medicalschool:

Neurons in the Brain

Flashes of light may one day be used to control the human brain, and that day just got a lot closer. (WIRED Magazine Science Article)

ikenbot:

How The Brain Turns Reality Into Dreams

Dreams make perfect sense when you’re having them. Yet, they leave you befuddled the next morning, wondering “where did that come from?” The answer may lie in the dreams of people with amnesia, researchers report in an issue of Science.

Much of the fodder for our dreams comes from recent experiences. For this reason, scientists have tentatively supposed that the dreaming brain draws from its “declarative memory” system, which includes newly learned information.

The declarative memory stores information that you can “declare” you know, such as the square root of nine, or the name of your dog. Often, you can even remember when or where you learned something - for example, the day you discovered the harsh truth about Santa Claus. That’s called episodic memory.

People who permanently suffer from amnesia can’t add new declarative or episodic memories. The parts of their brains involved in storing this type of information, primarily a region called the hippocampus, have been damaged. Although amnesiacs can retain new information temporarily, they generally forget it a few minutes later.

If our dreams come from declarative memories, people with amnesia shouldn’t dream at all, or at least dream differently than others do. But new research directed by Robert Stickgold of Harvard Medical School suggests quite the opposite. Just like people with normal memory, amnesiacs replay recent experiences when they fall asleep, Stickgold’s study shows. The only difference seems to be that the amnesiacs don’t recognize what they’re dreaming about.

Dreaming of Tetris

Every day, the people in the study played several hours of the computer game Tetris, which requires directing falling blocks into the correct positions as they reach the bottom of the screen. At night, the amnesiacs didn’t remember playing the game. But, they did describe seeing falling, rotating blocks while they were falling asleep.

A second group of players with normal memories reported seeing the same images. Therefore, Stickgold’s research team concluded, dreams must come from the types of memory amnesiacs do have, which are called “implicit memories.” These are memories that scientists can measure even when individuals don’t know that they have them.

One class of implicit memories is found in the procedural memory system, which stores information that you use without really being able to say how you know what you’re doing. When you ride a bicycle for the first time in years, or type on a keyboard without looking, you’re relying on procedural memory.

Another type of implicit memory uses “semantic” knowledge, and resides in different parts of the brain, including a region called the neocortex. Semantic knowledge involves general, abstract concepts. Both groups of Tetris players, for example, only described seeing blocks, falling and rotating, and evidently did not see a desk, room, or computer screen, or feel their fingers on the keyboard.

Without help from the hippocampus, new semantic memories are too weak to be intentionally recalled. But they can still affect your behavior - for example, causing you to buy a certain brand of something you saw in an advertisement you don’t remember.

In contrast, the information in episodic memories is associated with specific times, places or events. Without these “anchors” to reality, it’s no wonder that dreams are so illogical and full of discontinuity, the study’s authors say.

Stickgold believes that dreams serve a purpose for the brain, allowing it to make necessary emotional connections among new pieces of information. “Dreams let you consolidate and integrate your experiences, without conflict with other input from real life,” Stickgold said. “Dreaming is like saying, ‘I’m going home, disconnecting the phone, nobody talk to me. I have to do work.’”

Because the hippocampus seems to be inaccessible for this “off-line” memory processing, the brain may use the abstract information in the neocortex instead. According to Stickgold’s theory, dreaming is like choosing an outfit by reaching into bins labeled “shirts,” “pants” and so on. You’ll rummage up something to wear, but it won’t be a perfectly matching ensemble.

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© 2012 American Association for the Advancement of Science

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hidingerections:

The Brain Hidden Epidemic: Tapeworms Living Inside People’s Brains

“Nobody knows exactly how many people there are with it in the United States,” says Nash, who is the chief of the Gastrointestinal Parasites Section at NIH. His best estimate is 1,500 to 2,000. Worldwide, the numbers are vastly higher, though estimates on a global scale are even harder to make because neurocysticercosis is most common in poor places that lack good public-health systems. “Minimally there are 5 million cases of epilepsy from neurocysticercosis,” Nash says.

ikenbot:

Why We Dream: Real Reasons Revealed

The slumbering mind might not seem like an apt tool for any critical thinking, but humans can actually solve problems while asleep, researchers say. Not only that, but one purpose for dreaming itself may be to help us find solutions to puzzles that plague us during waking hours.

