Fig. 2.

Temperature cycles entrain rhythms in immortalized mouse hippocampal neurons. a Rhythms in mouse neurons. Compared to neuronal cultures examined under constant temperature conditions (n = 4), cells run under a temperature cycle (h at 35°C:h at 37.5°C) of 12: 12 (n = 4) showed shorter periods of Per2-luc expression that converged upon the period of the temperature cycle. Representative traces are shown for rhythms entrained to 12: 12 temperature cycles (b) (red) compared to neurons run in parallel under constant 35°C conditions (black). The white bar indicates a temperature of 35°C, and the gray bar indicates a temperature of 37.5°C (applies only to the samples measured under temperature cycles). * Significant (p < 0.05) difference compared to controls as determined by a two-tailed t test.