MIDTERM #1 Flashcards
Motor control is defined as?
the ability to regulate or monitor and direct and intiate the mechanisms essential to movement
What does motor control address?
How the CNS organizes individual muscles and joints into coordinated movements
How sensory information is used to select and control movement
How perception influences movement
How movement problems can be treated
How is movement generated?
Movement is generated by an individual to meet the demands of a specific task that is being performed in a specific environment
Factors that influence motor control?
Task
Individual
Environment
What is individual factors?
The interaction of structural (anatomy) and functional (physiology) processes within the individual influences the control of movement
What are the components of individual factors?
Perception (sensory): somatosensory, vestibular, visual
Cognition: problem solving, planning, attention
Action (motor): neuromuscular, biomechanical
“Perception” factors influence how?
how the individual integrates sensory information to regulate movement
e.g., body position, features of the environment
“Cognition” factors influence how?
how the individual establishes the intent or goals of movement
e.g., planning, problem-solving, motivation
“Action” factors influence how?
how the individual generates a motor output sent from CNS to muscles
e.g., size, strength, neural pathways
What is task factors?
The nature of the task regulates the neural mechanisms controlling movement
What are the components of task factors?
Discrete vs Continuous tasks
Closed vs Open tasks
Body Stability vs Transport/Mobility tasks
Object Manipulation tasks
Important to consider task factors when?
determining what tasks should be taught, in what order, and at what time
Important to consider task factors when?
determining what tasks should be taught, in what order, and at what time
How would you progress to moving out of bed into a chair for this hip surgery patient?
Move from supine to sitting, pivot legs, move to edge of bed and back, sit to stand, stand to sit
Recognize that this is a mobility task – gradually increase the mobility challenge
What are environmental factors?
The features of the environment regulate the neural mechanisms controlling movement
Regulatory features
Non-regulatory features
What are Regulatory features?
aspects of the environment that directly shape a movement (e.g., characteristics of a walking surface, size of an object)
What are Non-regulatory features?
aspects of the environment that may affect the performance of a movement (e.g., ambient light, distractions)
What are Theories of Motor Control?
A theory of motor control is a group of abstract ideas about how movement is controlled.
Ex. A pile of bricks alone is not of use, putting them together can create an organized and structured theory.
Many theories exist, each attempting to explain and interpret what is known about motor control processes
Motor control theories tend to vary based on?
The relative importance placed on various neural components (e.g., central, peripheral, supraspinal)
The relative importance of the environment in controlling movement
Generally, the theories are developed to try to solve the ?
“degrees of freedom problem”
What is the reflex theory?
Complex behaviour can be explained through the combined actions of individual reflexes
Each reflex in the chain is a consistent output in response to a specific stimulus
What is the limitations of the reflex theory?
Novel movements
Movements without a sensory stimulus
Rapid movements (processing time)
Same stimulus, different response (ability to override reflexes)
What is the hierarchical theory?
Motor control is organized such that higher centres (e.g., cerebral cortex) exert control over lower centres (e.g., spinal cord) – “top-down”
Maturation of reflexes is the basis of motor development and control
Reflexes controlled by lower centres are inhibited as higher centres emerge
Pathology in higher centres can lead to persistence or emergence of “primitive reflexes”
What is the limitations of the hierarchical theory?
Not all low-level behaviours are primitive (pain withdrawal), and not all high-level behaviours are mature
What is the motor programs theories?
Patterned motor responses (“motor programs”) can be initiated either by central processes (i.e., voluntary) or in response to a stimulus (i.e., a reflex)
Higher level motor programs that contain “rules” (i.e., schema) for accomplishing a task that can be applied in different circumstances
Central pattern generators (CPGs, spinal cord neural networks) that produce locomotor patterns in cats in the absence of sensory or descending input
What is the limitations of the motor programs theories?
Does not account for other factors that are used to plan and initiate movements (e.g., body position, fatigue, environment)
What is the systems theories?
The control of integrated movement is distributed among many interacting systems that work together to move a mechanical system (i.e., the body)
Focus on biomechanics – engineer’s perspective
Synergies represent muscles that act as a unit, higher control centres turn up and down activation of a synergy according to demands
Dynamical systems theory suggests that individual elements within a complex system “self-organize”
No need for an external command (i.e., motor program)
What is the limitations of the systems theories?
Presumption that the nervous system has a minimal role
Difficult application
Motor Program vs Systems Theories?
Opposing views on movement variability
Motor program theories – variability represents error
Systems theories – variability is a normal part of movement, allows adaptation to environmental changes
What is the ecological theory?
