Chronic Circadian Misalignment without Circadian Arrhythmicity or Sleep Deprivation Does Not Impair Adult Hippocampal Neurogenesis

Phan Q. Duy, Samer Hattar

Research output: Contribution to journalLetter

Abstract

Artificial light in modern society has led to the ubiquity of light exposure at night as individuals work night shifts and use light-emitting electronic devices before bedtime. These aberrant light conditions have detrimental consequences on cognitive and mental health, compelling the need to understand the mechanisms by which light affects brain functions. Although it was believed that aberrant light impairs health by first disrupting circadian rhythms and sleep, we showed that chronic exposure to a light cycle termed T7 (3.5 h of darkness, 3.5 h of light) caused mood and learning dysfunction in adult mice independent of sleep deprivation or circadian arrhythmicity, suggesting the direct effects of aberrant light on brain function. However, the mechanisms by which light directly causes mood and learning dysfunction remain poorly understood. In this study, we sought to determine whether exposure to the T7 cycle disrupts adult hippocampal neurogenesis, given that suppressed neurogenesis has been correlated with mood and learning dysfunction. After exposing adult mice to the T7 light cycle, we analyzed adult hippocampal neurogenesis by examining cellular proliferation and number of adult-born neurons. Contrary to our hypothesis that T7 would suppress neurogenesis, we found that adult mice exposed to 2 or 10 weeks of the T7 light cycle did not exhibit deficits in hippocampal neurogenesis. Our findings suggest that the direct effects of light on mood and learning do not depend on adult hippocampal neurogenesis.

Original languageEnglish (US)
Pages (from-to)621-626
Number of pages6
JournalJournal of Biological Rhythms
Volume32
Issue number6
DOIs
StatePublished - Dec 1 2017

Fingerprint

Sleep Deprivation
Neurogenesis
Light
Photoperiod
Learning
Darkness
Brain
Circadian Rhythm
Mental Health
Sleep
Cell Proliferation
Neurons
Equipment and Supplies

Keywords

  • hippocampus
  • learning
  • light
  • mood
  • neurogenesis

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Chronic Circadian Misalignment without Circadian Arrhythmicity or Sleep Deprivation Does Not Impair Adult Hippocampal Neurogenesis. / Duy, Phan Q.; Hattar, Samer.

In: Journal of Biological Rhythms, Vol. 32, No. 6, 01.12.2017, p. 621-626.

Research output: Contribution to journalLetter

@article{e2a12191c7c6484bad7e9eb9795b65e4,
title = "Chronic Circadian Misalignment without Circadian Arrhythmicity or Sleep Deprivation Does Not Impair Adult Hippocampal Neurogenesis",
abstract = "Artificial light in modern society has led to the ubiquity of light exposure at night as individuals work night shifts and use light-emitting electronic devices before bedtime. These aberrant light conditions have detrimental consequences on cognitive and mental health, compelling the need to understand the mechanisms by which light affects brain functions. Although it was believed that aberrant light impairs health by first disrupting circadian rhythms and sleep, we showed that chronic exposure to a light cycle termed T7 (3.5 h of darkness, 3.5 h of light) caused mood and learning dysfunction in adult mice independent of sleep deprivation or circadian arrhythmicity, suggesting the direct effects of aberrant light on brain function. However, the mechanisms by which light directly causes mood and learning dysfunction remain poorly understood. In this study, we sought to determine whether exposure to the T7 cycle disrupts adult hippocampal neurogenesis, given that suppressed neurogenesis has been correlated with mood and learning dysfunction. After exposing adult mice to the T7 light cycle, we analyzed adult hippocampal neurogenesis by examining cellular proliferation and number of adult-born neurons. Contrary to our hypothesis that T7 would suppress neurogenesis, we found that adult mice exposed to 2 or 10 weeks of the T7 light cycle did not exhibit deficits in hippocampal neurogenesis. Our findings suggest that the direct effects of light on mood and learning do not depend on adult hippocampal neurogenesis.",
keywords = "hippocampus, learning, light, mood, neurogenesis",
author = "Duy, {Phan Q.} and Samer Hattar",
year = "2017",
month = "12",
day = "1",
doi = "10.1177/0748730417736960",
language = "English (US)",
volume = "32",
pages = "621--626",
journal = "Journal of Biological Rhythms",
issn = "0748-7304",
publisher = "SAGE Publications Inc.",
number = "6",

