Posts Tagged ‘ music ’

Musical Learning

A new study throws some light on how musical aptitude can offset one very specific aspect of the aging process.

The question of Why Those Young Men Always Sound So Angry remains ripe for investigation.

In research comparing older patients with musical training to those without, older people who’d spent time regularly practicing or teaching music consistently displayed much faster neural reaction times to certain kinds of sounds.

The idea that the human brain has a deep relationship with music is obviously nothing new – but lately, research has been demonstrating more and more ways in which music is a major ingredient in mental health. For example, a 2007 study found that the brain reacts to music by automatically heightening attention, and one in 2010 found that an ear for harmony was correlated with a better ability to distinguish speech from noise.

The therapeutic implications of all this haven’t gone unnoticed. The neuroscientist Michael Merzenich has cured patients of chronic tinnitus (ear-ringing) by prescribing them musical training – and he’s had remarkable success using it to improve the responsiveness of autistic children.

Inspired by Merzenich’s work, a team led by Northwestern University’s Nina Kraus made up an experiment: They decided to record the reaction times of musicians‘ brains when they heard certain sounds, and compare those against the reaction times of people with no musical training.

As the journal Neurobiology of Aging reports, the team inserted electrodes directly into the patients’ brains during surgery, like this (WARNING – the following image is a very cool but very bloody photo of brain surgery): here, and recorded exactly how quickly their auditory cortex reacted to a variety of speech sounds.

They found that older musicians’ brains seemed to keep their youthful reaction speeds; at least when it came to a certain kind of sound: The syllable “da” – one of the “hard” vowel sounds known as formant transitions in science slang:

Although younger and older musicians exhibited equivalent response timing for the formant transition, older nonmusicians demonstrated significantly later re-sponse timing relative to younger nonmusicians … The main effect of musicianship observed for the neural response to the onset and the transition was driven solely by group differences in the older participants.

In other words, a musicians’ brain responds to the “da” sound just as quickly as it did in youth – but a nonmusician’s response time slows down significantly as it ages.

The slowdown isn’t much – only a few milliseconds – but in brain time, that can be enough to cause problems. See, we’re not talking about conscious reaction time here – this is electrophysiological reaction time – the speed at which information travels in the brain.

Why does this matter? Because mental issues like autism, senile dementia and schizophrenia are all related to very slight timing errors in the brain’s elaborate communication patterns. An aging brain isn’t so much an old clock as an old city. Ever notice how the most ancient cities tend to be the ones with the weirdest cultures? Well, there ya go.

Just like old cities, though, autism and dementia and schizophrenia – and aging – can be scary sometimes, but they’re also the sources of great breakthroughs, and remarkable insights, and all sorts of conversations that couldn’t have happened otherwise.

What I’m saying is, the only measurable difference between a disorder and a gift is that one is helpful and the other isn’t. And in most cases, that difference really comes down to timing.

The Colors, Man! The Colors!

Scientists have discovered direct neural correlates of synesthesia, a new study reports.

They sound like unicorns and rainbows.

Not only have they detected activation patterns corresponding to synesthesic activity (such as “seeing” certain colors when thinking of certain numbers or sounds) – they’ve isolated an actual functional difference in the brains of synesthesic people. And what’s more, they’ve discovered a way to crank up synesthesic activity.

Let’s break this down and talk about what they’ve done here.

To understand what’s going on, let’s take a quick glance at history. Synesthesia’s fascinated artists and scientists since way back – in fact, the first people to write about it were the ancient Greeks, who composed treatises on the “colors” of various musical sounds.

Centuries later, Newton and Goethe both wrote that musical tones probably shared frequencies with color tones – and though that idea turned out to be incorrect, it did inspire the construction of “color organs” whose keyboards mapped specific notes to specific shades.

The first doctor to study synesthesia from a rigorous medical perspective was Gustav Fechner, who performed extensive surveys of synesthetes throughout the 1870s. The topic went on to catch the interest of other influential scientists in the late 19th century – but with the rise of behaviorism in the 1930s, objective studies on subjective experiences became taboo in the psychology community, and synesthesia was left out in the cold for a few decades.

In the 1950s, the cognitive revolution made studying cognition and subjective experience cool again – but it wasn’t until the 1980s that synesthesia returned to the scientific spotlight, as neuroscientists and psychologists like  Richard Cytowic and Simon Baron-Cohen began to classify and break down synesthetic experiences. For the first time, synesthesic experiences were organized into distinct types, and studied under controlled lab conditions.

Today, most synesthesia research focuses on grapheme → color synesthesia – in which numbers and letters are associated with specific colors – because it’s pretty straightforward to study. And thanks to the “insider reporting” of synesthetes like Daniel Tammett, we’re getting ever-clearer glimpses into the synesthetic experience.

But as the journal Current Biology reports, today marks a major leap forward in our understanding of synesthesia: a team led by Oxford University’s Devin Terhune has discovered that the visual cortex of grapheme → color synesthetes is more sensitive – and therefore, more responsive – than it is in people who don’t experience synesthesia.

