A new method for continuous, long-term polysomnographic recording of neonatal rats

Study Objectives: Many findings suggest that in altricial mammals neonatal REM sleep has developmental functions. However, investigations of these dev elopmental functions has been hampered by technical limitations of the conv entional polysomnographic (PSG) recording technique. One limitation is that continuous (24 hour/day), long-term (weeks) PSG recordings have not been a chieved. A second limitation is that the metal screw electrodes and head pl ugs cemented to the skull cannot be removed to allow the neonate to mature into adulthood. As a result of these limitations, the relationship between neonatal sleep/wake variables and adult variables has not been studied. Als o the effects of polysomnographically controlled neonatal REM sleep depriva tion on adult variables have not been studied. The present work describes a new technique called the soft head plug (SH) method for continuous, long-t erm PSG recording. Design: In the new technique, electrodes are thin, strong, Teflon wires tha t are led by a suturing needle through the soft skull to the epidural space , then with a U-turn exited from the skull and tied to the entry wire. Thus , in contrast to the conventional technique, the soft head plug technique d oes not use screws as electrodes and does not cement a hard, relatively lar ge electrode plug to the skull, removal of which is fatal or very traumatic . The SH recording electrodes can be removed without damage to neonates, Setting: NA Patients: NA Interventions: NA Results: In the present study sleep/wake results with the soft head plug te chnique were reliable (replicated) and, compared with results of the conven tional method, valid. Conclusions: The results indicate that the soft head plug technique can be used to study relationships between neonatal sleep/wake variables and adult variables.