ABS 112: The Timing of Changes in Synaptic Function during Learning in Multiple Memory Systems

Naia Luz Marcelino, Asrah Rizvi, Jeremy Veenstra-VanderWeele, Kally Sparks

Van Wickle (2025) Volume 1, ABS 112

Introduction: The interplay between multiple memory systems, particularly the hippocampus (HPC) and striatum (STR), is crucial for learning and behavioral control. The HPC and STR are critical for mediating stimulus-stimulus and stimulus-response habitual learning, respectively [1]. Prior research indicates that developmental experience alters neural circuitry, as evidenced by changes in evoked responses within the granule and molecular layers of the dorsal HPC [2]. As such, we hypothesize that the parallel development of these two systems, HPC and STR, is critical for balancing their respective influence in adult learning and behavior.

Methods: This study aims to perturb development of the HPC and evaluate the impact on synaptic efficacy and subsequently, adult learning and cognition. Ultimately, we aim to investigate the specific timing of synaptic changes associated with learning in the HPC and STR to understand their dominance, compensation, and interactions during different learning processes in various stages of development. Our current work pilots electrophysiology and chemogenetics, Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), to establish the methodologies we will use in our studies.

Results: We used anesthetized recordings to examine evoked local field potential (LFP) responses in mice by adapting the original method from a 16-channel to a novel, 32-channel, recording probe. Confocal imaging suggests refining of DREADDs injection coordinates to better target silencing of the dorsal HPC. A chronic implant headcap was trialed, and our next steps include stimulating and recording an awake, behaving mouse with various behavioral assays.

Discussion: Our overarching work will provide insights into how the brain balances multiple memory systems during development and may have implications for understanding neurodevelopmental disorders affecting learning and memory.