WELLynx at Lesley University

ikenbot:

The Science Behind Our Strange, Spooky Dreams

The realm of sleep and dreams has long been associated with strangeness: omens or symbols, unconscious impulses and fears.

But this sometimes disturbing world of inner turmoil, fears and desires is grounded in our day-to-day experience, sleep researchers say.

“The structure and content of thinking looks very much like the structure and content of dreaming. They may be the product of the same machine,” said Matthew Wilson, a neuroscientist at MIT and a panelist at the New York Academy of Sciences discussion “The Strange Science of Sleep and Dreams” on Friday (Nov. 9).

His work and others’ explores the crucial link between dreams and learning and memory.

Dreams allow the brain to work through its conscious experiences. During them, the brain appears to apply the same neurological machinery used during the day to examine the past, the future and other aspects of a person’s (or animal’s) inner world at night. Memory is the manifestation of this inner world, Wilson said.

“What we remember is the result of dreams rather than the other way around,” he said.

Dreams as teachers

His work, and that of fellow panelist Erin Wamsley, a sleep scientist at Beth Israel Medical Center/Harvard Medical School, focuses on the relationship between memory and dreams in non-REM sleep. Vivid dreams often occur during REM sleep, named for the rapid eye movement associated with it, however, non-REM sleep also brings dreams but they are more fragmentary.

Wamsley’s research indicates dreams help people learn.

In a study published in the journal Current Biology in April 2010, she and colleagues found that study subjects who entered non-REM sleep and dreamed about a video game maze they had played hours earlier saw their performance increase dramatically more than those who slept but did not report any maze-related dreams. Meanwhile, thinking about the maze while awake did not improve the players’ performance.

Although this work focused on non-REM sleep, incorporation of learning happens in all stages of sleep, Wamsley told the audience.

Wamsley has also used another video game, this one of a downhill skiing, to probe the relationship between dreams and learning. Like the maze, this game was intended to be interactive and exciting for the subjects, Wamsley said.

Subjects reported their dreams after playing, and initially, their dreams put them directly back into the game, as if rehearsing. But as they fell deeper into sleep, their dreams became more extractive with less literal relationship to the game, she said. For instance, one subject described following boot prints in the snow.

This may be because in deeper sleep, the brain is trying to extract meaning from the experience earlier in the day. The subject’s dream about boot prints may have been a way to refine the dreamer’s concept of how to move through snow, she said.

Learning the maze

Like some of Wamsley’s subjects, Wilson’s also dreamed of mazes, but these mazes were real.

By accident, Wilson found when rats fall asleep their brains replay parts of their experience in a maze. By using fine electrodes to eavesdrop on the activity of single neurons in the hippocampus, a region of the brain associated with spatial memory, he saw this happen.

Individual neurons in rats’ and humans’ hippocampuses fire in response to spatial location, so each time a rat passes a certain point within the maze a single neuron fires. Once the rats fell asleep, Wilson found these neurons would fire as they were reactivated in patterns that represented brief segments of the maze, which could be run forward or in reverse, Wilson found.

In the future, science may develop ways to control cognitive functions enhanced by sleep, “using sleep and dreams as a tool the way we use learning and teaching while we are conscious,” he said.

In one study, he and colleagues successfully manipulated the content of rats’ dreams with a tone they had used earlier to direct the animals as they navigated a maze. The tone caused the rats to dream of the section of the maze they had been taught to associate with that tone.

Going without

No one can speak to the value of sleep more than someone deprived of it. Alan Berliner, a filmmaker who explored his own insomnia in his 2006 documentary “Wide Awake.” offered that perspective to the discussion.

“Every night when I put my head on the pillow, it’s like an adventure,” Berliner says in a clip of the film played during the discussion. He described songs, particularly Leonard Cohen’s “In My Secret Life,” looping in his head and his thoughts racing uncontrollably.

“I started to think the expression human error means sleepiness,” he said in the film.

The discussion, presented in collaboration with the Imagine Science Film Festival, was moderated by Tim McHenry of the Rubin Museum of Art.

For More on The Science of Dreams

scinerds:

Raw Food Not Enough to Feed Big Brains

Eating a raw food diet is a recipe for disaster if you’re trying to boost your species’ brainpower. That’s because humans would have to spend more than 9 hours a day eating to get enough energy from unprocessed raw food alone to support our large brains, according to a new study that calculates the energetic costs of growing a bigger brain or body in primates. But our ancestors managed to get enough energy to grow brains that have three times as many neurons as those in apes such as gorillas, chimpanzees, and orangutans. How did they do it? They got cooking, according to a study published online today in the Proceedings of the National Academy of Sciences.

“If you eat only raw food, there are not enough hours in the day to get enough calories to build such a large brain,” says Suzana Herculano-Houzel, a neuroscientist at the Federal University of Rio de Janeiro in Brazil who is co-author of the report. “We can afford more neurons, thanks to cooking.”

Humans have more brain neurons than any other primate — about 86 billion, on average, compared with about 33 billion neurons in gorillas and 28 billion in chimpanzees. While these extra neurons endow us with many benefits, they come at a price — our brains consume 20 percent of our body’s energy when resting, compared with 9 percent in other primates. So a long-standing riddle has been where did our ancestors get that extra energy to expand their minds as they evolved from animals with brains and bodies the size of chimpanzees?

