Electric Activity of the Olfactory Bulb in Man

Olfaction

“…The amount of odorant needed to induce them is exceedingly small but this may be partly a species-determined factor, for they are rarely absent in macrosmatic animals like the cat or rabbit (184,185), whereas in microsmatic species such as man (186) and pigeon (187), unfiltered room air is normally not enough to alter the spontaneous background activity. These waves are slower than the spontaneous discharge already discussed and show marked variation with species as well as with electrode position.…”

“…Although most odorous substances in low or medium concentrations will produce bursts, certain strong odorants or high concentrations of weaker odorants tend to depress all activity (186,188) , In chronic experi ments, this might result from the animal's holding its breath (189) , but similar results in acute experiments in which activity was recorded from the olfactory nerves (190) or bulbs (182) when the flow of odorant was com pletely controlled by the experimenter suggest that it is a true property of the system.…”