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aamukherjee Entropie -
alchymista Alchymista -
crownedrose Hymn To The Sea -
epistemophobiarunsdeep Falling Over Myself. -
expose-the-light Quarks to Quasars -
ikenbot cwl -
pieceinthepuzzlehumanity This Is The Right One -
project-argus Hello, Universe. -
torgothegreat God Delusion
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.
Best Illusion of the Year - Disappearing Hand Trick
A combination of visual, touch and position illusions come together in this freaky winner’s video. Gives me the willies just thinking about it. The illusion is part of a project to simulate sensory loss in stroke patients.
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.”
For more on Dreams, visit ikenbot.tumblr.com/dreams
Find me something more beautiful than those pretty little protective astrocytes. (Shown in blue, from http://www2.neuroscience.umn.edu/eanwebsite/RGC.htm)
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.
BRAINBRAWL 2012!!!
The Main Event? Connectomics: Sebastian Seung vs. Tony Movshon.
We’ve all seen the pictures in the past couple months. The connectome, the brain’s wiring diagram, has been drawn in unprecedented detail, and is organized in a surprisingly simple fashion. If we can describe every neuron in the brain, can we know precisely how the brain works?
Carl Zimmer and Radiolab’s Robert Krulwich moderate a discussion on whether we are more or less than our connectome. It’s a room full of amazingly smart people, talking about the Big Questions in neuroscience. Here’s the complete video, thanks to Neuwrite.
As Stuart Firestein asks, “Does a parts list and a wiring diagram provide a satisfactory description of a brain, and maybe even a way to repair it?”
(by armenenikolopov)
expose-the-light
Rainbow Brain Map Reveals Grid-Like Pattern
To the unaided eye, the most striking feature of the human brain is its squiggly pattern of bumps and grooves. But within those curves is a latticework of nerve fibers that cross each other at roughly right angles (above), according to a study published March 30 in Science.
The researchers used a recently-developed method called diffusion spectrum imaging to infer the position of nerve fibers in the living human brain from the way water flows through and around them. These scans revealed an orderly weave of fibers — a much simpler organization than many scientists would have suspected.
Scans in four monkey species found a similar pattern. The researchers suggest that this grid-like organization may be advantageous during brain development, providing the equivalent of highway lane markers to help growing nerve fibers find their way to the appropriate destination.
This story provided by ScienceNOW, the daily online news service of the journal Science.
As submitted by themattestrada:
Cell bodies of unipolar neurons surrounded with satellite cells. (via)
themattestradaA “citizen science” community to test the hypothesis that the uniqueness of a person, from memories to mental disorders, lies in his or her connectome.
Every person is unique. You know this, of course, but it has been surprisingly difficult to pinpoint where, precisely, your uniqueness resides. Scientists have speculated that the properties of your mind, from memories to mental disorders, are encoded in the unique pattern of connections between your brain neurons. This hypothesis is plausible, but solid evidence has been lacking, because we have never been able to see the brain’s “wiring” clearly. Fortunately, revolutionary new technologies are starting to provide the right kind of images, but in torrents that are so overwhelming that no single person can comprehend the data.
The solution is WiredDifferently, which will enlist citizen scientists to analyze nanoscale brain images using web browsers and mobile devices. They will trace the wires of the brain as if absorbed in play with a 3D jigsaw puzzle consisting of image pieces computed by artificial intelligence. The experience will rely on the spectacular graphics and other motivators of video gaming, but allow users to apply their minds to a worthy cause. WiredDifferently will transform 21st century science and society by mobilizing our collective hearts and minds to understand how the brain works and why it malfunctions.
ScienceDaily (Mar. 9, 2012) — Despite a century of research, memory encoding in the brain has remained mysterious. Neuronal synaptic connection strengths are involved, but synaptic components are short-lived while memories last lifetimes. This suggests synaptic information is encoded and hard-wired at a deeper, finer-grained molecular scale.
In an article in the March 8 issue of the journal PLoS Computational Biology, physicists Travis Craddock and Jack Tuszynski of the University of Alberta, and anesthesiologist Stuart Hameroff of the University of Arizona demonstrate a plausible mechanism for encoding synaptic memory in microtubules, major components of the structural cytoskeleton within neurons.
Microtubules are cylindrical hexagonal lattice polymers of the protein tubulin, comprising 15 percent of total brain protein. Microtubules define neuronal architecture, regulate synapses, and are suggested to process information via interactive bit-like states of tubulin. But any semblance of a common code connecting microtubules to synaptic activity has been missing. Until now.
Original paper here.
VS Ramachandran: The neurons that shaped civilization
This is a short video in which neuroscientist Ramachandran makes a really great work at explaining the fascination of mirror neurons.
[…] there is no real independent self, aloof from other human beings, inspecting the world, inspecting other people. You are, in fact, connected not just via Facebook and Internet, you’re actually quite literally connected by your neurons. And there is whole chains of neurons around this room, talking to each other. And there is no real distinctiveness of your consciousness from somebody else’s consciousness.
I’ve received a lot of questions about this today, I suggest everyone interested to watch this.
crownedrose
Researchers make living model of brain tumor
Researchers have created a living 3-D model of a brain tumor and its surrounding blood vessels. In experiments, the scientists report that iron-oxide nanoparticles carrying the agent tumstatin were taken by blood vessels, meaning they should block blood vessel growth. The living-tissue model could be used to test the effectiveness of nanoparticles in fighting other diseases. Results appear in Theranostics.
(clicking the image will bring you to the source article)
Drug Reverses Alzheimer’s Symptoms in Mice
Neuroscientists at Case Western Reserve University School of Medicine have made a dramatic breakthrough in their efforts to find a cure for Alzheimer’s disease. The researchers’ findings, published in the journal Science, show that use of a drug in mice appears to quickly reverse the pathological, cognitive and memory deficits caused by the onset of Alzheimer’s. The results point to the significant potential that the medication, bexarotene, has to help the roughly 5.4 million Americans suffering from the progressive brain disease.
Bexarotene has been approved for the treatment of cancer by the U.S. Food and Drug Administration for more than a decade. These experiments explored whether the medication might also be used to help patients with Alzheimer’s disease, and the results were more than promising.
It’s important to emphasise that this has cured symptoms in mice, and not humans; many drugs have been developed in the past that countered the symptoms of Alzheimer’s in mice only to be ineffective in humans. So, whilst being optimistic about future results with bexarotene, people also need to maintain a realistic approach that this may not become a viable treatment for humans.
aamukherjee