Why Music Makes Our Brain Sing

MUSIC is not tangible. You can’t eat it, drink it or mate with it. It doesn’t protect against the rain, wind or cold. It doesn’t vanquish predators or mend broken bones. And yet humans have always prized music — or well beyond prized, loved it.

In the modern age we spend great sums of money to attend concerts, download music files, play instruments and listen to our favorite artists whether we’re in a subway or salon. But even in Paleolithic times, people invested significant time and effort to create music, as the discovery of flutes carved from animal bones would suggest.

So why does this thingless “thing” — at its core, a mere sequence of sounds — hold such potentially enormous intrinsic value?

The quick and easy explanation is that music brings a unique pleasure to humans. Of course, that still leaves the question of why. But for that, neuroscience is starting to provide some answers.

More than a decade ago, our research team used brain imaging to show that music that people described as highly emotional engaged the reward system deep in their brains — activating subcortical nuclei known to be important in reward, motivation and emotion. Subsequently we found that listening to what might be called “peak emotional moments” in music — that moment when you feel a “chill” of pleasure to a musical passage — causes the release of the neurotransmitter dopamine, an essential signaling molecule in the brain.

When pleasurable music is heard, dopamine is released in the striatum — an ancient part of the brain found in other vertebrates as well — which is known to respond to naturally rewarding stimuli like food and sex and which is artificially targeted by drugs like cocaine and amphetamine.

But what may be most interesting here is when this neurotransmitter is released: not only when the music rises to a peak emotional moment, but also several seconds before, during what we might call the anticipation phase.

The idea that reward is partly related to anticipation (or the prediction of a desired outcome) has a long history in neuroscience. Making good predictions about the outcome of one’s actions would seem to be essential in the context of survival, after all. And dopamine neurons, both in humans and other animals, play a role in recording which of our predictions turn out to be correct.

To dig deeper into how music engages the brain’s reward system, we designed a study to mimic online music purchasing. Our goal was to determine what goes on in the brain when someone hears a new piece of music and decides he likes it enough to buy it.

We used music-recommendation programs to customize the selections to our listeners’ preferences, which turned out to be indie and electronic music, matching Montreal’s hip music scene. And we found that neural activity within the striatum — the reward-related structure — was directly proportional to the amount of money people were willing to spend.

But more interesting still was the cross talk between this structure and the auditory cortex, which also increased for songs that were ultimately purchased compared with those that were not.

Why the auditory cortex? Some 50 years ago, Wilder Penfield, the famed neurosurgeon and the founder of the Montreal Neurological Institute, reported that when neurosurgical patients received electrical stimulation to the auditory cortex while they were awake, they would sometimes report hearing music. Dr. Penfield’s observations, along with those of many others, suggest that musical information is likely to be represented in these brain regions.

The auditory cortex is also active when we imagine a tune: think of the first four notes of Beethoven’s Fifth Symphony — your cortex is abuzz! This ability allows us not only to experience music even when it’s physically absent, but also to invent new compositions and to reimagine how a piece might sound with a different tempo or instrumentation.

We also know that these areas of the brain encode the abstract relationships between sounds — for instance, the particular sound pattern that makes a major chord major, regardless of the key or instrument. Other studies show distinctive neural responses from similar regions when there is an unexpected break in a repetitive pattern of sounds, or in a chord progression. This is akin to what happens if you hear someone play a wrong note — easily noticeable even in an unfamiliar piece of music.

These cortical circuits allow us to make predictions about coming events on the basis of past events. They are thought to accumulate musical information over our lifetime, creating templates of the statistical regularities that are present in the music of our culture and enabling us to understand the music we hear in relation to our stored mental representations of the music we’ve heard.

So each act of listening to music may be thought of as both recapitulating the past and predicting the future. When we listen to music, these brain networks actively create expectations based on our stored knowledge.

Composers and performers intuitively understand this: they manipulate these prediction mechanisms to give us what we want — or to surprise us, perhaps even with something better.

In the cross talk between our cortical systems, which analyze patterns and yield expectations, and our ancient reward and motivational systems, may lie the answer to the question: does a particular piece of music move us?

When that answer is yes, there is little — in those moments of listening, at least — that we value more.

Gestures of Human and Ape Infants Are More Similar Than You Might Expect

Thirteen years after the release of On the Origin of Species, Charles Darwin published another report on the evolution of mankind. In the 1872 book The Expression of the Emotions in Man and Animals, the naturalist argued that people from different cultures exhibit any given emotion through the same facial expression. This hypothesis didn’t quite pan out—last year, researchers poked a hole in the idea by showing that the expression of emotions such as anger, happiness and fear wasn’t universal (PDF). Nonetheless, certain basic things—such as the urge to cry out in pain, an increase in blood pressure when feeling anger, even shrugging when we don’t understand something—cross cultures.

