deep in their bones or feel extremely hot. They may experience
extreme thirst or appetite.
As the limbic system dies, there is emotional instability, inability to control anxiety, rapid
switches from states of fearfulness, to restlessness, to irritability to aggressiveness, and
eventually to helplessness.
Parietal Lobe
The parietal lobe is the centre for spatial perception, sensory integration and
concentration, affecting the ability to recognize places, objects and people. It also
receives and processes information about temperature, taste, touch, and movement
coming from the rest of the body. Reading and arithmetic are also processed in this
region and it affects ability to concentrate or focus.
If the parietal lobe is damaged a person may:

become disoriented or lost

have problems identifying people and objects

experience imaginary visual images (hallucinations)

have grand mal or petit mal seizures (10% with dementia)

lose ability to recognize parts of body

show deterioration in hand skills

have deterioration in speech organization and syntax (order of words)

not recognize objects by touch
Temporal Lobe
The temporal lobe is the centre of speech and language control, processes
hearing, and is the centre of time awareness.
If damaged the person may:

have problems finding the right word

ask questions repeatedly, lose thought in mid-sentence, speak
haltingly, substitute words, repeat words, echo sounds, speak
gibberish

find that time and seasons become meaningless
Occipital Lobe
The Occipital Lobe helps process visual information
With the loss of peripheral vision, the person may
 only see straight ahead
 lose ability to look up
 lose ability to focus or track on a moving object

progressive vision impairment – only distinguish contrasts
Motor Cortex
The Motor Cortex is responsible for motor function
Damage in the Motor Cortex may lead to:
- problems initiating and following through with movements
- problems swallowing
- symptoms that include leaning to the side or forward, muscle weakness, poor
balance, muscle cramping, trouble getting up from seated position, feeling of
restlessness, problems with gait and posture
-
hypermetamorphosis – fascination with and picking at small objects
-
in late stages person curling into fetal position
Frontal Lobe
The frontal lobe, at the front of our head, behind our forehead, is known as the
executive or management centre of the brain; initiation centre; or adult behaviour
centre. The frontal lobe is responsible for a number of important functions, which are all
affected by Alzheimer Disease. The frontal lobe helps control skilled muscle
movements, mood, planning for the future, setting goals, and judging priorities
When damaged the person:

has diminished social judgement

loses critical functions of cognition (thought formation, reasoning, judgement,
abstract thinking, and social consequence)

becomes totally focussed on personal needs

cannot be aware of or feel concern for others

is uninhibited in all actions, including sexual activity

demands instant gratification
With loss of planning ability, a person has difficulty organizing such tasks as getting
dressed, planning a meal, getting from home to work, or accomplishing other familiar
tasks.
The ability to initiate activity may be lost; the person may appear apathetic or
uninterested in doing anything, even previously enjoyed activities, such as hobbies. This
can be frustrating for families who may believe that the person is unwilling to do things.
In contrast, a person with damage to the frontal lobe may be unable to stop doing
something, such as rubbing hands together or tapping on a table. This symptom is
called ‘perseveration.’ Perseveration can lead to frustration on the part of caregivers if
the activity that the person is doing is bothersome.
The frontal lobe of the brain is also the regulator for insight and feedback regarding
socially appropriate behaviour. Impairment in the frontal lobes can lead to a number of
socially challenging events, which may include: verbal outbursts or sexual behaviour
inappropriate to the time, person or location. The incorrect feedback from the brain
leaves the person unaware of the impact of their actions.
Cerebellum
The cerebellum in the subcortex controls vital involuntary systems: heart, lungs,
diaphragm, and digestive system. When damaged the body begins to shut down. The
person experiences irreversible weight loss.
Brain and Behaviour - The complexity and combinations of damage and resulting
losses can contribute to paranoia, delusions, disorientation, anxiety, fear, loss of
willpower, even nausea and feelings of general malaise. Each dementing
disease/disorder has its own pattern of progression, producing its own sequence of
behaviours. It is important to remember that not all persons with dementia display the
same symptoms. Care providers should be able to recognize the difference between the
normal aging process and behaviours associated with dementia.