adaptation to visual changes Flashcards
what is a visuomotor map
defines the relationship between muscle activity adn visual consequences of mvmt
what does a child’s NS have to do
learn the mapping bewteen muscle activity and amount/direction of limb motion
what occurs with a shift in visual field (prism goggles)
alters the relationship between muscle activity and visual feedback about limb motion
what is the slow process
internal models - responding to SPE
what are the properties of the slow process
- temporally stable (learns and forgets slowly)
- implicit (away from conscious awareness)
- low reaction time
- stable across breaks
- driven by SPE
- fixed properties (increases and remains constant)
what are the properties of the fast process
- temporally UNstable (turns on and forgets quickly)
- explicit (planning cost and strategy driven)
- requires high reaction time
- labile (not retained)
- sensitive to performance errors
- changes with experience (becomes less important)
what is shown by overall learning
reflects the summed contribution of fast and slow processes
what is implicit learning
implicit learning = overall adaptation — planned aimpoints (explicit learning)
what is the effect of visuomotor rotations on explicit aiming and implicit learning
- rapid change in aimpoints (peak right after VMR introduction)
- continued exposure causes a decline in explicit aiming and steady increase in implicit learning (adaptation)
what do explicit aiming and implicit learning resemble
explicit aiming resembles fast process
implicit learning (adaptation) is the internal model and resembles the slow process
what does explicit aim reporting encourage
explicit aiming strategy
increases average RATE of adaptation (not amount)
increases rate of washout (lower retention)
what is seen in the control condition (less emphasis on explicit aiming)
slower rates of learning and washout
- relies more on internal model
- higher retention
what happens to reaction time when visuomotor map changes unexpectedly
reaction time increases
- suggests explicit planning cost imposed by changes in the task
- reaction time cost re emerges with each change
adaptation = reaction time cost back to baseline
what do constraints on planning time expose
presence of explicit planning / aiming strategies
what is seen with high preparation time (see the target for longer before reaching)
- faster learning and washout
- can cognitively resolve during long planning time so there is less deviation during washout
- show that they are using more of the explicit strategy during longer planning time
what is seen with low preparation time (change in target right before mvmt)
slower learning and washout
- no difference in late adaptation between high and low prep time (switches to internal model)
what do learning patterns use
both sensory prediction errors (SPE) and performance errors (PE)
what is performance error
PE = explicit aim direction + implicit forward model – rotation size
PE = overall adaptation – rotation
what do the SPE and PE drive
SPE drives updates in the internal model (forward) - implicit learning
PE drives explicit aiming strategies and selected goal
what areas of the brain are involved in visuomotor learning
cerebellum - more active in implicit (internal models)
parietal cortex - area 5 and 7
PFC - more active in explicit (cognitive/conscious processes)
what is the impact of cerebellar damage on VMR adaptation
- smaller adaptations and washout
- reduced rate and amount of learning
- smaller deviations in washout
- impair overall learning
how does reduced volume in cerebellar structures impact VMR and FF learning
reduced volume in posterior lobe = lower VMR learning
reduced volume in anterior lobe = lower FF learning
same concept for lesions
