From the Ted Talk by Andrey Vyshedskiy: The neuroscience of imagination
Unscramble the Blue Letters
Imagine, for a second, a duck teaching a French class, a ping-pong match in orbit around a blcak hole, a dolphin balancing a pppilenae. You probably haven't actually seen any of these things, but you could iaignme them itlsatnny. How does your brain produce an image of something you've never seen? That may not seem hard, but that's only because we're so used to doing it. It turns out that this is actually a cplemox problem that requires sophisticated coordination inside your barin. That's because to create these new, weird images, your brain takes familiar peiecs and assembles them in new ways, like a collage made from fragments of photos. The brain has to juggle a sea of thousands of electrical signals getting them all to their destination at precisely the right time. When you look at an object, tauohnsds of neurons in your posterior cortex fire. These neurons encode various characteristics of the object: spiky, fruit, brown, green, and yeollw. This synchronous firing strengthens the connections between that set of neurons, lniikng them together into what's known as a naunreol ensemble, in this case the one for pineapple. In neuroscience, this is called the Hebbian principle, neurons that fire together wire together. If you try to imagine a pineapple later, the whole ensemble will light up, assembling a complete mental image. Dolphins are encoded by a different neuronal ensemble. In fact, every object that you've seen is encoded by a neuronal ensemble associated with it, the nnouers wired together by that synchronized firing. But this principle doesn't explain the infinite nuembr of objects that we can conjure up in our imaginations without ever seeing them. The neuronal eblnmsee for a dolphin balancing a pineapple doesn't exist. So how come you can imagine it anyway? One hypothesis, called the Mental Synthesis Theory, says that, again, timing is key. If the neuronal ensembles for the dolphin and pineapple are activated at the same time, we can perceive the two separate oetbjcs as a slnige image. But something in your brain has to coordinate that firing. One pliasbule candidate is the prefrontal cortex, which is involved in all complex cognitive fntiuocns. Prefrontal cortex neurons are connected to the posterior cortex by long, sdlipny cell extensions claled neural fibers. The mental synthesis theory proposes that like a puppeteer pulling the sintrgs, the prefrontal cortex neurons send electrical signals down these neural fibers to mupltile esblmnees in the posterior cortex. This activates them in unison. If the neuronal ensembles are turned on at the same time, you enepixrece the csipmoote igame just as if you'd actually seen it. This conscious purposeful syaohrtnocniizn of different neuronal ensembles by the prefrontal cortex is called mental synthesis. In order for mental sythesis to work, signals would have to arrive at both neuronal ensembles at the same time. The problem is that some neurons are much farther away from the prefrontal cortex than others. If the signals travel down both fibers at the same rate, they'd arrive out of sync. You can't change the length of the ctoonnenics, but your brain, especially as it develops in childhood, does have a way to change the conduction velocity. nreual fibers are wrapped in a fttay substance called melyin. Myelin is an insulator and speeds up the eaeclictrl signals zipping down the nerve fiber. Some neural fibers have as many as 100 layers of myelin. Others only have a few. And fibers with thicker lyreas of myelin can conduct signals 100 times faster or more than those with thinner ones. Some scientists now think that this difference in myelination could be the key to uniform conduction time in the brain, and consequently, to our meantl synthesis ability. A lot of this miaieylnton happens in childhood, so from an early age, our vibrant imaginations may have a lot to do with building up brains whose carefully myelinated connections can craft creative syhipomnes throughout our lives.
Open Cloze
Imagine, for a second, a duck teaching a French class, a ping-pong match in orbit around a _____ hole, a dolphin balancing a _________. You probably haven't actually seen any of these things, but you could _______ them _________. How does your brain produce an image of something you've never seen? That may not seem hard, but that's only because we're so used to doing it. It turns out that this is actually a _______ problem that requires sophisticated coordination inside your _____. That's because to create these new, weird images, your brain takes familiar ______ and assembles them in new ways, like a collage made from fragments of photos. The brain has to juggle a sea of thousands of electrical signals getting them all to their destination at precisely the right time. When you look at an object, _________ of neurons in your posterior cortex fire. These neurons encode various characteristics of the object: spiky, fruit, brown, green, and ______. This synchronous firing strengthens the connections between that set of neurons, _______ them together into what's known as a ________ ensemble, in this case the one for pineapple. In neuroscience, this is called the Hebbian principle, neurons that fire together wire together. If you try to imagine a pineapple later, the whole ensemble will light up, assembling a complete mental image. Dolphins are encoded by a different neuronal ensemble. In fact, every object that you've seen is encoded by a neuronal ensemble associated with it, the _______ wired together by that synchronized firing. But this principle doesn't explain the infinite ______ of objects that we can conjure up in our imaginations without ever seeing them. The neuronal ________ for a dolphin balancing a pineapple doesn't exist. So how come you can imagine it anyway? One hypothesis, called the Mental Synthesis Theory, says that, again, timing is key. If the neuronal ensembles for the dolphin and pineapple are activated at the same time, we can perceive the two separate _______ as a ______ image. But something in your brain has to coordinate that firing. One _________ candidate