Dreams are highly visual and often illogical in nature, which makes them ripe for the type of “out-of-the-box” thinking that some problem-solving requires, said Deirdre Barrett, a psychologist at Harvard University.

Barrett’s theory on dreaming, which she discussed at the Association for Psychological Science meeting here last month, boils down to this: Dreaming is really just thinking, but in a slightly different state from when our eyes are open.

“Whatever the state we’re put in, we’re still working on the same problems,” Barrett said. Although dreams might have initially evolved for a different purpose, they likely have been refined over time so they can serve double-duty: help the brain reboot itself and problem-solve.

Dreams and evolution

A theory to explain dreams, or any human behavior for that matter, needs to take into account evolution, Barrett said. But many early theories of dreaming either didn’t address evolution at all, or downright contradicted it, she said.

For instance, Sigmund Freud proposed dreams exist to fulfill our wishes. But such gratification in an imaginary world would do little to help us adapt our instincts to the physical world, which is one key point of evolution, Barrett said.

Others have proposed dreams are more of a side effect of the sleep cycle. Dreams usually occur during Rapid Eye Movement, or REM, sleep. This stage is thought to serve several functions: to rest a part of the brain (since some areas are active while others aren’t) and to replenish brain chemicals, such as neurotransmitters.

This has led some to say that dreams happen simply because REM sleep happens, Barrett said. The psychologist Steven Pinker once likened dreams to computer screen savers, saying that it perhaps “doesn’t really matter what the content is as long as certain parts of the brain are active.”

However, Barrett disagrees. “My opinion is that, evolution just isn’t wasteful, that when things evolve for one purpose, that generally they don’t continue throughout time to have only that purpose, but anything else that may be useful about them gets refined,” she said in a telephone interview with LiveScience prior to the convention.

She also noted that REM sleep has been around for quite some time, since mammals evolved some 220 million years ago. “The longer something has existed during evolutionary history, the likelier it is to have other functions overlaid on it,” she said at the convention.

Problem-solving

Barrett has studied problem-solving in dreams for more than 10 years, and documented many examples of the phenomenon.

In one experiment, Barrett had college students pick a homework problem to try to solve in a dream. The problems weren’t rocket science; they were fairly easy questions that the student simply hadn’t gotten around to solving yet. Students focused on the problem each night before they went to bed. At the end of a week, about half the students had dreamed about the problem and about a quarter had a dream that contained the answer, Barrett said.

So at least in the cases where problems are relatively easy, some people can solve them in their sleep.

Barrett has also extensively reviewed scientific and historical literature, looking for examples of problems solved in dreams.

She found examples of almost every type of problem being solved in a dream, from the mathematical to the artistic. But many were related to problems that required individuals to visualize something in his or her mind, such as an inventor picturing a new device.

The other major category of problems solved in dreams included “ones where the conventional wisdom is just wrong about how to approach the problem,” Barrett said.

Dreams might have evolved to be particularly good at allowing us to work out puzzles that fall into those two categories, she said.

“I think that dreams and REM sleep have probably further evolved to be useful for really as many of the things that our thinking is useful for,” Barrett said. “It’s just extra thinking time, so potentially any problem can get solved during it, but it’s thinking time in the state that’s very visual and looser in associations, so we’ve evolved to use it especially to work on those kinds of problems.”

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expose-the-light:

Top 10 Biggest Brain Damaging Habits

1. No Breakfast

People who do not take breakfast are going to have a lower blood sugar level.This leads to an insufficient supply of nutrients to the brain causing brain degeneration.

2. Overreacting

It causes hardening of the brain arteries, leading to a decrease in mental power.

3. Smoking

It causes multiple brain shrinkage and may lead to Alzheimer disease.

4. High Sugar consumption

Too much sugar will interrupt the absorption of proteins and nutrients causing malnutrition and may interfere with brain development.       

5. Air Pollution

The brain is the largest oxygen consumer in our body. Inhaling polluted air decreases the supply of oxygen to the brain, bringing about a decrease in brain efficiency.

6. Sleep Deprivation

Sleep allows our brain to rest. Long term deprivation from sleep will accelerate the death of brain

7. Head covered while sleeping

Sleeping with the head covered, increases the concentration of carbon dioxide and decrease concentration of oxygen that may lead to brain damaging effects.

