Can you upload a human mind into a computer? A neuroscientist ponders what’s possible

The human brain has 86 billion neurons that make trillions of connections. Grafissimo/DigitalVision Vectors via Getty Images


Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

Is it possible to upload the consciousness of your mind into a computer? – Amreen, age 15, New Delhi, India

The concept, cool yet maybe a little creepy, is known as mind uploading. Think of it as a way to create a copy of your brain, a transmission of your mind and consciousness into a computer. There you would live digitally, perhaps forever. You’d have an awareness of yourself, you’d retain your memories and still feel like you. But you wouldn’t have a body.

Within that simulated environment, you could do anything you do in real life – eating, driving a car, playing sports. You could also do things impossible in the real world, like walking through walls, flying like a bird or traveling to other planets. The only limit is what science can realistically simulate.

Doable? Theoretically, mind uploading should be possible. Still, you may wonder how it could happen. After all, researchers have barely begun to understand the brain.

Yet science has a track record of turning theoretical possibilities into reality. Just because a concept seems terribly, unimaginably difficult doesn’t mean it’s impossible. Consider that science took humankind to the Moon, sequenced the human genome and eradicated smallpox. Those things too were once considered unlikely.

As a brain scientist who studies perception, I fully expect mind uploading to one day be a reality. But as of today, we’re nowhere close.
Living in a laptop

The brain is often regarded as the most complex object in the known universe. Replicating all that complexity will be extraordinarily difficult.

One requirement: The uploaded brain needs the same inputs it always had. In other words, the external world must be available to it. Even cloistered inside a computer, you would still need a simulation of your senses, a reproduction of the ability to see, hear, smell, touch, feel – as well as move, blink, detect your heart rate, set your circadian rhythm and do thousands of other things.

But why is that? Couldn’t you just exist in a pure mental bubble, inside the computer without sensory input?

Depriving people of their senses, like putting them in total darkness, or in a room without sound, is known as sensory deprivation, and it’s regarded as a form of torture. People who have trouble sensing their bodily signals – thirst, hunger, pain, an itch – often have mental health challenges.

That’s why for mind uploading to work, the simulation of your senses and the digital environment you’re in must be exceptionally accurate. Even minor distortions could have serious mental consequences.

For now, researchers don’t have the computing power, much less the scientific knowledge, to perform such simulations.

New and updated scanning technology is a necessity.
Scanning billions of pinheads

The first task for a successful mind upload: Scanning, then mapping the complete 3D structure of the human brain. This requires the equivalent of an extraordinarily sophisticated MRI machine that could detail the brain in an advanced way. At the moment, scientists are only at the very early stages of brain mapping – which includes the entire brain of a fly and tiny portions of a mouse brain.

In a few decades, a complete map of the human brain may be possible. Yet even capturing the identities of all 86 billion neurons, all smaller than a pinhead, plus their trillions of connections, still isn’t enough. Uploading this information by itself into a computer won’t accomplish much. That’s because each neuron constantly adjusts its functioning, and that has to be modeled, too.

It’s hard to know how many levels down researchers must go to make the simulated brain work. Is it enough to stop at the molecular level? Right now, no one knows.

Technological immortality comes with significant ethical concerns.
2045? 2145? Or later?

Knowing how the brain computes things might provide a shortcut. That would let researchers simulate only the essential parts of the brain, and not all biological idiosyncrasies. It’s easier to manufacture a new car knowing how a car works, compared to attempting to scan and replicate an existing car without any knowledge of its inner workings.

However, this approach requires that scientists figure out how the brain creates thoughts – how collections of thousands to millions of neurons come together to perform the computations that make the human mind come alive. It’s hard to express how very far we are from this.

Here’s another way: Replace the 86 billion real neurons with artificial ones, one at a time. That approach would make mind uploading much easier. Right now, though, scientists can’t replace even a single real neuron with an artificial one.

But keep in mind the pace of technology is accelerating exponentially. It’s reasonable to expect spectacular improvements in computing power and artificial intelligence in the coming decades.

One other thing is certain: Mind uploading will certainly have no problem finding funding. Many billionaires appear glad to part with lots of their money for a shot at living forever.

Although the challenges are enormous and the path forward uncertain, I believe that one day, mind uploading will be a reality. The most optimistic forecasts pinpoint the year 2045, only 20 years from now. Others say the end of this century.

But in my mind, both of these predictions are probably too optimistic. I would be shocked if mind uploading works in the next 100 years. But it might happen in 200 – which means the first person to live forever could be born in your lifetime.

