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  • Imagine a future where nobody dies

  • instead, our minds are uploaded to a digital world.

  • They might live on in a realistic, simulated environment with avatar bodies,

  • and could still call in and contribute to the biological world.

  • Mind uploading has powerful appeal

  • but what would it actually take to scan a person's brain and upload their mind?

  • The main challenges are scanning a brain in enough detail to capture the mind

  • and perfectly recreating that detail artificially.

  • But first, we have to know what to scan.

  • The human brain contains about 86 billion neurons,

  • connected by at least a hundred trillion synapses.

  • The pattern of connectivity among the brain's neurons,

  • that is, all of the neurons and all their connections to each other,

  • is called the connectome.

  • We haven't yet mapped the connectome,

  • and there's also a lot more to neural signaling.

  • There are hundreds, possibly thousands of different kinds of connections,

  • or synapses.

  • Each functions in a slightly different way.

  • Some work faster, some slower.

  • Some grow or shrink rapidly in the process of learning;

  • some are more stable over time.

  • And beyond the trillions of precise, 1-to-1 connections between neurons,

  • some neurons also spray out neurotransmitters

  • that affect many other neurons at once.

  • All of these different kinds of interactions

  • would need to be mapped in order to copy a person's mind.

  • There are also a lot of influences on neural signaling

  • that are poorly understood or undiscovered.

  • To name just one example,

  • patterns of activity between neurons

  • are likely influenced by a type of cell called glia.

  • Glia surround neurons and, according to some scientists,

  • may even outnumber them by as many as ten to one.

  • Glia were once thought to be purely for structural support,

  • and their functions are still poorly understood,

  • but at least some of them can generate their own signals

  • that influence information processing.

  • Our understanding of the brain isn't good enough to determine

  • what we'd need to scan in order to replicate the mind,

  • but assuming our knowledge does advance to that point,

  • how would we scan it?

  • Currently, we can accurately scan a living human brain

  • with resolutions of about half a millimeter

  • using our best non-invasive scanning method, MRI.

  • To detect a synapse, we'll need to scan at a resolution of about a micron

  • a thousandth of a millimeter.

  • To distinguish the kind of synapse and precisely how strong each synapse is,

  • we'll need even better resolution.

  • MRI depends on powerful magnetic fields.

  • Scanning at the resolution required

  • to determine the details of individual synapses

  • would requires a field strength high enough to cook a person's tissues.

  • So this kind of leap in resolution

  • would require fundamentally new scanning technology.

  • It would be more feasible to scan a dead brain using an electron microscope,

  • but even that technology is nowhere near good enough

  • and requires killing the subject first.

  • Assuming we eventually understand the brain well enough to know what to scan

  • and develop the technology to safely scan at that resolution,

  • the next challenge would be to recreate that information digitally.

  • The main obstacles to doing so are computing power and storage space,

  • both of which are improving every year.

  • We're actually much closer to attaining this technological capacity

  • than we are to understanding or scanning our own minds.

  • Artificial neural networks already run our internet search engines,

  • digital assistants, self-driving cars, Wall Street trading algorithms,

  • and smart phones.

  • Nobody has yet built an artificial network with 86 billion neurons,

  • but as computing technology improves,

  • it may be possible to keep track of such massive data sets.

  • At every step in the scanning and uploading process,

  • we'd have to be certain we were capturing all the necessary information accurately

  • or there's no telling what ruined version of a mind might emerge.

  • While mind uploading is theoretically possible,

  • we're likely hundreds of years away

  • from the technology and scientific understanding

  • that would make it a reality.

  • And that reality would come with ethical and philosophical considerations:

  • who would have access to mind uploading?

  • What rights would be accorded to uploaded minds?

  • How could this technology be abused?

  • Even if we can eventually upload our minds,

  • whether we should remains an open question.

Imagine a future where nobody dies

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B1 US TED-Ed scan scanning uploading brain resolution

How close are we to uploading our minds? - Michael S.A. Graziano

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    ktyvr258 posted on 2019/10/31
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