When will I be able to upload my brain to a computer?

READER QUESTION: I am 59 years old, and in reasonably good health. Is it possible that I will live long enough to put my brain into a computer? — Richard Dixon.

We often imagine that human consciousness is as simple as input and output of electrical signals within a network of processing units – therefore comparable to a computer. Reality, however, is much more complicated. For starters, we don’t actually know how much information the human brain can hold.

Two years ago, a team at the Allen Institute for Brain Science in Seattle, mapped the 3D structure of all the neurons (brain cells) comprised in one cubic millimeter of the brain of a mouse – a milestone considered extraordinary.

Greetings, humanoids

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Within this minuscule cube of brain tissue, the size of a grain of sand, the researchers counted more than 100,000 neurons and more than a billion connections between them. They managed to record the corresponding information on computers, including the shape and configuration of each neuron and connection, which required two petabytes, or two million gigabytes of storage. And to do this, their automated microscopes had to collect 100 million images of 25,000 slices of the minuscule sample continuously over several months.

Now if this is what it takes to store the full physical information of neurons and their connections in one cubic millimeter of mouse brain, you can perhaps imagine that the collection of this information from the human brain is not going to be a walk in the park.

Data extraction and storage, however, is not the only challenge. For a computer to resemble the brain’s mode of operation, it would need to access any and all the stored information in a very short amount of time: the information would need to be stored in its random access memory (RAM), rather than on traditional hard disks. But if we tried to store the amount of data the researchers gathered in a computer’s RAM, it would occupy 12.5 times the capacity of the largest single-memory computer (a computer that is built around memory, rather than processing) ever built.

The human brain contains about 100 billion neurons (as many stars as could be counted in the Milky way) – one million times those contained in our cubic millimetre of mouse brain. And the estimated number of connections is a staggering ten to the power of 15. That is ten followed by 15 zeroes – a number comparable to the individual grains contained in a two meter thick layer of sand on a 1km-long beach.

A question of space

If we don’t even know how much information storage a human brain can hold, you can imagine how hard it would be to transfer it into a computer. You’d have to first translate the information into a code that the computer can read and use once it is stored. Any error in doing so would probably prove fatal.

A simple rule of information storage is that you need to make sure you have enough space to store all the information you need to transfer before you start. If not, you would have to know exactly the order of importance of the information you are storing and how it is organised, which is far from being the case for brain data.

If you don’t know how much information you need to store when you start, you may run out of space before the transfer is complete, which could mean that the information string may be corrupt or impossible for a computer to use. Also, all data would have to be stored in at least two (if not three) copies, to prevent the disastrous consequences of potential data loss.

This is only one problem. If you were paying attention when I described the extraordinary achievement of researchers who managed to fully store the 3D structure of the network of neurons in a tiny bit of mouse brain, you will know that this was done from 25,000 (extremely thin) slices of tissue.

Image of orange slices.