Identifying Brain Cells That Keep Us Awake
Researchers at UCLA have identified the group of neurons that mediates whether light arouses us or not.
TBL1X Gene Involved In Autism Spectrum Disorder
An X-chromosome-wide association study in autism families identifies TBL1X as a novel autism spectrum disorder candidate gene in males.
“Love Hormone” Helps Direct Development of Brain
Hormones released from nerves regulate a series of vital body processes, including the balance of fluids and uterine contractions in childbirth.
November 3, 2011--------News Archive
Steroids in Preemies Impair Brain Growth
Premature infants given drugs to support lung maturation and normalize blood pressure, are at increased risk for having impaired growth of the cerebellum.
Potential Treatment for Sickle Cell Disease
Increasing the expression of proteins TR2/TR4 can lead to higher fetal hemoglobin levels in sickle cell patients.
New Drug Shows Promise Against Multiple Sclerosis
A new drug targets a molecule - CD20 found on the surface of B cells and B cells seem to induce the immune system T cells to attack.
November 2, 2011--------News Archive
Babies Understand Each Other at Ten Months Old
At 10 months, babies start to understand another person’s thought process, providing new insights on how communication develops.
Bacteria Swap Genes Between Species Readily
Microbes have developed a quick and effective way to exchange genetic information from animals to humans.
Pinpointing Cause of Unexplained Miscarriage
The same kind of blood-clotting in coronary arteries or blood vessels in the brain which causes heart attacks and strokes also happens in the placenta.
November 1, 2011--------News Archive
Pregnant Mothers At Risk From Air Pollution
A Californian-based study has looked in detail at air quality and the impact of traffic-related air pollution on premature birth.
Linking A Spectrum of Childhood Diseases
An international collaboration of scientists has identified a genetic mutation causing a rare childhood disease characterized by inflammation and fat loss.
Placenta and Uterus Battle Becomes Preeclampsia
A battle brews in the mother’s womb between the father’s biological goal to produce the biggest, healthiest baby possible vs. the mother’s need to live through delivery.
October 31, 2011--------News Archive
Fetal Heart Rate Not a Good Indicator for Health
Maternal-fetal medicine specialists at Intermountain Medical Center seek better 'road map' to improve deliveries, healthier babies.
Swedish Discover Bisphenol A Affects Newborn Brain
An observed effect induced in neonatal baby mice after exposure to Bisphenol A, persisted into adulthood.
Not Your Mother's Birth Control
Today's hormonal forms of birth control are vastly different from those used by earlier generations of women, both with lower levels of hormones and with different means of delivery (not just a pill), but many of the same problems related to women's pleasure remain.
Bright light arouses us. Bright light makes it easier to stay awake. Very bright light not only arouses us but is known to have antidepressant effects. Conversely, dark rooms can make us sleepy. It's the reason some people use masks to make sure light doesn't wake them while they sleep.
Now researchers at UCLA have identified the group of neurons that mediates whether light arouses us or not. Jerome Siegel, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, and colleagues report in the current online edition of the Journal of Neuroscience that the cells necessary for a light-induced arousal response are located in the hypothalamus, an area at the base of the brain responsible for, among other things, control of the autonomic nervous system, body temperature, hunger, thirst, fatigue and sleep.
These cells release a neurotransmitter called hypocretin, Siegel said. The researchers compared mice with and without hypocretin and found that those who didn't have it were unable to stay awake in the light, while those who had it showed intense activation of these cells in the light but not while they were awake in the dark.
This same UCLA research group earlier determined that the loss of hypocretin was responsible for narcolepsy and the sleepiness associated with Parkinson's disease. But the neurotransmitter's role in normal behavior was, until now, unclear.
"This current finding explains prior work in humans that found that narcoleptics lack the arousing response to light, unlike other equally sleepy individuals, and that both narcoleptics and Parkinson's patients have an increased tendency to be depressed compared to others with chronic illnesses," said Siegel, who is also a member of the UCLA Brain Research Institute and chief of neurobiology research at the Sepulveda Veterans Affairs Medical Center in Mission Hills, Calif.
Prior studies of the behavioral role of hypocretin in rodents had examined the neurotransmitter's function during only light phases (normal sleep time for mice) or dark phases (their normal wake time), but not both. And the studies only examined the rodents when they were performing a single task.
In the current study, researchers examined the behavioral capabilities of mice that had their hypocretin genetically "knocked-out" (KO mice) and compared them with the activities of normal, wild-type mice (WT) that still had their hypocretin neurons. The researchers tested the two groups while they performed a variety of tasks during both light and dark phases.
Surprisingly, they found that the KO mice were only deficient at working for positive rewards during the light phase. During the dark phase, however, these mice learned at the same rate as their WT littermates and were completely unimpaired in working for the same rewards.
Consistent with the data in the KO mice, the activity of hypocretin neurons in their WT littermates was maximized when working for positive rewards during the light phase, but the cells were not activated when performing the same tasks in the dark phase.
"The findings suggest that administering hypocretin and boosting the function of hypocretin cells will increase the light-induced arousal response," Siegel said. "Conversely, blocking their function by administering hypocretin receptor blockers will reduce this response and thereby induce sleep."
Further, Siegel noted, "The administration of hypocretin may also have antidepressant properties, and blocking it may increase tendencies toward depression. So we feel this work has implications for treating sleep disorders as well as depression."
Other authors on the study included Ronald McGregor (first author), Ming-Fung Wu, Grace Barber and Lalini Ramanathan, all of UCLA, the Veterans Affairs Greater Los Angeles Healthcare System and the UCLA Brain Research Institute.
The research was supported by the National Institutes of Health and the Medical Research Service of the Department of Veterans Affairs. The authors report no conflict of interest.
Original article: http://newsroom.ucla.edu/portal/ucla/brain-cells-responsible-for-keeping-218204.aspx