# Function of biphasic sleep in infants

> **NIH NIH R01** · UNIVERSITY OF MASSACHUSETTS AMHERST · 2024 · $393,197

## Abstract

PROJECT SUMMARY
Sleep is critical for infant physical and cognitive development and yet understanding sleep time and timing is a
source of stress to parents and families. Thus a better understanding of when infants sleep, specifically the
transition from two to one naps, will support infant cognitive development and contribute to guidance for families.
The objective of the proposed research is to examine, longitudinally, the role of multiple sleep bouts in memory
consolidation across the triphasic to biphasic sleep transition in infancy. The overarching hypothesis is that naps
maintain their usefulness across these transitions, but that multiple naps become less essential to the
preservation of memories as infants naturally transition to one nap per day. More specifically, it is predicted that
memories can be held longer without interference as the child develops across this age range, making the
morning nap less essential to memory while the afternoon nap remains essential. Participants will be 100 infants,
who will complete 2 sessions, a sleep and a wake session, every three months (9, 12, and, 15 months). A
deferred imitation task will be used to assess nap-related changes in memory consolidation. Actigraphy will be
used to objectively assess nap habituality. Polysomnography will be used to understand the physiological
mechanism underlying memory benefits and it will also provide a proxy for brain development. Collectively, the
work will (1) assess memory consolidation over morning and afternoon nap intervals across the triphasic to
biphasic sleep transition in infants; (2) examine the mechanism supporting declarative memory consolidation in
infancy; and (3) establish the developmental trajectory of key sleep physiology features within naps across this
developmental age range. An exploratory aim will examine whether changes in estimated brain development
predict the triphasic to biphasic sleep transition. The outcomes have theoretical significance. These results will
be significant for the field of sleep research, providing critical insight into development of sleep regulation
processes and longitudinal changes in sleep patterns. Additionally, results will be informative to developmental
scientists, suggesting that the timing of studies will contribute to performance. The outcomes also have
translational significance. A better understanding of nap transitions will inform pediatricians and parents as they
make recommendations and decisions about infant sleep and allow for identification of infants with abnormal
sleep development trajectories.

## Key facts

- **NIH application ID:** 10881777
- **Project number:** 5R01HL169995-02
- **Recipient organization:** UNIVERSITY OF MASSACHUSETTS AMHERST
- **Principal Investigator:** Rebecca M C Spencer
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $393,197
- **Award type:** 5
- **Project period:** 2023-07-05 → 2028-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10881777

## Citation

> US National Institutes of Health, RePORTER application 10881777, Function of biphasic sleep in infants (5R01HL169995-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10881777. Licensed CC0.

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