Cerebellum and Cranial Nerves Flashcards
(94 cards)
What is the Cerebellum used for?
What do lesions to the cerebellum lead to?
UMN syndrome or LMN syndrome?
motor output
lesions lead to deficits in motor output and mobility
lesions to cerebellum do not result in UMN syndrome (does not cause spasticity, hyper, pathological reflexes)
Does lesion to cerebellum cause UMN syndrome?
NO
lesions to cerebellum do not result in UMN syndrome (does not cause spasticity, hyper, pathological reflexes)
Cerebellum: motor or sensory?
not only a motor effector but takes sensory input
Cerebellum Function (5)
- coordinates activity, fluid movement and postures
- comparison of motor activities to intend plan and modify it if not achieved (continual loop)
- modification of motor output based on sensory input and motor output: continuous loop
- compensation for motor tasks: predictive / anticipatory
big role in predictive movement: feed forward, anticipatory *if cerebellar lesion hard time with anticipatory balance but less impaired with reactive balance - major role in learning new motor programs because of its modifying function
If Cerebellum Damaged
learning new motor programs is limited: challenge in PT because we depend on motor learning – here plasticity cannot occur
*if cerebellar lesion hard time with anticipatory balance but less impaired with reactive balance
depending on where lesion is in the cerebellum can change deficits
Vestibulocerebellum
another name
receives input from _____ and outflow to ________
lesions result in _________
what happens in lesion?
archicerebellum
receives input from and outflow to the vestibular nuclei
lesions result in inability to use vestibular inputs (even though vestibular input comes in)
luckily the pons can help to some extent
if lesion to vestibulocerebellum can vestibular input still come in?
YES
Spinocerebelleum
another name
role
receives input from _____ and outflow to ________
lesions result in _________
what happens in lesion?
paleocerebellum
input: from spinocerebellar tracts (alot from spinal cord)
outflow to:
movement completion: termination of movement
muscle tone: initiate–>accelerete –>peak –>deccelerate –>terminate
lesion of the spinocerebellum results in overshooting when reaching for something reach past object: abnormality in maintaining the muscle tone (ie in a rebound test)
big effect on muscle tone–spasticity is excessive tone
if i hold my arm out, agonists and antagonsits are being used to keep my arm in this position
(regulating muscle tone and in adapting the body to changing circumstances. )
Rebound Test
hold arm straight, ability to maintain tone because firing of muscles is equal and opposite on all sides maintaining muscle tone
What does lesion to spinocerebellum cause?
abnormality in maintaining the muscle tone (ie in a rebound test)
NOT IN FLACCIDITY
NOT IN RIGIDITY
but ability to maintain an EVEN tone
ie doorbell: lesion to spinocerebellum- amount of pressure put onto the doorbell did not stay the same because could not maintain an even pressure/tone
Cerebrocerebellum
- another name
- role
- receives input from _____ and outflow to ________
- lesions result in _________
what happens in lesion?
- neocerebellum
- control of rapid movements, sudden movements (throw a ball and he quickly reacts to catch it)
precise movement control
motor planning - lateral cerebral hemispheres recieve input from pontine nuclei and has output to the thalamus, motor cortex, and premotor cortex
- dysmetria
disdiadokinesia
Vestibulocerebellum (online)
input/output
function
damage
The vestibulocerebellum,receives a substantial amount of its input from the vestibular nerve. This is unique since no other portion of the cerebellum receives direct input from a sensory nerve.
Additionally, there are connections from the vestibular nuclei to the vestibulocerebellum.
The vestibulocerebellum is an important regulator of the vestibular system.
Most important function of this is to allow adaptation to vestibular damage.
Damage to this region will result in vertigo and nystagmus.
Spinocerebellum (online)
input/output
function
damage
important in regulating muscle tone and in adapting the body to changing circumstances.
receives extensive input from the spinal cord. several direct and indirect spinocerebellar pathways terminate in the spinocerebellum
The input from muscles and the spinal cord reflex pathways are necessary for proper regulation of muscle tone and movement.
Since the spinocerebellum includes both vermal and paravermal zones of the cerebellum, there are connections with both the fastigeal nuclei and the interposed nuclei.
