155 posts tagged neuroscience
Do Cats Control My Mind?
New neuroscience research says that Toxo—the cysts in our brains from cats—can improve our self-control. For the 30 percent of people who have this infection, it’s about more than promiscuity, schizophrenia, and car crashes.
“It is definitely not smart to intentionally infect yourself. I’ve already had people ask.” A third of the world has been infected, though. Tiny cysts nested in one’s brain and muscles attest. The parasite Toxoplasmosis gondii comes into us by undercooked meat, well-intentioned placentas, gardening soil, or, most infamously, cats. It is the reason that pregnant women are not supposed to empty litter boxes. “If you’re young and healthy and have it already, it might provide some benefit, as we saw in our research,” Ann-Kathrin Stock, a cognitive neurophysiology researcher at the University of Dresden in Germany, told me. “But the adverse effects are potentially huge. If you ever really get sick it might be what kills you.” Many people have what feels like a cold after they get infected with Toxo. The symptoms pass, and the person feels fine. But the Toxo lives on inside them, hidden dormant in little cysts, kept in check by constant pressure from the person’s immune system. If our immune systems become weak, because of a serious illness later in life, though, the Toxo can break out and attack organs like the brain or retina. “You might lose your ability to see, or lose your cognitive faculties,” Stock said. Neuroscientist Joraslov Flegr, an eminent voice in Toxo research, told The Atlantic last year that, “Toxoplasma might even kill as many people as malaria, or at least a million people a year.” What does it mean to learn that it can also have beneficial effects? (via Do Cats Control My Mind? - James Hamblin - The Atlantic)
Did you make it to work on time this morning? Go ahead and thank the traffic gods, but also take a moment to thank your brain. The brain’s impressively accurate internal clock allows us to detect the passage of time, a skill essential for many critical daily functions. Without the ability to track elapsed time, our morning shower could continue indefinitely. Without that nagging feeling to remind us we’ve been driving too long, we might easily miss our exit. But how does the brain generate this finely tuned mental clock? Neuroscientists believe that we have distinct neural systems for processing different types of time, for example, to maintain a circadian rhythm, to control the timing of fine body movem nts, and for conscious awareness of time passage. Until recently, most neuroscientists believed that this latter type of temporal processing – the kind that alerts you when you’ve lingered over breakfast for too long – is supported by a single brain system. However, emerging research indicates that the model of a single neural clock might be too simplistic. A new study, recently published in the Journal of Neuroscience by neuroscientists at the University of California, Irvine, reveals that the brain may in fact have a second method for sensing elapsed time. What’s more, the authors propose that this second internal clock not only works in parallel with our primary neural clock, but may even compete with it.
To flexibly deal with our ever-changing world, we need to learn from both the negative and positive consequences of our behaviour. In other words, from punishment and reward. Hanneke den Ouden from the Donders Institute in Nijmegen demonstrated that serotonin and dopamine related genes influence how we base our choices on past punishments or rewards. This influence depends on which gene variant you inherited from your parents. These results were published in Neuron on November 20. The brain chemicals dopamine and serotonin partly determine our sensitivity to reward and punishment. At least, this was a common assumption . Hanneke den Ouden and Roshan Cools investigated this assumption together with colleagues from the Donders Institute and New York University. Den Ouden explains: “We used a simple computer game to test the genetic influence of the genes DAT1 and SERT, as these genes influence dopamine and serotonin. We discovered that the dopamine gene affects how we learn from the long-term consequences of our choices, while the serotonin gene affects our choices in the short term.”
Researchers have shed light on the chemistry that bonds one person to another by taking brain scans of men being stroked while in their underpants. The Finnish study found that gentle stroking – which was not in sexually arousing areas – changed levels of opioid brain chemicals which work behind the scenes to form lasting bonds in animals. The findings suggest that opioids might be the critical chemicals that enables human brains to distinguish between strangers and people who are closer to us, such as friends, families and lovers. “We know this is hugely important for humans because we have these strong, lasting bondings with friends and relatives and so on. But what kind of system maintains these bonds, and makes them last?” said Lauri Nummenmaa who studies the neural circuitry of emotions at Aalto University in Finland. Studies in animals have shown that opioids can play a crucial role in pairing up. Prairie voles are monogamous in the wild, but when given a drug that blocks opioid in their brains, they seek out other partners. If opioids are blocked in monkeys, they groom others less and neglect their babies. To see whether opioids were important in human bonding, the researchers invited nine couples into the lab. The men stripped off to their underpants and lay under a blanket in a PET scanner. The first scan was taken while the men were alone. For the second, their partners touched them gently all over, but avoided anywhere likely to arouse them sexually. “I’m really proud of the Finnish general public,” said Nummenmaa. “We had no problem whatsoever in recruiting people for the experiment.” When the researchers compared the men’s scans, they noticed that gentle stroking caused a drop in natural opioids in brain areas called the ventral striatum and the anterior cingulate cortex, which are mainstays of the brain’s reward circuitry. This was counter to expectations: they had expected levels to rise. Nummenmaa said that opioid might work in a similar way to a painkiller, with the body needing less the more comfortable it was. “The opioid system is typically engaged during pain, so you get a boost in painful situations. The social touching might be doing exactly the opposite. You can think of it as pain alleviation. That might be the underlying mechanism for why hooking up with others makes us feel so good in the first place,” said Nummenmaa. Details of the study were given at the Society for Neuroscience meeting in San Diego.
