sentence: A type I phase-shifting light pulse at CT16 produced larger phase delays in the rest-activity rhythms of Grm2 / 3 than Grm2 / 3 mice ( F = 5.498 , P = 0.024 ; Fig 2C ) ; the average phase delay was 1.51 h in Grm2 / 3 mice , but only 1.16 h in Grm2 / 3 mice .