报告题目：Time-varying statistical measures for studying brain functional connectivity报告人：Hongmei Zhu York University, Canada日期：2012年12月20日14:00地点：信息学院四楼报告厅Abstract: Time-frequency analysis is a powerful tool for understanding non-stationary characteristics of data such as brain signals. It can not only reveal brain activities occurred in a single brain region but also be used to derive statistical measures, such as coherence, to describe functional dynamics between different brain regions. In this talk, we address the use of time-frequency analysis to estimate time-varying statistical measures and then apply them to investigate motor cortex activities under the multisource interference task.Bio: Dr. Zhu is an Associate Professor at the Department of Mathematics and Statistics, York University, Canada. She holds a PhD in Applied Mathematics at the University of Waterloo and worked as a MS Society of Canada postdoctoral fellowship at the Seaman MR Centre at Foothills Hospital, University of Calgary between 2001 and 2004. Hongmei’s research interests are in the areas of time-frequency analysis, data analysis, numerical computations and their applications in real-world problems arisen from biomedicine and other industries.
Have you ever met someone who just wasn’t into music？ They may have a condition called specific musical anhedonia， which affects three-to-five percent of the population。
Canada Research Chair (Tier II) in Neurobiology of Motor Learning
Researchers at the University of Barcelona （Spain） and the Montreal Neurological Institute and Hospital of McGill University （Canada） have discovered that people with this condition showed reduced functional connectivity between cortical regions responsible for processing sound and subcortical regions related to reward。
Director, Brain Behaviour Laboratory
CIHR Delegate & Health Research Advisor to the VP Research
To understand the origins of specific musical anhedonia， researchers recruited 45 healthy participants who completed a questionnaire measuring their level of sensitivity to music and divided them into three groups of sensitivity based on their responses。 The test subjects then listened to music excerpts inside an fMRI machine while providing pleasure ratings in real-time。 To control for their brain response to other reward types， participants also played a monetary gambling task in which they could win or lose real money。
TED演讲题目“After watching this, your brain will not be the same”
Using the fMRI data， the researchers found that while listening to music， specific musical anhedonics presented a reduction in the activity of the nucleus accumbens， a key subcortical structure of the reward network。 The reduction was not related to a general improper functioning of the nucleus accumbens itself， since this region was activated when they won money in the gambling task。
Specific musical anhedonics， however， did show reduced functional connectivity between cortical regions associated with auditory processing and the nucleus accumbens。 In contrast， individuals with high sensitivity to music showed enhanced connectivity。
After Watching This, Your Brain Will Not BeThe Same by Lara Boyd
The fact that subjects could be insensible to music while still responsive to another stimulus like money suggests different pathways to reward for different stimuli。 This finding may pave the way for the detailed study of the neural substrates underlying other domain-specific anhedonias and， from an evolutionary perspective， help us to understand how music acquired reward value。
Dr. Lara Boyd,physical therapistandneuroscientist, saysAfter
Watching This, Your Brain Will Not Be The Sameat TEDxVancouver. Below is the fulltranscript. This event took place TEDxVancouver at Rogers Arena on November 14,2015.
Lack of brain connectivity has been shown to be responsible for other deficits in cognitive ability。 Studies of children with autism spectrum disorder， for example， have shown that their inability to experience the human voice as pleasurable may be explained by a reduced coupling between the bilateral posterior superior temporal sulcus and distributed nodes of the reward system， including the nucleus accumbens。
Dr. Lara Boyd– Physical therapist and neuroscientist
“These findings not only help us to understand individual variability in the way the reward system functions， but also can be applied to the development of therapies for treatment of reward-related disorders， including apathy， depression， and addiction，” says Robert Zatorre， a Montreal Neurological Institute neuroscientist and one of the paper’s co-authors。
So how do we learn? And why does some of us learn things more easily thanothers? So, as I just mentioned, I’m Dr. Lara Boyd. I am a brain researcherhere at the University of British Columbia. These are the questions thatfascinateme.
So brain research is one of the greatfrontiersin the understanding ofhuman physiology,and also in theconsideration of what makes us who we are. It’s an amazing time to be a brainresearcher and, I would argue to you that I have the most interesting job inthe world.
