Following complete bulbectomies, male hooded rats showed an increase in irritability and difficulty of handling, but a decrease in timidity or fear responses. After rats had learned to drink in an open field, a cat was confined in the center, and fear was defined by the behavior of controls, viz., almost total suppression of drinking and long periods of freezing, broken by brief bursts of high-speed activity. Bulb animals could not have differed more radically. Bulbs showed neither freezing nor suppression of drinking. The present results could not be attributed to differences in shock reactivity; nor could they be attributed to differences in learning or retention. Bulb animals also showed an impairment on the acquisition of step-down passive avoidance but no difference in step-downs after acquisition. These results argue against an impairment of response inhibition. The present study suggests that bulbectomy increases irritability and decreases timidity. © 1974.
Mollenauer, S., Plotnik, R., & Snyder, E. (1974). Effects of olfactory bulb removal on fear responses and passive avoidance in the rat. Physiology and Behavior, 12(1), 141–144. https://doi.org/10.1016/0031-9384(74)90080-8