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TEDGlobal: Sebastian Seung mapping the connectome

Sebastian Seung asks the room at TEDGlobal whether they are more than their genes. After all, genes seem like they have awesome power. They control our appearance and our vulnerability to diseases. But we think we’re more than our genes. He urges us to cheer “I am more than my genes”.

Okay, so what are we. He offers, “I am my connectome”.

We’ve only produced one connectome – that of the nematode C. elegans. It took twelve years to painstakingly map 7000 connections between a couple hundred neurons. The human connectome – a map of every connection between every neuron – contains more than a million times as much info as the human genome.

It’s possible that our memories are stored in the connectome, and possible that our personalit and intellect is as well. We don’t know if we are our connectomes because we don’t have the technology to test it.

How do you make a connectome? Take thin slices of a mouse brain, assemble them into a 3D models to see a neuronal structure and begin coloring them, so each neuron is a different color. You can start to see the intersection of two neurons – a synapse – where neurons can transfer neurotransmitters. Basically, this process is turning a stack of neurons into a giant coloring book.

Seung shows us a silly self-help book titled, “Guys are waffles, Girls are spaghetti.” Whether or not the thesis of the book – that men’s emotions are compartmentalized, while women’s are connected to all aspects of life – he tells us that “everyone’s brains are like spaghetti. Actually, finely branching capellini.” Everything touches everything else – not quite, but enough to make the problem of mapping the connectome deeply overwhelming.

The hope is that with microscopes and huge supercomputers, we can assemble and explore a vast human connectome. But this would be one of the greatest technological challenges of all time. For now, scientists are hoping just to find partial connectomes of tiny chunks of mouse brains.

The brain is constantly changing, Seung tells us. Synapses can be created and eliminated, and can grow larger and smaller. To a certain extent, they’re programmed by your genes. But neural activity can also cause connections to change – your experiences change your connectome. Each connectome is unique – it’s where nature meets nurture, how identical twins can end up very different people.

Neural activity is constantly changing – it’s like the water of a stream. The connections of the neural network are like the streambed, determining where it flows. But over timestreambed is changed, by the flow of the water, just as the structure of the brain could be changed by thought.

Seung offers a challenge to “prophets” who promise us immortality through cryonics, spending $100,000 to have your brain stored in liquid nitrogen. Should we laugh at these guys? “I don’t know,” he tells us, “let’s test scienticially.” Let’s get a frozen brain and try to obtain the connectome. If we cannot get it, we might resurrect the body, but we cannot ressurect the mind.

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