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2012-02-17 00:01:07

lecture 9
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  1. Gross anatomy of cerebellum
    • located dorsal to pons and 4th ventricle and medulla
    • -separated from overlying cerebral cortex by tentorium cerebelli
    • -2 symmetrical halves, partly d ivided by posterior cerebellar incisure (containing a dorsal flap, the falx cerebri)
  2. Major anatomical divisions (flecting functional regions)
    • -vermis
    • -intermediate hemisphere
    • -lateral hemisphere

    • folds on terminal folia (equivalent to gyri in cerebral cortex)
    • cortex = organized into groups of folia = 10 lobules and 3 lobes
  3. what lobules the cerebellum have?
    • total: 10
    • Anterior: I - V
    • Posterior: VI - IX
    • Flocunodular: X
  4. Cerebellar peduncles
    all axons travelling to and from the cerebellum course thru superior, middle, and inferior
  5. Are thye efferents or afferents?
    the superior, middle, and inferior of hte cerebellar peduncles
    • superior: efferents
    • middle: afferents
    • inferior: efferents + afferents
  6. deep cerebellar nuclei - key elements of neural circuit
    • 4 nuclei:
    • fastigial,
    • globose,
    • emboliform,
    • dentate
  7. spinocerebellum; where, control?
    • originate in spinal cord to cerebellum
    • inputs from sc; controls posture and movement of trunk and limbs; provides some immediate feedback based on sensory input from muscles
    • -comprises the vermis + intermediate hemisphere to both anterior and posterior lobes
    • -projects thru fastigial and interposed nuclei
    • -has somatotropic organization
    • have 4 AFFERENT tracts
  8. what are the four spinocerebellar tracts?
    • dorsal spinocerebellar tract,
    • cuneocerebellar tract,
    • ventral spinocerebellar tract,
    • rostral spinocerebellar
  9. the dorsal spinocerebellar tract and cuneocerebellar tract travels...
    • in ipsilateral lateral column; both enters cerebellum thru ipsilateral inferior cerebellar peduncle
    • -sensory info comes from periphery
  10. ventral spinocerebellar tract
    • travels after a decussation in ventral portion of hte lateral column and enter cerebellum via superior cerebellar peduncle.
    • once in cerebellum fibres cross again; input is ipsilateral
  11. ventral spinocerebellar tract
    rostral spinocerebellar
    both relay itnernal feedback signals reflecting amounts of neural activity in descending pathways
  12. input -output organization
    • all major inputs feeds to deep cerebellar nuclei as well as cerebellar cortex
    • outs thru dcn
  13. spinocerebellar output:
    • vermis sends efferents thru fastigial n. to...
    • 1) inferior cerebellar peduncles -to- medial descending pathways and reticulospinal and vestibulospinal
    • 2) inferior cerebellar peduncles -to- VL -to- primary motor cortex descends -to- medial (ventral) corticospinal tract
  14. where does the intermediate hemisphere sends the efferents?
    • ..through interposed n. to...
    • 1) superior cerebellar peduncle -to- red nucleus (magnocellular) -to- rubrospinal tract
    • 2) sperior cerebellar peduncle -to- VL -to- lateral corticospinal tract
  15. cerebrocerebellum does what? locate where? and projects where?
    • participates in planning of movement
    • -located in lateral hemisphere
    • -projects to dentate nucleus
    • -this part of the cerebellum is interconnected with the cerebral cortex, rather than receiving its input from spina cord
    • AFFERENT input - from entire controlateral cerebral cortex
  16. What is the afferent input?
    • 1. contralateral cerebral cortex
    • 2. middle pontine n.
    • 3. middle cerebellar peduncle
    • 4. contralateral cerebellar cortex

    • efferent pathway -to- dentate n. to either ...
    • 1. red n. (parvocellular) to inferior olivary n. (ipsilateral)
    • 2. VL -to- primary motor cortex and premotor cortex & prefrontal cortex ( influences behavior and learning)
  17. vestibulocerebellum; functions, input, located, projects?
    • -maintain balance and controlling head and eye movements
    • -input from vestibular labyrinth
    • -located in floculonodular lobe
    • -projects to vestivular nuclei (takes place of DCN)

    • afferent input:
    • -primary vestibular afferents (only primary sensory n. projects directly to cerebellum)
    • -secondary vestibular neurons in vestibular nuclei

    Efferent path
  18. Efferent path
    • vestibular cerebellar cortex
    • -to-
    • vestibular nuclei
    • -to-
    • either Med and later VS tracts OR
    • Med longitudinal fasciculus (eyes, head)
  19. cytoarchitecture and circuitry of cerebellar cortex
    have 3 cell layers
    • molecular,
    • purkinje,
    • granular
  20. what are the 5 cell types?
    • purkinje
    • granule cell
    • Stellate Cells
    • Basket Cells
    • Golgi Cells
  21. Purkinje is?
    • inhibitory -GABA
    • -contacted by climbing fibres
    • -major output neuron (only neuron prjecting outside cerebellar cortex)
    • located in PCL (projects to DCN)
    • projects to vestibular nuclei thru inferior cerebellar peduncle (icp)
  22. Granule cell
    • interneurons
    • -contacted by mossy fibres
    • -only excitatory neuron
    • -puts out just 1 parallel fibre up to molecular layer to purkinje dentrites
  23. Stellate Cells
    • interneurons
    • -contact Purkinje cell dendrites (inhibitory)
    • locate: outer molecular layer (inhibitory, taurine)
  24. Basket Cells
    • interneurons
    • -contact Purkinje soma (basket around it)
    • -inhibitory
    • locate: inner molecular layer (inhibitory, GABA NT)
  25. golgi cells
    • interneurons
    • -contacts granule cell within glomeruli (inhibitory)
    • glial capsule and specificity of connections
    • located: granule cell layer (inhibitory, GABA)
  26. where does Clarke's Nucleus and accessory cuneate nucleus relay sensory info to?
    to the spinocerebellum
  27. Clarke's nucleus ranges from where?
    C8 to L2 within medial portion of intermediate zone
  28. axons in the spinal cord travels...
    • in dorsal spinocerebellar tract to icp (medulla)
    • from ventral spinocerebellar tract to scp (pons) -[orginate from spinal border cells]