Test 3 Basal Nuclei CC

Question 1

4 Concepts for basal nuclei understanding

Answer 1

1. Motor damage and deficit in cognition, perception and mentation
2. parallel circuits
3. function through disinhibition
4. Disease are from disruption of neurochemical interactions

Question 2

Schizophrenia

Answer 2

increase in number and sensitivity of D2 receptors.

Question 3

Parkinson’s Disease- normal onset age?

What causes it? Symptoms and progression?

Answer 3

Parkinson’s Disease 45-65 years old

• Loss of melanin containing dopaminergic neurons in substantia nigra=decreased thalamocortical neuronal activity
  
  • Lateral to medial loss–dementia is last sx
  • motor loop==> Executive loop==> visuomotor loop==> motivational loop
• Sx: slight asymmetric gait or clumsiness==> less arm swing, ipsilateral resting tremor (becomes bilateral), gamma rigidity (cogwheel= increased muscle tone), eye movement problems, loss of postural reflexes, shuffling gait ==> dementia/cognitive impairment
• Akinesia and bradykinesia

Question 4

Huntington’s Disease

• Cause?
• Structures affected?
• Sx?

Answer 4

Huntington’s Disease

• Loss of medium spiny neurons in striatum that project to GPe and Loss of Ach neurons in straital complex–loss of parts of indirect pathway (usually inhibits movements)
  
  • dorsal to ventral; anterior to posterior; medial to lateral
  • Executive loop==>motor loop==>motivational loop
• Sx: absentmindedness, irritability, depression, clumsiness, sudden falls==> choreiform movement ==>degeneration of cognitive function and speech==>dementia

Question 5

Hypokinetic disorders

• what are they?
• Wheres the lesion?
  *

Answer 5

• Akinesia or bradykinesia
• lesion of neostriatum= putamen and caudate nucleus.
  
  • No inhibitory connection between neostriatum and internal globus pallidus= constant inhibition of thalamus and thus cortex
• Akinesia= delayed initiation of movement
• Bradykinesia= slow movement ( decreased amplitude as well)

Question 6

Akinesia

Answer 6

Akinesia-impairment of INITIATION of movement= disruption of basal nuclei

Question 7

Bradykinesia=

Answer 7

Bradykinesia- reduction in velocity and amplitude of movement.

• disruption of balance between outflow of direct and indirect pathway to thalamus.
• increase in activation of antagonist muscles.

Question 8

Hyperkinetic disturbances

Answer 8

Hyperkinetic disturbances= Disturbance of indirect pathway through motor loop= loss of excitatory subthalamopallidal neurons.

1. Ballismus
2. Choreiform movement
3. Athetoid movement

Question 9

Ballismus

Answer 9

Ballismus= usually hemiballismus. Uncontrolled flinging movement of UE>LE.

Cause: Vascular lesion localized to contalateral subthalamic nucleus

Question 10

Choreiform Movement

Answer 10

Choreiform Movement- irregular and brisk dance-like movement of the limbc. Decreased muscle tone.

Question 11

Athetoid Movement

Answer 11

Athetoid Movement= writing of distal portions or extremity.

brisk= choreoathetosis

intense and sustained= athetotic dystonia

Question 12

Glutamate Excitotoxicty

Answer 12

Glutamate Excitotoxicty- cause of early Huntington’s (before onset of clinical sx), also causes cell death after acute stroke

• glutamate persists at NMDA receptors (instead of being degraded)==> calcium influx never stops==>cell death
• causes decreased glycose metabolism in neostriatum

Question 13

Pugilistic parkinsons?

Juvenile parkinsons? Young onset?

Answer 13

Pugilistic parkinsons=Parkinson disease caused by repeated trauma (boxers)

Juvenile parkinsons= onset younger than 20

Young-onset parkinson= 20-40 years

Question 14

Festinating gait

Answer 14

Seen in patients with Parkinson’s Disease. Slow start (shuffling gait).

Question 15

1. When do Parkinson clinical signs begin?
2. Histologic section shows?
3. Treatment? (best)
4. Other treatments

Answer 15

Parkinson Disease

1. Clinical Sx: When 70-80% of nigral neurons and coresponding granules and dopamine are lost
2. Lewey bodies- round eosinophilic structures with light halo
3. L-dopa (crosses BBB) with carbidopa (doesn’t cross BBB, prevents PNS uptake of L-dopa so more can get to brain)
4. Surgical removal of ventral intermediate nucleus of thalamus, or posteriolateral part of GPi; electrode implantation, embryonic tissue implant

Question 16

Wilson’s Disease

1. Onset; defect
2. How defect causes diseaes
3. Sx
4. Brain?

Answer 16

Autosomal Recessive, Hepatolenticular Degeneration= Wilson’s Disease

1. Onset= 11-25 years; defect in copper metabolism
2. Copper accumulation in liver==>necrotic lesions==> cirrhosis; damage to lenticular nucleus in the brain. Aminoaciduria (kidney damage), Kayser Fleischer ring.
3. Liver cirrhosis ==years later==> neuro abnormalities (mood)
   
   • tremor, dysarthria, diminished dexterity, unsteady gait, rigidity
   • WING BEATING TREMOR- starts after arms are extended
   • mask-like facial expression, gaping mouth
4. degernation of putamen

Question 17

Tremor associated with

1. Lateral cerebellar lesion
2. Wilsons
3. Huntingtons
4. Parkinsons

Answer 17

1. Lateral cerebellar lesion= intention tremor
2. Wilson= wing-beating tremor
3. Huntington- NO TREMOR- CHOREA
4. Parkinsons= resting tremor

Question 18

Treatment for Wilson’s Disease?

Answer 18

Wilson’s diease treatment= copper chealating agents

Question 19

Sydenham Chorea

1. Etiology
2. Cause
3. Sx
4. prognosis

Answer 19

Sydenham Chorea

1. girls>boys; ages 5-15
2. consequence of rheumatic fever
3. Rapid irregular aimless movement of limbs, face and trunk, muscle weakness, hypotonia. Irritability, motional lability, OCD, ADD.
4. Self-limiting disease

Question 20

Tardive Dyskinesia

1. Cause
2. Brain abnormality
3. Symptoms
4. Prognosis

Answer 20

Tardive Dyskinesia

1. Caused by chronic treatment with neuroleptic medications
2. Blocked D2 receptors in VTA
3. Sx: uncontrollable involuntary movements of face, mouth and tongue; Cogwheel rigidity
4. Temporary or permanent, stopping drugs could make teh condition worse