Neuro Exam 4.8

  1. Which motor control system is the Basal Ganglia a part of?
    extrapyramidal (developed before pyramidal)
  2. What does the basal ganglia control?
    • involuntary, instinctive skeletal m activity (don't have to think about it)
    • reflexive
  3. Where is the basal ganglia?
    deep seated nuclei w/in white matter of cerebral hemispheres of telencephalon
  4. What are the primary players of the basal ganglia?
    • caudate nucleus
    • lenticular nucleus
  5. What makes up the lenticular nucleus?
    • putamen
    • globus pallidus
  6. What structures make up the extrapyramidal system?
    • basal ganglia
    • red nucleus (midbrain)
    • substantia nigra (midbrain)
    • subthalamic nucleus (diencephalon)
  7. Does the basal ganglia have a direct connection with the SC?
    no, indirect relationship to LMN
  8. How does the basal ganglia communicate with the SC (how does it carry out reflexive motor control to the LMN)?
    by using reticulospinal, corticospinal, nigroreticular, and thalamocortical tracts
  9. How does the basal ganglia use the reticulospinal tract?
    • sends info to reticular formation
    • which sends it to ventral horns of SC to influence LMN (alpha)
    • biased toward extensor activity
  10. How does the basal ganglia use the corticospinal tract?
    • sends info to pre-central gyrus (influences UMN in precentral gyrus)
    • to in turn influence LMN
  11. How does the basal ganglia use the nigroreticular tract?
    sends info to substantia nigra in midbrain to reticular formation to reticulocortical tract to influence LMN
  12. How does the basal ganglia use the thalamocortical tract?
    sends info to thalamus which sends info to cortex through thalamocortical tract to influence corticospinal tract
  13. What does the basal ganglia utilize to carry out functions?
    inhibitory processes
  14. Is the basal ganglia intimately integrated with pyramidal system?
    yes, the two can't work in isolation of one another
  15. What are the functions of the basal ganglia?
    • assists in inhibiting co-contraction in aantagonistic mm of limbs
    • assists in adjusting body position during movement for a specific task
    • works at subconscious or reflexive level
    • determines direction, speed, force of movement
    • involved with CPG
  16. What is an example of the basal ganglia assisting in inhibiting co-contraction in antagonistic mm of the limbs?
    • thalamocortical influence (info is from thalamus to caudate nucleus to precentral gyrus)
    • utilizes Renshaw cells
  17. What are the basal ganglia inhibitory mechanisms?
    • determines direction, speed, force of movement
    • involved with CPG
  18. What is an example of the basal ganglia determining direction, speed, force of movement?
    if you want to hit someone with a pillow, you would use your BG so it can recruit the UMN to tell LMN to work
  19. How is the basal ganglia involved w/ CPG?
    where they are remembered.  Start as voluntary and w/ repetition they become remembered (CPGs stored in BG)
  20. Characteristics of Basal Ganglia Damage: Parkinson's disease/Parkinsonian symptoms
    hypkinesia (akinesia)
  21. Hypokinesia:
    • reduction in the initiation, implementation, and facilitation of execution of movement (slow movement)
    • movements initiated slowly and stop with difficulty
    • voluntary movements
  22. akinesia:
    when you can't move something at all
  23. What are characteristics of hypokinesia?
    • hypertonia
    • rigidity
    • conscious movements may be suppressed w/ hypokinesia
    • abnormal postures may be assumed
    • reciprocal arm swing during gait is absent
    • DTR usually normal
    • facial expression masked
  24. hypertonia:
    • reason they are moving slower
    • increase in m tone w/ resistance to PROM
    • if disruption involved the whole body (all mm)=rigidity
  25. Rigidity:
    associated w/ hypokinesia and hypertonia, implying that entire body presents it
  26. cogwheel rigidity:
    • increased jerky resistance for PROM (jerky like a cogwheel)
