The Neuroscience Of Music
Why does music make us feel? On the one hand, music is a purely abstract art form, devoid of language or explicit ideas. The stories it tells are all subtlety and subtext. And yet, even though music says little, it still manages to touch us deep, to tickle some universal nerves. When listening to our favorite songs, our body betrays all the symptoms of emotional arousal. The pupils in our eyes dilate, our pulse and blood pressure rise, the electrical conductance of our skin is lowered, and the cerebellum, a brain region associated with bodily movement, becomes strangely active. Blood is even re-directed to the muscles in our legs. (Some speculate that this is why we begin tapping our feet.) In other words, sound stirs us at our biological roots. As Schopenhauer wrote, “It is we ourselves who are tortured by the strings.”
We can now begin to understand where these feelings come from, why a mass of vibrating air hurtling through space can trigger such intense states of excitement. A paper in Nature Neuroscience by a team of Montreal researchers marks an important step in revealing the precise underpinnings of “the potent pleasurable stimulus” that is music. Although the study involves plenty of fancy technology, including fMRI and ligand-based positron emission tomography (PET) scanning, the experiment itself was rather straightforward. After screening 217 individuals who responded to advertisements requesting people that experience “chills to instrumental music,” the scientists narrowed down the subject pool to ten. (These were the lucky few who most reliably got chills.) The scientists then asked the subjects to bring in their playlist of favorite songs – virtually every genre was represented, from techno to tango – and played them the music while their brain activity was monitored.
Read more
Filed under brain music emotion neuroimaging emotional arousal neuroscience psychology science
Attention, Learning, and the Value of Information
Despite many studies on selective attention, fundamental questions remain about its nature and neural mechanisms. Here I draw from the animal and machine learning fields that describe attention as a mechanism for active learning and uncertainty reduction and explore the implications of this view for understanding visual attention and eye movement control. I propose that a closer integration of these different views has the potential greatly to expand our understanding of oculomotor control and our ability to use this system as a window into high level but poorly understood cognitive functions, including the capacity for curiosity and exploration and for inferring internal models of the external world.
Filed under brain attention eye movements information neuroscience psychology science
You glimpse a stranger standing in the street. The light is hazy and the person’s face and clothing are indistinct. Who is it? Chances are you will think it is a man—and the reason for this is a survival reflex, according to an unusual study published on Wednesday.
Psychologists at the University of California at Los Angeles delved into our quest for visual clues when we assess other people.
They asked male and female students to look at 21 human silhouettes, all of them the same height, but with a progressively changing waist-to-hip ratio. The figures began with an obviously female “hourglass” figure and, after incremental changes, ended with an obviously male “hunk” figure. The volunteers were asked to say whether each of the 21 silhouettes was male or female, the idea being to identify the point where they saw a shift in gender.
What was striking, said researcher Kerri Johnson, was a preference for the volunteers to deem a shape to be a man whenever it was ambiguous—or could readily have been taken for a woman. “I was surprised by the size of the effect. It was a much stronger effect than I ever imagined,” Johnson said in a phone interview.
In the natural world, the demarcation between a woman’s shape and man’s shape comes when the ratio of the waist and hip circumferences is 0.8. But the volunteers, on average, placed the boundary at 0.68. In other words, an identifiable female shape for them was close to the idealised curves of a pinup.
Johnson’s team carried out three further studies, using a slightly different methods to see whether their approach had been skewed, and found that the bias in favour of men was unchanged. Are these errors in perception? Not so, said Johnson, who believes it to be an ancestral survival mechanism.
A man is likelier than a woman to be a bigger physical threat and our default perception is to prepare for risk: it’s better to be safe than sorry. “We suspect that this might be for a self-protective reason,” she said. “If you are walking down a dark alley at night, a woman poses no great physical threat to you in general, but if you encounter an unknown man, he’s more likely to have a physical formidability that could pose some risks.”
Johnson conceded that there could be cultural or ethnic factors which influence judgement but argued that the same kind of bias would prevail anywhere. “I think it’s entirely likely that if we were to test this in different populations we would probably have the same basic effect, the same pattern of judgement, although the strength of the judgement might vary,” she said.
The findings show how gender stereotypes can be reinforced, sometimes dangerously so, said the study. A woman could struggle if she has a body shape that is perceived as masculine and thus unattractive. “Consistent with other research, this is likely to produce preferences for extreme body shapes, particularly for women,” said the study.
