blk5 wk3

  1. Peripheral vestibular disorders
    • benign paroxysmal positional vertigo
    • vestibular neuritis
    • endolymphatic hydrops/Meniere's disease
  2. BPPV
    • >50YO, head trauma, prior inner ear injury prolonged recumbency, migraine w/aura
    • diagnose w/Dix-Hallpike Maneuver (lay down)
    • Nyatagmus: delayed onset, <1min, fatigue
  3. Vestibular neuritis
    • inflammation secondary to viral reactivation
    • isolated vertigo, nausea, no hearing loss, gradual improvement over weeks
    • good recovery
    • positive head impulse test: delayed correction of eye movement for head movement (VOR) (if cerebellar infarct, negative test)
  4. Endolymphatic hydrops
    • abnormal fluid balance in inner ear, dilation
    • end-stage response to vascular, autoimmune, metabolic insults
    • >2 vertigo episodes >20min
    • hearing loss
    • tinnitus or fullness
    • treatment: diuretics, salt restriction, stress reduction, shunt
  5. peripheral v central nystagmus
    • peripheral: unidirectional, vertical or horizontal comp, inhibit w/ smooth pursuit, normal neuro exam and ocular control
    • central: direction changing, not related to inner ear structure, no inhibition w/ fixation, no compensation, other ocular probs, abnormal neuro exam
  6. Pathway of motor learning in cerebellum
    • climbing fibers trigger complex spike in Purkinje cells
    • recently active parallel fiber inputs from granule cells are "punished"
    • protein kinase C is a coincidence detector necessary for LTD, reduced # of AMPA receptors
    • inhibitory interneuron/parallel fiber connections are strengthened
    • LTP of mossy fibers to deep nucleus neurons
  7. What are the different inputs to the cerebellum and where do they come from?
    • pons: mossy fibers travel thru middle cerebellar peduncle
    • spinal cord: mossy fibers travel thru inferior cerebellar peduncle
    • vestibular nuclei: mossy fibers travel thru inferior cerebellar peduncle
    • inferior olive: climbing fibers thru inferior cerebellar peduncle (1:1 fiber:PK cell)
  8. What are the outputs of the cerebellum?
    • carried by Purkinje cell axons
    • vestibular nuclei
    • deep nuclei: dentate nucleus, interposed nucleus, fastigial nucleus
    • deep nuclei then project to: thalamus/cortex, red nucleus/spinal cord, inferior olive (influence climbing fiber input), vestibular nuclei and reticular formation (influence posture/balance)
  9. Cells that use GABA as a neurotransmitter
    Purkinje, Golgi neuron, basket cell
  10. dentate nucleus
    • with the lateral parts of the cerebellar hemispheres and serves as the major output nucleus of the cerebrocerebellum
    • damage of the dentate nucleus = cerebellar signs that you would find with damage of the lateral cerebellar hemispheres, i.e. limb ataxia and action (intention) tremor
    • leave the cerebellum through the superior cerebellar peduncle and project to motor nuclei of the thalamus, on their way to the cerebral cortex
  11. Medial longitundinal fasciculus
    • carries information from the abducens nucleus to the oculomotor nucleus
    • from the medial vestibular nucleus to the medial vestibulospinal tract to regulate head position
  12. lateral vestibulospinal tract
    • mediates balance and posture
    • is not fed by the MLF
  13. vestibular semicircular canals
    • kinocilia are on the utricle side of the hair cells in the horizontal canal, but on the opposite side in the other 2 canals
    • hair cells depolarize when the cupula is pushed in the direction of the kinocilia
    • planes of the 3 semicircular canals are all orthogonal to one another
    • right vestibular nerve is excited during a horizontal rightward turn
  14. areas that get direct input from the vestibular nuclei
    • cerebellum
    • eye movement nuclei (including the abducens)
    • reticular formation
    • lateral & medial vestibulospinal tracts
  15. Nystagmus to the right can be caused by:
    • Damage to the left vestibular end organ
    • Spinning around to the right
    • Damage to the left Scarpa’s ganglion
  16. what prevents regeneration in the CNS?
    • Oligodendrocytes express several inhibitory proteins (Nogo, MAG, OMgp)
    • bind to Nogo Receptors on the neuronal surface and actively inhibit regrowth.
  17. Unlike long-term depression (LTD) at parallel fiber synapses onto cerebellar Purkinje cells, NMDA receptor-dependent LTD at excitatory synapses in the CA1 region of the hippocampus requires:
    Activation of protein phosphatases by increases in intracellular calcium levels.
  18. auditory path, caudal to rostral
    • superior olivary nucleus
    • lateral lemniscus
    • inferior colliculus
    • medial geniculate nucleus
Card Set
blk5 wk3
neuro blk5 wk3