Cerebellum - PowerPoint PPT Presentation

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Cerebellum

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Plays a role in automating and optimizing behavior ... IVth vent. Vermis. Intermediate hem. Spinocerebellum: Vermis. Intermediate hem. Spinocerebellum ... – PowerPoint PPT presentation

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Title: Cerebellum


1
Cerebellum
John H. Martin, Ph.D. Center for Neurobiology
Behavior Columbia University
2
Cerebellar Signs
Hypometria Response delays
Ataxia
Incoordination/rapid alternatingmovements(disdi
adocho-kinesia)
PNS Fig. 42-16
3
Research Points to Several Key Cerebellar
Functions
  • Comparison of intent and action (ie., errors) and
    generates corrective signals
  • Motor learning and adaptation
  • Plays a role in automating and optimizing
    behavior
  • Motor cognition and general cognition emotions
    (new evidence controversial)

4
Goal Cerebellar function
  • Overview of motor system hierarchy
  • Cerebellar anatomy
  • Principal pathways out of the cerebellum-- How
    the cerebellum impacts the motor pathways
  • Experimental approaches to reveal
  • Motor learning
  • Mental processes underlying movement control
  • Role in cognition and emotions

5
Motor Hierarchy
1 Som sensory
6
Cerebellar Functional Anatomy
7
Cerebellar Anatomy
PNS Fig. 42-1
8
Input-output Organization
Deep Cerebellar Nuclei
Fastigial
Cerebellar cortex
Interposed
Dendate
Vestibularnuclei
NTA Fig. 13-2,4
9
Cerebellar divisions
IVth vent
NTA Fig. 13-1
10
Cerebellar Cortex
Inputs
Climbing fibersfrom Inferior olive
Mossy fibers
Output
Purkinje neurons
Interneurons
Granule neurons
Stellate neurons
Basket neurons
Golgi neurons
Molecular
Purkinje
Granular
NTA Fig. 13-11
11
With inhibitory circuits
Without inhibitory circuits
Inhibitionreduces size of active
Purkinje neurons
Lateral inhibition Output morefocused
moreprecise
Parallel fiber input to cerebellar cortex
12
Cbm unfold
Functional divisions of cerebellar cortex --gt
Deep nuclei
PNS Fig. 42-2
13
Functional divisions of cerebellar cortex --gt
Deep nuclei
Spinocerebellum
Vermis
Intermediate hem
CerebrocerebellumLateral hemisphere
Vestibulo-cerebellum Floculo-nodularlobe
Motor execution
PNS Fig. 42-3 NTA Fig. 13-1
14
Medial lateral systems
Interposed nuclei
Fastigial
Vestibulocerebellum via vestibular nuclei
NTA Fig. 10-2
15
Intermediate and Lateral Hemispheres
Vermis Vestibulocerebellum
Planning andlimb control
Thalamus and Cortical motor areas
Brain stem nuclei
Cerebellar cortex Deep nuclei
Brain stem nuclei
Axial control
PNS Fig. 42-10, 12
Bilateral
Ipsilateral
16
Functions of the Cerebellum
  • Motor learning/adaptation
  • Non-motor functions
  • Active tactile exploration
  • Higher brain functions (cerebellar
    cognitive-affective syndrome)

17
MotorLearning
Before
Before
Prisms
Prisms
After
After
PNS Fig. 42-15
18
Non-motor Function
Passive stimulation
Discriminate roughness
Manipulate only
Manipulate discriminate
PNS Fig. 42-14
19
Cerebellar Motor Functions
  • Implemented via lateral and medial pathways,
    especially the corticospinal tract
  • Incorporated into motor programs via frontal
    motor areas (SMA, premotor cortex)
  • Becomes part of motor strategy via prefrontal
    cortex

20
Cerebellar Cognitive Affective Disorder
  • Lesions of the posterior cortex and vermis
  • Impairment of executive functions
  • Planning, verbal fluency, abstract reasoning
  • Difficulties with spatial cognition
  • Visuo-spatial organization, visual memory
  • Personality changes
  • Blunting of affect, inappropriate behaviors
  • Language disorders
  • Agrammatism

21
Conclusions
  • Cerebellar lesions produce
  • Incoordination errors not weakness
  • Lose ability to anticipate errors
  • Lose ability to correct
  • Motor learning
  • Requires sensory awareness
  • Implemented via the descending cortical and brain
    stem pathways
  • Cognitive and emotional disturbances
  • Anatomical connections to prefrontal and
    cingulate cortex (via thalamus)
  • No single function
  • Clearly mostly motor learning, optimizes
  • Functions may apply to cognitive and emotional
    behaviors
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