# The role of novelty and surprise in aversive conditioning

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2023 · $581,472

## Abstract

Abstract
Novelty and surprise have long been known to facilitate learning and memory. At a functional level this makes sense;
unexpected events have to be learned about so they can be predicted and responded to appropriately in the future. At a
psychological level, surprising events have been shown to enhance memory because they induce rehearsal. Subjects tend
to “think about” unexpected events more than familiar ones after they occur. This has been observed directly in humans
(explicit rehearsal) and indirectly in animals (implicit rehearsal). In both cases, the memory enhancement can be
eliminated by disrupting rehearsal with a distractor stimulus that is presented immediately after the novel event.
Presenting the same distractor stimulus several minutes later has no effect. This suggests rehearsal is short-lasting and
distinct from the process of memory consolidation, which stabilizes new information for several hours after learning. In
addition to increasing rehearsal, novel events also trigger the release of norepinephrine (NE) and dopamine (DA), which
are known to enhance synaptic plasticity. Blocking receptors for these neuromodulators in the hippocampus prevents
animals from forming new spatial and contextual memories. Based on these findings, we hypothesize that surprising
events enhance memory because they induce catecholamine release at the same time the hippocampus is actively
rehearsing/replaying new information. Our preliminary data demonstrate that NE and DA are both released in the
hippocampus during and after the presentation of an unexpected aversive stimulus. At the same time, there is an increase
in sharp-wave ripple oscillations (SWRs), which are known to contain replay sequences for recently encountered stimuli.
Consequently, we will test the hypothesis above by monitoring and manipulating catecholamine release in real-time
during an aversive learning task while simultaneously recording oscillations and single unit activity in the hippocampus.

## Key facts

- **NIH application ID:** 10682277
- **Project number:** 1R01NS129217-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Brian J Wiltgen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $581,472
- **Award type:** 1
- **Project period:** 2023-08-01 → 2027-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10682277

## Citation

> US National Institutes of Health, RePORTER application 10682277, The role of novelty and surprise in aversive conditioning (1R01NS129217-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10682277. Licensed CC0.

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