Quiz

Compare and contrast declarative (explicit) vs. procedure (implicit or non-declarative) memory. Address the following:

1. What is learned? Give examples.2. What brain areas are involved in the

formation of memory?3. Where is the memory stored?

Reading AssignmentsShumway-Cook: 21-39

Min H. Huang, PT, PhD, NCS

PTP 512Neuroscience in Physical Therapy

Motor Learning: Theories and Practical Applications

Outline for today’s lecture

• Define motor learning and learning• Procedural learning• Declarative and associated learning• Adam’s theory• Schmidt’s theory• Ecological theory• Motor learning occurs in stages• Measuring learning outcomes• Transfer of learning• Feedback and giving augmented feedback• Practice conditions

DEFINING MOTOR LEARNING

Motor Learning

• Motor learning is the understanding of acquisition and/or modification of movement.

• As applied to patients, motor learning involves the reacquisition of previously learned movement skills that are lost due to pathology or sensory, motor, or cognitive impairments. This process is often referred to as recovery of function.

PT Implications• How can I best structure practice (therapy)

sessions?• How often should my patient practice? • Will the motor skill learned in one context

transfer to another? • Will my patient be able to walk safely at

home/community after therapy?• Should I simply the task?• Should my patient practice weight shifting

in the // bars vs. walking in the gym (part vs. whole practice)?

Learning vs. Motor Learning

• Learning is a relatively permanent change in behavior due to practice, or the process of acquiring knowledge about the world.

• Motor learning: a set of processes associated with practice leading to a relatively permanent change in the capacity for skilled actions.

Concepts of Motor Learning• Learning is a process of acquiring the

capacity for skilled action• Learning results from experience or practice• Learning cannot be measured or observed

directly; it is inferred from behavior• Learning produces relatively permanent

changes in behavior; short term change is not learning)

Motor Performance Motor Learning

• Motor Performance is the temporary change in motor behavior seen during a practice session–e. g. A patient learns how to shift more

body weight over the weaker leg at the end of the therapy session. However, the patient still bears more weight on the unaffected leg at the next visit to PT. Learning has not occurred.

Motor Performance Motor Learning

• Performance may be influenced by many other variables, e.g. fatigue, level of learning/skills, anxiety, motivation, cues or manual guidance given to the learner

• Motor Learning is a relatively permanent change in motor behaviors that are measured after a retention period and only result from practice.

FORMS OF MOTOR LEARNING

Nondeclarative (Implicit) Learning:Non-Associative Learning

• A single stimulus is given repeatedly and the nervous system learns about the characteristics of the stimulus

• Habituation –↓ response to the stimulus, e.g.

exercises to treat dizziness in patients• Sensitization –↑ response to the stimulus, e.g. training

to enhance awareness of loss of balance

http://www.youtube.com/watch?v=voZXtTUdQ00

Nondeclarative (Implicit) Learning: Associative Learning

• Classical Conditioning– learn to predict relationships between

two stimuli–e.g. before learning: verbal cues +

manual guidance stand up; after learning: verbal cue stand up–patients are more likely to learn if the

associations are relevant and meaningful

Nondeclarative (Implicit) Learning: Associative Learning

• Operant Conditioning– learn to associate a certain response,

from among many that we have, with a consequence; trial and error learning–e.g. relearn stability limits after ankle

sprain; verbal praise from PT–behaviors that are beneficial and

rewarded tend to be repeated

Procedural Learning

• Does NOT require attention, awareness, or other higher cognitive processes

• One automatically learns the rules for moving, i.e. movement schema

• Learning requires repeating a movement continuously under a variety of situations

• Patients with damage to cortex (e.g. TBI, dementia, aphasia) can still performance

Declarative (Explicit) Learning• Require attention, awareness, and reflection• Results in knowledge or facts (e.g. objects,

places, events) that can be consciously recalled and expressed in declarative sentences, e.g. “1st I move to the edge of chair. 2nd I lean forward and stand up”; instruction from PT; mental rehearsal; motor imagery

Declarative (Explicit) Learning

• Practice can transform declarative into procedural or nondeclarative knowledge–e.g. a patient first learns to stand up may

verbally repeat the instruction; after repeated practice, the patient may be able to stand up without instruction

• Processes of declarative learning: encoding consolidation storage retrieval

Think-Pair-Share

When helping a patient to relearn motor skills, should the PT emphasize non-declarative (implicit) or declarative explicit) learning?

