Basal Ganglia Flashcards
What makes up the extrapyramidal system?
Cerebral cortex, basal ganglia, dorsal thalamus
What does the extrapyramidal system do?
Initiate movement
What is included in the basal ganglia?
Cerebral cortex, caudate nucleus, putamen, globus pallidus, thalami, subthalami, susbtantia nigra
What are the 2 divisions of the substantia nigra?
Pars reticularis and Pars compacta
What does the pars reticularis do?
Sends efferent neurons that release GABA and serotonin
- Does not contain melanin
What does the pars compacta do?
Neurons contain melanin and dopamine
What part of the susbtantia nigra degenerates with Parkinson’s disease?
Pars compacta
What are the motor nuclei of the thalamus?
Ventral anterior and ventral lateral (VA and VL)
What all degenerates with Parkinson’s?
Substantia nigra, globus pallidus, upper brainstem
What are the symptoms of Parkinson’s?
Bradykinesia, tremor during rest, rigidity, masked face and glabellar reflex, postural embarrassment
What causes Huntington’s Chorea?
Loss of inhibition from GABAnergic neurons or degeneration of the corpus striatum/cerebral cortex
What is the pathway of inheritance for Huntington’s Chorea?
Autosomal Dominant
What are the symptoms of Huntington’s Chorea?
Dementia, behavioral disturbances, chorea
What is chorea?
Sudden, irregular, jerky and purposeless movements
What are the symptoms of hemiballism?
CONTRALATERAL wild, violent, flailing of UE and LE
What can cause hemiballism?
Unilateral lesions of subthalamus
Loss of glutamate inhibition upon globus pallidus
What is Athetosis?
Slow, involuntary, writhing movements of limbs and face
What causes Athetosis?
Degeneration of striatum
What is hemichorea?
Unilateral chorea movements
What causes hemichorea?
Vascular lesion in basal ganglia
What are the functions of the basal ganglia?
To start, stop or modulate movement
What is the function of the direct pathway?
Increase motor activity
What is the function of the indirect pathway?
Decrease unwanted motor activity
What is the purpose of the nigrostriatal pathway?
Modulation of direct/indirect pathways
What effect do nigrostriatal fibers have and if destroyed what occurs?
Excitatory - Parkinson’s
What effect to striatonigral fibers have and if destroyed what occurs?
GABAnergic (inhibitory) - Huntingtons Chorea