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Fruit and honey fuelled the early evolution of the human brain

Jennie Brand-Miller, University of Sydney; David Raubenheimer, University of Sydney, and Les Copeland, University of Sydney

Intelligence is an energetically expensive luxury – as the rise of artificial intelligence has reminded us. The human brain is no exception.

Comprising roughly 2% of the body weight, it uses one fifth the body’s energy in the resting state – compared with less than half of this in non-human primates. A five-year-old child devotes 66% of the energy they need to stay alive to their brain.

How did our ancestors foot the energy bill to run their uniquely large brains? Eating more meat is often considered to be the answer. But there’s a catch. The brain relies on a form of fuel that is not present in meat: glucose.

Our new study, published today in Science, shows that carbohydrates contributed more than half our total energy requirements over four million years of evolution. It holds important clues for why we crave sweet foods today – and how we can eat more healthily.

The matter of meat

Many anthropologists have credited meat eating as the stimulus to produce a large brain. After all, it required tools to butcher the carcass and access the fat-rich marrow inside bones.

Protein and fat in fruit and leaves are dilute, requiring hours of chewing, while animal foods are dense sources that can be devoured quickly. Bone marrow is a rich source of essential fats.

In truth, humans do not require more protein as a proportion of energy than other primates.

Our increasingly large brains and high reproductive rate demanded carbohydrate calories (found in plants but not meat), while our taller and heavier bodies needed fat calories to move those big muscles.

Although the body can synthesise glucose from precursors such as amino acids, the process is finite and energetically inefficient. Furthermore, there are limits on using just protein as fuel. For example, it can lead to a type of poisoning known as “rabbit starvation”.

A minimum amount of dietary carbohydrate was necessary. Our new study shows that, for much of evolution, the sugars in fruit and honey were the source.

Modelling ancient diets

We modelled the diets of hominins – the group consisting of humans and our immediate ancestors – over four million years of evolution.

First, we calculated overall demand for glucose by the organs and tissues which use it as their primary source of energy. Apart from the brain, red blood cells and the kidneys require glucose.

We then accounted for reproductive needs. The fetus and placenta use glucose not just as an energy source but as a structural component of growing tissues. Synthesis of DNA, RNA and nerve cell membranes requires glucose. During lactation, women use about 80g of glucose each day to produce the sugars in human milk.

Then we modelled the availability of macronutrients – carbohydrates, fats and proteins – from foods, starting with the diminutive ancient ape known as Lucy (Australopithecus afarensis).

This early ancestor of ours walked on two legs, and was likely to be a ripe fruit specialist like chimpanzees today. Over two thirds of her energy came from naturally-occurring sugars.

Indeed, some scientists think frugivory – a feeding strategy primarily characterised by eating fruit – kick-started the evolution of large brains because, living in tropical forests, our ancestors required good cognition to remember when and where the best fruits were ripening. They needed strategic thinking to beat the birds and other competitors.

We finished up with the known diet composition of contemporary human foragers in warm climates. In six incremental steps, we incorporated increasing proportions of animal-based food, starting with 5% of calories and finishing with 35–50%.

Around one million years ago, mastery of fire allowed cooked starch, which unlike raw starch can be easily digested to provide glucose, to replace some of the sugars. Relatively recently, about 100,000 years ago, grinding stones and hearths indicate that the starch inside cereal grains became more accessible.

Lessons for modern diets

Did early hominins consume sufficient carbohydrate to cover the obligatory demands of the brain and other tissues? Yes, if you were a male, but only just if you were a pregnant female.

As we ventured out of tropical environments into cold and arid territory, the intake of carbohydrates would have become limiting. Plants would be plentiful, along with protein and marrow fat, but fruit and honey would be seasonal.

We speculate that limited amounts of dietary carbohydrate selected for genes that result in higher blood glucose levels. This would improve the growth and future survival of the fetus.

Today, the same genes likely predispose us to type two diabetes and cardiovascular disease. Low carbohydrate diets may therefore be helpful in specific clinical contexts.

But our findings provide an evolutionary explanation why healthy humans require about half their energy as carbohydrates. They also give us insight into why humans crave sweetness – a pleasurable signal on the tongue that encouraged foods that fuelled the mind and body millions of years ago.

Intrinsically, sugars are highly reactive molecules that are bundled in nature with antioxidants and other natural compounds that reduce harm within the cell.

Ideally, we consume them in that form – as fruit – rather than refined sugars.The Conversation

Jennie Brand-Miller, Emeritus Professor of Human Nutrition, University of Sydney; David Raubenheimer, Leonard P. Ullman Chair in Nutritional Ecology, Nutrition Theme Leader Charles Perkins Centre, University of Sydney, and Les Copeland, Professor of Agriculture, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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