A new study, published today in the journal Frontiers in Psychology, compares such involuntary responses, but with an added twist: Some observable behaviors aren’t only universal to the human species, but to our closest relatives too—chimpanzees and bonobos.

Using video analysis, a team of UCLA researchers found that human, chimpanzee and bonobo babies make similar gestures when interacting with caregivers. Members of all three species reach with their arms and hands for objects or people, and point with their fingers or heads. They also raise their arms up, a motion indicating that they want to be picked up, in the same manner. Such gestures, which seemed to be innate in all three species, precede and eventually lead to the development of language in humans, the researchers say.

To pick up on these behaviors, the team studied three babies of differing species through videos taken over a number of months. The child stars of these videos included a chimpanzee named Panpanzee, a bonobo called Panbanisha and a human girl, identified as GN. The apes were raised together at the Georgia State University Language Research Center in Atlanta, where researchers study language and cognitive processes in chimps, monkeys and humans. There, Panpanzee and Panbanisha were taught to communicate with their human caregivers using gestures, noises and lexigrams, abstract symbols that represent words. The human child grew up in her family’s home, where her parents facilitated her learning.

Researchers filmed the child’s development for seven months, starting when she was 11 months old, while the apes were taped from 12 months of age to 26 months. In the early stages of the study, the observed gestures were of a communicative nature: all three infants engaged in the behavior with the intention of conveying how their emotions and needs. They made eye contact with their caregivers, added non-verbal vocalizations to their movements or exerted physical effort to elicit a response.

By the second half of the experiment, the production of communicative symbols—visual ones for the apes, vocal ones for the human—increased. As she grew older, the human child began using more spoken words, while the chimpanzee and bonobo learned and used more lexigrams. Eventually, the child began speaking to convey what she felt, rather than only gesturing. The apes, on the other hand, continued to rely on gestures. The study calls this divergence in behavior “the first indication of a distinctive human pathway to language.”

The researchers speculate that the matching behaviors can be traced to the last shared ancestor of humans, chimps and bobonos, who lived between four and seven million years ago. That ancestor probably exhibited the same early gestures, which all three species then inherited. When the species diverged, humans managed to build on this communicative capacity by eventually graduating to speech.

Hints of this can be seen in how the human child paired her gestures with non-speech vocalizations, the precursors to words, far more than the apes did. It’s this successful combinationof gestures and words that may have led to the birth of human language.

Evidence from a quiet MRI: Breastfeeding benefits babies’ brains

A study using brain images from “quiet” MRI machines adds to the growing body of evidence that breastfeeding improves brain development in infants. Breastfeeding alone produced better brain development than a combination of breastfeeding and formula, which produced better development than formula alone.

A new study by researchers from Brown University finds more evidence that breastfeeding is good for babies’ brains.

The study made use of specialized, baby-friendly magnetic resonance imaging (MRI) to look at the brain growth in a sample of children under the age of 4. The research found that by age 2, babies who had been breastfed exclusively for at least three months had enhanced development in key parts of the brain compared to children who were fed formula exclusively or who were fed a combination of formula and breastmilk. The extra growth was most pronounced in parts of the brain associated with language, emotional function, and cognition, the research showed.

This isn’t the first study to suggest that breastfeeding aids babies’ brain development. Behavioral studies have previously associated breastfeeding with better cognitive outcomes in older adolescents and adults. But this is the first imaging study that looked for differences associated with breastfeeding in the brains of very young and healthy children, said Sean Deoni, assistant professor of engineering at Brown and the study’s lead author.

“We wanted to see how early these changes in brain development actually occur,” Deoni said. “We show that they’re there almost right off the bat.”

The findings are in press in the journal NeuroImage and available now online.

Deoni leads Brown’s Advanced Baby Imaging Lab. He and his colleagues use quiet MRI machines that image babies’ brains as they sleep. The MRI technique Deoni has developed looks at the microstructure of the brain’s white matter, the tissue that contains long nerve fibers and helps different parts of the brain communicate with each other. Specifically, the technique looks for amounts of myelin, the fatty material that insulates nerve fibers and speeds electrical signals as they zip around the brain.

