Motor Systems II Flashcards
What are the four functions of the Cerebellum
1)Maintenance of posture and balance
2)Motor Learning
3)Cognitive Functions
4)Coordination of voluntary movements
Where is the cerebellum located and give another name for it
located at the base of the skull, often referred to as the “Little Brain”
What is the vermis of the cerebellum
The vermis connects the two hemispheres of the cerebellum
What is the Vallecula of the cerebellum
This is a depression located inferiorly on the cerebellum, in-between the two hemispheres
What is Arbor Vitae
This is the white matter of the cerebellum
What are the lobes of the cerebellum
Anterior Lobe
Posterior Lobe
Flocculonodular Lobe/ PosteroLateral Lobe
What is the primary fissure of the cerebellum
separates anterior and posterior lobe
What are the subdivisions of the cerebellum
1) Spinocerebellum
2) Vestibulocerellum
3)Cerebrocerebellum/Pontocerebellum
What is the function of the spinocerebellum
1)Control of muscle tone and coordination
2) Regulate body and limb movements
What is the function of the Vestibulocerebellum
Posture
Balance
Coordination of eye movements
What is the function of the cerebrocerebellum
Cognitive function of cerebellum
Planning and timing of movements
Evaluating sensory movements
How many layers is the cerebellar cortex made of
3 layer- Molecular, Purkinje and Granular
What does the molecular layer consist of
stellate cells
basket cells
Purkinje Layer
Purkinje cells, which also receive input from inferior olivery nucleus
Granular Layer
Granule cells
Unipolar brush cells
Golgi cells
Name the nuclei of the cerebellum
Fastigial Nucleus
Globose Nucleus
Emboliform Nucleus
Dentate Nucleus
How does the cerebellum receive input
Purkije cells and mossy and climbing fibres
Cerebellum output
Originate in the cerebellar deep nuclei
What are cerebellar peduncles
three fiber bundles carrying the input and output of the cerebellum
Inferior Cerebellar Peduncle
contains afferent fibers from medulla and efferents to the vestibular nuclei
INPUT AND OUTPUT TO CEREBELLUM
Middle Cerebellar Peduncle
Contains afferent from pontine nucleus
INPUT TO CEREBELLUM
Superior Cerebellar Peduncle
efferent fibers from cerebellar nuclei
OUTPUT OF THE CEREBELLUM
Where does the Cerebellum receive sensory input from
1)Inferior Olive (learning and memory)
2) Spinal Cord (monitor position and motion)
3)Vestibular Nucleus (posture and postion of neck head and eyes)
Pathway of cerebellar output
Cerebellar Cortex, Deep Cerebellar Nuclei, Ventral Lateral Complex, Primary motor and premotor cortex
Cerebellar Output Function
Eye movement, stance, gait, limb coordination
What is cerebellar dysfunction
Conditions affecting the cerebellum disrupt motor coordination and timing, usually accompanied by a loss in muscle tone
General Features of Cerebellar Dysfunction
Ataxia
Dysmetria
Decomposition of Movement
Limb tremor during movement
Ataxic Dysarthia: anomalous force, timing and ampliture of movement
Speech has Hypernasality
Cause of Cerebellar Dysfunction
Stroke
Physical Trauma
Tumors
Chronic alcohol excess
Infection
What is a medulloblastoma
a lesion in the vermis
Symptoms of Medulloblastoma
Headache
Vomitting
Drowsiness
Nystagmus; inaccurate visual tracking
Truncal Ataxia; inability to stand upright
What pathway does a lesion in the vermis affect
Lateral Vestibulospinal Tract
Where is a pontocerebellum lesion located
lesions in the dentate nucleus and superior cerebellar peduncle
Symptoms of a pontocerebellum lesion
incoordination of voluntary movements
What causes an anterior lobe lesion or degeneration of the cerebellum
Common in chronic alcoholics. Caused by a loss in cells (granule cells 10%, purkinje cells 20%, molecular layer 30%)
Symptoms of Anterior lobe lesion/ degeneration
Gait ataxia
affects lower limbs
failure of heel to toe walk
sensory ataxia
What are basal ganglia
a group of subcortical nuclei
How are basal ganglia grouped
Grouping of these nuclei is related to function rather than anatomy
What nuclei do basal ganglia consist of
Caudate Nuclei
Putamen
Globus Pallidus
Subthalamic Nucleus
Substantia Nigra
What is the function of the basal ganglia
motor control
motor learning
executive functions and behaviors
control of emotions
Input to the basal ganglia
Most cortical areas project to the striatum of the basal ganglia
All the projections are referred to collectively as the corticostriatal pathway
travel through internal capsule to reach caudate and putaman directly
What is the function of a medium spiny neuron
integrate the influences of thousands of cortical pyramidal cells
Basal Ganglia Dysfunction
Damage to the basal ganglia will result in involuntary movement or impairments to motion
May have difficulty, starting, stopping and sustaining movement
Causes of Basal Ganglia Dysfunction
drug overdose
head injury
metabolic
mitochondrial (leighs)
Huntingtons
Parkinson
