# A raphe-hippocampus pathway for regulation of memory specificity during consolidation

> **NIH NIH R01** · DREXEL UNIVERSITY · 2021 · $388,680

## Abstract

PROJECT SUMMARY/ABSTRACT
Newly formed memories are fragile and need to go through a process before they become stabilized
and resistant to interference. This process is known as memory consolidation that takes days, weeks
or even longer. Therefore, multiple memory traces are inevitably consolidated in parallel, as animals
continuously form new memories of everyday life. However, it is unclear how memory specificity is
maintained during the consolidation process. The current proposal aims to directly address how
recently formed episodic memories are properly consolidated, and how dysregulated consolidation
processes result in intermixed or overgeneralized memories. Converging evidence suggests that
hippocampal sharp-wave ripple activity, which primarily occurs during slow-wave sleep and immobility,
is critical for consolidation of episodic memory. Ripple activity refers to a fast (~200 Hz) field oscillation
and is believed to be associated with reactivation of the recently formed memories. Growing studies
support the notion that hippocampal ripples communicate with the neocortex including the anterior
cingulate cortex (ACC) for transformation of short-term memory (hippocampus-dependent) into long-
term memory (neocortex-dependent). We recently discovered that a subcortical region, the median
raphe (MnR), plays a key role in regulation of hippocampal ripple activity and likely the ripple–ACC
information exchange. A distinct population of MnR neurons increases firing at the termination of ripple
events and pauses future ripple occurrence for regulation of the consolidation process. The central
objective of this study is to test our hypothesis that MnR activity prevents different memories from
intermixing by separating ripples, as well as ripple–ACC exchanged contents during the consolidation
process. Supported by considerable preliminary data, we propose to pursue this objective through the
following three specific aims. Aim 1 investigates the identity of the MnR neurons that regulate
hippocampal ripple activity. Aim 2 investigates how physiological MnR activity regulates information
exchange between the hippocampus and ACC, and how disrupted MnR activity may lead to intermixed
memory associated with distinct contexts and emotions. Aim 3 investigates if the ACC sends feedback
signals to the hippocampus via the MnR for regulation of memory consolidation. Results from this
study will advance our understanding of memory formation associated circuits, and notably, reveal a
new MnR–hippocampus–ACC circuitry for controlling memory specificity during consolidation. This
could provide insight for improvement of memory and intervention into overgeneralized memory
disorders such as the post-traumatic stress disorder (PTSD).

## Key facts

- **NIH application ID:** 10073352
- **Project number:** 5R01MH119102-03
- **Recipient organization:** DREXEL UNIVERSITY
- **Principal Investigator:** DONG WANG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $388,680
- **Award type:** 5
- **Project period:** 2019-02-15 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10073352

## Citation

> US National Institutes of Health, RePORTER application 10073352, A raphe-hippocampus pathway for regulation of memory specificity during consolidation (5R01MH119102-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10073352. Licensed CC0.

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