Deoni and his team looked at 133 babies ranging in ages from 10 months to four years. All of the babies had normal gestation times, and all came from families with similar socioeconomic statuses. The researchers split the babies into three groups: those whose mothers reported they exclusively breastfed for at least three months, those fed a combination of breastmilk and formula, and those fed formula alone. The researchers compared the older kids to the younger kids to establish growth trajectories in white matter for each group.

The study showed that the exclusively breastfed group had the fastest growth in myelinated white matter of the three groups, with the increase in white matter volume becoming substantial by age 2. The group fed both breastmilk and formula had more growth than the exclusively formula-fed group, but less than the breastmilk-only group.

“We’re finding the difference [in white matter growth] is on the order of 20 to 30 percent, comparing the breastfed and the non-breastfed kids,” said Deoni. “I think it’s astounding that you could have that much difference so early.”

Deoni and his team then backed up their imaging data with a set of basic cognitive tests on the older children. Those tests found increased language performance, visual reception, and motor control performance in the breastfed group.

The study also looked at the effects of the duration of breastfeeding. The researchers compared babies who were breastfed for more than a year with those breastfed less than a year, and found significantly enhanced brain growth in the babies who were breastfed longer — especially in areas of the brain dealing with motor function.

Deoni says the findings add to a substantial body of research that finds positive associations between breastfeeding and children’s brain health.

“I think I would argue that combined with all the other evidence, it seems like breastfeeding is absolutely beneficial,” he said.

Pioneering Study Demonstrates Benefit of Imaging Technique in Identifying Mental Illness

MRI may be an effective way to diagnose mental illnesses such as bipolar disorder, according to experts from the Icahn School of Medicine at Mount Sinai. In a landmark study using advanced techniques, the researchers were able to correctly distinguish bipolar patients from healthy individuals based on their brain scans alone. The data are published in the journal Psychological Medicine.

Currently, most mental illnesses are diagnosed based on symptoms only, creating an urgent need for new approaches to diagnosis. In bipolar disorder, there may be a significant delay in diagnosis due to the complex clinical presentation of the illness. In this study, Sophia Frangou, MD, Professor of Psychiatry and Chief of the Psychosis Research Program at the Icahn School of Medicine at Mount Sinai teamed up with Andy Simmons, MD, of the Kings College London and Janaina Mourao-Miranda, MD, of University College London, to explore whether brain imaging could help correctly identify patients with bipolar disorder.

“Bipolar disorder affects patients’ ability to regulate their emotions successfully, which puts them at great disadvantage in their lives,” said Dr. Frangou. “The situation is made worse by unacceptably long delays, sometimes of up to 10 years, in making the correct diagnosis. Bipolar disorder may be easily misdiagnosed for other disorders, such as depression or schizophrenia. This is why bipolar disorder ranks among the top ten disorders causing significant disability worldwide.”

Dr. Frangou and her team used MRI to scan the brains of people with bipolar disorder and of healthy individuals. Using advanced computational models, they were successful in correctly separating people with bipolar disorder from healthy individuals with 73 percent accuracy using their brain imaging scans alone. They replicated their finding in a separate group of patients and healthy individuals and found a 72 percent accuracy rate.

Dr. Simmons added, “The level of accuracy we achieved is comparable to that of many other tests used in medicine. Additionally, brain scanning is very acceptable to patients as most people consider it a routine diagnostic test.”

“This approach does not undermine the importance of rigorous clinical assessment and the importance of building relationships with patients but provides biological justification for the type of diagnosis made,” said Dr. Frangou. “However, diagnostic imaging for psychiatry is still under investigation and not ready for widespread use. Nonetheless, our results together with those from other labs are a harbinger of a major shift in the way we approach diagnosis in psychiatry.”

A 20-minute bout of yoga stimulates brain function immediately after

Researchers report that a single, 20-minute session of Hatha yoga significantly improved participants’ speed and accuracy on tests of working memory and inhibitory control, two measures of brain function associated with the ability to maintain focus and take in, retain and use new information. Participants performed significantly better immediately after the yoga practice than after moderate to vigorous aerobic exercise for the same amount of time.

The 30 study subjects were young, female, undergraduate students. The new findings appear in the Journal of Physical Activity and Health.

“Yoga is an ancient Indian science and way of life that includes not only physical movements and postures but also regulated breathing and meditation,” said Neha Gothe, who led the study while a graduate student at the University of Illinois at Urbana-Champaign. Gothe now is a professor of kinesiology, health and sport studies at Wayne State University in Detroit. “The practice involves an active attentional or mindfulness component but its potential benefits have not been thoroughly explored.”

