Clin Neuro Cerebellum done Flashcards
Dysmetria of limbs
(inaccuracy of tar-geted movements)
Cerebellar ataxia produces a characteris-tic set of signs…
1.Gait becomes unsteady with tendency to falls 2.Hand coordination is impaired 3.Dysarthria or Dysphagia 4.Possible ocular symptoms related to ab-normal control of eye movements
2.Kinetic tremor of limbs and an uncon-trolled oscillation of limbs during rela-
tively slow but…
Targeted movment.
Intentional tremors.
3.Early stance and gait problems include
3.1.the inability to do a tandem stance orstand with feet together
3.2.stance becomes broad-based and
displays increased sway of the body
- Tandem gait becomes impaired and,
later, regular gait can be frankly ataxic
with a broad-based and lurching quality.
5.Eye movements show gaze-evoked or
other types of nystagmus, abnormal pur-suit of visually presented objects (jerky appearance due to intrusion of saccadesinto pursuit)
5.1.and inaccurate saccades when the person is asked to move the eyes quickly towards a target (hypometric or hypermetric saccades) 6.There is also a scanning type of dysar- thria.
.
Etiology of Cerebellum Damage most coomon
TBI
Etiology of Cerebellum Damage
Developmental abnormality
Arnold ChiariMalformation
Etiology of Cerebellum Damage
Demyelinating disease
MS
Etiology of Cerebellum Damage
Hereditary disease
Friedreich’s Ataxia
Etiology of Cerebellum Damage
Vascular insufficiency
CVA
Etiology of Cerebellum Damage
Drug and alcohol intoxications
Neoplasms
Cerebellum Organization“A structure of “three’s”
- 3 zones (Hemisphere’s)
- Vermal (Median) Zone
- Paravermal (Intermediate) Zone• Hemispheric (Lateral) Zone
- 3 lobes
- Anterior lobe
- Posterior lobe
- Flocculonodular lobe
- 3 functional areas
- Spinocerebellum
- Cerebrocerebellum
- Vestibulocerebellum
- 3 deep nuclei
- Fastigial Nucleus
- Interposed Nuclei
- Globose Nucleus
- Emboliform Nucleus
- Dentate Nucleus
- 3 cellular layers
- Molecular Layer
- Purkinje Layer
- Granular Layer
- 3 “highways” (peduncles)
- Superior Cerebellar Peduncle
- Middle Cerebellar Peduncle
- Inferior Cerebellar Peduncle
- 3 major afferents
- Corticopontocerebellar Pathway• Spinocerebellar Pathway
- Cortico-olivocerebellar Pathway• 3 major efferents
- Dentorubrothalamic Pathway
- Medial descending system
- Lateral descending system
Vermal!
(Median)!
Vermis!
Fastigial Nucleus
The worm is fast!
Paravermal%
(Intermediate)!
Medial!Cb!
Hemispheres!
Interposed!
Nuclei!(Globose!&!Emboliform)!
The side medial is to have so ething i terposed there.
Hemispheric%
(Lateral)!
Lateral!Cb!
Hemispheres!
Dentate!Nucleus!
Like Dante’s peak that it spewed all that ash into the atmosphere which sounds like hemisphere.
Anatomically divided into 3 lobes
- Anterior lobe
- Posterior lobe
- Flocculonodular lobe
• It is connected to the rest of the brain by 3 dense fiberbundles called peduncles
Anterior lobe’s name
Spinocerebellum,
Because here we see a change from the original idea of the spinal cord. That there it was the anterior that was motor and the dorsal that was sensory, but here the cerebellum is sensory at its anterior, like, no more of this sensory being at the posterior, its time to take a front row seat! V
Spinocerebellum
Muscle tone posture
stereotyped activities
The anterior is with the vermis, the worm like structure, so this looks like a spine, so we can say that it is to be for posture.
Cerebro,
cerebellum
Non-stereotyped activities.
This is brainy and so it does not require the usualy way to do things, it can go and do things that are all different.
Ha ha ha
Yes it can!
That worm, vermis, anterior, needs things that are stereotyped
Flocculo,nodular((
Ves=bulo,
cerebellum
Nodulus(&(Flocculi(
Head,eye(mvt/(coord,(balance(
&((posture(
Foliculous is the eye which needs the head, which when you have the eyes and head you also have the posture
Spinocerebellum
Controls proprioception related to:
• Muscle tone
• Maintenance of posture, because the spino is about posture
• Controls the execution & coordination of muscle ac-tivity of stereotyped activities, the vermis needs simple stereotyped actions
• Somatotopic Organization of Spinocerebellum
• Vermis – controls axial ms (head/trunk)
• Superior vermis – fine, precise motor coordina-
tion
• Inferior vermis – gross motor coordination
• Paravermis – controls limb ms (hands/feet)
Cerebrocerebellum function
Associated with planning, coordination, & execution of:• Rapid, Fine, non-stereotyped movements
• (ie. Ice skating, water skiing)
Vestibulocerebellum
Function
- Vestibular function
- Eye functions
- Coordination of Head and Eye Movements
- Constant maintenance of Balance & Posture
3 “highways” (peduncles)
- Superior Cerebellar Peduncle
- Middle Cerebellar Peduncle
- Extra large in size
- The structure connecting the cb to pons•
Inferior Cerebellar Peduncle
3 major afferents
• Corticopontocerebellar Pathway
Spinocerebellar Pathway
• Cortico-olivocerebellar Pathway
Corticopontocerebellar Pathway is the __________ pathway in the cerebelum.