}

TY - JOUR

T1 - Chronic Circadian Misalignment without Circadian Arrhythmicity or Sleep Deprivation Does Not Impair Adult Hippocampal Neurogenesis

AU - Duy, Phan Q.

AU - Hattar, Samer

PY - 2017/12/1

Y1 - 2017/12/1

N2 - Artificial light in modern society has led to the ubiquity of light exposure at night as individuals work night shifts and use light-emitting electronic devices before bedtime. These aberrant light conditions have detrimental consequences on cognitive and mental health, compelling the need to understand the mechanisms by which light affects brain functions. Although it was believed that aberrant light impairs health by first disrupting circadian rhythms and sleep, we showed that chronic exposure to a light cycle termed T7 (3.5 h of darkness, 3.5 h of light) caused mood and learning dysfunction in adult mice independent of sleep deprivation or circadian arrhythmicity, suggesting the direct effects of aberrant light on brain function. However, the mechanisms by which light directly causes mood and learning dysfunction remain poorly understood. In this study, we sought to determine whether exposure to the T7 cycle disrupts adult hippocampal neurogenesis, given that suppressed neurogenesis has been correlated with mood and learning dysfunction. After exposing adult mice to the T7 light cycle, we analyzed adult hippocampal neurogenesis by examining cellular proliferation and number of adult-born neurons. Contrary to our hypothesis that T7 would suppress neurogenesis, we found that adult mice exposed to 2 or 10 weeks of the T7 light cycle did not exhibit deficits in hippocampal neurogenesis. Our findings suggest that the direct effects of light on mood and learning do not depend on adult hippocampal neurogenesis.

AB - Artificial light in modern society has led to the ubiquity of light exposure at night as individuals work night shifts and use light-emitting electronic devices before bedtime. These aberrant light conditions have detrimental consequences on cognitive and mental health, compelling the need to understand the mechanisms by which light affects brain functions. Although it was believed that aberrant light impairs health by first disrupting circadian rhythms and sleep, we showed that chronic exposure to a light cycle termed T7 (3.5 h of darkness, 3.5 h of light) caused mood and learning dysfunction in adult mice independent of sleep deprivation or circadian arrhythmicity, suggesting the direct effects of aberrant light on brain function. However, the mechanisms by which light directly causes mood and learning dysfunction remain poorly understood. In this study, we sought to determine whether exposure to the T7 cycle disrupts adult hippocampal neurogenesis, given that suppressed neurogenesis has been correlated with mood and learning dysfunction. After exposing adult mice to the T7 light cycle, we analyzed adult hippocampal neurogenesis by examining cellular proliferation and number of adult-born neurons. Contrary to our hypothesis that T7 would suppress neurogenesis, we found that adult mice exposed to 2 or 10 weeks of the T7 light cycle did not exhibit deficits in hippocampal neurogenesis. Our findings suggest that the direct effects of light on mood and learning do not depend on adult hippocampal neurogenesis.

KW - hippocampus

KW - learning

KW - light

KW - mood

KW - neurogenesis

UR - http://www.scopus.com/inward/record.url?scp=85038369354&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85038369354&partnerID=8YFLogxK

U2 - 10.1177/0748730417736960

DO - 10.1177/0748730417736960

M3 - Letter

C2 - 29129126

AN - SCOPUS:85038369354

VL - 32

SP - 621

EP - 626

JO - Journal of Biological Rhythms

JF - Journal of Biological Rhythms

SN - 0748-7304

IS - 6

ER -