Olfactory Recognition: A Simple Memory System

TLDR

Mice possess an olfactory (pheromone) recognition memory at the first relay in the sensory system, a function essential for females to sustain pregnancy in the presence of their stud male’s odors. The memory is formed by Hebbian changes in synaptic efficacy at dendrodendritic synapses in the accessory olfactory bulb. One‑trial learning, contingent on norepinephrine activation during mating, produces a memory that lasts weeks and enables females to recognize familiar males, thereby mitigating pregnancy block.

Abstract

Mice have an olfactory (pheromone) recognition memory located at the first relay in the sensory system. It is acquired with one-trial learning, contingent upon norepinephrine activation at mating, and lasts for several weeks. The mechanism involves Hebbian (association-dependent) changes in synaptic efficacy at dendrodendritic synapses in the accessory olfactory bulb. As a result of this memory, males made familiar by mating are recognized by the females, thereby mitigating pregnancy block. Such a memory function is biologically important to the female, as it is required to sustain pregnancy in the presence of her stud male's odors.