One answer came in the late 1990s when Harvard University primatologist Richard Wrangham proposed that the brain began to expand rapidly 1.6 million to 1.8 million years ago in our ancestor, Homo erectus, because this early human learned how to roast meat and tuberous root vegetables over a fire. Cooking, Wrangham argued, effectively predigested the food, making it easier and more efficient for our guts to absorb calories more rapidly. Since then, he and his colleagues have shown in lab studies of rodents and pythons that these animals grow up bigger and faster when they eat cooked meat instead of raw meat — and that it takes less energy to digest cooked meat than raw meat.

In a new test of this cooking hypothesis, Herculano-Houzel and her graduate student, Karina Fonseca-Azevedo, now a neuroscientist at the National Institute of Translational Neuroscience in São Paulo, Brazil, decided to see if a diet of raw food inherently put limits on how large a primate’s brain or body could grow. First, they counted the number of neurons in the brains of 13 species of primates (and more than 30 species of mammals). The researchers found two things: one, that brain size is directly linked to the number of neurons in a brain; and two, that that the number of neurons is directly correlated to the amount of energy (or calories) needed to feed a brain.

After adjusting for body mass, they calculated how many hours per day it would take for various primates to eat enough calories of raw food to fuel their brains. They found that it would take 8.8 hours for gorillas; 7.8 hours for orangutans; 7.3 hours for chimps; and 9.3 hours for our species, H. sapiens.

These numbers show that there is an upper limit on how much energy primates can get from an unprocessed raw diet, Herculano-Houzel says. An ape’s diet in the wild differs from a modern “raw food diet,” in which humans get sufficient calories from processing raw food in blenders and adding protein and other nutrients. In the wild, other apes can’t evolve bigger brains unless they reduce their body sizes because they can’t get past the limit of how many calories they can consume in 7 hours to 8 hours of feeding per day. But humans, she says, got around that limit by cooking. “The reason we have more neurons than any other animal alive is that cooking allowed this qualitative change — this step increase in brain size,” she says. “By cooking, we managed to circumvent the limitation of how much we can eat in a day.”

This study shows “that an ape could not achieve a brain as big as in recent humans while maintaining a typical ape diet,” Wrangham says.

It’s Not Just What You Eat, But When You Eat It: Penn Study Shows Link Between Fat Cell and Brain Clock Molecules

Fat cells store excess energy and signal these levels to the brain. In a new study this week in Nature Medicine, Georgios Paschos PhD, a research associate in the lab of Garret FitzGerald, MD, FRS director of the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, shows that deletion of the clock gene Arntl, also known as Bmal1, in fat cells, causes mice to become obese, with a shift in the timing of when this nocturnal species normally eats. These findings shed light on the complex causes of obesity in humans.

The Penn studies are surprising in two respects. “The first is that a relatively modest shift in food consumption into what is normally the rest period for mice can favor energy storage,” says Paschos. “Our mice became obese without consuming more calories.” Indeed, the Penn researchers could also cause obesity in normal mice by replicating the altered pattern of food consumption observed in mice with a broken clock in their fat cells.

This behavioral change in the mice is somewhat akin to night-eating syndrome in humans, also associated with obesity and originally described by Penn’s Albert Stunkard in 1955.

The second surprising observation relates to the molecular clock itself. Traditionally, clocks in peripheral tissues are thought to follow the lead of the “master clock” in the SCN of the brain, a bit like members of an orchestra following a conductor. “While we have long known that peripheral clocks have some capacity for autonomy – the percussionist can bang the drum without instructions from the conductor – here we see that the orchestrated behavior of the percussionist can, itself, influence the conductor,” explains FitzGerald.

(Source: runpencilrun)

and the word of the day is OMPHALOSKEPSIS

jtotheizzoe:

Bellybutton Bacterial Biodiversity

How what’s growing on you can help us figure out what we’re made of

How can swabbing the belly button lint of a bunch of science folks teach us about how our bodies interact with the living world around us? Jason Tetro has the story at The Huffington Post:

The body is continually in flux with the environment to find harmony between various kinds of exposures and the body’s reaction to them through the workings of the immune system. Inert or even mutually-beneficial exposures, such as good germs, will be allowed by the body and even encouraged. Those that are parasitic, such as pathogens, will be fought off and destroyed. As life goes on, we tend to hold on to the germs that we like and keep them growing happily with us as we continue our journey. Our bellybutton microbiome therefore reveals how each of us as a member of the Earth’s biome has interacted with and reacted to the dynamics of nature.

For a species that is so interested in itself, we know surprisingly little about the microbes that reside on and in us. By identifying, sequencing, studying and connecting the various beasties in our bellies and elsewhere, we will know more about how our body separates harm from good, and how we depend on microbes for our very existence.

Check out more at the Bellybutton Biodiversity Project.

Previously: Journey through the Human Microbiome Project with the artwork of Perrin Ireland.

(via HuffPo)

alchymista:

Skin Cultures

Once upon a time, when a patient required suffered from severe burns, surgeons would be forced to graft pigskin as temporary bandage of sorts. But with modern technologies, we have the ability to remove human skin from alternate locations of the body and even use substitutes engineered through either synthetic means or from collagen of certain animals, such as sharks or cows.