What we know about the brain is changing at abreathtaking pace, and much of what wethought we knew and understood about the brain turns out to be not true, orincomplete. Now some of these misconceptions are more obvious than others. Forexample, we used to think that after childhood the brain did not, really couldnot change.And it turns out
that nothing can be farther than the truth.
misconception about the brain is that you only use parts of it at any given
time and silent when you do nothing. Well, this is also untrue. It turns out
that even when you are at a rest, and thinking of nothing, your brain is highly
active. So it’s been advances in technology, such as MRI, that’s allowed us to
make these and many other important discoveries. And perhaps the most exciting, the most interesting and
transformative of these discoveries is that, every time you learn a new fact or
skill, you change your brain. It’s something we callneuroplasticity.
So as little as least 25 years ago we thought that after aboutpuberty, the onlychanges that took place in the brain were negative. The loss of brain cellswith aging, resulted damage, like a stroke.And then studies began to show remarkable amounts of
reorganization in the adult brain. And the ensuing research has shown us that
all of our behaviors change our brain. That these changes are not limited by
age, it’s good news right? And in fact they are taking place all the time. And
very importantly, brain reorganization helps to support recovery after you
damage your brain.
The key to eachof these changes isneuroplasticity.So what does it look like? So your brain can change in three very basic ways tosupport learning.And the
first ischemical.So brain actually functions bytransferring chemicals signals between brain cells, what we callneurons(神经元，神经细胞),and this triggers series of actions andreactions. So to support learning your brain can increase the amount of theconcentrations of these chemical signaling that’s taking place between neurons.Now because this kind of change can happen rapidly, this supports short termmemory or the short term improvement in the performance of amotor skill.
The second waythat the brain can change to support
learning is byaltering
its structure. So during learning the brain can change the connectionsbetween neurons.Now here the
physical structure of the brain is actually changing so this takes a bit more
time.These types of changes are related to the long termmemory, the long term improvement in a motor skill.
processes they interact, and let me give you an example of how. So we’ve all
tried to learn a new motor skill. Maybe playing a piano, maybe learning to
juggle. You have had the experience of getting better and better within a
single session of practice, and thinking“I have
And then maybe you return the next day and all those improvements from theday before they are lost. What happened? Well in the short term, your brain wasable to increasethe chemical
signalingbetween yourneurons.But for some reason those changes did not induce the structural change
that are necessary to support long term memory.Remember thatlong term memories take time. And what you see in the short term does notreflect learning.It’s these
physical changes that are now going to support long term memories, and chemical
changes that support short term memories.
Structural changes also can lead to integrated networks of brain
regions that function together to support learning.And it can alsolead to certain brain regions that are important for very specific behaviors tochange your structure or to enlarge. So here are some examples of that. Sopeople who readbraillethey have larger hand*sensory areas*in their brain than those ofus who don’t. Yourdominanthand motorregion, which is on the left side of your brain, if you are right handed, islarger than the other side. And research shows that London taxi cab drivers whoactually have to memorize a map of London to get their taxi cab license, theyhave larger brain regions devoted to spacial, or mapping memories.
Now the last way that your brain can change to support
learning is byaltering
its function.As you use abrain region it becomes more and more excitable and easy to use again. And asyour brain has these areas that increase their excitability the brain shiftshow and when they are activated. With learning we see that whole networks ofbrain activity are shifting and changing.
So neuroplasticity is
supported by chemical, by structural and by functional changes. And these are
happening across the whole brain.*They can occurin isolation from one another, but most often they take place in concert.Together they support learning. And they’re taking place all the time.*
So I just told you really how
awesomely neuroplastic your brain is.So why can’tyou learn anything you choose to with ease? Why do our kids sometimes fail inschool? Why as we age do we tend to forget things? And why don’t people fullyrecover from brain damage?That is, what is it that limits and facilitates neuroplasticity?
And so this is what I study. I studyspecificallyhow it relates to recovery from stroke. Sorecently stroke dropped from being the third leading cause of the death in theUnited States to be the fourth leading cause of the death. Great news, right?But actually it turns out that the numbers of people having a stroke has notdeclined. We arejust better at keeping people alive after asevere stroke. It turns out to be verydifficult to help the brain recover from stroke. And frankly we have failed todevelop effective rehabilitationinterventions.
The net result of this is that stroke is the leading cause of long termdisability in adults in the world. Individuals with stroke are younger andtending to live longer with that disability. And research from my groupactually shows that the health relatedquality of lifeofCanadians with stroke hasdeclined.
