Blogs / 80beats

The most famous neuroscience patient and test subject died last week, and the researchers who worked with him say they’ll never forget the man who never remembered them. The patient known as H.M. lost the ability to form new memories after he had brain surgery at the age of 27, and studies of his behavior taught researchers basic lessons about how memory and learning work. “He was a very gracious man, very patient, always willing to try these tasks I would give him,” [said Brenda] Milner, a professor of cognitive neuroscience. “And yet every time I walked in the room, it was like we’d never met” [The New York Times].

Henry Gustav Molaison, a Hartford [Connecticut] native, existed in relative obscurity. But as “H.M.,” the name used to disguise his identity, Molaison gained an anonymous sort of fame, a man who had been studied by more than 100 researchers and became a staple of psychology class lectures…. “I’ve been lecturing about him and teaching about him for years and years, decades, and I’ve never known his name” [Hartford Courant], says psychiatrist David Glahn. Molaison died at a Connecticut nursing home on Tuesday at the age of 82, of respiratory failure.

Molaison began having seziures after a childhood bicycle accident, and by the age of 27 they were seriously interfering with his daily life. In 1953 surgeons removed two slices of his brain and cut into a region called the hippocampus–this stopped his seizures, but also gave Molaison a form of amnesia where he could remember events from before the surgery but couldn’t form any new long-term memories.

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Dogs have a sense of fairness, and get jealous and upset when several dogs perform a trick but only one is rewarded, a new study has found. “They are clearly unhappy with the unfair situation”, says [lead researcher Friederike] Range. She also suspects that this sensitivity might stretch beyond food to things like praise and attention. “It might explain why some dogs react with ‘new baby envy’ when their owners have a child”, she says [New Scientist].

While some owners may say that they’ve known about the deep emotional lives of their dogs for ages, the new experiments mark the first time a complicated emotion like jealousy has been observed in dogs in a controlled laboratory setting. “We are learning that dogs, horses, and perhaps many other species are far more emotionally complex than we ever realized,” [says] Paul Morris, a psychologist at the University of Portsmouth who studies animal emotions…. “They can suffer simple forms of many emotions we once thought only primates could experience” [Times Online].

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If you could take a pill to boost your concentration and mental stamina, would you do it? Around the country, thousands of college students are already answering “yes” to that question and are using prescription medications like Ritalin as study aids, and researchers say the demand for such “smart pills” is likely to grow. Now, in a new essay, a group of neuroscientists and bioethicists is arguing that society shouldn’t frown on such practices; instead the authors assert that “we should welcome new methods of improving our brain function,” and that doing it with pills is no more morally objectionable than eating right or getting a good night’s sleep [Chronicle of Higher Education].

Stimulants like Ritalin and Adderall are prescribed for attention deficit hyperactivity disorder and are commonly used by people without a prescription to help them focus their attention, while a narcolepsy drug called Provigil is sometimes used by people trying to keep their brains alert and awake. The new essay cited a recent survey that found nearly 7 percent of students in U.S. universities have used prescription stimulants, and on some campuses, as many as a quarter of students have used the drugs for non-therapeutic purposes. “It’s a felony, but it’s being done,” [coauthor Martha] Farah said [Reuters].

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Contrary to conventional wisdom, marijuana may actually fight memory loss, scientists report—but only if taken in small doses amounting to just one puff a day. Researchers tested a compound similar to THC, the main psychoactive substance in marijuana, on rats and found that the chemical reduces inflammation in the brain and promotes the growth of new brain cells. Elderly rats given the compound performed better on learning and memory tasks. “Could people smoke marijuana to prevent Alzheimer’s disease if the disease is in their family? said [researcher Gary Wenk]. “We’re not saying that, but it might actually work” [Telegraph].

In one part of the study, researchers injected the THC-mimicking drug, called WIN-55212-2, into young rats with inflammation in their brains. The drug reduced inflammation. In a second part, the researchers injected WIN into older rats that were then put into a swimming tank with hidden resting spots. The medicated rats were better able to find and remember the resting spots. Dissection of the rat brains revealed not only reduced inflammation but the growth of new neurons. The results were presented at last week’s Society of Neuroscience meeting.

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In a new study, researchers attached electrodes to individual neurons in monkeys’ brains and then rerouted those neuronal signals through a brain-machine interface, which converted them into electrical signals that controlled the monkeys’ own paralyzed muscles. Researchers say this roundabout feat of bioengineering could eventually lead to new treatments and prosthetics for paralyzed people.

The implant exploits the fact that even when the neural connection between a brain region and the muscles it controls is severed or damaged by, say, a stroke or spinal injury, the controlling neurons remain active. For example, people living with quadriplegia who try to move their arm still generate arm-movement signals in the motor cortex of their brain, even after several years of paralysis [New Scientist]. The new study is the first to send the signals back to the user’s own muscles, as opposed to related research in which the signals are fed into electronic devices.

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Bumblebees that have a close encounter with a dangerous predator are still cautious and wary the next day, even though their trepidation slows them down as they forage for food. In a new study, researchers used robot spiders to briefly trap the bees and study their behavior afterwards, and found that in the end, some of the bumblebees get a little paranoid…. “They’re behaving as if they’re starting to see ghosts,” [co-author Lars] Chittka says [Science News].

The researchers used small robots to imitate the look and behavior of crab spiders, which are one of the major predators of bumblebees. They lie in wait in flowers which the bees need to visit to collect nectar, and are difficult to spot because they can change colour to match their surroundings [New Scientist].

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It’s a demonstration of unconscious brain power: A new neuroscience study shows that people can make decisions based on input that is invisible to the conscious mind. Researchers say the findings aren’t evidence of the efficacy of subliminal messages, which have mostly been discredited. But there has been a more subtle phenomenon, billed as the foundation of intuition, where seasoned poker players may play more successfully because they can pick up subtle signals in the body language of their opponents - without consciously realising it - to work out if they are bluffing [Telegraph].

In the study, published in the journal Neuron [subscription required], test subjects were repeatedly shown brief abstract animations before being asked whether they wanted to take a gamble, which could either earn or lose them a small amount of money. The animations had hidden symbols that indicated whether the subject would win or lose on the subsequent bet; over time, test subjects got better at predicting whether they would win or not.

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Researchers have discovered five new genetic defects that are linked to autism and that appear to share a common function: They’re associated with learning, and are part of a network that allows a child’s brain to build new connections in response to experience [Web MD].

Symptoms of autism typically emerge during the first five years of life — a period when a child normally picks up language, social skills and many other new abilities. Scientists call this kind of growth “experience-dependent learning,” and researchers know that it is associated with enormous changes in brain circuitry. At least 300 genes switch on and off to regulate experience-dependent learning [Time]. Researchers say that the newly identified genes, as well as others already linked to autism, may fail to turn on during this crucial developmental stage, preventing children from learning those social skills and abilities.

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