A FUNCTIONAL-ANALYSIS OF ULTRADIAN ACTIVITY IN LABORATORY MICE

The ultradian alternation of rest/activity periods displayed by 10 C3H mice in diurnal condition, and by 10 others in nocturnal conditions, was compared with simulated sequences that respectively optimized thre e functional criteria, i.e. energy input, energy output, and net energ y gain, accumulated over 11 consecutive hours. The simulated sequences were generated by means of a dynamic programming algorithm used in co njunction with a food-intake dynamic behavioural model. On one hand, t he results obtained do not confirm the hypothesis whereby the animals optimize energy input or output criteria. On the other hand, they do n ot invalidate the hypothesis according to which the effect of the C3H mouse's ultradian activity rhythm would be to maximize net energy gain over a nycthemeral period, possibly under constraints that can only b e identified through additional experimentation.