Human biological rhythm in traditional Chinese medicine

Traditional Chinese medicine(TCM)has a comprehensive and thorough understanding of biological rhythm.Biological rhythm is an inherent connotation of“harmony between human and nature”,one of the thoughts in TCM.TCM discusses emphatically circadian rhythm,syzygial rhythm and seasonal rhythm,and particularly circadian and seasonal rhythms.Theories of Yin Yang and Five Elements are the principles and methods,with which TCM understands biological rhythms.Based on theories in TCM,biological rhythm in essence is a continuous variation of the human body state synchronized with natural rhythms,and theories of Yin Yang and Five Elements are both language tools to describe this continuous variation and theoretical tools for its investigation and application.The understandings of biological rhythm in TCM can be applied to etiology,health care,disease control and treatment.Many understandings in TCM have been confirmed by modern research and clinical reports,but there are still some pending issues.TCM is distinguished for its holistic viewpoint on biological rhythms.

Circadian fluctuations in three types of sensory modules in healthy subjects

This study was designed to observe and compare the circadian fluctuations in tactile sense, joint reposition sense and two-point discrimination in healthy subjects. Twenty-one healthy adult subjects received perceptual ability tests through these three different sensory modules at approximately 9：00, 13：00 and 18：00 in a day. The distribution of ranking for perceptual ability was significantly different among the three different time points in each individual, with highest perceptual ability in the evening compared with noon and morning, in terms of tactile sense and two-point discrimination. These findings suggest that the perceptual ability of healthy subjects fluctuates according to the time points in a day.

Daily activity rhythms, chronotypes, and risk-taking behavior in the signal crayfish

Consistent inter-individual differences in daily activity rhythms(i.e.,chronotypes)can have ecological consequences in determining access to food resources and avoidance of predators.The most common measure to characterize chronotypes in animals as well as humans is the onset of activity(i.e.,early or late chronotypes).However,daily activity rhythms may also differ in the relative amount of activity displayed at particular time periods.Moreover,chronotypes may also be linked to other consistent inter-individual differences in behavior(i.e.,personality),such as the propensity to take risks.Here,we used the signal crayfish Pacifastacus leniusculusto test the presence of chronotypes and risk-taking personality traits and a potential behavioral syndrome between these traits.We first exposed crayfish to 5 days of light-darkness to measure daily activity rhythms and then we applied a visual predator-simulating stimulus in 2 different contexts(neutral and food).Our results showed consistent(i.e.,across 5 days)inter-individual differences in the relative nocturnal activity displayed in the early and middle,but not in the late part of darkness hours.Moreover,while crayfish displayed inter-individual differences in risk-taking behavior,these were not found to be consistent across 2 contexts.Therefore,we were not able to formally test a behavioral syndrome between these 2 traits.In conclusion,our study provides the first evidence of chronotypes in the relative amount of activity displayed at particular time periods.This could be a valuable information for applied ecological aspects related to the signal crayfish,which is a major invasive species of freshwater ecosystems.