Timing and hippocampal theta in animals.

All animals have at least two different internal clocks, one governing cognition of time of day, and the other concerning awareness of seconds and minutes. In the latter case, organisms show scalar properties. The timing mechanisms in the brain may function similarly throughout the animal kingdom, but this is not yet clear. Previous studies have shown that the hippocampus is intricately involved with the process of interval timing. Data concerning electrophysiological field potentials in the hippocampus show obviously rhythmic activity, known as hippocampal theta activity. An information-processing model of interval timing postulates three distinct stages: a clock, a memory, and a decision stage /11/. The timing process includes memory processing, which means that the hippocampus works together with working memory to estimate current time passing.