The team demonstrated this by applying transcranial magnetic stimulation (TMS) to the visual cortices of volunteers, which led to a thrilling discovery:

Synesthetes display 3-fold lower phosphene thresholds than controls during stimulation of the primary visual cortex. … These results indicate that hyperexcitability acts as a source of noise in visual cortex that influences the availability of the neuronal signals underlying conscious awareness of synesthetic photisms.

In short, the visual cortex of a synesthete is three times more sensitive to incoming signals than that of a non-synesthete – which means tiny electrochemical signals that a non-synesthete’s brain might consider stray noise get interpreted into “mind’s-eye” experiences in a synesthete’s visual cortex.The question of what, exactly, causes this difference in the first place remains a Science Mystery, ripe for investigation.

But wait – this study gets much, much cooler.

There’s a technology called transcranial direct current stimulation (TDCS), which changes the firing thresholds of targeted neurons – making them more or less likely to fire when they get hit with a signal. The researchers applied TDCS to specific parts of the visual cortex, and found that they could “turn up” and “turn down” the intensity of the synesthesic experience:

Synesthesia can be selectively augmented with cathodal stimulation and attenuated with anodal stimulation of primary visual cortex. A control task revealed that the effect of the brain stimulation was specific to the experience of synesthesia.

In other words, they’ve discovered a technological mechanism for directly controlling the experience of synesthesia.

So Burning Question #1 is, Could TDCS be used to induce synesthesia – or create hallucinations – in non-synesthetes? With the right neurological and psychological preparation, it certainly seems possible. And Burning Question #2 is, could it be used to “turn down” the intensity of hallucinations in people with schizophrenia and other psychological disorders? It’ll take a lot more lab work to answer that question with any certainty – but I’d say it merits some lookin’ into.

In the meantime, I’m going to find some nice green music to listen to.

______________

1. This means synesthesia is somewhat similar to Charles Bonnet syndrome – in which blind patients see vivid, detailed hallucinations when their under-stimulated (and thus, hyper-sensitive) visual cortices catch a stray signal – and to musical ear syndrome, in which deaf people vividly hear singing. Here’s an amazing TED talk by Oliver Sacks on that very topic.

The Brain Lab Tour

This past weekend, I got to visit one of the coolest places I’ve ever seen: the UCLA Laboratory of Neuro Imaging (LONI). So just for today, I’m gonna take a break from news reporting, and tell you a little about what goes on inside an actual cutting-edge neuroscience lab. Sound good? OK, let’s go!

I'd be okay with just bringing a tent and camping out here.

I’m not sure quite what I was expecting to see as I stepped through the lab’s electronically locked door – certainly not the roomful of clean, open-walled work areas that greeted me. I might’ve been standing in a sleek law office, or an advertising agency – except that the flatscreens adorning the walls displayed colorful 3-D brain maps and reams of dense scientific data.

Imagine being five years old, celebrating Christmas morning at Disneyland - you get the idea.

But before I could start running around making googly-eyes at everything, it was time to meet my host – the delightful Eileen Luders, who’d offered to give me a tour of the lab when I’d gushed about my enthusiasm for her work. Eileen studies neural correlates of meditative states, and she’s also interested in isolating tiny structural variations that correspond to specific kinds of intelligence. More on this awesomeness shortly.

After introductions and a bit of happy chitchat, Eileen led me to a small screening room, whose entire front wall was an enormous wraparound high-resolution video screen. From the control booth, a lab technician dimmed the lights and played us a promo video that was ten minutes of pure heaven. We flew through huge, detailed 3-D brain atlases, watching neural pathways assemble and disassemble before our eyes. We plunged into the brains of schizophrenics and drug abusers and meditators, as data from fMRI and DTI and OTI exploded into multicolored digital sculptures of these brains’ structures and functions.

When it was over (all too soon), I asked Eileen what the lab normally uses this room for. “Mostly meetings,” she said with a chuckle.

As we strolled back to her office, she explained the principle on which this lab works: all the scans are processed by one huge supercomputer array housed in a well-locked room. All a team (or scientist) needs to perform a basic scan is the lab’s permission, about $600, and the time and technical know-how to program the scan they want and parse its results into meaningful data.

Researchers do most of this coding and data analysis from the comfort of the cubicle-esque work areas that fill most of the lab – and this non-centralization frees up more time on the scanners for other researchers, which keeps the lab more affordable and efficient for everyone.

And then we got to talking about some really cool stuff.

I asked Eileen what had gotten her so interested in the neuroscience of meditative states, and she told me she’s always been fascinated by the chasm between subjective experience (i.e., learning how to meditate) and objective science (i.e., what happens in our brains when we meditate). So, she’s been working to help narrow that gap – to study the brain activity of meditators as they meditate, give them feedback about the results – and essentially do her best to act as a fairly seamless translator between mind and machine (and vice versa).

I asked her what it was like having monks visit the lab. She told me two things: “They’re incredibly sharp; incredibly present,” she said. “And they were really excited to see if the bathroom was as cool as everything else.” In short, monks frickin’ rule.

