>>>
we're back now, 8:36 with "mysteries of the brain." this morning, how the brain fuctions in everyday situations. we'll take you on a
virtual tour
in a moment, but first here's dr.
nancy snyderman
.
>> reporter:
it weighs only three pounds. it's made mostly of water. and it contains 100 billion neurons. the same number of stars in our galaxy. the
human brain
. most of us pay little or no attention to how it actually works, but it is arguably the most important organ in the
human body
. blinking, tying your shoe, walking, even breathing, almost everything you do and every thought you have is controlled by the brain. every second a single neuron in your
brain may
send out as many as 1,000 signals. these signals can zip from neuron to neuron at speeds of 250 miles an hour. a highly complex control center that allows us to perform the simplest of tasks every minute of every day.
>>
hey,
nancy
. good morning.
>>
hey, matt.
>>
we'll start with taking a look at memory. first of all, for everything the brain does and accomplishes, it's relatively small in some of us, i would imagine.
>>
the size of the grapefruit is the size of one's brain, about three pounds. what's cool is the neurons, especially in women, fire from both sides of the brain. men tend to not use both sides of the brain as much, but the memory parts that we're talking about is in the central part of the brain. an area called the hypocampus.
>>
what do i have to do here?
>>
we'll flash up right now various names and
words and pictures
. i want you to look at them. one thousand one, one thousand two, one thousand three, one thousand four, one thousand five. matt,
close your eyes
. recite to me in no specific order what you saw.
>>
cowboys,
golden retriever
, meredith, boots, coffee, a hat, like a weird
indiana jones
hat. that's it.
>>
you forgot the star and the "today" rainbow.
>>
pretty darn close. there's no perfect score for this. but you had to rely on a familiar face, something that, oh, maybe has relationship or not, maybe what you ate, maybe what you drank, something sexy, your dog. you're recruiting interestingly from all different parts of your brain even though it starts in the center.
>>
people who have a good memory, do they have a bigger section of the brain that controls it?
>>
yes. you and i have been to london a gazillion times. you know the
london taxi
drives. they have to memorize 250,000 different routes. in
london taxi
drivers, because there's no specific grid, the central part of their brain is bigger than in non-taxi drivers in london.
>>
that's cool stuff.
>>
memory matters. it's really cool.
>>
all right.
nancy
, thank you very much. let's swing over to meredith.
>>>
okay, matt, thank you. whether it is coffee or cigarettes, we've got our vices, but did you know -- hello. sometimes it only takes one sip, one drag for changes to occur in the brain that can lead to addiction.
>>
interesting that it's you and vices.
>>
i'm going to ignore you. what happens to the brain when we get addicted to something?
>>
it all comes back to the
pleasure center
of the brain. whether you're eating something, sex, nurturing a baby. there's a cool fwrafgraphic that shows that -- if we can pull it up in here or a full screen.
>>
there you go.
>>
here it is. it starts in this area, the same sort of area of the hypocampus. this gives you the reward that it feels good. but here's the problem. that same reward path can lead to addiction. so something as simple as a martini or smoking, particularly in adolescents when their brain is developing, that reward path can become the pathway to addiction.
>>
do all of these affect the same part of the brain?
>>
dthey do. it also applies to gambling and
sex addiction
. this is real vodka. just to prove that we don't fake things at the "today" show.
>>
don't go away yet, missy. are there people more prone to addiction?
>>
yes. and we're increasingly finding the genes for it, especially men and adolescened a leadolescents addicted to speed. there is a genetic link. but i want to warn adolescents, you think you can mess around with cigarettes and cocaine and alcohol. when your brain is still developing, that reward pathway becomes addiction very fast. some pretty cool research that you may restructure and rewire the brain. that pathway is important. now i'm going to leave you to your martini.
>>
i smell something, i hear it --
>>
that's right. in fact, all of our senses are on overload right now.
>>
i can taste the martini.
>>
we are the sizzling bacon right here in front of us. and i wish this was smella smellavision. man, it smells good.
>>
you hear the crackle, crackle, crackle. you know something is in the skillet. then you and i can smell the bacon. there's nothing like bacon. that lights up different parts of the brain. you hear it. you smell it. that goes right to your nose. but interestingly, what you see is registered in your eyes but the olfactory aspect is in the back of your brain. then you taste it. if i tell you that you know what this tastes like, you have a memory for bacon because you know you've had that registered in the past.
>>
so you just talked about all of these different senses. if you start to lose, you know, with age one of those senses, then does that affect -- can you possibly lose this kind of experience in all of them?
>>
i have taken care of people in california who lost their
sense of smell
after
viral infection
. and people in the wine industry then can't taste wine. i've seen careers go away because one sense affects the others. it's like when you have a cold and you lose your ability to really want food. it's because you can't taste it. here's something i want to do with you for a second.
>>
okay.
>>
we always say, well, if you could lose any sense, what would it be? vision or hearing? people always say i'd rather lose my hearing. don't take away my
sense of sight
.
close your eyes
. if i say remind me of the trip you took last year and what a beach looks like or the forest or your son's cheek, you have a memory of that.
>>
uh-huh.
>>
now
open up your eyes
. that's a terrible place to be.
>>
you're right.
>>
interestingly, when people lose their hearing, it's a place that's more hollow than losing vision. and people don't expect that.
>>
if you lose your hearing or lose one of your senses or begin to lose it, is there some way to sort of compensate or are you really stuck? you're talking about people getting stuck.
>>
you can compensate. one sense we left out, which is -- which is feel. and what's very interesting is when people sometimes lose the feeling in the tips of their fingers and they think, oh, well it's no
big deal
, if i touch this pan, i'm going to get a burn. if i get a thorn in my finger, i may not realize i'll get an infection. we need them all and we recruit all parts of our brain. women use their brains firing across both halves more than men. if i give you a math problem and i give matt a math problem, matt will hyperfocus on it, you'll recruit from everywhere. we
think differently
.
>>
there you go. that explains a lot.
>>
nothing against matt. now you can have the martini.
>>
i know. thanks so much. we've got much more -- and a special thanks to the
museum of natural history
. it's on display in new york through
august 14th
. you're coming to the city, you need to check that out.
nancy
will be back tomorrow to answer your questions about
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