1b Motor Cortical Control Flashcards
What is meant by the hierarchical organisation?
high order areas of hierarchy are involved in more complex tasks, and lower level areas of hierarchy perform lower level tasks
What do the cerebellum and the basal ganglia do in the motor system of heirarchy?
adjust the commands received from the other parts of the motor system
What are the two pyramidal descending tracts?
corticospinal
corticobulbar
Why are the pyramidal tracts called pyramidal?
because they pass through the pyramids of the medulla
What do the pyramidal descending tracts do?
voluntary movement of the body and face muscles
What are the extrapyramidal tracts?
descending tracts which do not pass through the pyramids of the medulla
Which descending tracts are responsible for the involuntary movements of balance, posture and locomotion?
Extrapyramidal
Where is the primary motor cortex located?
Anterior to the central sulcus
What does the primary motor cortex do?
Controls fine, discrete and precise voluntary movements
What does the premotor area do?
Involved in planning movements, by regulating externally cued movements
what does the supplementary motor area do?
Planning complex movements and becomes active prior to voluntary movements
Where does the lateral corticospinal tract decussate?
In the medulla - innervates the limb muscles
Where does the anterior corticospinal tract decussate?
Spinal cord - innervates the trunk muscles
What is the principal motor tract for voluntary movement of the face and the neck?
Corticobulbar
What is the function of the vestibulospinal tract?
Stabilise head during body movements, or as head moves
Coordinate head movements with eye movements
Mediate postural adjustments
What is the function of the reticulospinal tract?
Most primitive descending tract - from medulla and pons
Changes in muscles tone associated with voluntary movement
Postural stability
What is the function of the tectospinal?
Orientation of the head and neck during eye movements
What is the function of the rubrospinal tract?
Innervate lower motor neurons of flexors of the upper limb
What is paresis?
graded weakness of movement
What are the three negative signs of an upper motor neuron lesion?
Loss of voluntary movement
Paresis
Paralysis = complete loss of voluntary muscle activity
What is spasticity?
Increased muscle tone
What is hyper-reflexia?
Exaggerated reflexes
what is clonus?
Abnormal oscillatory muscle contraction
What are the positive signs of an upper motor neurone lesion?
Increased abnormal motor function due to loss of inhibitory descending inputs
Spasticity: increased muscle tone
Hyper-reflexia: exaggerated reflexes
Clonus: abnormal oscillatory muscle contraction
Babinski’s sign
what is Apraxia?
disorder of skilled movement - patients lose information about how to perform skilled movements
Lesions to which areas can cause apraxia?
Frontal lobe and the inferior parietal lobe - premotor cortex, and supplementary motor area