The paper appears in the British journal Proceedings of the Royal Society B
(Source: medicalxpress.com)
Filed under perception bias survival mechanism gender stereotypes body shape neuroscience psychology science
Sharks see world as 50 shades of grey
Sharks are colour blind, a new molecular study by Australian scientists has confirmed, filling a gap in our knowledge about the evolution of colour vision. Dr Susan Theiss, from the University of Queensland, and colleagues, report their findings in the journal Biology Letters.
The evolution of colour vision has been studied in most vertebrates, but until recently, elasmobranchs (sharks, skates and rays) had been overlooked. Previous physiological research has shown some rays have colour vision but it suggested sharks were colour blind.
These previous studies looked at opsins, which are light-sensitive proteins found in the photoreceptor cells of the retina. Rod opsins are used in low light and produce a black and white image, while cone opsins are used in bright light, and often to see colours. Two or more different types of cone opsins are needed for colour vision.
While some ray species have multiple cone opsins as well as rods, studies in various shark species suggested they had only a single cone visual pigment.
To check whether this really was the case, Theiss and colleagues isolated the visual opsin genes from two wobbegong shark species: the spotted wobbegong Orectolobus maculatus and the ornate wobbegong O. ornatus.
Their findings confirm that wobbegongs possess only one cone opsin, meaning they see the world in shades of grey. The findings help fill in the picture of how colour vision evolved in different species.
"We know the earliest vertebrates had colour vision, but it has been lost by some groups over the course of evolution," says co-author Associate Professor Nathan Hart, a neuroecologist at the University of Western Australia.
Filed under vision visual system color vision color blind sharks evolution neuroscience science
Our eyes adapt to screens
The time most of us spend looking at a screen has rapidly increased over the past decade. If we’re not at work on the computer, we’re likely to stay tuned into the online sphere via a smart phone or tablet. Shelves of books are being replaced by a single e-book reader; and television shows and movies are available anywhere, any time.
So what does all this extra screen time mean for our eyes?
Well, you’ll be pleased to hear that like many good eye myths, there is simply no evidence to support this old wives’ tale.
Once we reach the age of ten years or so, it is practically impossible to injure the eyes by looking at something – the exception, of course, being staring at the Sun or similarly bright objects. Earlier in life, what we look at – or rather, how clearly we see – can affect our vision because the neural pathways between the eye and brain are still developing.
When we read off a piece of paper, light from the ambient environment is reflected off the surface of the paper and into our eyes. The retina at the back of the eye captures the light and begins the process of converting it into a signal that the brain understands.
The process of reading from screens is similar, except that the light is emitted directly by the screen, rather than being reflected.
Filed under brain vision visual adaptation visual system neuroscience psychology science
Electrical stimulation of the visual cortex may one day give image perception to blind people.
Work presented at the Society for Neuroscience meeting in New Orleans today suggests a way to create a completely new kind of visual prosthetic—one that restores vision by directly activating the brain.
In a poster session, researchers presented results showing how electrical stimulation of the visual cortex can evoke the sensation of simple flashes of light—including spatial information about those flashes.
While other researchers are trying to develop artificial retinas that feed visual signals into existing sensory pathways (see “A Retinal Prosthetic Powered by Light" and "Now I See You" for instance), the team behind the new work, from the Baylor College of Medicine and the University of Texas Health Science Center in Houston, is exploring the possibility of bypassing those routes all together. This could be vital for those whose retinas are unable to receive retinal stimulation.
The researchers used electrodes to stimulate the brains of three patients who were already undergoing brian surgery to treat epilepsy. All three were able to detect bright spots of light, called phosphenes, when certain regions of their brains were stimulated. And, in seven out of eight trials, the patients were able to correctly see the orientation of a phosphene—in one of two orientations, depending on the stimulation they received.
The work builds upon a study published by the same team in Nature Neuroscience this summer. In that study, the researchers defined which areas of the brain produce phosphene perception when patients’ brains were electrically stimulated.
A press release related to the earlier work says that the researchers “plan to conduct a larger patient study and create multiple flashes of light at the same time. Twenty-seven or so simultaneous flashes might allow participants to see the outline of a letter.”
Filed under blindness neuroscience prosthetics retina vision visual perception Neuroscience 2012 science
Scientists read dreams: Brain scans during sleep can decode visual content of dreams
A team of researchers led by Yukiyasu Kamitani of the ATR Computational Neuroscience Laboratories in Kyoto, Japan, used functional neuroimaging to scan the brains of three people as they slept, simultaneously recording their brain waves using electroencephalography (EEG).
The researchers woke the participants whenever they detected the pattern of brain waves associated with sleep onset, asked them what they had just dreamed about, and then asked them to go back to sleep.
