Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Is sleep 'hard-wired' into the brain?

Is sleep 'hard-wired' into the brain?

November 25, 2002

Falling asleep is usually thought of as something we can control ourselves as part of our behaviour patterns. In a new article in the December Journal of the Royal Society of Medicine, Dr Bidi Evans argues that waking and sleeping is actually controlled by a physical mechanism that is 'hard-wired' into the brain. She suggests that evidence from people with brain damage shows that coma patients literally cannot wake up, because their waking mechanism is 'broken'. Dr Evans recommends that sleep medicine, usually studied by psychiatrists and psychologists, "should enter the mainstream of neurological thinking" where more neural specialists could contribute to research.

What we know about sleep
Waking up: The waking up process was first described fifty years ago. The 'reticular activating mechanism' (RAM) starts in the nerve cells around the central canal and switches the brain from deep sleep to wakefulness.
Falling asleep: Instead of being a passive process, as originally thought, falling asleep may be an active one - the 'arousal inhibitory mechanism' that stops us from being conscious.




How we wake up in an emergency
Every four seconds in dreamless sleep there is a short burst of activity deep in the brain known as a 'sleep spindle'. The burst interrupts activity in the brainstem and combines with slower waves in the cortex to actively stop the RAM from re-activating the brain. Since the spindle occurs intermittently, if we need to wake up - for example to care for a crying baby - we still can. Dr Evans argues that deep sleep is a kind of "reversible unconsciousness".

How brain damage can stop the brain from waking
Dr Evans suggests that since the sleep system involves three different levels of the brain, damage to any or all of these levels can mean that the brain can no longer wake itself up.
Level 1: the cerebral hemisphere. If this part of the brain is damaged (eg by meningitis , Alzheimer's) then the RAM cannot activate the cortex, so the patient does not fully wake up. People with level 1 damage still have 'sleeping' and 'waking' periods in the brain, but in the waking periods the cortex does not allow them to be properly aware. This is sometimes known as persistent vegetative state.
Level 2: the thalamus and upper mid brain controls the intermittent mechanism that allows us to be woken up when necessary. Damage here (eg by stroke, tumours) can cause spasms and extreme changes in cerebrospinal fluid pressure. The patient will be unconscious but may suddenly start to breathe hard with an increase in heart rate.
Level 3: the lower mid-brain and upper pons is where most of the sensory input to the brain is received, so if you are damaged here, even strong stimuli will not wake you up.

Dr Evans compares the sleep processes she describes with other neural mechanisms such as vision, which is affected if the optic nerve or related fibres in the brain are injured. "If the sleep mechanisms are damaged, the result will be unconsciousness, i.e. coma."

Royal Society of Medicine



Science Research Departments



Earth Science

Alternative Energy  |   Anthropology and Archaeology  |   Earthquakes and Volcanoes  |   Environment and Nature News  |   Global Warming  |   High-Energy and Particle Physics  |   Ozone Hole  |   Scientists Slow Light  |   Tsunami


Space Science

Astronomy and Space News  |   Black Holes  |   Chandra X-Ray Observatory  |   Extrasolar Planets  |   Hubble Telescope  |   International Space Station  |   Jupiter Galileo Mission  |   Jupiter Cassini Mission Flyby  |   Mars Exploration  |   Mars Odyssey 2001  |   Mars Global Surveyor  |   Mars Polar Lander  |   Mars Climate Orbiter  |   Mars Pathfinder  |   Meteors and Asteroids  |   Mir Space Station  |   NEAR Asteroid Probe Mission  |   Pluto Planet Debate |   Search for Extraterrestrial Life  |   Space Shuttle Program  |   Space Shuttle Mission: STS-102  |   Space Weather


Life Science

Animal News  |   Biotechnology and Genetics  |   Brain Research  |   Human Cloning  |   Dinosaur and Fossil Discoveries  |   Endangered Species  |   Gene Therapy  |   Genetically Modified Food  |   Stem Cell Research  |   Whales and Whaling
Scientific Explorer's Mind Blowing Science Kit for Young Scientists

Scientific Explorer's Mind Blowing Science Kit for Young Scientists
by Scientific Explorer

Mind blowing experiments to delight and educate young scientists! Erupt a color changing volcano.  Mix up magic ooze with a mind of its own.  Play with sand that never gets wet.  Mix safe chemicals and watch colors change before your eyes. You'll amaze yourself and your friends as you explore the science behind these truly remarkable reactions.



The Everything Kids' Science Experiments Book: Boil Ice, Float Water, Measure Gravity-Challenge the World Around You! (Everything Kids Series)

The Everything Kids' Science Experiments Book: Boil Ice, Float Water, Measure Gravity-Challenge the World Around You! (Everything Kids Series)
by Tom Robinson (Author)

Science has never been so easy - or so much fun! With The Everything Kids' Science Experiments Book, all you need to do is gather a few household items and you can recreate dozens of mind-blowing, kid-tested science experiments. High school science teach Tom Robinson shows you how to expand your scientific horizons - from biology to chemistry to physics to outer space.

