Science Current Events | Science News | Brightsurf.com
 

Mapping neural networks to strengthen circadian rhythms

June 01, 2016

If you've ever felt groggy the morning after traversing time zones, you can thank the temporary mismatch between your body's 24-hour circadian rhythm and your new local time. In mammals, this rhythm is governed on a neuronal and hormonal level by the suprachiasmatic nucleus, a tiny region of the brain's nestled directly above the two optic nerves. But it's not just a long flight that can throw us out of whack. As we age, the suprachiasmatic nucleus, or SCN, tends to exhibit a weaker circadian rhythm, which can result in sleep disorders, metabolic syndrome and depression.

While the evidence behind this age-related weakening has been established in medical literature, the mechanisms behind it, and the connectivity structure of the neurons, have remained elusive. To better understand these neuronal and hormonal mechanisms and help develop potential treatments, researchers at the University of Shanghai for Science and Technology in China have conducted experimental analyses of the SCN's connections, with the goal of determining its degree of heterogeneity. This is a measure of how many "hub" nodes within a network connect to other nodes.

Networks, in general, consist of nodes and links. If the degree of heterogeneity in a network is high, these hubs link to many other nodes; if it's low, the network topology is considered "flat," and the difference between the hubs and the other nodes is small.

The SCN's master clock consists of about 20,000 neurons coupled together through neurotransmitters. Within this network, about 25 percent of the neurons are coupled together into a subgroup that receives light from the retina. The remaining 75 percent of the neurons are coupled to these neurons -- these subgroups are known, respectively, as the ventrolateral and dorsomedial subgroups.

In their current paper, which appears this week in CHAOS, from AIP Publishing, the researchers analytically mapped these connections in the SCN as four different types of networks ranging from low to high levels of heterogeneity. These were the all-to-all network, the Newman-Watts network, the Erdös-Rényi network and the Barabási-Albert scale-free network.

The researchers found that in the "all-to-all" network, which was the least heterogenous, the SCN tends to lose the circadian rhythm induced by the other three networks, making it the least likely network type. They also found that the amplitude, or wave-like crest, of the circadian rhythm is largest in the Barabási-Albert scale-free network.

"The experiments suggest that the SCN is a heterogeneous network, but so far the details of the network structure of the SCN haven't been discovered," said Changgui Gu, an associate professor at the University of Shanghai for Science and Technology.

According to Gu, if the network structure of the SCN were heterogenous, this could be used to strengthen the circadian rhythm through bifurcation theory, in which a small, smooth change made to a boundary value in a system causes a qualitative change in the network's pattern of arrangement.

Future research for Gu and his colleagues may involve collaborations with medical researchers to develop drugs that can strengthen the SCN network's heterogeneity to counteract the weakening effects of age.

###

The article, "The circadian rhythm induced by the heterogeneous network structure of the suprachiasmatic nucleus," is authored by Changgui Gu and Hujie Yang. It appears in the journal CHAOS on May 31, 2016 (DOI: 10.1063/1.4949012). After that date, it can be accessed at: http://scitation.aip.org/content/aip/journal/chaos/26/5/10.1063/1.4949012.

ABOUT THE JOURNAL

CHAOS is devoted to increasing the understanding of nonlinear phenomena in all disciplines and describing their manifestations in a manner comprehensible to researchers from a broad spectrum of disciplines. See http://chaos.aip.org.

American Institute of Physics


Related Circadian Rhythm Current Events and Circadian Rhythm News Articles


New findings linking abnormalities in circadian rhythms to neurochemical to changes in specific neurotransmitters
Results of the first study of its kind to link abnormalities in circadian rhythms to changes in specific neurotransmitters in people with bipolar disorder will be published this week in the journal Biological Psychiatry.

Powering up the circadian rhythm
At noon every day, levels of genes and proteins throughout your body are drastically different than they are at midnight.

Rhythm of 'detox' and feeding genes in fruitflies and mice coordinated by neuropeptide
A 24-hour rhythm of cellular detoxification in flies and mammals is coordinated by a neuropeptide that also drives feeding in both organisms, found a team led by Amita Sehgal, PhD, a professor of Neuroscience and director of the Chronobiology Program, in the Perelman School of Medicine at the University of Pennsylvania.

New findings explain the connection between melatonin and type 2 diabetes
A new experimental and clinical study from Lund University in Sweden shows that the sleep hormone melatonin impairs insulin secretion in people with a common gene variant.

New study illuminates key aspects of how we fall asleep and wake up
Falling asleep and waking up are key transitions in everyone's day. Millions of people have trouble with these transitions - they find it hard to fall asleep or stay asleep at night, and hard to stay awake during the day.

Altered circadian rhythm worsens Parkinson's disease, Temple researchers show
Chronic lack of sleep and irregular sleep-wake cycles may be risk factors of Parkinson's disease, new work by researchers at the Lewis Katz School of Medicine at Temple University (LKSOM) suggests. In an animal model, the researchers show that disturbances in circadian rhythm that exist before Parkinson's onset dramatically worsen motor and learning deficits brought on by the disease.