This was done in three-hour blocks, and repeated between seven and ten times, on different days, for each participant. During each block, participants were woken up ten times per hour. Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports.
Read more
Filed under brain sleep dream neuroimaging Neuroscience 2012 neuroscience psychology science
Why crying babies are so hard to ignore: Study suggests the sound of a baby crying activates primitive parts of the brain involved in fight-or-flight responses
Ever wondered why it is so difficult to ignore the sound of a crying baby when you are trapped aboard a train or aeroplane? Scientists have found that our brains are hard-wired to respond strongly to the sound, making us more attentive and priming our bodies to help whenever we hear it – even if we’re not the baby’s parents.
"The sound of a baby cry captures your attention in a way that few other sounds in the environment generally do," said Katie Young of the University of Oxford, who led the study looking at how the brain processes a baby’s cries.
She scanned the brains of 28 people while they listened to the sound of babies and adults crying and sounds of animal distress including cats meowing and dogs whining.
Using a very fast scanning technique, called magnetoencephalography, Young found an early burst of activity in the brain in response to the sound of a baby cry, followed by an intense reaction after about 100 milliseconds. The reaction to other sounds was not as intense. “This was primarily in two regions of the brain,” said Young. “One is the middle temporal gyrus, an area previously implicated in emotional processing and speech; the other area is the orbitofrontal cortex, an area well-known for its role in reward and emotion processing.”
Young and her colleague, Christine Parsons, presented their findings this week at the annual meeting of the Society for Neuroscience in New Orleans.
Filed under brain Neuroscience 2012 magnetoencephalography brain activity crying baby sound neuroscience psychology science
There’s a reason genius and solitude seem to go hand in hand, a new study says. Social rejection leads to creative problem solving.
Don’t let rejection get you down—it might be the ticket to creativity, science says. That’s right: If regular rejection doesn’t cause you to lose all self-confidence and withdraw from the world entirely, it just might boost your ability to think outside of the mainstream and draw upon a unique worldview, suggesting that the kind of people society considers “geniuses” might tend to have a go-it-alone, loner mentality.
Research conducted by Cornell and Johns Hopkins University researchers has shown that people who are able to handle rejection in the proper manner—by shrugging it off and blazing their own, independent trails—can experience heightened creativity and even commercial success through an ability to eschew mainstream thought and groupthink and instead pursue their own creative solutions to problems. They tested their hypothesis through a series of experiments in which they manipulated the experience of social rejection; subjects in the study were led to believe that everyone in a group exercise could choose whom to work with on a team project, only to be told later that no one had selected them for a team.
For people with an independent mindset, this rejection inspired them to go on and complete the exercise in a way that was deemed more creative (we’re not exactly sure how “creativity” was measured). For people without an independent mindset—well, we’re not really sure what kind of impact this exclusion had on them (hopefully someone later told them it was just an experiment, it was all in good fun, and really, everyone here thinks you’re great).
The researchers acknowledge that for some, the consequences of rejection can be quite negative. Their research is only intended to show that for those of a certain mindset, social rejection can have a silver lining, driving home something that we more or less already knew: it’s not easy being a genius.
(Source: popsci.com)
Filed under brain creativity science social rejection rejection problem solving neuroscience psychology
The idea that an individual might suffer from a sexual addiction is great fodder for radio talk shows, comedians and late night TV. But a sex addiction is no laughing matter. Relationships are destroyed, jobs are lost, lives ruined.
Yet psychiatrists have been reluctant to accept the idea of out-of-control sexual behavior as a mental health disorder because of the lack of scientific evidence.
Now a UCLA-led team of experts has tested a proposed set of criteria to define “hypersexual disorder,” also known as sexual addiction, as a new mental health condition.
Rory Reid, a research psychologist and assistant professor of psychiatry at the Semel Institute of Neuroscience and Human Behavior at UCLA, led a team of psychiatrists, psychologists, social workers, and marriage and family therapists that found the proposed criteria to be reliable and valid in helping mental health professionals accurately diagnose hypersexual disorder.
The results of this study — reported in the current edition of the Journal of Sexual Medicine — will influence whether hypersexual disorder should be included in the forthcoming revised fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), considered the “bible” of psychiatry.
The importance of the study, Reid said, is that it suggests evidence in support of hypersexual disorder as a legitimate mental health condition.
"The criteria for hypersexual disorder that have been proposed, and now tested, will allow researchers and clinicians to study, treat and develop prevention strategies for individuals at risk for developing hypersexual behavior," he said.
(Source: newsroom.ucla.edu)
Read more …
Filed under sex addiction hypersexual disorder mental health disorder DSM-5 neuroscience psychology science
