Mod 9 V1 - Overview of Motor System Flashcards
The somato (human body) sensory system is part of the nervous system that allows us to _______ & _______ movements enabling us to interact with the environment we are sensing.
plan & execute
What are the 3 types of movements for the somato motor system?
REFLEXIVE movements:
Activation of thermonociceptor hand is near heat and pulled away without thinking about it. Involuntary and direct response to sensory stimuli.
VOLUNTARY movements:
Hearing the phone and decided whether to answer it or let it ring.
RHYTHMIC movements:
Special type of voluntary movements.
What are the 4 traits of VOLUNTARY MOVEMENTS?
- Involves choices between alternative
- Context-dependent association with sensory stimuli
- Modifiable
- Learned (motor learning)
The somatic motor system allows us to plan and execute movements enabling us to interact with our environment.
A. True
B. False
A. True
Explanation:
This statement is true: the somatic nervous system is the part of the nervous system that allows us to plan and execute movements enabling us to interact with and impact the environment we are sensing.
Which type of movement produced by the somatic motor system has a context dependent association with stimuli, is modifiable and can be learned with practice?
A. Voluntary
B. Reflexive
C. Rhythmic
A. Voluntary
Explanation:
Voluntary movements involve choices between alternatives (not indicated in question stem), have a context dependent association with stimuli, are modifiable, and the can be learned with practice. Reflexive movements are movements that are made is direct response to sensory stimuli; the are involuntary and stereotyped; rhythmic movements are a special class of voluntary movements.
Define MOTOR CONTROL
The process of initiating, directing, and grading purposeful voluntary movement.
What are the 3 problems the motor system must solve to produce voluntary movement?
Motor Planning
Executing
Monitoring
Explain MOTOR PLAN, EXECUTING, and MONITORING.
Motor Planning:
Converting an intention or goal into a plan which involves a series of SENSORIMOTOR TRANSFORMATIONS.
Executing:
Activate motor nuerons.
Monitoring:
Monitoring the execution and evaluating the plan through sensory feedback: (1) correct errors and (2) update the plan.
What are the two steps of sensorimotor transformations in motor planning? Explain what extrinsic kinematics, intrinsic kinematics, and kinetics are.
- Converting EXTRINSIC KINEMATICS to INTRINSIC KINEMATICS - inverse kinematics
- Converting INTRINSIC KINEMATICS to KINETICS - inverse dynamics.
Extrinsic kinematics: location of target object in space with reference to body ie. the path the hand must take
through space to reach the object.
Intrinsic kinematics (joint rotations required to move the hand along the path to obtain the target object.
Kinetics: forces required to produce the desired joint rotations.
The motor system will use _______ and _______ control mechanisms to produce voluntary movements.
feedforward & feedback
Define FEEDFORWARD CONTROL MECHANISM
Using sensory information in ADVANCE known as anticipatory control/planning in advance –e.g. coordinating multiple muscle groups for limb movements and planning ANTICIPATORY POSTURAL ADJUSTMENTS (APAs) to those limb movements.
Define FEEDBACK CONTROL MECHANISM
Using sensory information AFTER to make adjustments; monitoring the movement and comparing the desired movement with the actual movement - error correction.
In order to convert an intention into an action the motor system must go through a series of sensorimotor transformations.
A. True
B. False
A. True
Explanation:
This statement is true: the motor system must identify the goal and then use sensory information about objects in the environment and sensory information about the performers body position to determine the extrinsic kinematic and then convert those to intrinsic kinematics (desired joint rotations to reach the target) and then convert the intrinsic kinematics to kinetics (forces need to produce the joint rotations).
Sensory feedback used after a movement is executed will allow the system to do which of the following?
A. Plan movements in advance
B. Correct errors in a movement
C. Execute a movement
B. Correct errors in a movement
Explanation:
The motor system will monitor a movement that is being executed to make sure the intended plan is working. This sensory feedback can be used to correct the movement if errors occur and it can be used to update the motor plan for future use.
Based on the motor system schematic, what are the 5 brain regions/areas that constitute the motor system and what are they responsible for?
- MOTOR CORTICES
Responsible for planning, initiating, and directing voluntary movements - upper motor neurons (UMN) which terminate on lower motor neurons (LMN). - BRAINSTEM CENTERS
Responsible for eye movements, rhythmic movements, and postural control - UMN which terminates on LMN. - BASAL NUCLEI
Responsible for the proper initiation and termination of appropriate motor plans. - CEREBELLUM
Responsible for coordination & fine-tuning of movements. - SPINAL CORD & BRAINSTEM
Contain local circuit neurons AKA interneurons (e.g., central pattern generators) & LMN which innervate skeletal muscle and provide the final output of the motor system by commanding skeletal muscles to contract.
Based on the motor system schematic, what are the 3 levels of the region?
Highest level of Motor Hierarchy:
Motor cortices (role in motor planning and generating execution commands) and brainstem centers (role in rhythmic movement, eye movement, postural control)
* Upper motor neurons – descending signals to lower motor neurons
Lowest level of Motor Hierarchy:
Spinal cord (laminae VII and IX) and brainstem (CN somatic motor nuclei)
* Local circuit neurons (integrate sensory input from periphery and descending signals) modulate activity of LMN = final motor output to skeletal muscles.
Side loops: modulate activity of the highest level of the motor hierarchy. (1) basal nuclei/ganglia = gatekeeper -
initiation/termination of motor plans; (2) cerebellum = coordinator/comparator – error correction/updating motor plans
Based on the motor system schematic, which structures pertain to the spinal cord? HINT: two laminae.
Laminae VIII (8) & IX (9)
Based on the motor system schematic, which structures pertain to the brainstem?
CN somatic motor nuclei
Based on the motor system schematic, which skeletal muscles are controlled by the spinal cord and by the brainstem in the lowest level of the hierarchy?
Spinal cord = axial and appendicular
Brainstem = face and head
Based on the motor system schematic, what are the two side loops and what are their roles?
The two side loops are the basal nuclei and the cerebellum and their role is to modulate the UMN at the highest level of the motor hierarchy.
BASAL NUCLEI
Known as the gatekeeper. It prepares UMN circuits for the initiation of desired movements and suppression of unwanted movements - gating movement initiation and termination.
CEREBELLUM
Known as the comparator and coordinator. It compares the motor plan with the current state of the system and send corrections to the cortex, and it will compare the intended movement with the actual movement as it unfolds generating error signals used to correct the movement online or be used to update the motor plan for future attempts - important structure for motor learning based on trial and error.
Based on the motor system hierarchy, how is sensory input used by the highest and lowest levels of hierarchy and the cerebellum?
Highest level of motor hierarchy:
Plan appropriate movement patterns.
Lowest level of motor hierarchy:
Modulate activity of LMN - important for reflexive movements.
Cerebellum
Comparing movement plan with the actual movement as it’s unfolding.
Which 2 tracts are part of the DORSOLATERAL SYSTEM? Point out their location.
- LATERAL CORTICOSPINAL TRACTS
- RUBROSPINAL TRACTS (minimal; origin in the red nucleus of the midbrain).
Which 3 tracts are part of the VENTROMEDIAL SYSTEM? Point out their locations.
- ANTERIOR CORTICO SPINAL TRACTS (origins in three distinct regions of the cerebral cortex, namely the primary motor cortex (pre-central gyrus, area 4), the pre-motor cortex (area 6) and the primary sensory cortex (post-central gyrus, areas 3, 1, 2)
- RETICULOSPINAL TRACTS (origin in the reticular formation of the pons and medulla oblongata)
- VESTIBULOSPINAL TRACTS (origin in the vestibular nuclei)