Is being a morning person in your DNA?
23andMe, Inc., the leading personal genetics company, today announced the results of one of the largest genome-wide association studies of its kind, identifying genetic variants associated with being a morning person.

Sleep disturbance in epilepsy: Causes and consequences
Researchers are only beginning to understand the implications of disrupted sleep in people with epilepsy.

Gravity, who needs it?
What happens to your body in space? NASA's Human Research Program has been unfolding answers for over a decade.

UCI study finds jet lag-like sleep disruptions spur Alzheimer's memory, learning loss
Chemical changes in brain cells caused by disturbances in the body's day-night cycle may be a key underlying cause of the learning and memory loss associated with Alzheimer's disease, according to a University of California, Irvine study.
More Circadian Rhythm Current Events and Circadian Rhythm News Articles

Circadian Rhythms: A Very Short Introduction (Very Short Introductions)

Circadian Rhythms: A Very Short Introduction (Very Short Introductions)
by Russell Foster (Author), Leon Kreitzman (Author)


The earth's daily rotation affects just about every living creature. From dawn through to dusk, there are changes in light, temperature, humidity, and rainfall. However, these changes are regular, rhythmic and, therefore, predictable. Thus, the near 24 hour circadian rhythm is innate: a genetically programmed clock that essentially ticks of its own accord.

This Very Short Introduction explains how organisms can "know" the time and reveals what we now understand of the nature and operation of chronobiological processes. Covering variables such as light, the metabolism, human health, and the seasons, Foster and Kreitzman illustrate how jet lag and shift work can impact on human well-being, and consider circadian rhythms alongside a wide range of disorders, from schizophrenia to...

Rhythms of Life: The Biological Clocks that Control the Daily Lives of Every Living Thing

Rhythms of Life: The Biological Clocks that Control the Daily Lives of Every Living Thing
by Russell G. Foster (Author), Leon Kreitzman (Author)


Why can’t teenagers get out of bed in the morning? How do bees tell the time? Why do some plants open and close their flowers at the same time each day? Why do so many people suffer the misery of jet lag? In this fascinating book, Russell Foster and Leon Kreitzman explain the significance of the biological clock, showing how it has played an essential role in evolution and why it continues to play a vitally important role in all living organisms.The authors tell us that biological clocks are embedded in our genes and reset at sunrise and sunset each day to link astronomical time with an organism’s internal time. They discuss how scientists are working out the clockwork mechanisms and what governs them, and they describe how organisms measure different intervals of time, how they are...

The Adrenal Reset Diet: Strategically Cycle Carbs and Proteins to Lose Weight, Balance Hormones, and Move from Stressed to Thriving

The Adrenal Reset Diet: Strategically Cycle Carbs and Proteins to Lose Weight, Balance Hormones, and Move from Stressed to Thriving
by Alan Christianson NMD (Author), Sara Gottfried MD (Foreword)


GO FROM WIRED AND TIRED TO LEAN AND THRIVING…
 
   Why are people gaining weight faster than ever before?  The idea that people simply eat too much is no longer supported by science.  The emerging idea is that weight gain is a survival response.  Our bodies are under attack from all directions—an overabundance of processed food, a polluted world, and the pressures of daily life all take their toll.  These attacks hit a little known but very important set of glands, the adrenals, particularly hard. 
   One of their many jobs is to maintain a normal cortisol rhythm (cortisol is a hormone associated with both stress and fat storage).  When this rhythm is off, we can become overwhelmed more quickly, fatigued, gain weight, and eventually, develop even more severe...

Reset Your Inner Clock: The Drug-Free Way to Your Best-Ever Sleep, Mood, and Energy

Reset Your Inner Clock: The Drug-Free Way to Your Best-Ever Sleep, Mood, and Energy
by Michael Terman Ph.D. (Author), Ian McMahan Ph.D. (Author)


Sleep problems and depressed mood go hand in hand, forming a frustrating cycle. Michael Terman has analyzed the brain functions that feed these disorders. In Reset Your Inner Clock, he reveals the heart of his findings, a powerful program that recalibrates our internal clocks--our exquisitely designed sensitivity to the timing and brightness of light exposure. He shows how these need to be tuned to the modern demands of a 24/7 society.

Beginning with a questionnaire that pinpoints the problem areas, Terman helps readers decipher when their natural internal night begins and ends. The treatment process then begins, incorporating the power of natural light with supplemental light therapy. His program has brought relief to thousands of sleep sufferers, as well as those burdened by...

The Circadian Prescription: Get in Step with Your Body's Natural Rhythms

The Circadian Prescription: Get in Step with Your Body's Natural Rhythms
by Sidney MacDonald Baker (Author), Karen Baar (Author)


The first book to provide an easy-to-follow dietary and lifestyle program to enhance the body's natural rhythms for optimum health.

