Psych 3L03 Neuroscience Laboratory

PROJECT 1: BRAIN MECHANISMS FOR SKILL LEARNING
LECTURE AFTER THE EXPERIMENT



RESEARCH DESIGN ISSUES

validity

reliability

validity: extent to which a measure of X truly measure X and not Y

reliability: extent to which measures of the same phenomenon are consistent and repeatable

DV: variable we measure

IV: variable we manipulate

CIRCUMSTANCES DEPENDENT VARIABLE (BEHAVIOURS)
Independent Variable Condition 1 Condition 2
control variables
random variables
confounding variables

confounding variables: any extraneous variable that covaries with the independent variable and could provide an alternative explanation of the results.

RESEARCH DESIGN ISSUES IN THIS EXPERIMENT

(Possible discussion topics in lab report)
DESCRIPTION SOLUTIONS
POSSIBLE CONFOUNDING VARIABLES
intrinsic asymmetry in EPSP between two hemispheres control groups (without training, compare two sides of brain), or recording from same animals (before & after training)
direction of change in EPSP following learning unknown
not selective in training only one paw modify apparatus and procedure to allow training of one paw only, control the use of the other paw, documentation of use and successful grasp by both paws
experimenter bias blind to the animal group membership
recording site might not be specific for grasping movement? Stimulate recording site to see the motor response
EPSP change due to effect of repeated motor output rather than learning per see correlate motor behaviour (rather than motor skill learned) with the amount of EPSP change
NEED FOR CONTROL VARIABLES
difficulty of the training task control location of the food, create fixed time interval between trials (e.g., max of 30 food intakes per 5 minutes)
reduce distractions use forceps rather than hand to hold the food, reduce noise, no extra stimulation, not training multiple rats on the same table
same experimenter for same rat
time of the day for training make it same
NEED FOR RANDOM VARIABLES
more animals tested
multiple recording and stimulating sites (and depths)
alternate electrodes from two sides of brain (in case there is an impedance difference between electrodes)
multiple sweeps for each stimulating parameter
FUTURE IMPROVEMENT (other DVs to investigate)
vary the duration between the time of recording and the last training session
different recording and stimulating parameters
differential plasticity of two sides of brain (controlling preferred and unpreferred paw) training unpreferred paw