An Implantable, Low-Power Instrumentation for the Long Term Monitoring of the Sleep of Animals under Natural Conditions

Sleep is a universal and complex state and it is widely agreed that this state is present in every animal species. However, the evolutionary origins of sleep remain ignored or misunderstood, which has led researchers to study, in various species, this common behaviour of all living organisms. Sleep is commonly studied at various levels under laboratory conditions, using tethered devices which record electroencephalographic or electromyographic readings. These artificial settings tend to induce stress, reduce animal freedom and prevent the use of sleeping shelters. In this paper, we present a novel, implantable instrumentation for a complete characterization of sleep under natural conditions suitable for a wide range of animal species, even for animals as small as pigeons or mice. Several configurations of this system are possible to enable the measurement of up to 16 electrophysiology channels, 3 temperature channels as well as 3-axes accelerometry. With an embedded flash memory card for the storage of data collected, the system can be used as a datalogger for the recording of signals in the field.