Emphasizes the importance of determining how an individual detects and uses information from the environment
Shift from sensory-motor system to perception-action system
The perception of environmental information is most important to supporting the actions needed to accomplish the task
Considers the role of the environment from a psychological, rather than physical (i.e., systems), perspective
What is the limitations of the ecological theory?
Downplays the importance of the organization of the various components of the nervous system
Scientific theory and clinical practice: Neurofacilitation approaches?
Informed by reflex and hierarchical theory
Reflex chains are under top-down control – cortex -> brainstem -> spinal cord
Sensory input stimulates normal movement patterns
Cortical damage release abnormal reflexes, need to restore cortical control
Neurologic recovery similar to development
Steps to Neurofacilitation approaches?
1) Inhibit “abnormal” movement patterns, facilitate “normal” movement patterns
2) Repeat normal movement patterns until they transfer to functional tasks
What are task-oriented approaches?
Informed by elements of all theories discussed
Movement emerges as an interaction among many different systems
Movement is organized around a behavioural goal and is constrained by the environment
Predictive and adaptive control in response to sensory feedback
Behaviour is a result of the neural damage and the function of the remaining systems
Functional task training, not basic movement patterns
Need to solve the problem – many solutions
Motor learning is defined as?
a relatively permanent change in the capacity to perform a motor skill
Learning is something that sticks. (Not lucky performance)
Capacity – learning is a construct, you have capacity to perform skill but it doesn’t mean you will perform well every time.
Another definition of Motor learning is defined as?
the (re)acquisition and/or modification of movement skills under “normal” circumstances (motor learning) or following injury (recovery of function) that leads to improved motor performance
Key points about motor learning?
Learning is a process (takes time)
Depends on interaction between motor, sensory/perceptual and cognitive processes
Occurs through experience or practice, as the individual, task and environment interact
Cannot be measured directly
Inferred from retention/transfer tests
What is performance?
observable behaviour, execution of a skill at a specific time and in a specific situation
What is learning?
Cannot be directly observed, must be infered by observing performance
Changes in performance during practice do not necessarily reflect learning
2nd definition: the (re)acquisition and/or modification of movement skills…”
What are performance variables?
factors that affect a person’s performance but not necessarily the learning of the task (e.g., alertness, anxiety, fatigue)
What is Motor sequence learning?
incremental acquisition of sequential movements into a well-articulated behaviour
What is Motor adaptation?
capacity to compensate for environmental changes
What is the process that modifies a behaviour?
Learning
What is memory?
The ability to remember past experiences
Allows you to store and retrieve the information that you learn
The “record” left by a learning process
What is explicit memory?
conscious ability to recall information and previous experiences (i.e., facts, events)
What is implicit memory?
unconscious changes in behaviour that occur as a result of prior experiences
What is explicit learning?
The formation of explicit memories requires conscious awareness and attention
Explicit learning is most effective when the individual is motivated and attentive
In early skill learning, athletes may depend on explicit memory, but in later stages skills are typically drawn from implicit memory
What is Implicit, non-associative learning?
Occurs when you encounter a single stimulus repeatedly
Habituation and sensitization
What is habituation?
decrease in responsiveness that occurs with repeated exposure to a non-painful stimulus (e.g., treating dizziness or vestibular dysfunction)
What is sensitization?
increase in responsiveness to a threatening or painful stimulus (ex. you previously injured self and act ina way to avoid that stimulus again)
What is Implicit, associative learning?
The development of an association between two stimuli (classical), or an association between a behaviour and a consequence (operant)
Classical conditioning
What is classical conditioning?
Unconditioned stimulus = physical cue
Conditioned stimulus = Verbal cue
Response = Walk
Now imagine going back to one but replacing physical cue with verbal cue – now the person gives their own cue and tries to have it e replaced with some intrinsic cue that they are walking.
What is operant conditioning?
A behaviour becomes associated with a particular consequence, producing either a tendency to repeat (reinforcement) or not to repeat (punishment) – the “law of effect”
What is operant conditioning?
A behaviour becomes associated with a particular consequence, producing either a tendency to repeat (reinforcement) or not to repeat (punishment) – the “law of effect”
What is Implicit, procedural learning?
The development of an ability to perform a task without attention or conscious thought following repetition of the task (e.g., practice)
What are Theories of Motor Learning?
Several theories of motor learning that:
Attempt to explain and interpret what is known about motor learning processes
Provide a framework for clinical practice that influences clinical decision-making
What are Theories of Motor Learning?
Several theories of motor learning that:
Attempt to explain and interpret what is known about motor learning processes
Provide a framework for clinical practice that influences clinical decision-making
What are the Motor learning processes?
Schema theory
Ecological theory
What are the Motor learning stages?
3-stage Fitts and Posner model
3-stage Systems model
What is the Schmidt’s Schema Theory?
