prism adaptation dr. roger newport room b47. drop-in sessions: tuesdays 12-2pm....
TRANSCRIPT
Prism Adaptation
Dr. Roger NewportRoom B47. Drop-In Sessions: Tuesdays 12-2pm.
Laura Condon Room A47. Mondays 1-2pm.
http://www.psychology.nottingham.ac.uk/staff/rwn/Teaching/C82MPR.html
Week 1: Introduction. Listen to introductory lecture. Get allocated to groups. Start researching literature. Begin planning experiment.
Week 2: Pilot Study. Test and fine tune your experiment.
Week 3: Experiment Week. Run your experiment.
Week 4: Stats Analysis. Listen to stats talk. Perform analysis.
Week 5: Presentation week. Tell everyone about your fascinating experiment.
This week
Prism adaptation demonstration
Prism adaptation explanation
Hints and tips and dos and don’ts
Stats preview
Divide into groups
Get on with it
This lab class needs YOU!
Prism adaptation demonstration
TT T
T TT TT
How optical prism displacement works
The prism adaptation effect and the negative aftereffect
TT T
Adaptation1st reachLater reaches
50
-5Aftereffect
50
-5
Pretest
50
-5
Prism adaptation: the 2 adaptation processes
Perceptual recalibration (slow)
Unconscious correction of sensory misalignment
Probably involves cerebellum
Visual straight ahead rotation
Strategic control (fast)
Probably involves PPC
Conscious correction of visual error
E
E = expectedhandposition
On-line correction
Deliberate misreaching
Recalibration of felt hand position to match visual shift
Perceptual recalibration
Unconscious correction of sensory misalignment
Negative aftereffect
Only perceptual recalibration leads to the negative aftereffect
Prisms offPrisms on
The true test of prism adaptation is in the magnitude of the aftereffect
Occurs despite knowledge of prisms removal not strategic control
Prisms: what are they good for?
Studying motor learning
Studying sensorimotor integration
Studying cortical plasticity
Rehabilitation
Posterior Parietal Cortex Human imaging and patients
Cerebellum Monkey and human lesions impair adaptation
Premotor (vPM) impaired re-adaptation following inactivation (in monkeys)
PD = 100tan = (PD/100)tan-1
Prism dioptres
1m (
100c
m)
PD = the amount of visual shift at 1m
Technical stuff: What is a prism dioptre?
Wedge prism
Fresnel prism
Technical stuff: Types of prisms
Things that are important for prism adaptation
Vision of the hand
Knowledge of end-point error
Speed of movement
End-point corrections
Speed between phases
Rule of thumb: quickly executed rapid trials in which you only see your direction error towards the end of the movement gives the best adaptation
Things you must not do:
Lose, damage or fail to return my prismsUse incongruent lenses (strength or direction)Leave subjects unsupervisedDrive (and other obviously stupid things like DIY)
Not recommended
Things you could manipulate:
Transfer of adaptation from limb to limbTransfer from eye to limbTransfer between tasks/posture Passive vs active adaptationTerminal vs concurrent exposureFast vs slow movementsEnd-point error feedbackTime/decayCognitive interferenceRe-adaptation
http://www.psychology.ilstu.edu/gredding/Publications.html
Where does E-prime come into this?
Your experiment MUST have an e-prime component
E-prime options:
Measurement of end-point errorPresentation of adaptation stimuli
How a standard prism experiment might look
Condition 1PreExp (e-prime?)Post
Condition 2PreExp (e-prime?)Post
We may only need to record the last few pre-exposure and the first few post-exposure in each manipulation
For this lab class your study should be a 2x3 repeated measures design
Two factors:one with two levelsone with three (pre, exp, post)
You choose the factor with 2 levels
Each participant performs ALL conditions
To analyse this experiment we will be using:
planned comparisons
We can use planned comparisons when we have specific predictions about the outcome of the experiment
We only have to test our specific predictions and nothing else
This makes analysis simple and honest.
Planned comparisons are essentially t-tests that take into account the variability of the all the data in the model.
We will go into these in more detail in week 4, but it is important that when you plan your experiment you are aware of your predicted outcomes and how you will test them.
Simplifies analysis
Reduces risk of type I errors
P value correction not normally necessary
Interpretation is easy as each comparison is derived from a specific hypothesis
No tricky interactions to interpret
Only have results that you are interested in
Advantages of planned comparisons:
Disadvantages: SPSS does not (easily) do the comparisons we need
Accuracy
-20-15-10-505101520
Pre Post
Exposure
mm YM1
YM2
What do we really want to know?What are our hypotheses?Why are we doing this experiment?
Planned comparisons
Accuracy
-20-15-10-505101520
Pre Post
Exposure
mm YM1
YM2
What do we really want to know?What are our hypotheses?Why are we doing this experiment?
What to do now
Divide into groups
Collect and sign for your prism goggles
Get on with itPlay with prisms
Read some background literature
Start planning experiment
B
A
D
C
E