All living things are subject to natural patterns of eating, sleeping, and other vital functions. Disrupting these daily, or circadian, rhythms through poor diet or lifestyle results in a wide range of conditions, from fatigue and emotional imbalance to intensified symptoms of insulin resistance and other chronic health problems.

The Circadian Prescription offers a breakthrough, scientifically sound 10-point program to help anyone:

sleep better and feel energized all day long;
alleviate symptoms of menopause, jet lag, and ADD;
treat and prevent infertility, prostate disease, and Syndrome X;
enhance mental acuity and...

Why Isn't My Brain Working?: A Revolutionary Understanding of Brain Decline and Effective Strategies to Recover Your Brain's Health

Why Isn't My Brain Working?: A Revolutionary Understanding of Brain Decline and Effective Strategies to Recover Your Brain's Health
by Dr. Datis Kharrazian (Author)


Losing your memory? Can't focus or concentrate? Do you have brain fog or tire easily? Have you lost your zest for life or motivation? Do people tell you this is all a normal part of aging? If so, your brain may be growing old too fast, or degenerating. Modern diets, a stressful lifestyle, and environmental toxins all take their toll on the brain. This doesn't just happen to seniors-brain disorders and degeneration are on the rise for young and old alike. The good news is the brain is extremely adaptable and wants to get well. You simply have to know how to feed and care for your brain. How do you know if your brain isn't working? See if some of these signs and symptoms of brain degeneration apply to you: Memory loss • brain fog • depression • anxiety • difficulty learning • lack...

Chronotherapy: Resetting Your Inner Clock to Boost Mood, Alertness, and Quality Sleep

Chronotherapy: Resetting Your Inner Clock to Boost Mood, Alertness, and Quality Sleep
by Michael Terman Ph.D. (Author), Ian McMahan Ph.D. (Author)


An enlightened approach to insomnia, depressed mood, fatigue, and other sleep-related problems of everyday life, harnessing the power of light therapy to reset the natural clock.

Sleep problems and depressed mood often go hand in hand, forming a frustrating cycle. Michael Terman, PhD, has devoted his career to studying the brain functions that feed these disorders. His discoveries in chronotherapy have been widely recognized as game-changers by the medical establishment, and his 2010 New York Times op-ed, “Sleeping (or Not) by the Wrong Clock,” shot to number one on the paper’s list of most-forwarded online articles. In Chronotherapy, Terman and McMahan reveal the heart of his findings, a powerful program that recalibrates our internal clocks—our exquisitely designed,...

Internal Time: Chronotypes, Social Jet Lag, and Why You're So Tired

Internal Time: Chronotypes, Social Jet Lag, and Why You're So Tired
by Till Roenneberg (Author)


Early birds and night owls are born, not made. Sleep patterns may be the most obvious manifestation of the highly individualized biological clocks we inherit, but these clocks also regulate bodily functions from digestion to hormone levels to cognition. Living at odds with our internal timepieces, Till Roenneberg shows, can make us chronically sleep deprived and more likely to smoke, gain weight, feel depressed, fall ill, and fail geometry. By understanding and respecting our internal time, we can live better. Internal Time combines storytelling with accessible science tutorials to explain how our internal clocks work-for example, why morning classes are so unpopular and why "lazy" adolescents are wise to avoid them. We learn why the constant twilight of our largely indoor lives makes us...

Circadian Physiology, Third Edition

Circadian Physiology, Third Edition
by Roberto Refinetti PhD. (Author)


Biological processes that repeat themselves every 24 hours within a biological system are called circadian rhythms. Circadian rhythms are generated by the circadian clock, which affects the operation of practically every function in the body. Now in its third edition, this book presents the latest information on basic research in circadian biology and its applications in business and medicine. The book reviews the history of the field, explains  classical and novel research methods,  explores behavioral, physiological, and ecological processes, and describes neural and molecular mechanisms  of circadian rhythmicity. It also examines applications in the selection of the optimal timing for work and play, prevention of jet lag, avoidance of the shift-work malaise, and treatment of sleep...

Sleep, Circadian Rhythms, and Metabolism: The Rhythm of Life

Sleep, Circadian Rhythms, and Metabolism: The Rhythm of Life
by William Olds (Editor)


This title includes a number of Open Access chapters. Providing a nuanced study of the connections between sleep, circadian rhythms, and metabolis, this informative book examines how circadian actions affect the liver and adipose tissue, the brain, and metabolism. This important book introduces the reader to circadian rhythms in the body and the external cues that set them, discusses on a molecular and organ level how disrupting these clocks results in metabolic and sleep disorders, and looks at the clinical applications of circadian rhythms, with a focus on sleep. The book covers a variety of important research in the field, including: • The power of computational biology to uncover new nodes in the network of circadian rhythms • Circadian rhythms as they relates to obesity • How...

© 2017 BrightSurf.com