Experiential Learning in Biology 482: In vivo Animal Research in Neurobiology

Thanks for the question - from what is in the literature from my lab and others it seems that the light exposure is more of a driving force for the altered anxiety/behavioral changes found in the human and rodent literature. The photopigment that relays light cues to the brain for clock function is melanopsin (different than the pathway for vision) and if you remove melanopsin from an animal they cannot synchronize to a standard day, but they are also seemingly immune to the behavioral changes due to different amounts of light exposure. MEanwhile, saturate fat consumption alters the clock gene transcription of liver and fat cells but not in the brain, but it does lead to internal disruption. The poor metabolic function is probably due to disrupted clock, rather than the amount of light exposure. If you feed the diet only during the active period (when the animals are awake only) the mice do not become obese. I recent had a paper accepted where I put the animals in 21 hour day - the animals were able to synchronize to the 21 hour day and did not show any issues with their metabolism/body weight, but showed increased impulsivity and anxiety. But another study with a 20 hour day where the animals cannot synchronize show both metabolic and behavoral changes.

Thank you!