Motor Control I Flashcards
motor learning vs motor control
motor learning
-behavioral component
motor control
-physiological component
motor learning
-emphasizes
brain’s role in acquiring, planning, initiating, and modifying movement
motor control
- area of study dealing with…
- -may also be described as…
- interaction of…
understanding of the physiological and neural aspects of movement
-may also be described as NM control
interaction of the CNS, PNS, and musculoskeletal systems that execute movement and monitor/integrate sensory information
cognitive map
-what is it?
group of abstract ideas that help to describe the control of movement and how a movement can be learned by an individual
cognitive map
-usually contains…
underlying assumptions
- interaction of central or peripheral control mechanisms
- what variables determine the organization of control
cognitive map
-provides a framework to…
explain the key variables around which movement is organized
predict movement control outcomes based on manipulation of these variables
guide for hypothesis-driven clinical action
-results in active problem solving by the clinician
cognitive map
-what is the important characteristic of all motor control theories
includes explanation of how we control coordination
-i.e. what variables is the nervous system trying to control and command
what is coordination
patterning of head/body/limbs relative to patterning of environment and objects
degrees of freedom
-what is it?
describes the number of ways in which a given unit (part of the body) is capable of moving
- related to number of joints moving
- number of muscles/motor units activated
DF problem
- under normal circumstance, no _____ exists between a _____ and a _____
- -examples
no one-to-one correspondence exists between a motor problem (task) and a motor solution
- redundant anatomical df’s
- redundant kinematic df’s
- -different trajectories, velocities, accelerations
- -can still achieve same goal
- redundant neurophysiological df’s
- -multiple neurons for same muscle
DF Problem
-what is the issue
sensory processing as a control mechanism in controlling movement
-how is sensory input processed during movement depending on the person/task/environment?
open-loop control
-explain
feed-forward
top-down control strategy
downplays accessibility or need for feedback in initiation and execution of the movement
closed-loop control
-explain
feedback
explain movement as outcome of feedback-initiated reflex actions and pre-patterned neural systems
error detection and correction maintain desired goal during the movement itself
open-loop vs. closed-loop control
-fundamental difference
presence of feedback to modify motor command during the movement
open-loop control mechanisms
two-level hierarchy
- executive
- -command center generates action plan that contains all necessary information to complete motor response
- effectors
- -muscles and limbs; carry out command without modification
open-loop control mechanisms
- components of executive
- components of effectors
executive -stimulus identification -response selection -response program effector -cortex -spinal cord -muscles movement is output
would an expert or a novice trying to learn a guitar riff use an open loop?
expert
-don’t really need feedback anymore to be able to play the riff
role of feedback in open-loop control
feedback constantly present, but comes too late to adjust the ongoing movement
once pre-structured commands are initiated, command must run as planned
feedback received can be used only to modify subsequent attempts
open-loop control mechanisms
- most effective for controlling movements that occur…
- _____ instructions are given that specify _____
most effective for controlling movement that occurs in stable, predictable environment where need for modification is low
advance instructions are given that specify what is to be performed, as well as sequence and timing
-rapid movements (<200 ms)
closed-loop control mechanisms: feedback-controlled system
-command center needs only to…
command center needs only to generate action plan that initiates movement
- sensory feedback continually compared to desired movement
- detected discrepancies sent back to command center for correction
what is the difference in the content of the instructions in closed- vs. open-loop
open
-full command
closed
-command to initiate with ability to adjust on the fly
closed loop examples
- nervous system
- functional activity
nervous system
-stretch reflex
functional activity
-slack-lining
four key components of closed-loop control mechanisms
executive
effector
feedback
comparator
closed-loop control mechanism: executive
- purpose
- responsible for…
decision maker responsible for -stimulus identification -response selection -response programming
closed-loop control mechanism: effector
- function
- what does it in the body?
enacts the decisions
-spinal cord, muscles, motor programs
closed-loop control mechanism: feedback
- function
- types
reference of correctness/goal
types
-interoceptive = inside the body
-exteroceptive = outside the body (i.e. visual, auditory)
closed-loop control mechanism: comparator
- types
- -what do each do?
slow movements
-feedback fine tunes muscle force patterns
fast movements
-visual checking after completion of movement
closed-loop control mechanisms
-what does a typical feedback loop look like?
system goal is defined
sensory information is compared to actual information about movement
executive is informed about an error
executive sends command to the effector
match is made, error is corrected to = zero
-if error = zero, executive sends command to “turn off the furnace” or command for action
-if error exists, executive sends command to “turn on the furnace”
closed loop control: timeline for feedback-based corrections
- peak muscle twitck
- updated commands reach MUs
peak muscle twitch
-75 ms
updated commands reach MUs
-190 ms