1) Identify task and “class of actions”
2) Retrieve the appropriate Generalized Motor Program (GMP)
3) Add the Movement-specific parameters to the GMP depending on performance characteristics
Ex. Class of action ex. kicking, throwing, walking, etc.
Movement-specific parameters ex. see that you’re holding a golf club and not a baseball bat.
What is a schema in terms of the CNS?
Schema are the rules used by the CNS to make decisions regarding which movement-specific parameters to apply.
What is the recall schema?
Used to select a response
Relates the initial conditions (e.g., weight of an object) and movement parameters (e.g., force used) with a desired movement outcome
Learn from your outcome to do better next time
What is the recognition schema?
Used to evaluate a response
Compares the expected outcome and sensory consequences of the movement with the actual outcome and sensory consequences
What is something learning involves?
Learning involves constantly updating recall and recognition schema (remember inverse models?)
What is the ecological theory in terms of motor learning?
Related to systems and ecological theories of motor control
Focuses on:
The interaction between the perceptual and motor systems
Practice involves the search for optimal strategies – finding the most appropriate motor response and perceptual cues
task-relevant mapping of perception and action
Augmented feedback can facilitate the search
Emphasizes the exploration of the “perceptual-motor workspace” – Discovery-based learning
Both Schema and Ecological Theories of motor learning suggest that practice variability is important for skill learning. How?
Schema theory – variable practice promotes formation of accurate recall and recognition schema across contexts
Ecological theory – variable practice promotes linking of perceptual cues with the appropriate motor response
Beer Example*
Regulatory- how much beer is in glass
Non-regulatory- colour of beer
Motor learning slide 31
Memorize chart
What stages are involved in the 3-stage Systems Model?
Novice:
Movement simplified by reducing degrees of freedom (e.g., constraining multiple joints by co-activating muscles)
Makes task easier to perform, but not efficient or adaptable
Advanced stage:
Increase in degrees of freedom (e.g., allow movements at additional joints)
Improvement in coordination, efficiency, adaptability
Expert stage:
Exploiting the mechanical and inertial properties of the moving segments
Continued improvements in coordination and efficiency
Rehabilitation = ?
Re-learning
Recovery vs Compensation?
Recovery – restoration of an original movement strategy to accomplish a task
Compensation – implementation of an alternative movement strategy to accomplish a task
What is Constraint-induced movement therapy (CIMT)?
“Use it or lose it”
Used to overcome “learned non-use” of an affected limb due to neurologic damage
The unaffected limb is constrained while the individual takes part in an intense and repetitive training regimen over a relatively short period of time
What is the constraint-induced movement therapy (CIMT)’s links with motor learning principles?
Promotes explicit recognition that the limb can be used
Develop associations between its use and success
Relearning of skills-sequences and adaptation
Redevelopment of schema
Searching for solution
What is Neuroplasticity?
to change and re-organize in response to experience or environmental constraints
the capacity of the central nervous system
2 components of Neuroplasticity?
1: Chemical changes (e.g., neurotransmitters, neurotrophins, neuropeptides) -> fast -
2: Structural changes (e.g., dendritic branching, synaptogenesis) -> slow – takes time
Refer to snowboarding example Physiology of Motor Learning slide 5
What is long-term potentiation?
Activity-dependent increase in synaptic efficacy
What is synaptic efficacy?
the strength of connections between neurons
Did something for a long time and there was an increase in the strength of neurons
Everytime you perform a skill you’re activating those pathways and eventually they get stronger and it becomes easier.
What is long-term depression?
Activity-dependent decrease in synaptic efficacy
When it isn’t activated it starts the whither away
Ex. you don’t practice a skill for a while and stop being as good at skill
What is the direction of the neural correlates of explicit memory?
Association areas – e.g., posterior parietal cortex -> Medial temporal lobe areas – rhinal cortex, amygdala -> Hippocampus -> Prefrontal cortex
2 pathways:
Prefrontal cortex -> Medial temporal lobe areas – rhinal cortex, amygdala
OR
Prefrontal cortex -> thalamus -> hippocampus
Difference between hippocampus and pre frontal cortex?
Hippocampus has the info
Prefrontal cortex guides you onto the right tracks
What did Wilder Penfield discover?
Performing medial temporal lobe surgery in patients with epilepsy
Stimulated temporal lobes of conscious patients
Patients experienced memories as though they were happening again!
What is Non-associative learning?
An increase (sensitization) or decrease (habituation) in the responsiveness to a particular stimulus following repeated exposure to the stimulus
What is the effect of Sensitization?
Increased responsiveness
What is the effect of Habituation?
Decreased responsiveness
What is the Short-Term Mechanisms
(Functional/Physiological) of Sensitization?
Increased EPSP amplitude
