Evoked olfactory responses in neonatal rats.

Although there is behavioral evidence that rat pups respond to odors, the physiological basis of the response is unclear. In the present study, eight different odors were presented to 44 anesthetized rat pups between the ages of 0 and 20 days, and recordings of electrical activity were made from the olfactory bulb. The major finding was that, contrary to earlier neurophysiological findings, even on the first day of life--when spontaneous electrical activity is minimal--evoked potentials, in the form of synchronized waveforms two to four times the amplitude of the background level of spontaneous activity, can be recorded to a variety of odor stimuli.