# Neural circuitry and functional significance of extra-SCN pacemakers

> **NIH NIH R01** · UT SOUTHWESTERN MEDICAL CENTER · 2020 · $384,225

## Abstract

Project Summary
Circadian rhythms are fundamental to living organisms. The mammalian circadian system, which controls daily
rhythms of behavior and physiology, is a multi-oscillatory system composed of a master pacemaker in the
hypothalamic suprachiasmatic nucleus (SCN) and many other oscillators in peripheral organs. However, the
SCN is not the only pacemaker. When arousing stimuli are present, circadian behavior rhythms are observed
even when circadian clocks in the SCN and peripheral tissues are disabled. The molecular mechanisms,
anatomical loci, and functional significance of these extra-SCN pacemakers are not known. We have
assembled molecular and imaging toolsets and technologies to identify the neural circuitry and physiological
outputs of those extra-SCN pacemakers. The proposed studies will uncover the functional significance of the
enigmatic extra-SCN circadian pacemakers in mammals.
The discovery of the loci and physiological roles of the extra-SCN pacemakers will expand our understanding
of the molecular and physiological processes of the circadian system. Importantly, our studies will investigate
how the SCN and extra-SCN pacemakers interact to regulate feeding and sleep. Disruption of circadian
rhythms and sleep by shiftwork and exposure to artificial light at night increases the risk of human diseases. In
addition, sleep and circadian rhythms are impaired in several neurological disorders and in persons with drug
addictions. Therefore, understanding how extra-SCN pacemakers control circadian rhythms will elucidate novel
processes that could be manipulated to manage circadian disruption in humans.

## Key facts

- **NIH application ID:** 10051362
- **Project number:** 1R01NS114527-01A1
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **Principal Investigator:** SHIN YAMAZAKI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $384,225
- **Award type:** 1
- **Project period:** 2020-09-15 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10051362

## Citation

> US National Institutes of Health, RePORTER application 10051362, Neural circuitry and functional significance of extra-SCN pacemakers (1R01NS114527-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10051362. Licensed CC0.

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