MIdterm 2 - Unit 5 Lecture 3 Flashcards
function of cerebellum
Regulates movement and posture indirectly by adjusting output of major descending motor systems
the Cerebellum has no direct connections with motor neurons. true or false
true
why does the complete removal of cerebellum cause no muscle weakness or loss of perception
Because it doesn’t take away the ability to contract the muscle
But you lose the ability to coordinate or update or learn
cerebellum Receives information for …
programming and execution of movement
why do the outputs from the cerebellum go back to motor areas either in the brain stem or the cortex
to modulate motor output (correct for errors)
what structure Houses almost half of the neurons of the entire brain
cerebellum
what are the 4 roles the cerebellum plays in voluntary movement
Timing: correct order and timing of individual muscle activation; timing of movements
Coordination: assemble components of complex multi-joint or multi- limb movements
Comparator: compensates for errors in movement by comparing sensory feedback with motor intention (Corollary Discharge or Efference Copy)
Motor learning: acquire new motor skills
explain the prism glasses experiment and how it effects motor learning
Experiment where when you put goggles on it changes your visual environment so that your proprioceptive feedback doesnt quite match your visual feedback
In a normal healthy individual, when they reach to a target in normal situation with no googles, no prisms, they are fairly accurate
When they put on the goggles it changes their visual perception of the target and all of a sudden they’ve thrown way off target
And overtime they adapt they change that skill in order to use the visual, kinesthetic and proprioceptive information to produce an accurate movement
Then when they take the goggles off there is an after effect, it goes in the opposite direction
But then it washes away sooner or later
what happens to those with Cerebellar dysfunction that complete the prism experiment
Individual with cerebellar dysfunction can’t account for this error
In this case what happens is to begin with, they’re not as good, there variability is quite high in normal situations
Put the goggles on, now they missed the target by the deviation of the prisms
And they don’t take into account when performing these subsequent maneuvers, which means that they don’t adapt
Because they haven’t adapted they simply go back to normal performance
what happens to those with Cerebellar dysfunction that complete the prism experiment
Individual with cerebellar dysfunction can’t account for this error
In this case what happens is to begin with, they’re not as good, there variability is quite high in normal situations
Put the goggles on, now they missed the target by the deviation of the prisms
And they don’t take into account when performing these subsequent maneuvers, which means that they don’t adapt
Because they haven’t adapted they simply go back to normal performance
what are the 3 anatomical lobes of the cerebellum
Anterior Lobe
PosteriorLobe
Flocculonodular Lobe
what are the 2 hemispheres and vermis of the cerebellum
Lateral Region
Intermediate region
Vermis (midline): ridge in centre
what are the Three functional regions of the cerebellum
Cerebro cerebellum
Spino cerebellum
Vestibulo cerebellum
describe the Cerebro cerebellum
Cerebro cerebellum is from the the cerebral cortex into the cerebellum, specifically going to the lateral hemispheres
describe the Spino cerebellum
Going from spinal cord to cerebellum
Involved in relaying afferent info to the Intermediate hemispheres and vermis
Where do the inputs for the Vestibulo cerebellum go to
Flocculonodularlob
why does the cerebral cortex send the motor program to the cerebellum
It sent here so that it can be compared with that feedback that’s coming in eventually
how does the cerebellum compare feedback
through two fibers or areas:
the cortical pontine cortex to pons
then pons to cerebellum
Vermis receives Afferent information about
head and proximal parts
Intermediate hemispheres receives Afferent information
limb movements (somatosensory input)
Vestibulocerebellum Receives Afferent information from
vestibular and visual inputs
Primary (direct) and secondary (vestibular nuclei) vestibular sensory neurons project to
ipsilateral flocculonodular lobe
Most cerebellar outputs relayed by
deep cerebellar nuclei
Dentate receives input from __________
lateral hemisphere
emboliform and globose receive input from
Interposed Nuclei: input from intermediate hemisphere
Fastigial receives input from
vermis
describe the cerebro cerebellum pathway
- goes to the Lateral hemisphere to Dentate nucleus
- Dentate nucleus Then project to
(contralateral)thalamus
3.Thalamus to cerebral cortex
describe the spinal cerebellar pathway
- Intermediate hemisphere to Interposed nuclei
2.Then project to (contralateral) thalamus or
red nucleus - Thalamus to cerebral cortex
describe the Vestibulocerebellum pathway
Vermis to Fastigial nucleus, then to:
Vestibular nuclei
Reticular formation
Cortex via thalamus
Flocculonodular lobe output?
vestibular nuclei
bidirectional connections between vestibular
nuclei and cerebellum. True or false
true
what are the Cerebellar Dysfunctions learned in class
Dysmetria
Dysrhythmia
Dysdiadochokinesia
Hypotonia
what is Dysmetria
Abnormal amplitude, undershoot or overshoot, of movement
what is Dysrhythmia
Abnormal rhythm and timing of movement
what is Dysdiadochokinesia
Abnormality with alternating movements
what is Hypotonia
Abnormally low muscle tone
what is Cerebellar Ataxia
poor muscle control that causes clumsy voluntary movements.
why do Cerebellar Disorders occur
lesions of the intermediate and lateral hemispheres
Lesions of the vermis
Lesion of the flocculonodular lobe
