Fig. 2

Olfactory bulb blood flow responses to olfactory nerve stimulation in aged rats. The effects of various intensities (a–b) and frequencies (c–e) of electrical stimulation of the unilateral olfactory nerve on regional olfactory bulb blood flow on the side ipsilateral to the stimulus. a–b Stimulus frequency, 20 Hz. c Stimulus intensity, 400 μA. d–e Stimulus intensity, 300 or 400 μA. a, c Sample recordings of regional blood flow in the olfactory bulb. b, d, e Maximum levels of regional olfactory bulb blood flow. These occurred within 8 s (first peak) or 15–22 s (second peak) of stimulation onset. These are expressed as the percentage of the pre-stimulus basal blood flow (the mean of the values recorded in the 10 s before time zero), by which blood flow was increased. Each column and vertical bar represents a mean ± SEM (n = 5)