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Updated: Jul 14, 2026
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A Lateralized Odor Learning Model in Neonatal Rats for Dissecting Neural Circuitry Underpinning Memory Formation
Published on: August 18, 2014
Associative Processes in Early Olfactory Preference Acquisition: Neural and Behavioral Consequences.
Regina M Sullivan1, Donald A Wilson, Michael Leon
1University of California, Irvine, California.
Psychobiology (Austin, Tex.)
|January 1, 1989
Summary
Learning in rat pups requires the conditioned stimulus (CS) and unconditioned stimulus (US) to be presented together or in sequence. Forward pairings, but not backward, lead to learned odor preferences and neural changes in the olfactory bulb.
Area of Science:
- Neuroscience
- Behavioral Science
- Developmental Biology
Background:
- Classical conditioning in young animals relies on specific temporal relationships between stimuli for learning.
- Olfactory classical conditioning in rat pups typically requires forward or simultaneous presentation of conditioned stimulus (CS) and unconditioned stimulus (US).
Purpose of the Study:
- To investigate how the temporal relationship between CS and US influences neural modifications in the olfactory bulb during early olfactory classical conditioning.
- To determine if neural changes in the olfactory bulb mirror the behavioral learning constraints observed in olfactory conditioning.
Main Methods:
- Wistar rat pups were trained from postnatal days 1-18 using either forward (odor preceding stroking) or backward (stroking preceding odor) CS-US pairings.
- Post-training assessments included behavioral odor preference tests, 2-deoxyglucose (2-DG) uptake in the olfactory bulb, and single-unit recordings of olfactory bulb responses.
Main Results:
- Only rat pups receiving forward CS-US pairings demonstrated a learned preference for the odor CS.
- Forward pairings also resulted in modified neural responses to the odor CS within the olfactory bulb, as evidenced by 2-DG uptake and single-unit recordings.
- Backward pairings did not lead to behavioral preferences or detectable changes in olfactory bulb neural activity.
Conclusions:
- The acquisition of modified olfactory bulb neural responses during classical conditioning is constrained by the same temporal rules as behavioral learning.
- Forward temporal sequencing of CS and US is critical for both behavioral and neural plasticity in the developing olfactory system.
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