A Neuroscientist’s Radical Theory of How Networks Become Conscious
It’s a question that’s perplexed philosophers for centuries and scientists for decades: Where does consciousness come from? We know it exists, at least in ourselves. But how it arises from chemistry and electricity in our brains is an unsolved mystery. Neuroscientist Christof Koch, chief scientific officer at the Allen Institute for Brain Science, thinks he might know the answer. According to Koch, consciousness arises within any sufficiently complex, information-processing system. All animals, from humans on down to earthworms, are conscious; even the internet could be. That’s just the way the universe works. “The electric charge of an electron doesn’t arise out of more elemental properties. It simply has a charge,” says Koch. “Likewise, I argue that we live in a universe of space, time, mass, energy, and consciousness arising out of complex systems.” What Koch proposes is a scientifically refined version of an ancient philosophical doctrine called panpsychism — and, coming from someone else, it might sound more like spirituality than science. But Koch has devoted the last three decades to studying the neurological basis of consciousness. His work at the Allen Institute now puts him at the forefront of the BRAIN Initiative, the massive new effort to understand how brains work, which will begin next year. Koch’s insights have been detailed in dozens of scientific articles and a series of books, including last year’s Consciousness: Confessions of a Romantic Reductionist. WIRED talked to Koch about his understanding of this age-old question. (via A Neuroscientist’s Radical Theory of How Networks Become Conscious - Wired Science)
Sanguinetti showed study participants images of what appeared to be an abstract black object. Sometimes, however, there were real-world objects hidden at the borders of the black silhouette. In this image, the outlines of two seahorses can be seen in the white spaces surrounding the black object. Credit: Jay Sanguinetti (via Study: Your brain sees things you don’t)
As any indignant teacher would scold, students must be awake to learn. But what science is showing with increasing sophistication is how the brain uses sleep for learning as well. At the annual meeting of the Society for Neuroscience in San Diego Nov. 10, 2013, Brown University researchers will discuss new research describing the neural mechanism by which the sleeping brain locks in learning of a visual task. The mounting evidence is that during sleep the brain employs neural oscillations—brainwaves—of particular frequencies to consolidate learning in specific brain regions. In August, Brown scientists reported in the Journal of Neuroscience that two specific frequencies, fast-sigma and delta, that operated in the supplementary motor area of the brain were directly associated with learning a finger-tapping task akin to typing or playing the piano. The new results show something similar with a visual task in which 15 volunteers were trained to spot a hidden texture amid an obscuring pattern of lines. It’s a bit like an abstracted game of “Where’s Waldo” but such training is not merely an academic exercise, said Takeo Watanabe, professor of cognitive, linguistic, and psychological sciences at Brown. “Perceptual learning in general has been found to improve the visual ability of patients who have some decline of function due to aging,” Watanabe said.
The Biblical parable of the Good Samaritan, a traveler who stops on the road to help a badly wounded robbery victim that others had passed by, is a story that we see repeated again and again in the news. In Fort Lauderdale, Fla., after a woman lost control of her car on an Interstate freeway and flipped into a water-filled ditch, a man jumped in to rescue her from drowning. In Arizona, after a community college student lost a wallet containing her cash, credit cards, student ID and immigrant work permit, an unidentified person found it and dropped it off at her school’s office. In Oklahoma, after a teenage skateboarder tumbled from his board and suffered a concussion, a man he didn’t know found him by the side of the road and took him to get help. What motivates people to stop and help others that they didn’t previously know, with no apparent benefit to themselves? Traditionally, we’ve viewed people who engage in prosocial behavior — that is, voluntary acts performed to benefit others or society as a whole — as being motivated by moral character or spiritual beliefs. But in recent years, increasing evidence has emerged to suggest that the tendency to be a do-gooder may be influenced by genes. In a newly-published study in the journal Social Neuroscience, for example, researchers found that a single variation in a genotype seems to affect whether or not a person engages in prosocial acts. Individuals who have one variation of the genotype have a tendency toward social anxiety — that is, unease around other people, and are less inclined to help others in ways that involve personal interaction.