SELECTIVE STIMULATION AND ELECTROPHYSIOLOGICAL RESPONSES OF THE OLFACTORY BULB OF THE OPOSSUM.

Abstract

The present study was designed to compare electrophysiological data with the results obtained from human Ss who were asked qualitatively to scale odors. To achieve this end, recordings from the area of the mitral cells in the opossum's olfactory bulb were carried out with tungsten microelectrodes. The stimuli used were odorants from the extreme ends of the five oblique factors obtained in the human study. The results indicate that chemicals with large positive factor loadings have a facilitative effect on the activity in the anterior olfactory bulb and that chemicals with large negative factor loadings have a facilitative effect on the activity in the posterior olfactory bulb. Further investigation of the four chemicals comprising the extreme positive poles of the factors led to the conclusion that chemicals with large positive factor weights exert an inhibitory effect on the activity in the posterior olfactory bulb. It was also found that the magnitude of the physiological response to a chemical is significantly correlated with the chemical's factor loading.