Author Type

Undergraduate Student

Date of Award

Spring 4-30-2022

Document Type

Thesis

Publication Status

Version of Record

Submission Date

June 2026

College Granting Degree

Harriet L. Wilkes Honors College

Thesis/Dissertation Advisor [Chair]

Robert W. Stackman, Jr.

Abstract

Long-term memories are encoded within the hippocampus, but some are quickly forgotten. Brief exposure of mice to a novel context following encoding of object memory significantly enhances consolidation of the object memory. The memory-enhancing effect of post-training novelty may rely on locus coeruleus tyrosine-hydroxylase expressing neurons which co-release norepinephrine and dopamine in the hippocampus. To test the contribution of norepinephrine to this novelty effect, mice received propranolol, a synthetic beta-adrenergic receptor antagonist (10 mg/kg), to block norepinephrine or 0.9% saline as a control post-training. Pre-novel context exposure and object memory was tested 24 hr later. Results revealed that propranolol did not block the memory-enhancing effect of post-training novel context exposure. Further, the memory performance of the propranolol-treated mice was comparable to that of saline-treated mice. These findings support the view that enhanced consolidation of object memory brought about by post-training novel context exposure is not dependent upon norepinephrine neurotransmission.

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