The mainstream press here has a go at summarizing some of the neurobiology and technologies that would lead to whole brain emulation, a copy of a human mind running in software. Many futurists believe that a copy of the mind running as an emulation is an acceptable continuation of the individual. Thus when they advocate brain preservation via cryonics or plastination it is for the purpose of recording the data for later use, not maintaining the actual tissue for later repair and restoration as a biological brain.
To me this seems a strange viewpoint; a copy of you is not you. Good for the copy and best of luck to him or her, but you yourself remain preserved and inactive. The essence of identity is physical continuity of both pattern and material that expresses that pattern, under a slow pace of change. If someone swapped out half of your brain all at once, you stop being you; you as an entity died in the initial removal, and a copy was created with the replacement operation. If half of the neurons in your brain are exchanged for machinery, one at a time, over a decade of active life, then you are still you - each replacement is incorporated into a working pattern and the change in data is little greater than those occurring due to the ongoing process of being alive. These are important differences, the two examples standing on either side of a large grey area.
The size of the futurist faction who advocate mind uploading for continuation of the individual is large enough that anyone undergoing cryopreservation would be wise to take with them some expression of their desires on the matter, perhaps an inscribed metal plate under the tongue or similar: "Please restore the original; do not copy, do not emulate."
Some neuroscientists believe it may be possible, within a century or so, for our minds to continue to function after death - in a computer or some other kind of simulation. Others say it's theoretically impossible, or impossibly far off in the future. A lot of pieces have to fall into place before we can even begin to start thinking about testing the idea. But new high-tech efforts to understand the brain are also generating methods that make those pieces seem, if not exactly imminent, then at least a bit more plausible. Here's a look at how close, and far, we are to some requirements for this version of "mind uploading."
The hope of mind uploading rests on the premise that much of the key information about who we are is stored in the unique pattern of connections between our neurons, the cells that carry electrical and chemical signals through living brains. You wouldn't know it from the outside, but there are more of those connections - individually called synapses, collectively known as the connectome - in a cubic centimeter of the human brain than there are stars in the Milky Way galaxy. The basic blueprint is dictated by our genes, but everything we do and experience alters it, creating a physical record of all the things that make us US - our habits, tastes, memories, and so on. It is exceedingly tricky to transition that pattern of connections into a state where it is both safe from decay and can be verified as intact. But in recent months, two sets of scientists said they had devised separate ways to do that for the brains of smaller mammals. If either is scaled up to work for human brains - still a big if - then theoretically your brain could sit on a shelf or in a freezer for centuries while scientists work on the rest of these steps.
The real challenge for aspiring mind uploaders will be figuring out how to create a fully functioning model of a human brain from a static snapshot of its connectome. To work, that model would have to include the molecular information in its neurons and synapses. Many neuroscientists think extracting that information would require another major step, others say structural details visible in the electron microscope might allow them to infer it. But some progress is being made - enough, anyway, so that the Obama administration signed off last year on a request by the National Institutes of Health for $4.5 billion to deliver a "comprehensive, mechanistic understanding of mental function" by 2025. Private foundations, like the Allen Institute for Brain Science and the Howard Hughes Medical Institute, have also announced major investments in basic brain research in recent years. And this summer, the blue-sky research arm of the United States intelligence agencies, Iarpa, distributed some $50 million in five-year grants to map the connectome in a cubic millimeter of mouse brain linked to learning behavior, record the corresponding neurons in live mouse brains and simulate the circuits in a computer.