“Yoga is becoming an increasingly popular form of exercise in the U.S. and it is imperative to systematically examine its health benefits, especially the mental health benefits that this unique mind-body form of activity may offer,” said Illinois kinesiology and community health professor Edward McAuley, who directs the Exercise Psychology Laboratory where the study was conducted.

The yoga intervention involved a 20-minute progression of seated, standing and supine yoga postures that included isometric contraction and relaxation of different muscle groups and regulated breathing. The session concluded with a meditative posture and deep breathing.

Participants also completed an aerobic exercise session where they walked or jogged on a treadmill for 20 minutes. Each subject worked out at a suitable speed and incline of the treadmill, with the goal of maintaining 60 to 70 percent of her maximum heart rate throughout the exercise session.

“This range was chosen to replicate previous findings that have shown improved cognitive performance in response to this intensity,” the researchers reported.

Gothe and her colleagues were surprised to see that participants showed more improvement in their reaction times and accuracy on cognitive tasks after yoga practice than after the aerobic exercise session, which showed no significant improvements on the working memory and inhibitory control scores.

“It appears that following yoga practice, the participants were better able to focus their mental resources, process information quickly, more accurately and also learn, hold and update pieces of information more effectively than after performing an aerobic exercise bout,” Gothe said. “The breathing and meditative exercises aim at calming the mind and body and keeping distracting thoughts away while you focus on your body, posture or breath. Maybe these processes translate beyond yoga practice when you try to perform mental tasks or day-to-day activities.”

Many factors could explain the results, Gothe said. “Enhanced self-awareness that comes with meditational exercises is just one of the possible mechanisms. Besides, meditation and breathing exercises are known to reduce anxiety and stress, which in turn can improve scores on some cognitive tests,” she said.

“We only examined the effects of a 20-minute bout of yoga and aerobic exercise in this study among female undergraduates,” McAuley said. “However, this study is extremely timely and the results will enable yoga researchers to power and design their interventions in the future. We see similar promising findings among older adults as well. Yoga research is in its nascent stages and with its increasing popularity across the globe, researchers need to adopt rigorous systematic approaches to examine not only its cognitive but also physical health benefits across the lifespan.”

Never forget a face? Researchers find women have better memory recall than men

New research from McMaster University suggests women can remember faces better than men, in part because they spend more time studying features without even knowing it, and a technique researchers say can help improve anyone’s memories.

The findings help to answer long-standing questions about why some people can remember faces easily while others quickly forget someone they’ve just met.

“The way we move our eyes across a new individual’s face affects our ability to recognize that individual later,” explains Jennifer Heisz, a research fellow at the Rotman Research Institute at Baycrest Health Sciences and newly appointed assistant professor in the Department of Kinesiology at McMaster University.

She co-authored the paper with David Shore, psychology professor at McMaster and psychology graduate student Molly Pottruff.

“Our findings provide new insights into the potential mechanisms of episodic memory and the differences between the sexes. We discovered that women look more at new faces than men do, which allows them to create a richer and more superior memory,” Heisz says.

Eye tracking technology was used to monitor where study participants looked—be it eyes, nose or mouth—while they were shown a series of randomly selected faces on a computer screen. Each face was assigned a name that participants were asked to remember.

One group was tested over the course of one day, another group tested over the course of four days.

“We found that women fixated on the features far more than men, but this strategy operates completely outside of our awareness. Individuals don’t usually notice where their eyes fixate, so it’s all subconscious.”

The implications are exciting, she says, because it means anyone can be taught to scan more and potentially have better memory.

“The results open the possibility that changing our eye movement pattern may lead to better memory,” says Shore. “Increased scanning may prove to be a simple strategy to improve face memory in the general population, especially for individuals with memory impairment like older adults.”

Fear: A Justified Response or Faulty Wiring?

Fear is one of the most primal feelings known to man and beast. As we develop in society and learn, fear is hard coded into our neural circuitry through the amygdala, a small, almond-shaped nuclei of neurons within the medial temporal lobe of the brain. For psychologists and neurologists, the amygdala is a particularly interesting region of the brain because it plays a role in emotional learning and can have profound effects on human and animal behavior.

On June 3, 2013, a new article studying amygdala activity in human beings will be published as part of JoVE Behavior, a new section of the video journal that focuses on the behavioral sciences. The technique, developed by Dr. Fred Helmstetter and his research group at the University of Wisconsin-Milwaukee, studies how the brain responds to anticipated painful stimuli, in this case an electric shock, in volunteer test subjects.

