Flashcards in Basal Ganglia Deck (36):
What was classically included in the basal ganglia
caudate nucleus & lentiform nucleus
What is another name for globus pallidus
What is another name for caudate + putamen
What is included in the paleostriatum/pallidum
globus pallidus interna
globus pallidus externa
What is included in the neostriatum/striatum
What is currently included in the basal ganglia
paleostriatum (pallidum) - GPin, GPex
neostriatum (striatus) - putamen & caudate
What is the function of the basal ganglia?
influences UMNs for the initiation and control of MSK motor activity
Where does the tail of the caudate nucleus end?
tail extends down into temporal lobe and ends adjacent to the amygdala nucleus (limbic system)
What are the two subnuclei of the lentiform nucleus?
globus pallidus (GPin, GPex)
Where are the caudate and putamen continuous with each other?
around the anterior limb of the internal capsule
What is the corpus striatum? What does it include?
region occupied by the basal ganglia at the base of the forebrain
includes neostriatum and paleostriatum
What is the subthalamus?
diencephalic motor nucleus
What is the substantia nigra?
Mesencephalic motor nucleus
DRAW THE MOTOR PATHWAYS INVOLVING THE BASAL GANGLIA.
The connection between the basal ganglia and the thalamus is all from the
globus pallidus interna
What is the overall effect of the direct pathway?
Increases motor output
What is the overall effect of the indirect pathway?
Decreases motor output
What effect does dopamine have on the basal ganglia?
excites direct pathway and inhibits indirect pathway
results in increase of motor output
What dopamine receptors are associated with the direct pathway? Are they excitatory or inhibitory?
What dopamine receptors are associated with the indirect pathway? Are they excitatory or inhibitory?
What is the fundamental pathology behind Parkinson's Disease?
dopaminergic neurons in pars compacta diminish over time
What are characteristics of PD?
resting tremor (pill-rolling)
True or False: dopamine crosses the BBB
What is given as a treatment for PD? Why?
L-dopa crosses BBB
can increase efficiency of the undegenerated neurons in the SN
Is Huntington's disease hypokinetic or hyperkinetic?
Is PD hypokinetic or hyperkinetic?
What degenerates in HD?
degeneration of neurons seen in neostriatum initially and in deeper layers of frontal cortex
How does HD present in the early stages?
irritability, forgetfulness, clumsiness
How does HD present in late stages.?
Is there a treatment for HD?
What is the mechanism of neuronal degeneration in HD?
glutamate persistence at NMDA receptor sites in affected neurons opens the neurons to Ca which increases neuron excitability
neurons degenerate (excitotoxicity)
What causes hemiballismus?
Penetrating vessel arising from medial component of posterior cerebrals goes to subthalamus. Hemiballismus results from infarcts in subthalamus. Takes the subthalamus out of the indirect pathway so there is uncontrolled cortical output.
What is the symptom of hemiballismus?
contralateral violent contraction of proximal musculature (ballistic movements)
Is hemiballismus reversible?
As long as the vascular lesion resorbs the condition will diminish.
What is an "extrapyramidal" syndrome?
dyskinesia that results from an insult to the basal ganglia