# Circuit Dynamics for encoding and remembering sequence of events

> **NIH NIH K99** · UNIVERSITY OF WASHINGTON · 2021 · $78,705

## Abstract

Project Summary
We experience the world as a continuous sequence of events, but we remember the events as
segmented episodes (e.g., my sister’s wedding). During encoding, we associate a sequence of relevant
events and segment deviant events. At retrieval, episodic memory utilizes the encoded associations to
replay the flow of events. The encoded associations lead to remembering the sequence of events that
occurred within an episode better than the flow of events across segments. The hippocampus and the
prefrontal cortices (PFC) are essential parts of the neural circuit for segmenting, linking and retrieving
memories of associated events.
This proposal aims to identify neural dynamics in the hippocampus-PFC circuit that support encoding a
naturalistic flow of events, i.e., sequences of words. We will determine the neural dynamics using
intracranial encephalography (iEEG) acquired from the hippocampus and PFC of epileptic patients, who
have electrodes implemented for pre-surgical seizure monitoring. Our experiment requires patients to
listen to a narrative and later recall the flow of events. During the past year, I developed a Natural
Language Processing (NLP) algorithm that quantifies the associations of words depending on the
narrative context. I will use NLP model for annotation of the iEEG data to determine neural dynamics
engaged during encoding sequences of words.
Our research program (mainly data collection), like all other human subject research, has been
significantly affected by the COVID mitigation efforts. We were not able to collect the required iEEG data
to fulfill the aims of the planned K99 phase during the past year. With the vaccination of researchers and
medical staff and screening of patients before the hospitalization, our data collection program is
reopening with considerations. The extension to the K99 will allow us to catch up with the data collection
that is required for the planned training on advanced data analysis.
The central hypotheses are that bidirectional communications between the hippocampus and PFC
support the encoding of sequences of events and successful subsequent memory. To address a causal
relationship between hippocampal function and event segmentation, I will study speech comprehension
and speech memory in developmental amnesic patients who suffer from hippocampal damage and have
trouble tracking reference points in a speech. The combination of iEEG, NLP modeling, and patients’
behavioral data will provide valuable insights into the neural dynamics of effective speech encoding that
predicts subsequent memory, which may inform development into therapeutic interventions.

## Key facts

- **NIH application ID:** 10375038
- **Project number:** 3K99MH120048-02S1
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Anna Jafarpour
- **Activity code:** K99 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $78,705
- **Award type:** 3
- **Project period:** 2019-04-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10375038

## Citation

> US National Institutes of Health, RePORTER application 10375038, Circuit Dynamics for encoding and remembering sequence of events (3K99MH120048-02S1). Retrieved via AI Analytics 2026-06-23 from https://api.ai-analytics.org/grant/nih/10375038. Licensed CC0.

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