So clearly we need to be better at helping people recover from stroke.And this is an enormous societal
problem, and it’s one that we are not solving.So what can be
done? One thing is absolutely clear: the best driver of neuroplastic change in
your brain is your behavior. The problem is that the dose of behavior, the dose
of practice that’s required to learn new and relearn old motor skills, it’s
very large. And how to effectively deliver these large doses of practice is a
very difficult problem. It’s also a very expensive problem.
So the approach that my research has taken is to develop therapies thatprime or that prepare the brain to learn. And these have includedbrain simulation, exercise and
robotics. But through my research I’ve realized that a major limitationto the development of therapies that speed recovery from stroke is thatpatterns of neuroplasticity are highly variable from person to person.
Now as a researcher, variability used to drive me crazy. It makes it verydifficult to use statistics to test your data and your ideas. And because ofthis,medical intervention studiesare specificallydesigned to minimize variability. But in my research it’s becoming really clearthat the most important, the most informative data that we collect, is showingthis variability.
So by studying the brain after a stroke, we’ve learned a lot and I thinkthese lessons are very valuable in other areas.So the first
lesson is that the primary driver of change in your brain is your behavior, so
there is no neuroplasticity drug you can take. Nothing is more effective than
practice at helping you learn and the bottom line is you have to do the work.
And in fact, my research has shown that increased
difficulty, increased struggle if you will, during practice actually leads to
both more learning and greater structural change in the brain.The problem hereis, is that neuroplastcity can work both ways. It can be positive, you learnsomething new and you refine the motor skill. And it also can be negativethough, you forgot something you once knew, you become addicted to drugs, maybeyou have chronic pain.So your brain is tremendously**
plastic and it’s being shaped both structurally and functionally by everything
you do, but also by everything that you don’t do.
The second lesson we’ve learned about the brain is that
there is no one size fits all approach to learning.So there is norecipefor learning.Consider the popular belief that it takes 10,000 hours of practice to learn andto master a new motor skill. Now I can assure you it’s not quite that simple.For some of us it’s going to take a lot more practice and for others it maytake far less.So the shaping of our plastic brains is it’s far
too unique for there to be any single intervention that’s going to work for all
And now this realization has forced us to considersomething call personalized medicine. So this is the idea that to optimizeoutcomes each individual requires their own intervention. And the idea actuallycomes from cancer treatments. And here it turns out that genetics are veryimportant in matching certain types of chemotherapy with specific forms ofcancer.
My research is showing that this also applies to recovery
from stroke. So there’re certain characteristics of brain structure and
function we called biomarkers. And these biomarkers are proving to be very
helpful and helping us to match specific therapies with individual patients.
And the data for my lab suggests it’s a combination of biomarkers that best
predicts neuroplastic change and patterns of recovery after stroke. And that’s
not surprising given how complicated the human brain is.
But I also think we can consider this concept much more broadly. Given theunique structure and function of each of our brains what we’ve learned aboutneuroplasticity after stroke applies to everyone.
Behaviors that you employ in your everyday life are important. Each ofthem is changing your brain. And I believe we have to consider not just personalizedmedicine butpersonalized learning.The uniquenessof your brain will affect you both as a learner and also as a teacher. And nowthis idea helps us to understand why some children can thrive in traditioneducation settings and others don’t. Why some of us can learn languages easilyand yet others can pick up any sport and excel.
So when you leave this room today, your brain will not be the same as whenyou entered this morning. And I think that’s pretty amazing.But each of you is going to have changed your brain differently.
Understanding these differences, these individual patterns, these variability
and change, is going to enable the next great advance in neuroscience. It’s
going to allow us to develop new and more effective interventions, and allow
for matches between learners and teachers, and patients and interventions. And
this does not just apply to recovery from stroke, it applies to each of us as a
parent, as a teacher, as a manager, and also because you are at TEDx today, a
life long learner.
Study how and what you learn best. Repeat those behaviors that are healthyfor your brain and break those behaviors and habits that are not. Practice.Learning is about doing the work that your brain requires. So the beststrategies are going to vary between individuals. You know what, they’re evengoing to vary within individuals. So for you learning music may come veryeasily, but learning to snowboard, much harder.
I hope that you leave today with a new appreciation of
how magnificent your brain is. You and your plastic brain are constantly being
shaped by the world around you. Understand that everything you do, everything
you encounter, and everything you experience is changing your brain. And that
can be for better, but it can also be for worse.
So when you leave today go out and build the brain you want.
Thank you very much.