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, were compared with simulated sequences that respectively optimized three functional criteria, i.e. energy input, energy output, and net energy gain, accumulated over 11 consecutive hours. The simulated sequences were generated by means of a dynamic programming algorithm used in conjunction with a food-intake dynamic behavioural model. On one hand, the results obtained do not confirm the hypothesis whereby the animals optimize energy input or output criteria. On the other hand, they do not invalidate the hypothesis according to which the effect of C3H mouse’s ultradian activity rhythm would be to maximize net energy gain over a nycthemeral period, possibly under constraints that can only be identified through additional experimentation.