THEORIES OF MOTOR LEARNING

Adams Closed-Loop Theory

• In motor learning, sensory feedback from the ongoing movements is compared with the stored memory of the intended movement

• Memory trace selects and initiates a movement

• Perceptual trace, built-up over practice, is the internal reference of correctness

Adams Closed-Loop Theory

• Clinical Implications–Accuracy of a movement is proportional

to the strength of the perceptual trace–Patient must practice the movement

repeatedly to ↑ the perceptual trace• Limitations–Cannot explain open loop movement or

novel movements

Schmidt Schema Theory• Emphasizes open-loop control processes

and generalized motor program • “Schema” is a generalized set of rules for

producing movements that can be applied to a variety of contexts

• Equivalent to motor programming theory of motor control

Schmidt Schema Theory• Information stored in short-term memory

after a movement is produced1.Initial movement conditions, e.g. body

position, weight of an object, step height2.Parameters of a generalized motor program3.Outcome of the movement, in terms of

knowledge of results4.Intrinsic sensory feedback of the movement

Schmidt Schema Theory

• Information stored in short-term memory is converted into two schemas

1.Recall schema selects a specific response and contains rules for producing a movement

2.Recognition schema evaluates the response correctness and informs the learner about the errors of a movement

Schmidt Schema Theory • Clinical Implications–Variability of practice↑ learning and

generalized motor program rules –Novel movement can be made accurately

based on previously learned rules• Limitations–Vague; no consistent research finding in

support of variable practice–Cannot account for one-trial learning (In the

absence of a schema)

Ecological Theory• Learning involves the exploration the

perceptual and motor workspace1.Identify critical perceptual variables, i.e.

regulatory cues2.Explore the optimal or most efficient

movements for the task3.Incorporate the relevant perceptual cues and

optimal movement strategies for a specific task

Ecological Theory• Clinical Implications–Patients learn to identify relevant

perceptual cues that are important for developing appropriate motor responses, e.g. identify relevant perceptual cues for reaching and lifting a heavy glass: weight, size, or surface of the glass vs. its color?

Fitts and Posner Three Stage Model: Cognitive stage

• Learner activities–Learn what to do–Learn about the task and goals–Require high degree of attention–Select among alternative strategies–Performance may be more variable–Fast improvement in performance –Develop a motor program

Fitts and Posner Three Stage Model: Associative Stage

• Learner activities–Refine the skills –Refine a particular movement strategy–Performance is less variable and more

consistent–Cognitive monitoring decreases – Improve the organization of the motor

program

Fitts and Posner Three Stage Model: Autonomous Stage

• Learner activities–Become proficient, save energy–Attention demands are greatly reduced–Movements and sensory analysis begin

to become automatic–Able to perform multiple tasks, scan the

environment–Ability to detect own errors improves

Implications for PT

• Motor learning probably occurs in stages• Activities of the patient are different in

the different stages• Activities of the therapist should be

different in the different stages

Systems Three-Stage Model

• Learners initially restrict degrees of freedom (DOF) and gradually release the DOF as the task is learned and the skills improve

• Novice Stage–Simplify movement by constraining joints

and ↓DOF, e.g. muscles co-contraction–Less energy efficient

Systems Three-Stage Model• Advanced Stage–Gradual release of additional DOF–More adaptive to different contexts

• Expert Stage–All DOF released–Efficient and coordinated movements–Exploit the mechanical and inertial

properties of the limbs and the environment

Gentile’s Two Stage Model• Early stage–Understand the task goals, develop

movement strategies, recognize regulatory features of the environment

• Late stage–Refine the movement, consistent and efficient

performance–Closed skills become fixation/consistent–Opened skills become diversification/

adaptive

Think-Pair-Share

A patient is learning to use a walker. What would the patient be able to do at each stage of learning?Cognitive stage (early)-Association stage (late)-Automatic stage (late)-

APPLICATION OF MOTOR LEARNING THEORIES

How to Measure Learning?• To separate the relatively permanent effects of

learning from the transient effect of practice, learning can be measured using retention or transfer designs.

