motion: Voluntary control Flashcards
what cortical areas are associated with production of voluntary movement
Primary motor cortex
supplementary cortex (anterior and lateral
Pre motor cortex ( anterior and medial
Pre frontal cortex
Parietal cortex
Summary of the Pre-motor cortex
Recieves sensory information (visual and muscle spindle info)
Applies the rules that determine whether it is appropriate to move
Identifies the intent of motion and decides what motion to produce
two divisions of the supplementary cortex
two divisions:
Supplementary motor area (SMA): Postural control
Pre-supplementary area (pre-SMA): plans the motor program required to make the action occur
-deciding if need to change tactics of motion
Main functions of the Supplementary motor cortex
Organize motor sequences
Aquire motor skills
Executive control to switch to do a different action to achieve the similar task
Main function of the Primary motor cortex
Pre central gyrus
Controls specific movements, especially those related to moving the arms/hands to the face and mouth
Regions of body that do fine motions (hands) have proportionally high representations
Arranged in columns
What are columns
A column will innervate a specific movement and will go through all 6 layers of the cortex
- layer 4 recieves sensory input (muscle and joint propriceptions)
- Layer 5 becomes the output of the corticospinal pathway
contain 2 sets of neurons
- one to start the motion
- one to maintain it as long as necessary
What is the definition of a Pre-motor neuron
Upper motor neuron that will synapse on a Alpha motor neuron
Not all upper motor neurons will synapse on an alpha motor neuron, could be gamma motor neurons
Why does the area a column innervate matter
if it innervates an area that controls a fine moton, the stimulation may produce a contraction of a single muscle
If we are innervating an area that controls more of a general motion, stimulation my produce contraction of a group of muscles (your back)
Significance of neighboring columns
Neighboring columns control related motions, not neighboring muscles
similarly a column may turn on or off an agonist while a neighboring neuron may turn off an on an antagonist muscle
general summary of the Premotor cortex
Determines whether it is okay to move
identifies the goal and the motion required to meet that goal
general summary of the supplementary motor cortex
postural controls
Identifies the specific motor sequence required
Changes tactics if necessary
General summary of the primary motor cortex
codes the individual motions required to reach the goal
Relaying the information to determine the objects location in relation to your body (1st map)
Reaching
Visual cortex info is relayed to the parietal cortex: V6A, PEc (posterior parietal cortex), MIP (medial intraparietal area) and the VIP (ventral intraparietal area)
The VIP will create a rough map of the space around you including the object you are focoused on
this info is carred to the F4 of the premotor cortex
F4 will create a detailed map of the space around you depending on the proximity of the object to you
-closer more firing and more detailed
Relaying the information to determine the objects location in relation to your body (2nd map)
Reaching
a rough 2nd map is created for the information about where your arm is in space found on the superior parietal cortex, V6A
this info is sent to the F2 in the premotor cortex
F2 creates a related map of the location of your arm in relationship to your body and the things around you
Grasping process
The anterior parietal area and the PFG (parts of the inferior parietal cortex) contains 3 neurons with 3 different functions
- Seeing an object to grasp (visually dominant)
- Grasping an object (Motor dominant)
- Both seeing and grasping an object (visuomotor neurons)
the anterior parietal area and the PFG relay their information to F5
F5 fires with the GOAL of the action of why am I grasping the object (doesnt matter the type of grip)
Reaching:
Visual Pathway required: Areas of parietal cortex required: Creation of maps Map of space (with object) Map of Body Awareness of goal encoding motor act
Yes- dorsal visual pathway
V6a, PEc, MIP, VIP
Yes creation of maps
VIP - rough; F4: detiled
F2 - map of arm in space
No awareness of goal
No encoding of motor act
Grasping
Visual Pathway required: Areas of parietal cortex required: Creation of maps Map of space (with object) Map of Body Awareness of goal encoding motor act
Yes - Dorsal visual pathway
AIP cortex, PFG
No creation of maps
Yes there is an awareness of goal (F5)
no encoding of motor act
Role of the Cerebellum
Sequence complex actions
Correct force/direction
Balance and eye movements
Learning of complex actions
Function of Spinocerebellum
Vermis: Postrual control
Paravermal: Force and direction of an ongoing motion
Function of Cerebrocerebellum
Lateral regions: Plan complex motions and their sequence
Function of Vestibulocerebellum
Flocculonodular lobe: Balance/eye movements for the future, not current
Inputs and outputs of the Spinocerebellum (medial)
Inputs:
Vestibular
Visual and auditory
Efferent copy of these two from the brain
Outputs:
Interpositus N
Fastigal N
Rubrospinal tract
Inputs and outputs of the Spinocerebellum (lateral)
Input:
Muscle afferent
Efferent copy from the brain
Output:
Interpositis nucleus
to rubrospinal tract
Important for correcting ongoing motions and control of ballistic motions
Inputs and outputs of the Cerebrocerebellum
Sequencing of rapid movements and planning complex motions
Inputs: all regions of the cerebral cortex
Outputs: Dentate and back to cortex
Inputs and outputs of the Vestibulocerebellum
Control of eye movement and balance particularly in the future
Input: Vestibular apparatus (direct or indirect)
Output: Fastigal nucleus
Vestibular nuclei
will ascend or descend
