Low cost rodent activity monitoring instrumentation

Chronic fatigue syndrome (CFS) is a condition that results in moderate to severe disability. A leading symptom of CFS is that patients report critical reductions in their levels of physical activity due to fatigue related symptoms. We have developed a rodent model, using rats, hamsters, and mice, that enables us to investigate fatigue and physiological rhythms in an integrated framework. The animal's activity is one measure of great importance in the study of these rhythms and chronic fatigue. To monitor a free-ranging rodent's activity we utilize two complementing methods: first, is an infra-red photo beam to detect and count turns of a running wheel, and second, is a force sensor located under the housing tub to detect general motion. Both methods are used in the animal's home cage and are made to be low cost, compared to commercial units, for implementation on many animals.