The fastigeal nuclei, in turn, connect to the reticular formation can affect muscle tone and crude movements via the reticulospinal tracts.
The interposed nuclei connect predominantly to the contralateral red nucleus through the superior cerebellar peduncle, origin for the rubrospinal tract that mainly influences limb flexor muscles.
-Therefore, the spinocerebellum can influence both muscle tone and coordination of the extremities.
-cerebellum is important in determining the appropriate response to changing situations.
For example, when attempting to resist a force on the extremities, a sudden release of force would result in a rebound of the the limb. The ability to rapidly check this motion requires feedback from muscle stretch and tension receptors.
Neocerebellum (online)
input/output
function
damage
The neocerebellum receives the vast majority of its input from the pontine nuclei. The pontine nuclei receive input from the majority of the cerebral cortex via corticopontine fibers. The pontine nuclei project exclusively through the middle cerebellar peduncles to the cerebellum, where these axons terminate as mossy fibers. It is the largest input to the cerebellum and almost exclusive input to the neocerebellum (which comprises most of the lateral hemispheres of the cerebellum).
involved in regulating the cerebral cortical motor output. The best-known effect of this is in procedural learning. —Activities such as riding a bike or learning to ski involve activity of the cerebellar hemispheres.
Damage to the lateral hemispheres results in lack of coordination of limb movement, with overshoot and undershoot (intention tremor).
The discussion to this point has largely focused on control of balance and of skilled voluntary movements. In addition to these functions. the cerebellar vermis receives visual input from the superior colliculus and is involved in coordinating eye movements. It also coordinates speech. Drunken speech, for example, derives from the effect of alcohol on the vermal portions of the cerebellum.
Signs of Cerebellar Dysfunction
5 traits
- Dysmetria
- Asynergia/dysnergia
- Rebound phenomena
- Tremor
- Hypotonia
Dysmetria
what is it
word root
what happens as a result
inability to accurately judge speed (of movement), force (of movement), or distance needed for task
“difficulty” + “measurement”
miss the target, too much force, too little force, cannot grade the amount of force needed for the task
Asynergia/Dysnergia
what is it
movement decomposition
lack movement fluidity
parts of the body working together in a particular/effective way to accomplish a task in synergy
motor planning that needs cerebellum to function normally is not occurring
movement is fractionated
decomposition: movement is less fluid, more robotic, less smooth movement. broken into short static components, because amount of control to make it fluid is gone and the nervous system reconstructs the movement to accomplish the task
Rebound Phenomena
- instructions
- normal result
- abnormal result
hold arm out in front of you
do not let me push you down
when PT removes hand, pt should have only one upswing–but in a cerebellar issue it swings around
Tremor
what is cerebellar tremor due to?
why is cerebellar tremor different than PD tremor?
cerebellar tremor is due to not maintaining stable tone
-need equal and opposite tone of flexors and extensors, adductors and abductors, agonists and antagonists
different from tremor seen in PD that is due to almost the opposite
Hypotonia
amount of tone that normally goes through the arm is lower rather than higher
Signs of Cerebellar Dysfunction (6)
findings
- findings usually ipsi-lateral (different than the contra-lateral in stroke or spinal cord lesion)
- ataxic gait: wide BOS, tremor and shaking
- dysarthria: cerebellar speech
—-need motor control of mouth/lips/tongue/ lower jaw/ and soft palate
—-sounds myffy
if diaphragm involved, not able to control pitch and volume - Nystagmus: rapid involuntary beating of eye in specific direction (direction indicates location of lesion) and impaired extra-occular movements
- loss of motor learning: feet forward loss, makes therapy difficult
- inability to learn from movement errors-may be aware made error but cannot correct it
are cerebellar dysfunctions contralateral or ipsilateral?
ipsilateral
What type of gait from cerebellar dysfunction?
- ataxic gait: wide BOS, tremor and shaking
dysarthria
what is it
cerebellar speech
—-need motor control of mouth/lips/tongue/ lower jaw/ and soft palate
—-sounds myffy
if diaphragm involved, not able to control pitch and volume
