WEEK 6 - Motor and Skill Learning

• What part of memory do motor skills fall under? LTM, procedural memory
• Are skills implicit? Not entirely, we can engage explicit components for performing skills
• What are ways humans interacting with the world? Contraction of muscles or sweating – that’s it e.g. talking is use of mouth muscles
• What brain region is primarily involved in procedural learning – skills and habits? Basal ganglia + other parts of the brain
• What is motor learning? Effects of training or practice on motor performance, the process by which movements are executed more quickly and accurately with practice
• What is the difference between performance vs learning?

  -              Learning refers to relatively permanent change in behaviour thus there is long-term retention

  -              Performance is temporary
• What is the result of learning? Formation of a motor memory
• According to Fitts 1964, what are the 3 verbal stages of learning?

  1.        Verbal cognitive stage – novice

  2.        Associative motor stage

  3.        Autonomous stage
• Why does learning take time? To become a true expert requires lots of practice and this is continuous  
• What is the 10-year rule? Takes 10 years to become a true expert with lots of practice and repetition
• What is the verbal-cognitive stage?

  -              Verbal stage as we rely on instructions given to execute skill

  -              Cognitive because you have to think about what you’re doing, what movements you are making – trying to understand task requirements

  -              Thus high cognitive-load as it is attention demanding

  -              Importance of instructional quality

  -              High variability
• What is the associative motor stage?

  -              Know what to do and how to do it

  -              Settle on main strategy

  -              Increased consistency

  -              Fine tuning

  -              Importance of practice

  -              Deal with increasing complexity of the task

  -              Minimise sensory prediction errors (what you intended to do vs what actually happened)

  -              Performance should be improving rapidly

  -              Spend a lot of time in this stage
• What is the autonomous stage?

  -              Actions have become automatic

  -              Less attention demanding

  -              Improved precision

  -              Less dependent on feedback – if you start thinking about what you are doing, your performance may suffer

  -              Multitasking

  -              Difficult to make changes – but improvements are still possible
• What process is critical in transition from skill acquisition to memory? Consolidation
• What did Dayan & Cohen 2011 propose about fast vs slow motor learning?

  -              Relative duration of learning is highly task specific

  -              For any given task, measurement of skill level shows rapid initial gains (fast learning) followed by incremental gains (slow learning) to near asymptotic levels
• What is fast learning? Rapid initial gains

  What is slow learning? Incremental gains
• How many practice sessions is required for slow learning? Multiple sessions of practice
•  

  What does fMRI show about fast learning?

  -              Decreases in DLPFC – presupplementary motor area

  -              Decreases in primary motor cortex (M1)

  -              Increases in posterior parietal cortex

  -              Increases in premotor cortex – supplementary area

  -              Increases in cerebellum and dorsomedial striatum
• What does fMRI show about slow learning?

  -              Anterior to posterior shift

  -              Prefrontal regions not contributing as much

  -              Practice increases sensory memory, primary motor cortex, primary sensory cortex

  -              Increasing in supplementary area

  These regions form a motor loop

  - Highly involved in motor execution + dorsolateral striatum

  - Decreases in cerebellum (acts as a comparator, comparing what you intend to do vs what you are currently doing)
• What are limitations to PET studies? BOLD signal increases may be interpreted as more activity thus brain region involvement OR less efficient/ more effortful involvement of brain regions  
• What is TMS used for? Coil placed over brain regions induces action potentials to cause muscle contractions

  -              Can be used to measure and/or modulate motor evoked potentials
• What are single/paired TMS pulses used for? Measuring cortical excitation and inhibition
• What is repetitive TMS used for? Modulating cortical excitability
• How is single/paired TMS used to measure thus make a map of the primary motor cortex?

