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

> **NIH NIH R01** · DREXEL UNIVERSITY · 2021 · $40,928

## Abstract

PROJECT SUMMARY/ABSTRACT
Hippocampal-neocortical interaction during sleep is critical for consolidation of newly acquired
information into long-term memory. There is substantial amount of evidence supporting that neocortical
regions including the anterior cingulate cortex (ACC) store long-term memories. However, it remains
unclear how the hippocampus, particularly the dorsal hippocampus (dHPC), communicates with the
ACC during the memory consolidation process – one main objective of the PI’s R01 grant. One puzzle
and challenge we face is that there is almost no direct projection from the dHPC to ACC, or vice versa;
thus, the dHPC communicates with the ACC via a relay region, likely the retrosplenial cortex (RSC)
which receives a dense projection from the dHPC and is reciprocally connected with the ACC. This
Supplements proposal intends to extent the PI’s R01 project by investigating dHPC–RSC interactions
as a potential mechanism underlying memory consolidation. Our preliminary results revealed that a
subset of RSC layer 5 neurons (~25%), termed ‘silent assembly’, display a high probability of activation
during short periods of cortical silence and precedes the activity of other RSC neurons, ACC neurons,
and dHPC neurons. The central objective here is to test our hypothesis that a coordinated dHPC–RSC
communication at the assembly level is critical for memory consolidation: first, activation of RSC layer 5
silent assembly during cortical silence initiates the memory consolidation process; second, dHPC
assembly sends information to the RSC layer 2/3 for transforming hippocampus-dependent memory
into cortex-dependent memory. Supported by considerable preliminary data, we propose to pursue this
objective through the following three specific aims. Aim 1 investigates the input that drives the RSC
silent assembly activity during cortical silence. Aim 2 investigates a causal relationship between RSC
silent assembly activity and memory consolidation. Aim 3 investigates how the communication of dHPC
and RSC assemblies evolve after a new learning experience. Results from this study will advance our
understanding of memory formation associated circuits and provide new insight into the mechanism of
initiation of memory consolidation. Meanwhile this study will provide the candidate an excellent
opportunity to master advanced data analysis and visualization skills that are critical for understanding
dynamic brain region interactions and information exchanges.

## Key facts

- **NIH application ID:** 10240905
- **Project number:** 3R01MH119102-03S1
- **Recipient organization:** DREXEL UNIVERSITY
- **Principal Investigator:** DONG WANG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $40,928
- **Award type:** 3
- **Project period:** 2019-02-15 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10240905

## Citation

> US National Institutes of Health, RePORTER application 10240905, A raphe-hippocampus pathway for regulation of memory specificity during consolidation (3R01MH119102-03S1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10240905. Licensed CC0.

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