Supporting Online Material

Animals and Circadian Time LE/BluGill rats (University of Illinois) 6-12 weeks old were used for the in studies of the SCN. A dense genome scan was performed at a 10cM interval between markers on LE/BluGill progenitors. The results of this scan, performed by the Medical College of Wisconsin Human and Molecular Genetics Center as part of the NHLBI Programs for Genomic Applications (PGA) U01 HL66579, showed that the colony is inbred, yielding one allele at each locus tested (http://pga.mcw.edu/pga-bin/strain_desc.cgi). Use of this inbred strain greatly reduced inter-experimental variation, contributing to high statistical significance with small sample sizes. Rats were entrained to a daily cycle of 12-h light:12-h dark (LD) and provided food and water ad libitum. Zeitgeber time (ZT) is determined from the animal’s LD cycle, with time of lights-on designated ZT 0. For samples obtained ex vivo, ZT is reckoned from this point. Because brain slices are maintained in constant conditions where the clock functions with a period of ~24-h without external time cues, the time of lights-on in the donor colony is designated as circadian time 0 (CT 0). Thus, subjective day (CT 0-12) corresponds to the light portion of the donor’s former lighting schedule; subjective night (CT 12-24) corresponds to the dark portion of the donor's cycle. All animal protocols were approved by the IACAC and in compliance with NIH and University guidelines.