The Basal ganglia Flashcards
How can the basal ganglia be divided into a rostral and caudal part?
Rostral - Striatum (putamen and globus pallidus) and globus pallidus (internal and external disease)
Caudal - subthalamic nucleus and substantia nigra
What types of circuits does the basal ganglia contain?
Motor circuit
Limbic circuit
Oculomotor disease
What is the difference between Huntington’s and Parkinson’s disease?
PD - not enough dopamine -
- increased muscle tone
- reduced movements
HD - too much dopamine
- decreased muscle tone
- overshooting movements
What is dopamine synthesised from?
What can it be systhesised into?
look at the enzymes - slide 16
L-Tyrosine
L-DOPA
Dopamine
Norepinephrine
Epinephrine
Why does dopamine act differently in different parts of the brain>
Acts on different neuroreceptors
What is the diagnostic criteria for Parkinsons?
Loss of dopinergic neurons in the substantia nigra
Detection of Lewy bodies in the remaining neurons
What changes in the brain in Huntington’s disease?
Cells die in the striatum
Lateral ventricles appear ‘enlarged’ because the caudate has shrunk away
What is the overall function of the basal ganglia?
Facilitation, integration ‘fine tuning of movements’
What are the interactions in the brain for inhibition/ excitation of the basal ganglia?
signals go…
Cortex > Basal ganglia > cortex > movement
Between basal ganglia and cortex…
Substantia nigra produces dopamine, the ‘lubricant’ for he basal ganglia
Striatum (P + CN) produces GABA, the ‘brakes’ for the basal ganglia
GABA gets affected by HD
what are the main symptoms of Parkinsons?
Brady/Akinesia - writing smaller, deteriorated walking
Tremor - at rest, may be one side only
Rigidity - pain, problems turning in bed
What drug is used for Parkinsons?
What are the downsides?
What is the brain surgery option for treating Parkinsons?
Stimulation… functional lesioning of the subthalamic nucleus leads to dramatic improvement
It inactivates the ‘brake’ the subthalamic nucleus
What are the clinical features of Huntington’s disease? What are the characteristics of the genetics?
Chorea
Dementia/psychiatric illness
Personality change
Genetics - autosomal dominant, fully penetrant
What are the regional patterns in Huntingtons?
Dementia and personality change in the cortex (personality in the prefrontal)
Chorea - caudate nucleus?
Balance problems - cerebellum
