字幕表 動画を再生する 英語字幕をプリント Shh I'm accessing my mind palace like Sherlock Holmes…huh… living room is a bit smaller than I expected… bedroom's kinda cramped… But LOTS of storage! I actually STORE in there? Hey there my neuro-nerds, Trace here for DNews. Now we all know that our brains can store an incredible amount of information -- a lifetime of memories, everything from the good, the bad and the downright embarrassing. Up until recently, it was thought that the brain could only hold the equivalent of 100 terabytes of information, max -- which, let's face it, is a lot. But it turns out our brains may actually have ten times that capacity. In a 2016 study conducted by The Salk Institute, researchers discovered our brains could store at least a petabyte of information! A petabyte is the equivalent of approximately one thousand terabytes or one million gigabytes! To put it another way, if you were to continuously play a petabyte of 4-minute songs, it would take 2,000 years to listen to all of them. To-do list, check. Obviously, this unit of measurement is generally used for computer memory not brain capacity, but neuroscientists can also use bytes as a useful comparison for our brain's own storage capacity. So, both elephants and whales have physically larger brains, but relatively speaking, our body-to-brain ratio is about the same as a mouse! Learning about how our brains store and process information can give us insight into why we seem to be more intelligent than other animals. When you experience something, let's say, your first kiss, that experience is converted into pulses of electrical energy coming from your external senses (lips, nose, hands, for example) and your internal senses (emotional responses and heart rate). That electrical energy is fired across the brain through a network of neurons until it reaches the hippocampus -- a sort of memory data bank, though some recent studies suggest that certain long-term memories might also be stored in the Cerebral cortex. Everything we do produces pulses, thousands of them every day, and each one travels across neurons via specific gap called a synapse. In that synaptic junction, neurotransmitter chemicals ferry the pulses from one neuron to the next as fast as possible. The brain has roughly 86 billion neurons, not 100 billion, only 86. Specifically. Myth busteeedddd!! And each brain cell connects to at least one other, but likely more! Meaning there are TRILLIONS of synapses. The gap between the neurons is small, only 20 to 40 nanometers, but studies seem to indicate these synapses are crucial in the process of making and storing memories. To find out how, the Salk Institute used a 3D digital model of a rat's hippocampus, and examined how synapse size effects brain capacity and efficiency, and in doing so, noticed something unusual… in 10 percent of cases a single neuron had two synapses connected to the same neighboring neuron… They were sending two copies of the exact same message! Curiously, those two synapses varied in size by 8 percent, and when it comes to synapses, size really DOES matter. Larger synaptic gaps require more neurotransmitter chemicals so they're more likely to succeed in communicating their electrical data to the neighbouring neuron. That simple eight percent variation enabled researchers to create mathematical models, concluding that synapses come in 26 different discrete sizes! Exiting RIGHT?! Trust me, it is. This size variation is almost ten times what was previously thought. Suggesting that more size variability means, in digital terms, synapses are able to process 4.7 bits of memory. Previously scientists thought synapses could only process one or two bits… A small change, but, again, given there are trillions of synapses spread throughout the brain, the researchers calculated one petabyte capacity. Now, before we get too excited, remember, this study wasn't modeled on a human brain… but a rat brain, although scientists think it could translate to humans. And some neuroscientists believe the estimation is low! Maybe we could store 2-3 petabytes of memory! It's a lot to think about…! Pun intended. We know you love watching online, but DNews is also on Science channel! Amy and I share a minute of the best in science in between awesome programming. So check out as Science Presents DNews at 9! Every weeknight, Monday through Friday, and use your twitter to let them know if you want more!