Motor Control Flashcards
hierarchical organisation (motor control)
higher order > more complex tasks e.g. programme/decide movement, coordinate muscle activity
lower order > low level tasks e.g. execution of movement
functional segregation (motor control)
motor system organised is a number of different areas for different aspects of movement
Draw a flow chart/diagram of the motor system hierarchy.
> = arrows from
motor cortices > cerebellum, basal ganglia, brainstem spinal cord
basal ganglia > thalamus > motor cortices
cerebellum > thalamus, brainstem
thalamus > motor cortices
brainstem > spinal cord, muscles of face, head, neck
spinal > muscles of body
The major descending tracts can be grouped into?
Pyramidal
Extrapyramidal
List examples of pyramidal tracts.
corticospinal
corticobulbar
List examples of extrapyramidal tracts.
vestibulospinal
tectospinal
reticulospinal
rubrospinal
Pyramidal tracts run from where to where?
motor cortex to spinal cord or cranial nerve nuclei in brainstem
Pyramidal tracts control what type of movements?
voluntary movements of body and face
Extrapyramidal tracts control what type of movements?
involuntary movements for balance, posture, locomotion
Where is the primary motor cortex located?
precentral gyrus, anterior to central sulcus
Primary motor cortex controls?
fine discrete precise voluntary movements
Where is the premotor area located?
anterior to primary motor cortex
Premotor area is involved in?
planning movements
regulates externally cued movements
Where is the supplementary motor area located?
anterior and medial to primary motor cortex
The supplementary motor area is involved in?
planning complex movements
becomes active prior to voluntary movement
internally cued movements
Describe the path of the corticospinal tract.
upper motor neurons > cerebral peduncle > 85-90% decussation in medullary pyramids > splits into lateral and anterior tracts > lower motor neurons (ant > trunk) (lat > limb)
Corticobulbar tracts is the principal motor pathway for?
voluntary movements in the face and neck
Functions of the vestibulospinal tracts?
stabilise head, coordinate head with eyes, mediate postural adjustments
Function of reticulospinal tract?
from med. to pons, change in muscle tone associated with voluntary movement, postural stability,
tectospinal tract runs from?
superior colliculus of midbrain
tectospinal tract is involved in?
orientation of head and neck during eye movements
Rubrospinal tract runs from?
red nucleus of the midbrain
Functions of rubrospinal tract
innervate lower motor neurons of upper limb flexors
negative signs of upper motor neuron lesion?
loss of voluntary motor fx
paresis (graded weakness)
paralysis
positive signs of upper motor neuron lesion?
^ abnormal motor fx (loss of inhibitory input)
spasticity
hyper reflexia
clonus (abnormal oscillatory muscle contraction)
Babinski’s sign
What is apraxia?
disorder of skilled movement, lost info on how to perform skilled movements
Lesions is what regions cause apraxia
inferior parietal lobe
frontal lobe
Most common causes of apraxia?
stroke
dementia
Lesions of lower motor neurons cause?
weakness, hypotonia, hyporeflexia, muscle atrophy, fibrillation, fasciculations
Upper motor neuron signs of MND
spasticity, brisk limbs/jaw reflexes, Babinski sign, loss of dexterity, dysphagia, dysarthria
lower motor neuron signs of motor neuron disease
weakness, muscle wasting, nasal speech, dysphagia, tongue fasiciculations / wasting
Function of caudate nucleus
decision to move
Function of lentiform nucleus
assists the cerebellum in coordinating small, precise muscle movements
(with the caudate nucleus forms the striatum which is part of the basal ganglia)
what is the basal ganglia?
region of the base of the brain that consists of three clusters of neurons (caudate nucleus, putamen, and globus pallidus) > thalamus, nucleus accumbens, amygdala, anterior commisure
Parkinson’s disease is the degeneration of (?) neurons that originate from (?) and projects to (?)
dopaminergic
substantia nigra
striatum
Symptoms of parkinson’s disease
bradykinesia, hypomimic face, akinesia, rigidity, tremor at rest
Huntington’s disease is the degeneration of (?) neurons in the (?) (?) (?)
GABAergic
striatum
caudate
putamen
What genetic abnormality causes Huntingdon’s disease?
autosomal dominant
chromosome 4
CAG repeats
Symptoms of Huntingdon’s
choreic movements speech impairment difficulty swallowing unsteady gait cognitive decline dementia
Ballism is usually from?
stroke affecting subthalamic nucleus
Symptoms of ballism
sudden uncontrolled flinging of the extremities,
symptoms occur contralaterally
Cerebellum is separated from the cerebrum by?
tentorium cerebelli
Motor function of cerebellum
coordinator and predictor of movement
Function of vestibulocerebullum?
Regulation of gait, posture and equilibrium
Coordination of head movements with eye movements
Tumour of vestibulocerebellum causes what?
syndrome similar to vestibular disease leading to gait ataxia and tendency to fall (even when patient sitting and eyes open)
Function of spinocerebellum?
Coordination of speech
Adjustment of muscle tone
Coordination of limb movements
Damage to spinocerebellum done usually by?
degeneration and atrophy associated with chronic alcoholism
Damage to spinocerebellum affects what?
affects mainly legs, causes abnormal gait and stance (wide-based)
Function of cerebrocerebellum?
Coordination of skilled movements
Cognitive function, attention,
processing of language
Emotional control
Damage to cerebrocerebellum mainly affects?
mainly arms/skilled coordinated movements (tremor) and speech
What are the main signs of cerebellar dysfunction apparent only on movement?
ataxia (loss of full control of body movements)
dysmetria (impaired ability to estimate distance in muscular action)
intention tremor (when attempting precise movement)
scanning speech (staccato)
dysdiadochokinesia (impaired ability to perform rapid, alternating movements)
function of basal ganglia
helps control eye movements
role in motivation, decision making and memory