8. Working your brain during illness

Working hard or studying with sickness may lead to a decrease in effectiveness of the brain as well as damage the brain.            

9. Talking Rarely

Intellectual conversations will promote the efficiency of the brain.

10. Lacking in stimulating thoughts

Thinking is the best way to train our brain, lacking in brain stimulation thoughts may cause brain shrinkage.

ikenbot:

Near-Death Experiences are Lucid Dreams, Experiment Finds

In a new exercise by a California organization that studies lucid dreaming, volunteers have been conditioned to dream near-death experiences, including the classic scenario of flying toward a light at the end of a tunnel. The researchers say their experiment demonstrates that these heavenly visions must be products of the human mind rather than supernatural phenomena.

In the sleep experiment at the Out-Of-Body Experience Research Center in Los Angeles, four groups of 10 to 20 volunteers were trained to perform a series of mental steps upon awakening during the night that might lead them to have out-of-body experiences. If able to “separate” from their bodies, they were then conditioned to try dreaming about floating through a tunnel toward a bright light. Eighteen of the volunteers said they were able to dream such an experience.

“Some of the test subjects not only succeeded in reproducing the out-of-body flight through a tunnel, but also enjoyed the ecstasy typical of the experience, and even flew all the way to the light and met their deceased relatives there,” center leader Michael Raduga stated in a press release about the work, which has not been published in a peer-reviewed journal.

More than 8 million Americans have had a near-death experience, and they most often occur during states of anesthesia-induced sleep, according to the center. Prior work by neurologists, including Kevin Nelson of the University of Kentucky, suggests that NDEs are indeed generated by the same brain mechanisms that cause lucid dreams. Nelson’s research shows that both types of experiences arise when part of the brain called the dorsolateral prefrontal region — our “logical center,” which is usually active only when we’re awake — becomes active during REM sleep, allowing extremely vivid dreams that seem to be happening in real life. He calls the transitional state between dreaming and wakefulness a “borderland of consciousness” and believes it is in this mixed state that lucid dreams and NDEs occur.

With Nelson’s research in mind, Raduga designed his experiment to determine if volunteers could be coached to dream up NDEs when in the transitional phase between sleep and waking. This would demonstrate that reports of NDEs, which are commonly cited as proof of the supernatural, really are just lucid dreams.

Volunteers who successfully generated NDEs described their experiences for the researchers. One participant, identified by the center asNadezhda S., stated: “I was able to leave my body after a couple of tries. Now that I was out of my body, I wanted to see the tunnel and it immediately appeared in front of me … Once I flew to the end of that tunnel … I saw my deceased husband there in the spirit. We spoke for several minutes. His words, touch, bearing, and feelings were real, just like during his life. Later on, when I felt it was time to leave, I went up to the tunnel, jumped and gently landed in my body.”

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coffeeandneurons:

Find me something more beautiful than those pretty little protective astrocytes.  (Shown in blue, from http://www2.neuroscience.umn.edu/eanwebsite/RGC.htm)

fuckyeahmolecularbiology:

Wide-field multi-photon fluorescence image of a rat hippocampus stained to reveal the distribution of glia (cyan), neurofilaments (green) and cell nuclei (yellow).

Image Source: the Whole Brain Catalogue.

quantumaniac:

The Candle Problem

Given a book of matches, a box of thumbtacks, and a candle, how can you fix the candle to the wall so that its wax won’t drip onto the table below?

See Answer Below

Pin the box to the wall, put the candle in the box, and light it.

In experiments, Gestalt psychologist Karl Duncker found that most subjects instead tried to pin the candle directly to the wall or to use melted wax to affix it there (neither worked). Duncker called this “functional fixedness” — a “mental block against using an object in a new way that is required to solve a problem.” In this case, subjects had “fixated” on the box’s function as a container, which prevented them from considering it as a platform. If the box was empty at the start of the experiment, they were more likely to find the correct solution.

In a 2000 study, psychologists Tim German and Margaret Defeyter found the 6- and 7-year-olds show signs of functional fixedness, but 5-year-olds appear immune to it: “Rather than taking into account only the properfunction of an object, they adopt and agents-goals view of function in which any intentional use of an object can be its function.”

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