Optogenetics: Controlling the Brain with Light [Extended Version]

The Brain with Light

In this web exclusive, the author offers a longer version of his December 2010 Scientific American article on how researchers can probe how the nervous system works in unprecedented detail, using a technique called optogenetics

Despite the enormous efforts of clinicians and researchers, our limited insight into psychiatric disease (the worldwide-leading cause of years of life lost to death or disability) hinders the search for cures and contributes to stigmatization. Clearly, we need new answers in psychiatry. But as philosopher of science Karl Popper might have said, before we can find the answers, we need the power to ask new questions. In other words, we need new technology.

Developing appropriate techniques is difficult, however, because the mammalian brain is beyond compare in its complexity. It is an intricate system in which tens of billions of intertwined neurons—with multitudinous distinct characteristics and wiring patterns—compute with precisely timed, millisecond-scale electrical signals, as well as with a rich diversity of biochemical messengers. Because of that complexity, neuroscientists lack a deep grasp of what the brain is really doing—of how specific activity patterns within specific brain cells ultimately give rise to thoughts, feelings and memories. By extension, we also do not know how the brain’s physical failures produce distinct psychiatric disorders such as depression or schizophrenia. The ruling paradigm of psychiatric disorders—casting them in terms of chemical imbalances and altered levels of neurotransmitters—does not do justice to the brain’s high-speed electrical neural circuitry. And psychiatric treatments have historically been largely serendipitous: helpful for many but rarely illuminating, and suffering from the same challenges as basic neuroscience.

When Small Numbers Lead to Big Errors

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As the U.S. military embarks on its review of Don’t Ask, Don’t Tell, to be delivered in a final report later this year, the question arises: How many service members are affected by the policy? To help answer that question, the Pentagon this past summer surveyed its troops, asking them if they served or had ever served with someone they believe to be gay. Leaving aside an obvious problem with the survey—that it is based on pure speculation—it also raises a common statistical challenge: asymmetry in population sizes. Because the vast majority of service members are heterosexual, many more straights will be misclassified as gays than vice versa.

This is a general problem in survey research. For example, Harvard University researcher David Hem­en­way has shown how some well-publicized studies have overestimated the number of guns used in the U.S. for self-defense by 10 times. Even if only 1 percent of respondents answer the survey incorrectly, the error is large compared with the proportion of the general population in any given year that uses guns in self-defense, which reasonable studies show to be about 0.1 percent.* In other words, the misclassification rate far exceeds the actual population size. To get around this problem, we would be wiser to trust surveys of crime victims, which restrict the gun use question to a smaller pool of subjects.

How to Reduce Allergies For Your Children

 

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Allergies are increasing in today’s children, so parents worry over the introduction of any new foods.

Allergies are the result of an overactive immune response to external substances. Most allergies are caused by lifestyles: external and internal factors both contribute to the problem. For your family, your grandmother’s generation had a stronger immune system than yours today; your family living out in the country is also better than you are.

1. External Factors

Now, children spend much more time indoors than outdoors. As house sealing conditions get better, artificial fragrance from household chemicals are becoming stronger. Carpets also harbor many dust mites. This indoor air pollution is the cause for some allergies.

2. Internal Factors

First, food diversity is significantly reduced. Americans only eat about 10 different types of foods every day. If you only eat a small variety of foods, any new food won’t be recognized by your body. At a supermarket, you see many seemingly different cans of food. In truth, many of the basic ingredients are more or less the same. Second, scientists found children who receive antibiotics in the first year of life have more than double the rate of allergies and asthma in later childhood. There are good bacteria inside stomach which help us to digest foods. When good bacteria are killed by antibiotics, you may not able to digest some foods, and you body will produce allergic reactions to them.

There is no cure for allergies today. Allergy medicines are only for relief from symptoms and are good for up to 24 hours. As they are getting stronger, so are their side effects.

The Importance of Right Diet

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Go into any supermarket and examine the labels on the countless attractive packages. Look to see what the ingredients are, and note the various chemicals that are added to preserve the food, to make it tastier, to add color, etc. Still the whole story has not been told. What about all the wholesome ingredients that they took out of the food? If you leave the wheat germ in the wheat when you grind it to flour, the wheat will in time turn rancid. For the preservation of the flour the wheat germ is usually removed.

White flour, similarly, is not only less coarse to chew upon; it also keeps longer. In fact, if you place a barrel of white flour next to a barrel of whole wheat flour, and allow the bugs to get at both of the barrels, you will notice that they are not even interested in the white so long as they can get to the brown. The white is lifeless; it doesn’t tempt them. In this sense, modern man shows less discrimination than a beetle!

Got E. coli? Raw Milk’s Appeal Grows Despite Health Risks

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Milk is well known as a great dietary source of protein and calcium, not to mention an indispensable companion to cookies. But “nature’s perfect food,” a label given to milk over time by a variety of boosters, including consumer activists, government nutritionists and the American Dairy Council, has become a great source of controversy, too.

The long-running dispute over whether milk, both from cows and goats, should be consumed in raw or pasteurized form—an argument more than a century old—has heated up in the last five years, according to Bill Marler, a Washington State lawyer who takes raw milk and other food poisoning cases.

A bumper crop of recent illness related to raw milk accentuates the problem. Last month, at least 30 people, including two children, tested positive for strains of campylobacter and Escherichia coli bacteria traced to raw (nonpasteurized) goat milk. In June five people in Minnesota were diagnosed with E. coli traced to raw cow’s milk from a local dairy. One, a toddler, was hospitalized after he developed hemolytic uremic syndrome, a type of kidney failure that is a potentially deadly E. coli complication.

Eat healthier food than the cheaper

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Frozen veggies can help you in getting rid off the obesity, nutrition experts in United States say. They have insisted in getting healthier food than the cheapest food.

The experts link the food habits with the lousy economy. They say that the lousy economy threatens to worsen already bulging waistlines because bad-for-you food happens to be the cheapest.

Dr Adam Drewnowski, who directs the University of Washington Center for Public Health Nutrition is pushing for the federal government to put more affordability into the calculation when it issues new dietary guidelines next year.

We wanted to make sure every calorie counted, he says. At the same time, Drewnowski has asserted that he will not ask people to live on salads. Reason: salad greens can be cost four times as much as green beans and not last nearly as long.

Drewnowski suggests potato and protein-rich eggs on the food table. He advocates for spinach if you can afford it. If not, iceberg lettuce has merit, he insists. If you do not have time for cooking from scratch or you live in a low-income neighborhood where good fresh produce is scarce frozen veggies can be better buys anyway, he says.

We want to shift the people from the most nutrient-rich foods to the most affordable nutrient-rich foods, says Drewnowski

When parents try to control every little bite

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Their preoccupation with their children’s diet is understandable. Rates of childhood obesity have soared in the U.S. in recent years, with about one-third of kids currently considered overweight or obese, according to government reports. Being overweight puts children at risk of long-term health problems such as type 2 diabetes and heart disease, as well as depression and poor self-esteem. But when parents go overboard, it can lead to unnecessary family battles and future eating problems, child psychologists and nutritionists warn.