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 |