Thinking about meditation, I wondered aloud whether singing and chanting might reflect an inherently different cognitive process from speech. There’s some (very preliminary) research suggesting that certain tones and vocalizations (such as chanting “aum” or humming a major scale) may help modulate patterns of neural activity far more directly than words can. Eileen mentioned that she’s done a bit of research on yogic chanting that might point in this direction. (Too bad we can’t time-travel back to 1968 and put these guys in one of her scanners.)

Anyway, it’s easy to see why Eileen’s also interested in finding neural correlates for specific kinds of intelligence. This got us talking about one of her other pet projects: looking for neural correlates of gender differences. She pointed out that women’s brains are, on average, a little smaller than men’s – “But when you adjust a male and female brain to equal size,” she said, “the differences aren’t nearly as obvious as they might appear at first glance.”  (A few days later, she sent me a published, peer-reviewed paper she’s written on this topic; I’m looking forward to diving into it.)

By this time, it was starting to get late, so Eileen offered me a quick tour of the lab before rushing off to do more Awesome Neuroscience Stuff. We peeked through the window of the supercomputer room, where multicolored lights flickered on rows of imposing black towers. We poked our heads into the wet lab, where neuroanatomists actually freeze and dissect brains. We stopped by a few workstations where technicians were busy designing scanning programs or analyzing their output. I wish I’d been able to take photos.

And then it was time to say goodbye. As Eileen and I shook hands at the doorway, I couldn’t help feeling that I wanted to give her a hug – to hug the whole lab, and everyone in it. It just made me so happy to think that there are other people like us – people filled with a deep yearning to understand what’s going on inside our heads, and just how it works – people driven to dedicate massive amounts of time and money to finding the pieces of this crazy puzzle, and starting to fit a few of those pieces together.

But most of all, I’m so glad that those people are kind, and friendly, and every bit as geeky as I am. Neuroscience FTW!

Musical Matchups

Our brains process music via different sensory pathways depending on what we think its source is, a new study finds.

Let me stop ya right there - "Stairway to Heaven" is off-limits.

As our brains organize information from our senses into a coherent representation of the world around us, they’re constantly hard at work associating data from one sense – say, sight – with data from another – say, hearing.

A lot of the time, this process is pretty straightforward – for instance, if we see a man talking and hear a nearby male voice, it’s typically safe for our brains to assume the voice “goes with” the man’s lip movements. But it’s also not too hard for others to trick this association process – as anyone who’s watched a good ventriloquism act knows.

Now, as the journal Proceedings of the National Academy of Sciences (PNAS) reports, a team led by HweeLing Lee and Uta Noppeney at the Max Planck Institute for Biological Cybernetics has discovered a way in which musicians‘ brains are specially tuned to correlate information from different senses when their favorite instruments are involved.

Neuroscientists have known for years that the motor cortex in the brains of well-trained guitar and piano players devotes much more processing power to fingertip touch and finger movement than the same area of a non-musician’s brain does. But what this new study tells us is that the brains of pianists are also much more finely-tuned to detect whether a finger stroke is precisely synchronous with a sound produced by the touch of a piano key.

To figure this out, the team assembled 18 pianists – amateurs who practice on a regular basis – and compared their ability to tell synchronous piano tones and keystrokes from slightly asynchronous ones while they lay in an fMRI scanner (presumably by showing them this video). The researchers also tested the pianists’ ability to tell when lip movements were precisely synchronized with spoken sentences.

The team then compared the musicians’ test results against the results of equivalent tests taken by 19 non-musicians. What they found was pretty striking:

Behaviorally, musicians exhibited a narrower temporal integration window than non-musicians for music but not for speech. At the neural level, musicians showed increased audiovisual asynchrony responses and effective connectivity selectively for music in a superior temporal sulcus-premotor-cerebellar circuitry.

In short, pianists are much more sensitive to a slight asynchrony between a keystroke and a piano tone than non-musicians are – but this sensitivity doesn’t also apply to speech and lip movements. In other words, pianists’ brains are unusually sensitive to asynchrony only when it involves piano keystrokes.

Another important finding is that the researchers could predict how sensitive the musicians would be to asynchrony based on asynchronies the fMRI scanner detected in their motor cortex:

Our results suggest that piano practicing fine tunes an internal forward model mapping from action plans of piano playing onto visible finger movements and sounds.

This means there’s a direct link between inter-neural coordination and ear-eye coordination. I don’t know about you, but I think that’s pretty incredible.

The researchers hope that as they study similar data from musicians who work with other instruments, they’ll come to better understand how our brains learn to associate stimuli from one sense from information from another – and maybe even how they learn when and when not to “sync up” these stimuli in our subjective experience of reality.

It’s too bad we can’t hook up the brain of, say, Mozart or Hendrix to an fMRI scanner – who knows what amazing discoveries we might make. But even so, I’m sure you can think of some living musical geniuses whose brains you’d like to see in action.

Follow

Get every new post delivered to your Inbox.

Join 75 other followers