You'll discover answers to questions like:
Is it possible to blow up a balloon without actually blowing into it?
What is inside coins?
Can a magnet ever be "turned off"?
Do toilets always flush in the same direction?
Can a swimming pool be cleaned with just the breath of one person?

Get ready to enter the laboratory and learn how to conduct cool experiments, understand scientific terms...

Scientific Explorer's Disgusting Science - A Kit for Studying the Science of Revolting Things

Scientific Explorer's Disgusting Science - A Kit for Studying the Science of Revolting Things
by Scientific Explorer

Grow your own friendly germs and fuzzy molds. Mix up a batch of coagulating fake blood. Even make a stinky intestine. learn the science behind unmentionable bodily functions while doing some truly NASTY Experiments.  Ages 8+



The Science Book: Everything You Need to Know About the World and How It Works (National Geographic)

The Science Book: Everything You Need to Know About the World and How It Works (National Geographic)
by National Geographic (Author), Marshall Brain (Foreword)

A delight for the casual reader, yet so complete and wide-ranging that science buffs and students will welcome it, The Science Book encapsulates centuries of scientific thought in one richly illustrated volume. Natural phenomena, revolutionary inventions, and the most up-to-date investigations are explained in detailed text, and 2,000 vivid illustrations—including 3-D graphics and pictograms—make the information even more accessible and amazing to discover.

The Science Book offers both a general overview of topics for the browsing reader and more specific information for those seeking deeper insight into a particular subject. Six major sections, ranging from the universe and planet Earth to biology, chemistry, physics, and mathematics, encompass everything from microscopic life...

Scientific Explorer's The Magic Science Wizard's Kit

Scientific Explorer's The Magic Science Wizard's Kit
by Scientific Explorer

Cast real smoke from your fingertips, make a wizard wand, and whip up color-changing potions in your test tube laboratory. Also included are laminated cards with wizard facts, an instruction booklet with 11 activities, lab equipment, and mysterious wizard powders that will mix together to mystify you!



Scientific Explorer's Tasty Science Chemistry in the Kitchen Kit

Scientific Explorer's Tasty Science Chemistry in the Kitchen Kit
by Scientific Explorer

Who knew science could taste so good? With this kit, you’ll whip up cupcakes, cookies, candy, and more—all in the name of science! Learn what makes cakes rise, candy crystallize, and more real chemistry happen in the kitchen. Tasty Science is packed with ingredients, recipes, activity cards, a test tube laboratory, and lots more to explore the science of taste.



The Complete Book of Science, Grades 5-6

The Complete Book of Science, Grades 5-6
by School Specialty Publishing (Author)

The Complete Book of Science for grades 5 to 6 teaches children important science skills!

Children complete a variety of exercises that help them develop a number of skills in this 352 page workbook. Including a complete answer key this workbook features a user-friendly format perfect for browsing, research, and review.

Over 4 million in print! The best-selling Complete Book series offers a full complement of instruction, activities, and information about a single topic or subject area. Containing over 30 titles and encompassing preschool to grade 8 this series helps children succeed in every subject area!

...

Magic School Bus Journey into the Human Body Science Kit

Magic School Bus Journey into the Human Body Science Kit
by Young Scientist Club

The Magic School Bus and Ms. Frizzle take Young Scientists on a wild ride into the human body with these breathtaking experiments. Young Scientists bend bones, make joints, map taste buds, expand lungs, build a stethoscope, measure lung capacities and heart rates, perform the iodine starch test, spin glitter, simulate synovial fluid, create a human body poster, and much, much more! This exciting kit includes a life-size poster with eight sheets of body part stickers. So put on your seat belts, students, and get ready to discover The Human Body!

Scientific Explorer's Glow in the Dark Fun Lab Science Kit

Scientific Explorer's Glow in the Dark Fun Lab Science Kit
by Scientific Explorer

You will love setting up your own Glow in the Dark Fun Lab. Create a light
wand, make your own glow stick, and even generate a human-powered light.



What Is the World Made Of? All About Solids, Liquids, and Gases (Let's-Read-and-Find-Out Science, Stage 2)

What Is the World Made Of? All About Solids, Liquids, and Gases (Let's-Read-and-Find-Out Science, Stage 2)
by Kathleen Weidner Zoehfeld (Author), Paul Meisel (Author)

Did you ever walk through a wall? Drink a glass of blocks? Have you ever played with a lemonade doll, or put on milk for socks? This latest addition to the Let's-Read-and-Find-Out Science series introduces the youngest readers to an important science concept: the differences between solids, liquids, and gases. Any child who wants to know why he can't walk through a wall will enjoy Kathleen Zoehfeld's simple text and Paul Meisel's playful illustrations.



© 2009 BrightSurf.com