L09: Motor Control- Role Of Motor Cortex And Spinal Reflexes Flashcards
What are the 2 types of motor descending pathways
Lateral
Ventromedial
What is the lateral motor pathways involved in
Voluntary control of movement
What is the ventromedial pathway involved in
Unconscious movement e.g standing up without thinking about it
What does the sensory consequence of movement feed to from the spinal cord
Brainstem
Thalamus
What does the thalamus feed into
The cerebral cortex
What does the primary motor cortex fed to
Directly to the spinal cord
Or
To the spinal cord via the brainstem
When basal ganglia and cerebellum receive info form the cerebral cortex where do they feed back to
Cerebral cortex
What are the 3 types of movements
Reflex
Rhythmic motor patterns
Voluntary
What is the reflex for
Protection
Where are reflexes generated
In the spinal cord
What are rhythmic motor patterns
Combination of reflex and voluntary movement
What is voluntary movement
Purposeful movement
What are lower motor neurones known as
Alpha motor neurones
What do alpha motor neurones do
Make muscle contraction
What 3 things control the lower motor nerurones
Sensory input
Spinal interneurones
Upper motor neurone
How can movement be generated without the need of higher centres
Circuit within the spinal cord that is driven by sensory outputs
What structures are controlled by the lateral motor neurones
Distal features such as fingers of hand and feet
What are lateral motoneurone involved in
Fine motor
Which structures are innervated by the medial motoneurone
Axial structures such as trunk and muscles
Proximal structures such as elbow and knee
What is the medial motorneurones involved in
Posture
Therefore what are lateral pathways involved in
Voluntary movement of distal muscles flexors
Therefore what are ventromedial pathway involved in
Posture by proximal/axial muscles extensors
What are the 2 tracts in the spinal cord involved in the lateral pathways
Corticospinal tract
Rubrospinal tract
What are the 4 tracts involved in the ventromedial pathway in the spinal cord
Vestibulospinal tract
Tectospinal tract
Pontine reticulospinal tract
Medullary reticulospinal tract
Where does the corticospinal tract start
In the motor cortex
Where floes the rubrospinal tract start
Red nucleus of the midbrain
Which areas of the motor cortex are axons of the corticospinal tract from
Areas 4 and 6 of the cortex
Where does the corticopsinal tract decussate
Pyramidal decussation
What structures does the corticospinal tract innervate
Distal muscles such as fingers
What motoneurone does corticospinal tract innervate
The alpha motor neurones
Where does the rubrospinal tract decussate
Straight after originating form the red nucleus
If there are lesions to the lateral pathway i.e corticospinal tract and rubrospinal tract what is affected
Voluntary movement
Is posture affected if lateral pathways are damaged
No because the ventromedial tracts are in damaged
If the lesion is selective corticospinal tract can the patient cover
Yes because the rubrospinal tract can compensate apart from the fine digit control
Where does all tracts of the ventromedial that originate from
Brainstem nuclei
What structures does ventromedial tracts control
Proximal and axial for posture/body position
What are the 4 pathways in the ventromedial pathways view as
In pair
What are the 2 pairs of the ventromedial pathways
1) Pontine reticulospinal and medulla reticulospinal tract
2) vestibulospinal and tectopsinal tract
Which nuclei does the pontine reticulospinal and medulla reticulo spinal tract originate from
Reticular nuclei
Where is the reticular nuclei/reticular formation for the pontine reticulospinal tract located
In the pons
Where is the reticular nuclei/ reticular formation for the medullary reticulospinal tract located
Medulla
What is the role of the pontine reticulo spinal tract
Enhance anti gravity reflexes of the spinal cord by facilitating leg extensors to maintain a standing position
What is the role of the medullar reticulospinal tract
Opposing effect to pontine reticulospinal tract it allows voluntary control by freeing antigravity muscles from reflex
Which nuclei does the vestibulospinal tract originate form
Vestibular nucleus in the medulla
Which nuclei does the tectospinal tract originate from
Superioir colliculus in the midbrain
What is the role of the vestibulospinal tract
Relays gravitational sensory info from the inner ear and maintain head and neck position as the body moves
What is the role of the tectospinal tract
Relays sensory info from the retina and visual cortex and orientates head and eyes to a visual stimulus
Give an example when the tectospinal tract is acitve
When you head a loud noise you turn your head to that side
What is the area 4 of the cortex
Primary motor cortex (M1)
What does area 6 in the cortex consist of
Pre motor area
Supplementary motor area
What is area 4 (primary motor cortex) involved in
Controlling fine motor for distal muscles
What is area 6 of pre motor area in cortex involved in
Controlling proximal muscles for posture and balance
What is area 6 (supplementary motor area) involved in
Planning initiation and bimanual coordination and connects across to the other side providing biannual co-ordination
What does 50% of the primary motor cortex have
Axons of the corticospinal tract
What are the features of neurones in the primary motor cortex
Pyramidal type
What may damage to the upper motor neurones by due to
Stoke
Tumour
What does damage to the upper motor neurones lead to
Muscle weakness
Spacitity due to increased muscle tone and hyperflexia
Damage to contralateral side
Does the vestibulospinal tract decussate
No
Is corticospinal tract ipsilateral or contralateral
Contralateral
Is the rubrospinal tract ipsilateral or contralateral
Contralateral
Is the pontine/ medullary reticulo spinal tract ipsilateral or contralateral
Ipsilateral
Is the vestibulospinal tract ipsilateral or contralateral
Ipsilateral
Is the tectospinal tract ipsilateral or contralateral
Contralateral
