RECORDING OF ELECTROENCEPHALOGRAMS AND ELECTROCARDIOGRAMS DURING DAYTIME SLEEP IN TRAINED CANINES - PREPARATION OF THE SLEEPING DOGS

Although respiration in trained canines is well investigated, the proc ess of preparing dogs has not been described in any great detail. More over, their daytime patterns of sleep and wakefulness during 1 or 2 h of electroencephalogram (EEG) and electrocardiogram (EGG) recordings a re not clear. Therefore, we describe the process of selecting and trai ning dogs, in which we recorded EEG and ECG in the laboratory. First, 14 of 1242 dogs dealt with over a 1 year period were chosen. They were trained for 2 h to lie quietly and to sleep in the laboratory; this t raining procedure was repeated 152 times. Three dogs were then selecte d and a permanent tracheostomy was performed in one. Finally, EEG and ECG were recorded with tile bipolar fine needle electrodes; respiratio n was recorded simultaneously through a tube inserted to a tracheostom y in one dog. Wakefulness, slow wave sleep (SWS) and rapid eye movemen t (REM) sleep (REMS) were identified according to the EEG pattern and on the basis of the behavioral criteria. Recordings were performed 12 or 13 times in each dog. Complete sleep cycles, including wakefulness, SWS and REMS in this sequence, were observed 3.9-4.1 times. The mean duration of SWS was 2.2-4.3 min and that of REMS was 3.5-4.6 min. The RE:MS latency was 33.9-41.8 min. Fluctuation of heart rate with respir ation, termed respiratory sinus arrhythmia, was noted in the EGG. Hear t bear increased with inspiration and decreased with expiration. The p resent study demonstrates how to select and train sleeping dogs and sh ows their undisturbed daytime sleep and wakefulness patterns.