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Updated: Apr 11, 2026
Assessment of Sexual Behavior of Male Mice
Published on: March 5, 2020
The Female Encounter Test: A Novel Method for Evaluating Reward-Seeking Behavior or Motivation in Mice
Yukio Ago1, Shigeru Hasebe1, Saki Nishiyama1
1Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan (Dr Ago, Mr Hasebe, Ms Nishiyama, Mr Oka, Mr Onaka, Drs Takuma, and Matsuda); Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan (Dr Hashimoto); United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University, and University of Fukui, Suita, Osaka, Japan (Drs Hashimoto and Matsuda); Department of Pharmacology, Graduate School of Dentistry, Osaka University, Suita, Osaka, Japan (Dr Takuma).
Background:
Reduced motivation is an important marker of psychiatric disorders, including depression. We describe the female encounter test, a novel method of evaluating reward-seeking behavior in mice.
Methods:
The test apparatus consists of three open chambers, formed with partitions that allow the animal to move freely from one chamber to another. A test male mouse is habituated in the apparatus, and subsequently a female and male mouse are introduced into a wire-mesh box in the left and right chamber, respectively. The time the test male mouse spends in the female or male area is measured for 10 min.
Results:
All six strains of mice tested showed a significant preference for female encounters. The preference was observed in 7-30-week-old mice. The preference was blocked by castration of the resident male test mouse, and was not affected by the phase of the menstrual cycle of the female intruder. The preference was impaired in mouse models of depression, including social isolation-reared, corticosterone-treated, and lipopolysaccharide-treated mice. The impairment was alleviated by fluvoxamine in isolation-reared and lipopolysaccharide-treated mice, and it was improved by the metabotropic glutamate 2/3 receptor antagonist LY341495 in corticosterone-treated mice. Encounter with a female, but not male, mouse increased c-Fos expression in the nucleus accumbens shell of test male mice. Furthermore, both the preference and encounter-induced increases in c-Fos expression were blocked by dopamine D1 and D2 receptor antagonists.
Conclusions:
These findings indicate that motivation in adult male mice can be easily evaluated by quantitating female encounters.
