motor control Flashcards
MN pools
group of LMNs in ventral horn, axons project to a single muscle
medial pools innervate?
proximal muscles
lateral pools innervate?
distal muscles
anterior pools innervate?
extensors
posterior pools innervate?
dorsal side innervated flexors
Tectospinal tract
movement of head towards sound or moving objects
Medial corticospinal tract
control of neck, shoulder, trunk, APAs
Medial reticulospinal tract
postural muscles, limb extensors, APAs
Medial vestibulospinal tract
bilaterally to neck/upper back
lateral vestibulospinal tract
extensors(antigravity)
lateral corticospinal tract
goal directed
contralateral fractionation of hand movement
rubrospinal tract
contralateral upper limb, gross movement
lateral reticulospinal tract
facilitates flexors, inhibits extensors
Which 2 tracts originate in the cortex?
Medial corticospinal tract
lateral corticospinal tract (pyramidal)
Which 5 tracts arise from the brainstem?
tectospinal tract medial reticulospinal tract medial/lateral vestibulospinal tract rubrospinal tract lateral reticuospinal tract
What are the 2 motor areas that lie in front of the primary motor cortex?
premotor
and
supplementary motor area
The central sulcus lies ___ of the primary motor cortex?
in back
What is behind the central sulcus?
primary somatosensory area
primary motor cortex?
voluntarily controlled movement
premotor area?
very heavily involved in planning visually guided movement
SMA?
planning bimanually, sequential internally related movement
what is the purpose of 1-3 layers of the cytoarchitectonics?
input and
output: project to other cortical areas for intracortical communication
What are corticomotorneurons?
Monosynaptic projections from layer 5 to spinal motor neurons and alpha inhibitory interneurons, which are important for fractionation
Why are corticomotorneurons important for fractionation?
They do not stop on the way, making them send the signal faster to the hand.
layer 5
pyramidal layer, major output layer, axons of pyramidal cells in this layer create the corticospinal tract also output to subcortical structures and other cortical areas
Where does the premotor area receive info from?
Receives info from the PPC and primary somatosensory cortex.
PMA (premotor area)
- input from PPC and prefrontal cortex
- signal direction of movement
- very active in planning period
- basic spatial parameters
- fires in response to seeing an object
- other neurons, mirror neurons begin to fire when observing an action
- signaling to MI: here’s the object, here’s the direction
- projection to hand and arm areas to MI
- REACHING, GRASPING system
SMA
- input from prefrontal cortex, basal ganglia
- very little input from PPC (
- tuned to INTENTION
- complex, bilateral movements (sequence learning, postural control)
- Selecting and executing actions deemed appropriate or withholding objects.
MAIN points from precision grip vs power grip
-precision grip required more neuro activity with miniml muscle activity
-power grip showed more muscle activity than neuro activity.
Proving that the primary motor cortex and muscle activation do not have a direct relationship.
The primary motor cortex represents functional tasks.
Explain the use of force and direction and how the MI works
- There are horizontal connections through the primary motor cortex that will have synergistic movement and force/direction.
- THE MI codes for force and direction