is the prefrontal cortex, which is involved in all complex cognitive _________. Prefrontal cortex neurons are connected to the posterior cortex by long, _______ cell extensions ______ neural fibers. The mental synthesis theory proposes that like a puppeteer pulling the _______, the prefrontal cortex neurons send electrical signals down these neural fibers to _________________ in the posterior cortex. This activates them in unison. If the neuronal ensembles are turned on at the same time, you __________ the ______________ just as if you'd actually seen it. This conscious purposeful _______________ of different neuronal ensembles by the prefrontal cortex is called mental synthesis. In order for mental sythesis to work, signals would have to arrive at both neuronal ensembles at the same time. The problem is that some neurons are much farther away from the prefrontal cortex than others. If the signals travel down both fibers at the same rate, they'd arrive out of sync. You can't change the length of the ___________, but your brain, especially as it develops in childhood, does have a way to change the conduction velocity. ______ fibers are wrapped in a _____ substance called ______. Myelin is an insulator and speeds up the __________ signals zipping down the nerve fiber. Some neural fibers have as many as 100 layers of myelin. Others only have a few. And fibers with thicker ______ of myelin can conduct signals 100 times faster or more than those with thinner ones. Some scientists now think that this difference in myelination could be the key to uniform conduction time in the brain, and consequently, to our ______ synthesis ability. A lot of this ___________ happens in childhood, so from an early age, our vibrant imaginations may have a lot to do with building up brains whose carefully myelinated connections can craft creative __________ throughout our lives.
Solution
multiple
mental
spindly
layers
linking
neurons
symphonies
pieces
number
fatty
plausible
experience
brain
yellow
thousands
called
objects
neural
electrical
myelin
single
functions
synchronization
neuronal
complex
strings
myelination
composite
black
ensemble
pineapple
instantly
ensembles
image
imagine
connections
Original Text
Imagine, for a second, a duck teaching a French class, a ping-pong match in orbit around a black hole, a dolphin balancing a pineapple. You probably haven't actually seen any of these things, but you could imagine them instantly. How does your brain produce an image of something you've never seen? That may not seem hard, but that's only because we're so used to doing it. It turns out that this is actually a complex problem that requires sophisticated coordination inside your brain. That's because to create these new, weird images, your brain takes familiar pieces and assembles them in new ways, like a collage made from fragments of photos. The brain has to juggle a sea of thousands of electrical signals getting them all to their destination at precisely the right time. When you look at an object, thousands of neurons in your posterior cortex fire. These neurons encode various characteristics of the object: spiky, fruit, brown, green, and yellow. This synchronous firing strengthens the connections between that set of neurons, linking them together into what's known as a neuronal ensemble, in this case the one for pineapple. In neuroscience, this is called the Hebbian principle, neurons that fire together wire together. If you try to imagine a pineapple later, the whole ensemble will light up, assembling a complete mental image. Dolphins are encoded by a different neuronal ensemble. In fact, every object that you've seen is encoded by a neuronal ensemble associated with it, the neurons wired together by that synchronized firing. But this principle doesn't explain the infinite number of objects that we can conjure up in our imaginations without ever seeing them. The neuronal ensemble for a dolphin balancing a pineapple doesn't exist. So how come you can imagine it anyway? One hypothesis, called the Mental Synthesis Theory, says that, again, timing is key. If the neuronal ensembles for the dolphin and pineapple are activated at the same time, we can perceive the two separate objects as a single image. But something in your brain has to coordinate that firing. One plausible candidate is the prefrontal cortex, which is involved in all complex cognitive functions. Prefrontal cortex neurons are connected to the posterior cortex by long, spindly cell extensions called neural fibers. The mental synthesis theory proposes that like a puppeteer pulling the strings, the prefrontal cortex neurons send electrical signals down these neural fibers to multiple ensembles in the posterior cortex. This activates them in unison. If the neuronal ensembles are turned on at the same time, you experience the composite image just as if you'd actually seen it. This conscious purposeful synchronization of different neuronal ensembles by the prefrontal cortex is called mental synthesis. In order for mental sythesis to work, signals would have to arrive at both neuronal ensembles at the same time. The problem is that some neurons are much farther away from the prefrontal cortex than others. If the signals travel down both fibers at the same rate, they'd arrive out of sync. You can't change the length of the connections, but your brain, especially as it develops in childhood, does have a way to change the conduction velocity. Neural fibers are wrapped in a fatty substance called myelin. Myelin is an insulator and speeds up the electrical signals zipping down the nerve fiber. Some neural fibers have as many as 100 layers of myelin. Others only have a few. And fibers with thicker layers of myelin can conduct signals 100 times faster or more than those with thinner ones. Some scientists now think that this difference in myelination could be the key to uniform conduction time in the brain, and consequently, to our mental synthesis ability. A lot of this myelination happens in childhood, so from an early age, our vibrant imaginations may have a lot to do with building up brains whose carefully myelinated connections can craft creative symphonies throughout our lives.