Lecture 22 - Introduction to Movement Disorders Flashcards
What are movement disorders?
Clinical disorders associated with basal ganglia disease.
What can movement disorders be sub-divided into?
Too little movement (hypo kinetic disorders)
Too much movement (hyperkinetic disorders)
What is Parkinson’s disease?
A degeneration disease characterised by a group of cardinal features that include rigidity, resting tremor, slowness in movement (bradykinesia) and balance problems.
Why is Parkinson’s and Lewy body dementia linked?
The main proteins involved in both are alpha-synuclein deposits in the brain.
LBD patients eventually get PD and PD patients sometimes get LBD.
Why do PD patients lose their smell and taste?
Basal monoamines in the brainstem are affected.
What does the basal ganglia contain?
Putamen
External globus pallidus (GPe)
Internal globus pallidus (GPi)
Substantia nigra
Subthalamic nucleus (STN)
Thalamus
Caudate nucleus
Where is the basal ganglia located in the brain?
Cerebrum
Describe the loops in the basal ganglia.
Four largely segregated cortical loops that have some cross talk.
Links the basal ganglia to the limbic system so movement selection can be informed by emotional and motivational state.
Links to the frontal lobe so that it is receiving proprioceptive feedback of ongoing motor activity.
Describe the direct pathway in the basal ganglia.
Striatum to GPi directly.
Activation = GPi inhibition > thalamic disinhibition > cortical activation.
Describe the indirect pathway in the basal ganglia.
Striatum to GPi indirectly via GPI and STN. GPi activation > thalamic inhibition > cortical inhibition.
What does the direct pathway in the basal ganglia facilitate?
The activation of desired movement pathways.
What does the indirect pathway in the basal ganglia facilitate?
The activation of inappropriate/conflicting movement pathways.
What is overactivity of the GPi predicted to cause?
A reduced activation of desired movements - bradykinesia.
What is under activity of the GPi predicted to cause?
Excessive activation of undesired movements - chorea.
What are the causes of Parkinson’s symptoms?
Parkinson’s disease
Drugs such as anti-dopaminergics
Cerebrovascular disease
Structural lesion in the basal ganglia.