Voluntary Movement Flashcards
Where is volitional movement organized?
Cortex
High motor areas get to decide what?
Whether or not to respond AND what to do in the response
How many layers input info to the cortex?
4: I, II, III, IV
Where is the major output from the cortex?
Level V
What kind of movements are produced from M1?
Simple single joint movements
ex) elbow flexion
Why is redundancy good for activation of several muscles?
Still have some muscle activation after trauma or injury
What does M1 code for?
Force
Direction
ex) gripping coffee mug more or less; reaching in front
Where does PMCd project to?
Largely to proximal muscles
When does PMCd project?
Fires during delay between cue and actions
Where does PMCv project to?
Hand and digit muscles
When does PMCv project?
Hand to correct shape
Watching or performing tasks
Why is damage to the corona radiata very BAD?
It’s a small area where a lot of connections run through
So many fiber tracts travel through
Focal lesion leading to deficits to sensory input and motor output
If there is a focal lesion on corona radiata, what will the deficits be?
Sensory input and motor output deficits
Is the somatotopic organization of M1 permanent or plastic? Why?
Highly plastic
for motor learning + injury
Property of premotor areas (PMC and SMA)?
Plan movements
Properties of SMA?
Sequential movements
Mental rehearsal
Which output pathway is the major voluntary movement producer?
Corticospinal
Neurons in corticospinal tract originate from where?
M1 (50%), PMA (30%), S1
The lateral corticospinal tract largely controls what?
Voluntary movement
Fine motor control
The ventral corticospinal tract largely controls what?
Neck and trunk
Which corticospinal tract does NOT have pyramidal crossing?
Ventral corticospinal tract
Which corticospinal tract ends in the spinal gray matter contralaterally?
Lateral corticospinal
Which corticospinal tract ends bilaterally in cervical and thoracic segments?
Ventral corticospinal
What is the initial symptom of a damaged corticospinal tract?
Initial contralateral weakness
Can individuals with damaged corticospinal tract recover from weakness?
Yes (ish)
After corticospinal tract damage, how will individuals present?
Permanent difficulty with fractionated finger movements
Permanent deficits in speed and force development
Synergy
Synergy Definition
Highly stereotyped + obligatory movements
Individuals can’t isolate joint for movement, moves as a unit
Reflexes Definition
Involuntary, stereotyped response to sensory input
Reflexes are sensory ___put and motor ___put
Sensory input, Motor output
Are reflexes modifiable?
Yes, influenced by descending control
What are central pattern generators (CPGs) in reflexes?
Network of interneurons in brainstem and SC
Strings the reflexes together
Example of rhythmic movement in CPG
Breathing and Walking
Which reflex does not involve a sensory input + motor output?
Stretch reflex - INTERNEURONS
Examples of a stretch reflex
stretch reflex via muscle spindle
autogenic inhibition via GTO
Corticospinal influences LMNs via
Direct excitatory connection to alpha mn (mvmt of digits)
Interneurons connect to alpha mn (excitatory = multijoint mvmts, inhibitory = modulate reflexes)