  -              Stimulate range of brain regions of the cortex

  -              We stimulate then record motor evoked potential – some sites will have large MEP and others won’t be as large

  -              Map is therefore generated
• Group was given a sequential task to master and TMS shows improvement with practice

  -              Representation of finger flexes for hand used in tapping task got bigger and bigger across 5 days

  -              Untrained hand which was not learning any task over 5 days showed no changes

  -              Control = people made same movements but not learning anything, and representation showed no changes (only changed a little bit)
• Why is removing the ‘brakes’/ reducing GABA important for M1 plasticity and motor training? In summary, by reducing GABAergic inhibition in M1 during motor training, the brain can facilitate plasticity, allowing for more dynamic adjustments and improvements in movement representations, ultimately enhancing motor learning and performance.
• What did Dayan and Cohen show about procedural consolidation?

  -              Despite period of no practice between day 1 and day 2, gains are occurring in skill (offline learning)

  
• -              after period of practice where no offline learning occurs (between 5-7 on x-axis), the next time you practice, your skill is about the same as where you left off

  -              presence of offline learning between 5-7 on x-axis shows jump in improvement in performance

  
• 1.     Offline Learning: This phase occurs after the initial practice or training session has ended, typically during periods of rest or sleep. During offline learning, the brain continues to process and consolidate the newly acquired motor skills or procedural memories. This process involves the strengthening and reorganization of neural circuits associated with the learned task, leading to long-term retention and improved performance. Offline learning is crucial for the consolidation of motor memories and the optimization of skill retention over time.
• 1.     Online Learning: This phase occurs during the actual practice or training session when the individual is actively engaged in performing the task. During online learning, immediate feedback, error correction, and skill refinement take place. Neural activity associated with the ongoing practice contributes to short-term changes in motor performance. Online learning is essential for the initial acquisition and refinement of motor skills, as it allows individuals to adjust their movements in real-time based on feedback and practice conditions
• • when memory is learnt and stabilised, when we revisit it, your skill is about the same as where you left off
  • If your memory is stable but you disrupt it via learning something else, practice 2 session returns to square 1

  
• How is neuroplasticity defined? Brain’s lifelong capacity to modify its structure and function according to experiences or changes in environmental demands
•  

  What are the 3 types of neural plasticity?

  1.        Functional (minutes-hours)

  2.        Microstructural (hours-days)

  3.        Macrostructural (weeks-months)
• What are functional changes?

  -              Unmasking latent excitatory synapses, removing inhibition

  -              Strengthen or weaken synapses (LTP and LTD), protein synthesis e.g. BDNF
• What are microstructural changes?

  -              Dendritic branching, synaptogenesis, axon sprouting, neurogenesis, angiogenesis (formation of new vascular/ capillary beds thus better supply of nutrients to neurons)
• What are macrostructural changes?

  -              Detectable changes on MRI e.g. change in size or volume of hippocampus
• What did Bliss and Lomo (1973) find about LTP?

  -              Response elicited by test stimulus to recording site within hippocampus was applied before and after high frequency stimulation of the cell

   

  -              After high frequency stimulation, exact same test stimulus recorded at the site provoked a much larger response i.e. larger EPSP at recording site

   

  -              When high frequency stimulation was repeated 4 times, response was larger and lasted for a longer time – multiple hours

  Demonstrating LTP – increased efficacy of transmission across synapses
•  

   

  Repetitive TMS

  -              Induces LTP

  -              Non invasive

  -              Handheld coil producing strong magnetic field, when placed on scalp induces electrical field in brain tissue causing neurons to generate APs

  -              Effects vary depending on frequencies in which stimulation is applied

  -              Low frequency ~1Hz = reduction in excitability – LTD-like effects

  -              High frequency = increase in excitability due to LTP like effects

  Effects last around 1 hour

  We can alter synaptic efficacy of stimulated CORTEX
• Thea-burst Stimulation TBS

  -              Stimulation applied in high frequency triplets

  -              3 pulses at 50hz

  -              Continues TBS = reduction in size of motor evoked potential thus LTD

  -              Intermittent TBS = 2-fold increase in motor evoked potential thus LTP
• What can rTMS be used to induce? Neuroplasticity

  What can rTMS augment? Learning