Light Entrainment Test
Objective: Test the ability of animals with restored circadian rhythms (via SCN grafts) to synchronize circadian rhythms to light intensities
Gather these items before starting the experiment. Check off items as you prepare.
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Protocol Steps
Establish baseline free-running rhythms
Place animals with restored rhythms in constant darkness to confirm free-running circadian rhythms are present
Note: This step confirms the graft has successfully restored circadian rhythmicity
View evidence from paper
“restoration of free-running rhythms in conditions of constant darkness is correlated with the presence in the graft”
Expose animals to light intensities
Present animals with varying light intensities to test their ability to entrain (synchronize) their circadian rhythms to light
Note: Test whether grafted animals can synchronize to light like SCN-intact control animals
View evidence from paper
“failed to synchronize (entrain) to light intensities to which SCN-intact animals responded”
Monitor locomotor activity
Record and analyze locomotor activity patterns to assess entrainment to light stimuli
Note: Locomotor activity is the primary measure of circadian rhythm expression
View evidence from paper
“implantations of brain grafts containing the fetal SCN reestablish circadian rhythms of locomotor activity”