Seeing red

24 02 2014

Elke accompanied me, Mike and a light meter to our mouse rooms on Friday, to help us evaluate our “dark” phase lighting. We wanted advice on on two issues. First, is the overhead red light mice are chronically exposed to during the dark phase sufficiently dark and red, even in the cages with the greatest exposure? And second, is the same true of the clip-on lights that we have scattered round the room, and turn on for in-cage observations?. Being exposed to light during the dark phase can reset animals’ clocks and make their activity cycles start/stop at different times on subsequent days, so this additional light on observation days (plus the glow from the lab iPad, any phone etc.) might add noise to our data. (We scrupulously check data for internal consistency before analyses, and enrichment treatments & barren cages are physically intermingled so that patches of light/shade are never add systemmatic error; but still, it’s always nice to understand the issues better, and stomp on sources of variance where we can).

Verdict: the overhead lights seem pretty good, but our clip-on lamps are way too bright and yellow. Lee filters can provide a simple solution however (phew), especially “Marius Red” (787 in the samples below).

Screen shot 2014-02-24 at 11.57.48 AM