TED技术:Mehdi Ordikhani-Seyedlar: What happens in your brain when you pay attention?

Paying close attention to something:Not that easy, is it?It's because our attention is pulledin so many different directions at a time,and it's in fact pretty impressiveif you can stay focused.

Many people think that attentionis all about what we are focusing on,but it's also about what informationour brain is trying to filter out.

There are two waysyou direct your attention.First, there's overt attention.In overt attention,you move your eyes towards somethingin order to pay attention to it.Then there's covert attention.In covert attention,you pay attention to something,but without moving your eyes.Think of driving for a second.Your overt attention,your direction of the eyes,are in front,but that's your covert attentionwhich is constantly scanningthe surrounding area,where you don't actually look at them.

I'm a computational neuroscientist,and I work on cognitivebrain-machine interfaces,or bringing togetherthe brain and the computer.I love brain patterns.Brain patterns are important for usbecause based on themwe can build models for the computers,and based on these modelscomputers can recognizehow well our brain functions.And if it doesn't function well,then these computers themselvescan be used as assistive devicesfor therapies.But that also means something,because choosing the wrong patternswill give us the wrong modelsand therefore the wrong therapies.Right?In case of attention,the fact that we canshift our attention not only by our eyesbut also by thinking —that makes covert attentionan interesting model for computers.

So I wanted to knowwhat are the brainwave patternswhen you look overtlyor when you look covertly.I set up an experiment for that.In this experimentthere are two flickering squares,one of them flickeringat a slower rate than the other one.Depending on which of these flickersyou are paying attention to,certain parts of your brainwill start resonating in the same rateas that flickering rate.So by analyzing your brain signals,we can track where exactlyyou are watchingor you are paying attention to.

So to see what happens in your brainwhen you pay overt attention,I asked people to look directlyin one of the squaresand pay attention to it.In this case, not surprisingly,we saw that these flickering squaresappeared in their brain signalswhich was comingfrom the back of their head,which is responsible for the processingof your visual information.But I was really interestedto see what happens in your brainwhen you pay covert attention.So this time I asked peopleto look in the middle of the screenand without moving their eyes,to pay attentionto either of these squares.When we did that,we saw that both of these flickering ratesappeared in their brain signals,but interestingly,only one of them,which was paid attention to,had stronger signals,so there was something in the brainwhich was handling this informationso that thing in the brain was basicallythe activation of the frontal area.The front part of your brainis responsiblefor higher cognitive functions as a human.The frontal part,it seems that it works as a filtertrying to let information come inonly from the right flickerthat you are paying attention toand trying to inhibit the informationcoming from the ignored one.

The filtering ability of the brainis indeed a key for attention,which is missing in some people,for example in people with ADHD.So a person with ADHDcannot inhibit these distractors,and that's why they can't focusfor a long time on a single task.But what if this personcould play a specific computer gamewith his brain connected to the computer,and then train his own brainto inhibit these distractors?

Well, ADHD is just one example.We can use these cognitivebrain-machine interfacesfor many other cognitive fields.It was just a few years agothat my grandfather had a stroke,and he lost complete ability to speak.He could understand everybody,but there was no way to respond,even not writingbecause he was illiterate.So he passed away in silence.I remember thinking at that time:What if we could have a computerwhich could speak for him?Now, after years that I am in this field,I can see that this might be possible.Imagine if we can find brainwave patternswhen people thinkabout images or even letters,like the letter A generatesa different brainwave patternthan the letter B, and so on.Could a computer one daycommunicate for people who can't speak?What if a computercan help us understandthe thoughts of a person in a coma?We are not there yet,but pay close attention.We will be there soon.

Thank you.


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