Partition test and sexual motivation in male mice

TL;DR

This study analyzes how partition tests relate to sexual motivation in male mice, questioning the direct link between behavioral activity and sexual motivation, and proposing odor association as a key factor.

Contribution

It offers a new interpretation of behavioral reactions in male mice, emphasizing odor cues and learned associations over direct sexual motivation indicators.

Findings

Behavioral activity near partition is influenced by female odor and maternal warmth.

Lack of correlation between behavioral and gonad responses questions traditional sexual motivation measures.

Odor association after sexual experience may underlie sexual motivation in male mice.

Abstract

Theoretical analysis of own and literature investigations of sexual motivation with the use of the partition test [Kudryavtseva, 1987, 1994] in male mice was carried out. It has been shown that appearance of a receptive female in the neighboring compartment of common cage separated by perforated transparent partition produces the enhancement of testosterone level in blood and stimulates the behavioral activity near partition as a reaction to the receptive female in naive males. In many studies this behavioral activity is considered as sexual motivation, arising in this experimental context in male mice. The lack of correlation between behavioral parameters and gonad reaction of males on receptive female, uninterconnected changes of these two parameters as well as the lack of sexual behavior between naive male and female when partition is removed cast doubt on this data interpretation. It has been supposed that in naive males behavioral reaction to a receptive female is induced by positive incentive - odor of the female associated with nursing and warmth from mother and other females which look after posterity. Short-term increase of the level of testosterone (possessing rewarding properties) is innate stimulus-response reaction which stimulates and prolongs behavioral interest of male to receptive female. It has been supposed that after sexual experience female odor is associated in experienced males with sexual behavior directed to the sexual partner and resulted in the formation of sexual motivation. The data are considered also in the light of the theory of motivated behavior including "liking", "wanting" and "learning" [Robinson and Berridge, 1993, 2000].