The effect of lesioning the basolateral amygdala on odor preference and related memory in adult male rats

Background: It has been shown that the basolateral amygdala (BLA) plays an important role in emotional behaviors, olfactory preference, and related memory in rats, such that inactivation of this area changes these behaviors. In the present study, the effect of BLA lesion on olfactory preference (relative to the urine of male, female, and immature rats) in male rats and their affected memory was evaluated.
Materials and Methods: Adult male Wistar rats (n=16) were used. Bilateral BLA lesions were created by passing a 1.5 mA current for seven seconds. Animals were exposed to four different odors, including male urine, female urine, immature rat urine, and water. In each trial, the time spent near each odor, the number of visits to each odor, and the distance traveled in each area related to each odor were recorded.
Results: The results showed that the control group rats showed the highest olfactory preference for female urine and the lowest preference for water as a combination with a neutral odor. BLA-lesioned rat showed an altered response of olfactory preference. In them, the first priority of odor preference shifted from female rat urine to immature rat urine. Spatial memory related to learning the location of olfactory sources was also impaired in these groups.
Conclusion: In conclusion, our findings show that the BLA plays a role in changing olfactory preference related to urinary chemical signals and their affected memory.
Keywords: Olfactory Preference, Memory, Basolateral Amygdala, Rats.