Brown Institute for Brain Science

Maternal Odor Preference/Homing Behavior

Rationale of Test

Early in development, pups can develop strong associative ties to cues linked with the nest (including maternal odor). In this test, we assess both the animals ability to discriminate the maternal odor from that of another dam, and their "desire" to approach the maternal odor.

Apparatus

Testing is carried out in a 12" x12" clean plexiglass cage. The cage is positioned under a digital video camera connected to a computer with digital tracking software. The arena is lit with near infrared light to minimize pup distress.

Procedure

Soiled bedding from the nest of the pups dam or from an unrelated dam are placed in opposing corners of the arena. The pup is placed in the center of the arena and allowed to freely explore for a period of 5 minutes. Time spent in proximity to the maternal odor relative to the unrelated odorant or un-baited corners are calculated based upon computer tracking.

Interpretation

Mice with intact maternal attachment will spend the majority of their time in close proximity to the maternal bedding compared with the bedding of an unrelated dam or empty corners. As part of this task, the latency to orient to and approach the maternal bedding is calculated. This represents the homing reflex of the pup, or attempt to return to the nest.

Relevant Controls

Assessment of olfactory sensitivity, assessment of locomotor activity.

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