    • due to increases in m tone
  27. Plastic rigidity (lead pipe)
    increased resistance to PROM that is constant, continuous, and smooth
  28. What abnormal postures may be assumed w/ hypokinesia?
    stooped, lean to one side
  29. How are facial expressions masked with hypokinesia?
    hard to laugh or smile, etc b/c requires motor function
  30. Pathology of Parkinson's Disease: Degeneration of substantia nigra of midbrain
    normally there are neurons in substantia nigra that release dopamine (an inhibitory NTM) to basal gagnlia
  31. Pathology of Parkinson's Disease: Decreased amounts of neurons leads to dopamine-depleted basal ganglia
    decreased levels of dopamine = decreased inhibition
  32. Pathology of Parkinson's Disease: Disinhibition-
    • basal ganglia can't be inhibited and will do things in an uncontrolled manner
    • causing activity that you don't want (hypotonia), involuntary movements
    • disinhibition Phenomenon
  33. Disinhibition Phenomenon:
    involuntary movement b/c basal ganglia is no longer inhibiting movement
  34. What are the involuntary movements associated with basal ganglia damage?
    hyperkinesia-hyperkinetic (involuntary movements)
  35. What are the symptoms of hyperkinesia-hyperkinetic?
    • static tremor
    • alternating tremor
    • athetosis
    • chorea
    • ballism
  36. Static tremor:
    • hallmark of basal ganglia dysfunction
    • rhythmic, fine, involuntary tremor when extremity is in fixed position
    • associated w/ Parkinson's
  37. What dysfunction causes static tremor?
    substantia nigra dysfunction
  38. How do you differentiate b/w cerebellar dysfunction and basal ganglia dysfunction?
    • cerebellar = intentional tremor (starts as you approach a target)
    • basal ganglia = static (fixed)
  39. Alternating tremor is due to:
    alternating contraction of opposing mm groups
  40. Alternating tremor, aka:
    pill rolling
  41. Alternating tremor:
    hyperkinesia characterized by regular, symmetrical, to and fro movements produced by patterned, alternating contraction of mm and their antagonists
  42. Is alternating tremor associated with Parkinson's?
  43. Does alternating tremor continue when pt does voluntary skeletal mm activity?
    no, tremor stops
  44. Does alternating tremor stop during sleep?
  45. What dysfunction causing alternating tremor?
    caudate nucleus dysfunction
  46. Athetosis:
    involuntary movement characterized by slow, writhing (squirmy), worm-like movements of the fingers
  47. Is Athetosis associated with Parkinson's?
  48. When does athetosis occur?
    at rest or during involuntary or voluntary movement
  49. What dysfunction causes athetosis?
    putamen dysfunction
  50. Chorea:
    sudden, involuntary, jerky movements w/ grimacing or twitching of facial mm and faulty vocalization
  51. Is chorea associated with Parkinson's?
  52. What disease is associated with chorea?
    Huntington's chorea
  53. Huntington's chorea:
    • autosomal dominant disorder
    • caudate nucleus atrophies or breaks down and becomes disinhibited
    • manifests in 4th decade of life
  54. What dysfunction causes Huntington's chorea?
    caudate nucleus damage
  55. When does chorea happen?
    at rest or voluntary movement
  56. What dysfunction causes chorea?
    caudate nucleus
  57. Ballism:
    • involuntary movements of an entire limb
    • begins proximally and proceeds distally
    • movements are quite dramatic
  58. Is ballism associated with Parkinson's?
  59. What causes ballism?
    subthalamic stroke (dysfunction of subthalmic nucleus
  60. Is the subthalmic nucleus part of the basal ganglia?
    no, but still part of extrapyramidal system which helps w/ voluntary movements
  61. Which basal ganglia NT/NM are excitatory?
    • ACh-acetylcholine
    • Glutamate
    • Aspartate
  62. Which basal ganglia NT/NM are inhibitory?
    • GABA
    • Dopamine (damage in Parkinson's)
    • Glycine (major inhibitory NT in NS)
Card Set
Neuro Exam 4.8
review of neuro part 8 for exam 4