Largest
Corticopontocerebellar Pathway enters through…
Enters via the Middle Cerrebellar Peduncle
We did say that the middle was the largest, that it. Connects the poms to the cerebellum.
And such a big name needs such a big channel.
Corticopontocerebellar Pathway
• Responsible for transmitting:
• Info about actual movement in progress•
Impending mnovement
Cortico=brains
So it actualy thinks of now and not just what is prearranged to happen.
• Allows for continuous monitoring & adjustment to produce smooth, fluid, coordinated movements.
3 major efferents
Dentorubrothalamic Pathway
Medial descending system
Lateral descending system
Dentorubrothalamic Pathway
• Output from hemispheric zone –> Dentate
• Principal efferent projection of the cerebellum
• Travels: Cerebellum to the Red Nucleus & Thalamus•
Responsible for:
• Motor planning
• Initiation
• Timing
• Precision of movements
• esp. the reciprocal contraction between agonist
and antagonist muscles of the limbs
Medial Descending System
• Output from vermal zone –> fastigial nucleus–>:
• Lateral vestibular nucleus (vestibulospinal tract)
• Reticular formation (reticulospinal tract) ! together this is known as the medial descending system
• Responsible for Maintenance of:
• Posture
• Balance
• Tone of extensor muscles
• Thalamus VL nucleus –> premotor & Primary MotorCortex –> Anterior corticospinal tract
• Controls motor activity of the axial & girdle mus-
cles
Lateral Descending System
• Output from the paravermal zone –> Interposed nuclei(Globose & Emboliform) –>:
• Red nucleus –> rubrospinal tracts that facilitates
tone in flexor muscles
• Thalamus –> lateral corticospinal tract
• Controls motor activity of the distal musculature of the limbs (esp. in the hands)
Cerebellum acts along with the ________ to regulate normal motorfunction.
Neither the Cerebellum or the ______ can
control muscle function by themselves
Cerebellum is defined as the perfect balance to the ______ and the epcerebellum but neither can do it alone.
Basal
Ganglia (BG)
What is movement (motor output)?
Movement is produced by complex interactions of
three systems:
1. Cerebral Cortex – planning & execution of movement
2. Basal Ganglia – initiation of motor activity & modula-
tion of cortical output
3. Cerebellum – coordination of movement
We already did say cerebellum and the basal ganglia, but we also are to make use of the cerebral cortex.
Cerebellum – coordination of movement
Is what particularly.
• Timing
• Speed
• Direction
Precision
You need to move and you need to move properly, ehich is the specific tine for the specific amount for the specific speed and the specific direction.
If you lack direction, then where are you going.
If you cannot choose its time, then when will yupou move.
If you cannot control the speed, then how fast.
And if you cannot aim your actions, then for what will you go and do the job.
So the cerebellum needs to be able to do,
Timing, speed, direction, and precision.
Right?
The Cerebellar effects on Motor output
• Sequence the motor activities
• Monitors and makes corrective
adjustments in the body’s motor
activities while they are being executed so that they will conform to the motor
signals directed by the cerebral motor
cortex and other parts of the brain
Consistently is gettig information in and it is
getting information out, and sometimes it is not using the cerebrum, but the basal ganglia must have the cerebrum.
Real time adjustements.
The most important part that will help out with
timing. Like dribbling a basketball.
We did mention the idea of timing, precision, speed , and direction.
But we also have to make it work with the cerebral cortex.
Additionaly, there is the issue of it acting in real tine so that all the aspects, of time, speed, direction, and precision are to actually be worked out properly.
Always function in association with other systems of motor control.
• The cerebellum plays major roles in:
• Timing of motor activities, timing
• Rapid, smooth progression from one muscle
movement to the next, precision, speed, and direction, and timing.
• Control the intensity of muscle contraction when themuscle load changes
• Controls the necessary instantaneous interplay
between agonist and antagonist muscle groups
By drippling the fingers, the finger tips, to make
sure that you are feeling the feelings, the
pressures, and all the againists and the
antagonist, to make all the different parts will be
able to work.
At some activities , it can just be the cerebellum
and not the the cerebrum.
Central pattern generators- it can be the
cerebellum, if all is controlled for.
The Role of the Cerebellum in Movement
Interacts with the other 2 parts of the brain to promote• Synchrony of movement • Accuracy of movement • Coordination of But especially: • Postural responses • Equilibrium • Voluntary and reflex muscular actions • Normal levels of muscle tone • Motor learning & memory of skilled motor activity
Thesea re all sub categories of timing, speed, precision, and direction.
You need all of thise four points for proper fine tuned movements. And one of the most well fine tuned movement is that if balance and posture.
• Receives Afferent projections from the:
Regulation of Movement (“Regulator”)
• Cord
• Cortex, since it gets info and sends that info to the cerebellum
• Subcortical brain regions, just like by the cortex, but there are areas below the cortex, like the basal ganglia
• Receives input from:
• Motor & non-motor areas
• Somatosensory, Vestibular, Auditory, & Visual•
Input and out is the point of reference, the cereberum to the
cerebellum is the input to cerebellum and output from the cerebrum.