Parkinson's Disease Flashcards
what are the common symptoms of Parkinson’s disease?
- Dyskinesia (involuntary, erratic, writhing movements of the face, arms, legs or trunk)
- Rigidity
- Slow Shuffle
- Tremor
what part of the brain is most affected in Parkinson’s?
basal ganglia, particular the substania nigra pars compacta
what is the substania nigra pars compacta?
the source of the important nigrostriatal dopamine pathway
+ motor movement
what is the basal ganglia responsible for?
a group of subcortical nuclei responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions.
what happens to the basal ganglia and substance nigra par compact in Parkinson’s?
dopamine secreting neurones begin to die and break down affecting the basal ganglia system
how does dopamine neurons beginning to die affect an individual?
- voluntary movements primarily affected
- all about control and timing of movements -> issues with starting and initiating movement
neuropathy of parkinson’s
- nigro-striatal pathway degeneration leading to a depletion of striata dopamine
- some degeneration of other dopamine pathways too - midbrain affected too
what is the striatum?
a cluster of interconnected nuclei that form a part of the basal ganglia. It is involved in decision making functions, such as motor control, emotion, habit formation, and reward
what would happen if you cut open the main brain area?
generally black because of the melanin
what were the treatment options prior to 1960?
no effective treatment available
what did they realise when Parkinson’s was an attribute of dopamine involvement?
lead to the use of drugs which increase brain dopamine levels
what is the issue with dopamine, itself?
cannot cross blood-brain barriers
How we ensure that the brain gets dopamine?
precursor, L-Dopa, enters the brain and is converted into dopamine
what are issues with dopamine?
causes severe side effects (dyskinetic movements, psychotism)
what treatment may be given if an individual is younger?
dopamine agonist
how much deep brain stimulation help Parkinson’s disease?
lesions of the sub thalamic nucleus (STN) or internal segment of globus pallidus effectively reduce Parkinson’s signs by respectively normalising or eliminating abnormal and excessive inhibitory output from the internal pallidal segment
how efficient is DBS?
- Improvement on slowness
- Complete elimination of tremors
- Improved facial expressiveness
- Better balance
what are the side effects of DBS?
- Neuropsychiatric
- Displacement
- Complications from surgery
- Risk of infection and bleeding during and after surgery (something common with all surgeries anyways)
Dopaminergic circuits in the basal ganglia are involved in the…
timing and readout of movements
dysfunction of dopaminergic circuits can lead to..
hyper or hypokinesias
an imbalance in the dopamine system is often associated with other cognitive problems -> what are these generalised executive dysfunction with reduction / impairment
- Cognitive flexibilityspeed
- Abstract thinking
- Working memory
- Cognitive speed
- Recall and perception
- Estimation of time
- Dementia vs. hallucinations
An imbalance in the dopamine system is often associated with other cognitive problems as well as
Dementia vs. hallucinations
Lack of motivation vs. risk seeking behaviours
dementia with lewy bodies vs. parkinson’s
both have movement and cognitive deficits, but they are still different conditions
what is dementia with Lewy bodies usually misdiagnosed as and what is the problem with this?
Alzheimer’s but they have different medications, one that may not be as effective for either of the other diseases
why might timing mechanisms that are affected in parkinson’s give rise to cognitive problems?
Dopamine system can also cause hallucinations as well as motor issues (loads of other symptoms that go along with parkinsons that can affect individuals just as much)
Dopaminergic neurotransmitter involved in Parkinson’s syndrome is used by many brain systems, which other neural systems use this transmitter?
Dopamine is responsible for the reward circuit (with a loss of inhibition leading to: compulsive gambling, risk seeking behaviour and suicide (inability to regulate reward))
Any problems that might be caused with deep brain stimulation?
- Device malfunction perhaps, headaches, bradykinesia (slowness of movement and speed)
- Can generate other movement-related disorders (i.e. a lot more involuntary movements)
- Strokes and seizures
- Invasive brain surgery may cause problems
- Unaccounted for changes in behaviour, mood or cognition caused by DBS might result in personal identity changes
Deep Brain Stimulation
- brain treatment acting on the basal ganglia
- motor control improves quite a bit, individual is able to have more control over their movement, is able to talk in longer strides without long interval pauses, able to catch oneself when pulled backwards
- hand movements have improved, less tremour, can pull facial movements
- can move and turn without difficult -> initiate movement voluntarily
- better ability to catch oneself when pulled backwards
what neurotransmitter system is affected in Parkinson’s disease?
dopamine
(potential motor region in the brain)
can you think of another condition affecting this brain system where the opposite problem is found and movement is freely created even when not intended?
Tourette’s Syndrome - participants move freely, usually very quickly, even when not intended to
Hellabiliusm: involved the arm and leg on one side, normally rotating continously (contorting on one side of the body) (usually from a CBA issue)
ISSUE WITH STOPPING THE MOVEMENT - But same dopamine system is involved, just in a slightly different way!
