Mice are at their best at night. But a new analysis suggests researchers often test the nightly creatures during the day, which could alter results and create 1 across various studies, if they record time-of-day information 2. Scientists assume that waking up lab mice in the daytime may twist research.
Of the 200 papers examined in the new study, more than half either failed to report the timing of behavioral testing or did so 3. On the contrary, they found only 20 percent reported 4 testing. The analysis was published in Neuroscience & Bio-behavioral Reviews.
West Virginia University neuro-scientist Randy Nelson, the study's lead author, says this is likely a matter of human 5. "It is easier to get students and schools to work during the day than at night," Nelson says. But that advantage 6.
"Time of day not only impacts the intensity of many 7, including mice activity, aggressiveness of their behavior, and hormone levels," but changes in those factors can only be 8 during certain parts of the daytime cycle, says University of Wyoming behavioral neuro-scientist William D. Todd. This means that "failing to report time of day of data collection and tests makes 9 of results extremely difficult," adds Beth Israel Deaconess Medical Center staff scientist Natalia Machado. Neither Todd nor Machado was involved in the new study.
10, the study researchers say it is critical that scientists report the timing of their work and consider the fact that animals' behavioral and physiological responses can 11 with the hour. As a first step, Nelson says, "obviously, taking time-of-day into consideration seems like 12 fruit in terms of line assing behavioral neuroscience research reliability, reproducibility and rigor (严谨性)
University of Calgary psychologist Michael Antle, who was also not involved in the analysis, says such differences in how studies are run 13 a "reproducibility crisis" in science, with other laboratories unable to 14 study results. "Running a study at the wrong time," he says, "could lead to us completely 15 a finding altogether."
