Endogenous Pacemakers AO3

• -Obscures other body clocks - body clocks (peripheral oscillators) are found in many organs & cells (lungs, skin). They are highly influenced by the actions of the SCN but can act independently. Damiola showed how changing feeding patters in mice altered circadian rhythms of cells in the liver for up to 12 hours leaving the SCN unaffected. This suggests there may be many other complex influences on the sleep/wake cycle aside from the master clock (SCN).
• -Can’t be studied in isolation- only in exceptional circumstances are endogenous pacemakers free running and unaffected by the influence of exogenous zeitgebers. Total isolation studies are rare. In everyday life, pacemakers & zeitgebers interact so it may make little sense to separate the two. This suggests the more researchers attempt to isolate the influence of internal pacemakers, the lower the validity of the research.
• +-Animal studies of the sleep-wake cycle are justified: there are similar mechanisms in all mammals, so generalisations can be made to the human brain. However in the DeCoursey study the animals were exposed to considerable risk and most died so such studies are unethical. This suggests studies like these can't be justified and researchers should find alternative ways of studying endogenous pacemakers.