1.56 Motor Control Flashcards
What is the function of the cerebral cortex?
Issues sequential and parallel commands
Changes intensity of different patterns
Modify timing
What are the basic functions of the brain stem?
Maintain axial tone for standing
Modify tone in response to vestibular input
Locomotor patterns
What are the basic functions of the spinal cord?
Programmed, local pattern of movement for all muscles
Locus of complex pattern of rhythmical and reciprocal motion
What is the difference between spinal cord and cortical patterns?
Spinal cord - hard wired - heredity
Cortical - can be learned - complex
What do area 5 and 7 correspond to?
Posterior parietal cortex
Motor pathway…
- Posterior parietal cortex
- Basal ganglia
- Pontine nuclei
- Deep cerebellar nuclei/ cerebellum
- Thalamus
- Premotor cortex
- Supplementary motor area
- primary motor cortex
What can disruption to the rubrospinal pathway result in…
Tremor or fragmented movements
Which part of the reticular formation controls walking?
Paramedian midbrain reticular formation
What does the Pontine (magnocellular) reticulospinal pathways control?
extensor LMNs
What does the Medullary (magnocellular) reticulospinal pathways control?
flexors LMNs
Explain the motor axons pathway during voluntary movement…
- activation of interneurones to inhibit antagonists alpha motor neurons
- activation of alpha and gamma motor neurone
- contraction of extrafusal and intrafusal fibres
- Feedback activates agonist and inhibits antagonist alpha motor neurones - gamma motor loop
- Ia fibres om passively stretched antagonist muscle find the respective alpha motor neurons refractory
What is the function of the posterior parietal cortex?
The parietal cortex receives somatosensory, proprioreceptive, and visual inputs, then uses them to determine such things as the positions of the body and the target in space.
It produces internal models of the movements to be made, prior to the involvement of the premotor and motor cortex
What is the function of the prefrontal areas?
• Part of the highest level of integration in the motor control hierarchy
• Decisions are made about what action to take
• Integrates information from different areas of brain
Concerned with personality, intellect, recall information, judgement, foresight, reasoning, conscience etc
helps determine characteristics of the movement of this purpose
With which other area are the prefrontal areas connected with?
parietal lobes - both are the highest point of integration - It is here that the decisions are made about what action to take
Where do the posterior parietal and prefrontal areas send their axons to?
Area 6 - pre motor area - higher stimulus required to evoke a stimulus
What is area 6?
Pre motor area
once it has been informed about the kind of action to take, helps to determine the characteristics of the movement for this purpose
initial phases of body orientation
DICTATES OPTIMAL POSITION TO THE MOTOR CORTEX
What would be the consequences if a person damaged the prefrontal cortices bilaterally?
Person becomes rude, inconsiderate, incapable of accepting advice, moody, inattentive, less creative, unable to plan for the future, and incapable of anticipating the consequences of rash or reckless words or behavior
What is the dorsal pre motor area related to?
Leg, trunk, arm and face
Large representation for proximal muscles
What is the ventral pre motor area related to?
Arm, face and lower leg
Large representation for distal muscles
What is the function of the pre motor area?
Output chiefly influences the medial system descending pathways
controls - the axial muscles and proximal limb muscles in the initial phases of orienting the body and the arm to a target.
Visual Steering/ guidance of movement,
Neurons in this area may discharge during the preparation for a movement.
Keeping balance etc. sets you up for a movement
What is the supplementary motor area split into?
Pre SMA and SMA Proper
What is the function of the SMA proper?
• SMA Proper has a complete somatotopic map
Contributes to Corticospinal tract & Connected to other motor areas
increased blood flow to needed areas
It is also responsible for assisting in coordination of posture and voluntary movements.
What is area 4?
Primary Motor Homunculus Mapping is represented somatotopically Facial area is bilaterally Rest is unilateral Surface area devoted
What is the rubrospinal pathway…
after primary motor cortex
inferior olive
cerebellum
red nucleus