“We’re interested in how the brain reacts to stimuli in the environment and how it changes when we form a memory of what we experience.” Dr. Helmstetter explains. “The amygdala is a part of the brain that’s important for the way we determine what is dangerous and what is safe around us and how we react to threat.  This experiment is novel in that we are able to look at activity in the amygdala on a very detailed time scale while it responds to human faces.“

The technique takes advantage of two neuroimaging techniques: magnetic resonance imaging and magnetoencephalography. Magnetic resonance imaging (MRI) is a method where a test subject’s brain can be imaged in high resolution while the test subject is immobilized, creating a map of the brain. Once this map has been obtained, magnetoencephalography (MEG) is used to record the magnetic fields created by the electrical activity within the brain. When the test subject is shocked, or anticipates a shock, amygdala activity is picked up by the MEG and mapped to the MRI computer model.

As an emotional control center in the brain, the amygdala serves as a key component in a line of neurological structures that identify and respond to perceived threat. Dr. Helmstetter tells us, “There is good evidence to suggest that anxiety disorders and other psychopathology might be directly related to altered functioning of the amygdala. Prior work with other non-invasive imaging modalities supports this idea but has only been able to average the results of neural activity over several seconds which results in a poor picture of how neurons react to a stimulus over time. This work represents a significant improvement and will allow new questions to be answered.”

The article is part of the launch of JoVE Behavior, the eighth section of JoVE. Founded in 2006, JoVE has rapidly expanded its scope from general biology to many disciplines by visualizing experimentation. Director of Content Aaron Kolski-Andreaco, PhD explains that, “By dedicating a section to behavior, JoVE has provided a platform for researchers to visualize experiments aimed at answering questions about how we think, feel, and communicate with one another.   Emphasizing this area of science is the next logical step for our journal, as the multidisciplinary study of behavior is enabled by technological advancements in physics, chemistry, and the life sciences - areas JoVE has already covered.”

Blood Vessels in the Eye Linked With IQ, Cognitive Function

The width of blood vessels in the retina, located at the back of the eye, may indicate brain health years before the onset of dementia and other deficits, according to a new study published in Psychological Science, a journal of the Association for Psychological Science.

Research shows that younger people who score low on intelligence tests, such as IQ, tend to be at higher risk for poorer health and shorter lifespan, but factors like socioeconomic status and health behaviors don’t fully account for the relationship. Psychological scientist Idan Shalev of Duke University and colleagues wondered whether intelligence might serve as a marker indicating the health of the brain, and specifically the health of the system of blood vessels that provides oxygen and nutrients to the brain.

To investigate the potential link between intelligence and brain health, the researchers borrowed a technology from a somewhat unexpected domain: ophthalmology.

Shalev and colleagues used digital retinal imaging, a relatively new and noninvasive method, to gain a window onto vascular conditions in the brain by looking at the small blood vessels of the retina, located at the back of the eye. Retinal blood vessels share similar size, structure, and function with blood vessels in the brain and can provide a way of examining brain health in living humans.

The researchers examined data from participants taking part in the Dunedin Multidisciplinary Health and Development Study, a longitudinal investigation of health and behavior in over 1000 people born between April 1972 and March 1973 in Dunedin, New Zealand.

The results were intriguing.

Having wider retinal venules was linked with lower IQ scores at age 38, even after the researchers accounted for various health, lifestyle, and environmental risk factors that might have played a role.

Individuals who had wider retinal venules showed evidence of general cognitive deficits, with lower scores on numerous measures of neurospsychological functioning, including verbal comprehension, perceptual reasoning, working memory, and executive function.

Surprisingly, the data revealed that people who had wider venules at age 38 also had lower IQ in childhood, a full 25 years earlier.

It’s “remarkable that venular caliber in the eye is related, however modestly, to mental test scores of individuals in their 30s, and even to IQ scores in childhood,” the researchers observe.

The findings suggest that the processes linking vascular health and cognitive functioning begin much earlier than previously assumed, years before the onset of dementia and other age-related declines in brain functioning.

“Digital retinal imaging is a tool that is being used today mainly by eye doctors to study diseases of the eye,” Shalev notes. “But our initial findings indicate that it may be a useful investigative tool for psychological scientists who want to study the link between intelligence and health across the lifespan.”

The current study doesn’t address the specific mechanisms that drive the relationship between retinal vessels and cognitive functioning, but the researchers surmise that it may have to do with oxygen supply to the brain.

“Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities,” they conclude.