Neuro: Basal Ganglia

Basal ganglia are a collection of (gray/white) matter located deep within (gray/white) matter of cerebral hemispheres & midbrain.

gray; white

Does a decrease in dopamine result in increased or decreased inhibition of M1? Does this occur via D1 or D2 receptors?

increased; D2

As a result of Parkinson's disease, does postural mm have increased or decreased excitation? What are the 2 consequences of this?

increased; truncal stiffness & impaired postural reactions

What 3 components can the basal ganglia be broken down into? Where do the 5 nuclei fall into these components?

input nuclei: caudate & putamen intrinsic nuclei: substantia nigra (pars compacta) & subthalamic nucleus output nuclei: globus pallidus (internal), substantia nigra (pars reticulata)

What are the 4 cardinal signs of Parkinson's disease?

rigidity, bradykinesia, tremor at rest, postural instability

Parkinson's disease is a (rapid/slow) progressive degeneration & depigmentation of the _________________, which results in the depletion of the (excitatory/inhibitory) neurotransitter substance, _________________.

slow; substantia nigra; inhibitory; dopamine

Disruption of the pathway between which nuclei produces Parkinson's disease? What is the name of this pathway?

striatum (caudate & putamen) & substantia nigra; striatonigral pathway

Hemiballismus occurs due to damage/stroke to what nucleus?

subthalamic nucleus

In patients with Parkinson's disease, there is what percent cell death before clinical signs or symptoms arise?

80% cell death

Which of the following is not an impairment of Parkinson's disease? Choose all that apply. A) ataxia B) bradykinesia C) flexion dystonia D) truncal rigidity E) tremor at rest

A) ataxia -- this is a sign of cerebellar lesion

Which of the following is a correct pathway? A) BG --> VA --> M2, M3 (motor execution) B) BG --> VA --> M2, M3 (motor planning) C) BG --> VL --> M2, M3 (motor execution) D) BG --> VL --> M2, M3 (motor planning)

B) BG --> VA --> M2, M3 (motor planning)

What is the most prevalent type of basal ganglia disorder?

Parkinson's disease

Is the basal ganglia involved in motor planning, motor learning, or both?

both

What are the 5 nuclei of the basal ganglia?

caudate, putamen, globus pallidus, subthalamic nucleus, substantia nigra

What is the direct pathway, of the basal ganglia circuits? Use the following terms: - cortex - globus pallidus - M2 - striatum - thalamus

cortex --> striatum --> globus pallidus --> thalamus --> M2

As a result of Parkinson's disease, does voluntary mm have increased or decreased: excitation, force, speed? What does this lead to?

decreased for all 3; smaller excursions

Does a decrease in dopamine result in increased or decreased M1 activity? Does this occur via D1 or D2 receptors?

decreased; D1

What 2 gait abnormalities result from Parkinson's disease?

festination & absent associative movement

The disruption of what pathway produces hemiballismus? What nuclei use this pathway (be specific)?

pallido-subthalamic pathway; subthalamic nucleus & internal globus pallidus

Stroke of what artery commonly leads to a localized lesion of the internal capsule? A) anterior cerebral artery B) anterior choroidal artery C) middle cerebral artery D) posterior cerebral artery E) posterior choroidal artery

B) anterior choroidal artery

Which of the following is true about the basal ganglia? Choose all that apply A) all motor control function is direct B) auto-regulation of externally generated movements C) initiates, terminates, and scales externally generated movements D) participates in motor learning E) plays a role in emotion

D & E are true -- A) --> indirect B) --> internally C) --> internally

Depletion of dopamine producing cells in the substantia nigra results in what? A) diminished excitatory output from the basal ganglia B) diminished inhibitory output from the basal ganglia C) excessive excitatory output from the basal ganglia D) excessive inhibitory output from the basal ganglia E) none of the above

D) excessive inhibitory output from the basal ganglia

In patients for whom dopamine replacement therapy is not successful, deep brain stimulation is an alternative treatment. In which 2 nuclei in the basal ganglia circuit is the stimulator placed?

internal globus pallidus & VA of thalamus