Motor Control Flashcards
Which area of the brain generally directs movement?
Primary motor cortex
List the different cortexes which are in front of the central sulcus.
Primary motor centre
Supplementary motor cortex
Premotor cortex
Prefrontal cortex
List the different cortexes which are behind the central sulcus.
Primary somatosensory cortex
Posterior parietal cortex
Which numbered area is the primary motor cortex?
Area 4
Which numbered area is the supplementary motor cortex and the premotor cortex?
Area 6
Which cortex is in area S1?
Primary somatosensory cortex
Which areas cover the posterior parietal cortex?
Area 5 and 7
Voluntary movement is controlled by motor control. Motor control is a functional hierarchy with three levels.
What is the function of the high level?
Stratergy
What are the structures involved in the strategy of the higher level?
Association neocortex and basal ganglion
Voluntary movement is controlled by motor control. Motor control is a functional hierarchy with three levels.
What is the function of the middle level?
Tactics
What are the structures involved with the tactics of the middle level?
Motor cortex and cerebellum
Voluntary movement is controlled by motor control. Motor control is a functional hierarchy with three levels.
What is the function of the low level?
Execution
What are the structures involved in the execution of the lower level?
Brainstem and spinal cord
Describe what is meant by strategy carried out by the high level?
The goal and the movement strategy to best achieve the goal
Describe what is meant by tactics carried out by the middle level?
The sequence of spaciotemporal muscle contractions to achieve the goal smoothly and accurately.
Describe what is meant by the execution carried out by the low level?
Activation of motor neurons and interneurons to generate the goal-directed movement
Name the two lateral pathways which connect the brain to the spinal cord.
Corticospinal tract
Rubrospinal tract
What do the two tracts connect?
1. Corticospinal
2. Rubrospinal
- Cortex and spine
- Red nuclei to spine
What do the two types of lateral pathways, corticospinal and rebrospinal, do?
Control voluntary movements of distal muscles under direct cortical control.
What do the ventromedial pathways do?
Control posture and locomotion, under brainstem control.
Name the ventromedial pathways.
Tectospinal
Vestibulospinal tract
Pontine reticulospinal tract
Medullary reticulospinal tract
Which lateral pathway is the longest?
Corticospinal tract
Describe the origin of the corticospinal tract (CST).
2/3 originate in areas 4 and 6 of frontal motor cortex
1/3 is somatosensory
At which point does the CST decussate?
Medulla/spinal cord junction
The rubrospinal tract starts at the red nucleus but where in the brain is this?
Midbrain
What happens if there are lesions to the CST and RST?
Fine movements of arms and hands are lost.
Cannot move shoulders, elbows, wrist and fingers independently.
What would happen if there a lesion to the CST alone and the RST remained unharmed?
Initially, same defects seen (loss of movements of upper limbs) but will reappear after a few months as been taken over by RST
Large pyramidal neurones in the motor cortex project via the CST. What do they do?
Monosynpatically excite pools of agonist interneurons.
Also branch and excite inhibitory interneurons.
What do the excited inhibitory interneurons which have been excited by pyramidal neurones inhibit?
Pools of antagonist motoneurons
What does the vestibulospinal tract, one of the ventromedial pathways, do?
Stabilizes head and neck
What does the tectospinal tract, one of the ventromedial pathways, do?
Ensures the eyes remain stable as the body moves
Where do the pontine and medullary reticulospinal tracts originate?
Brainstem
What do the pontine and medullary reticulospinal tracts do?
Use sensory information about balance, body position and vision
Which other part of the brain is intimately involved in body position, balance and vision?
Cerebellum
Which muscles do the pontine and medullary reticulospinal tracts innervate?
Trunk and antigravity muscles in limbs
What do voluntary movements require input from?
From motor cortex via lateral pathways