Ontogeny of electrical activity of main olfactory bulb in freely-moving normal and malnourished rats

Abstract

Electroencephalographic activity (EEG) was recorded from the main olfactory bulb (MOB) in freely-moving, normally-nourished, (NP, normal-protein diet) and malnourished (LP, low-protein diet) rats from 4 days of age through adulthood. MOB EEG was analyzed for dominant frequency components using power spectral techniques. For NP rats, a single dominant frequency component (induced wave) was present in the MOB EEG at 4–6 days of age. From 10 days of age through adulthood, the MOB EEG contained two dominant frequency components (induced and intrinsic waves). Both the induced wave and intrinsic waves increased in center-frequency to reach maturity at approximately 30 days of age. Rats reared on low-protein diets (8% casein, prenatal and postnatal) displayed relatively permanent retardation in the development of induced wave center-frequencies and a delay in the development of the intrinsic wave center-frequencies. These results closely parallel the morphological development of the MOB in normally-nourished and malnourished rats.