# Cortical ensemble coding and circuit dynamics of fear suppression

> **NIH NIH K01** · UNIVERSITY OF VERMONT & ST AGRIC COLLEGE · 2021 · $162,751

## Abstract

Project Summary
Traumatic experiences, such as combat exposure or sexual/physical abuse can lead to the development of
post-traumatic stress disorder (PTSD). Patients with PTSD often show generalized fear to non-dangerous or
“safe” stimuli, and have difficulty learning that a previously threatening stimulus is now safe. Although impaired
safety learning is a suggested biomarker of PTSD, the precise mechanisms that underlie this impairment are
unclear. Notably, human imaging studies have revealed hypoactivity of the ventromedial prefrontal cortex
(vmPFC) and retrosplenial cortex (RSC) in patients with PTSD (Hayes et al., 2012; Pissiota et al., 2002)
suggesting the possibility that vmPFC – RSC dysfunction might underlie impairments in safety learning
observed in patients with PTSD. Consistent with a role for the RSC in safety learning, a recent study from our
lab found that permanent damage of the RSC specifically impairs safety learning (Todd et al., 2016a; see also
Gabriel, Sparenborg, & Stolar, 1987). Nevertheless, although the RSC has a putative role in processing safety
cues, little is known about how cell populations within the RSC encode safety, or the nature of RSC – vmPFC
interaction during safety learning.
In this project, large-scale single unit ensemble recording and analysis, and local field recordings and analysis,
will be combined with chemogentics and learning-theory based behavioral analysis to investigate vmPFC –
RSC circuitry in the control of safety learning and behavior. The proposed experiments will therefore establish
how cortical ensembles encode safety, and explore interaction between the vmPFC and RSC during two forms
of safety learning. Thus, the proposed research is significant in that it will yield a detailed understanding of the
mechanisms underlying safety learning, ultimately informing the link between cortical dysfunction and mental
illness, including PTSD.
In addition to its significance, the current project will provide the trainee with an excellent opportunity to master
in vivo electrophysiological recordings and analysis in freely behaving rats. The trainee intends to use this
technique, combined with chemogenetic manipulation of neural activity to establish an independent line of
research probing the neural circuits underlying learning, memory, and behavior. In addition, the proposed
award will ensure the trainee acquires the professional skill necessary to reach his career goals. This training
will take place at Dartmouth College, an exceptional research and teaching intuition, under the guidance of an
established team of mentors as well as an external advisory committee comprised of luminaries in the fields of
behavioral neuroscience and PTSD research. This proposal is well-designed to provide Dr. Todd with the
continued career development necessary to establish himself as an independent investigator and leader in the
field.

## Key facts

- **NIH application ID:** 10417340
- **Project number:** 7K01MH116158-04
- **Recipient organization:** UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
- **Principal Investigator:** Travis Todd
- **Activity code:** K01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $162,751
- **Award type:** 7
- **Project period:** 2021-07-01 → 2022-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10417340

## Citation

> US National Institutes of Health, RePORTER application 10417340, Cortical ensemble coding and circuit dynamics of fear suppression (7K01MH116158-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10417340. Licensed CC0.

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