1.Test the subject after a retention interval, typically >= 24 hr

2.Choose the same task (retention test) or a variation of the task (transfer test)(e.g. different speed or lighting conditions for walking)

Practice Level: How Much?PRACTICE, PRACTICE, PRACTICE

• Animal Studies–9,600 retrievals over 4 week period

(Nudo, 1996)–7,000 trials of food catching in 5 weeks

(Pavlides, 1993)• Humans?–Dose-response log-linear relationship–Are patients getting enough practice?

Feedback (FB)

• FB is all the sensory information that is available as a results of a movement

• Types by mode of delivery– Intrinsic (e.g. proprioception)–Extrinsic (e.g. instruction from PT)

• Types of FB by information provided–Knowledge of results (KR)–Knowledge of performance (KP)

Knowledge of Performance (KP)

• Information about the movement patterns• Usually intrinsic but can also be extrinsic• Proprioception, Biofeedback, video

recording, verbal instruction (e.g. “Your elbow was too low.”)

Knowledge of Results (KR)

• Information about the result or outcome of the movement in terms of the goal

• Verbal instruction (e.g. “You were off the target.”), proprioception (e.g. feeling loss of balance during a fall)

Characteristics of Good Feedback• Timing–Allow some time to reflect between trials

• Summary FB–Summary FB after a few trials works

better than after every trial–Give more frequent summary feedback

(e.g. after every 5 trials) for complex tasks than for simple tasks

Characteristics of Good Feedback• Accuracy –Positively reinforce correct performance

• Augmented (extrinsic) Feedback–Video/visual of movement patterns alone

does not help; need to provide error-correcting cues as well–AVOID VERBAL BOMBARDMENT –Can be given concurrently or afterwards

Characteristics of Good Feedback

• Frequency and Fading Schedule–More impaired patients may require

more frequent FB. –Avoid giving FB every trial.–Decrease the amount of FB given across

learning stages so the patients won’t become dependent on FB.

Practice Conditions• Massed vs. Distributed Practice Schedule–Distributed in early stage (e.g. 20 min X 3

days) to avoid fatigue and massed in later stage (e.g. 60 min in one day)

• Constant vs. Variable Practice –Usually variable practice (walk at different

speeds) results in better learning outcomes than constant practice (walk at the same speed) in health adults

Practice Conditions• Random vs. Blocked Practice–Contextual Interference: practice that

makes the performance more difficulty initially may result in more effective learning in the long term–Random practice (practice multiple tasks in

15 min) results in better learning than blocked practice (practice one task in 15 min) in healthy adults but not necessarily patients

Practice Conditions

• Whole- vs. Part-Task Practice–Task specificity says the best practice is

the task itself– If utilizing a part technique, the part (e.g.

hip and knee flexion, extension) must be a naturally occurring component of the whole (e.g. walking)

Practice Conditions• Transfer–Amount of transfer is determined by the

similarity between the two tasks or the two environments–The more closely the practice environment

resemble those in the performance environment, the better the transfer

• Guided vs. Discovery Practice

Practice Conditions

• Mental Practice–The same neural circuits producing the

movement are also active during mental practice –Can produce large positive effects on

performance of the task (Rawlings 1972)–Physical + mental practice produces the

best learning outcome

Practice Conditions• Action Observation– Reorganization of the

primarily motor cortex in patients with stroke after observation of the desired action + motor training, but not observation of irrelevant movement + motor training

– Implications for patients with poor motor ability

Mirror neuron system: Inferior parietal lobule (IPL), Ventral premotor cortex (PMv), inferior frontal gyrus (IFG).

Garrison, 2010