How Mapping The Human Brain Will Help Us Understand Personality And Mental Illness

human brain connectomehuman brain connectome

Photo: Human Connectome Project, Science, March 2012.

When asked what makes us human, many people will say that our large brain is what really sets us apart from the rest of the animal kingdom. But, even after centuries of searching, we haven’t been able to adequately suss out what about the brain makes us uniquely human.It’s not the size of our noggin — other animals have bigger brains, yet don’t embody the unique humanness of homo sapiens. And our brains have the same basic makeup — with the same cells using the same chemicals to communicate — as the brains of many other animals. So what is it exactly that makes us different?

In a 2010 TED talk, MIT researcher Sebastian Seung suggested that the traits that make us human actually come from what he calls our “connectome” — the connections between different parts of the brain and even between individual brain cells.  

Essentially, he says, “we are our connectome.”

For centuries, scientists have been mapping brain regions associated to different parts of the body and to different aspects of personality. But now that we know what parts of the brain control what functions, we need to put humpty dumpty back together: We need to learn how these functions are incorporated into a whole.

By understanding the networks that connect different parts of the brain, researchers are hopeful they will learn how 86 billion brain cells come together to become one person.

History of connections

The first connectome was created in the 1970s, of the simple brain of the worm C. elegans. It consisted of 300 individual brain cells and the 7,000 connections between them.

They used a very crude method, which involves slicing thin sections of brain, staining them with dyes to make the individual cells visible, and taking individual pictures in sequence to analyse them.

It took 12 years.

In 2010, the National Institutes of Health set out to decipher the human connectome using more modern tools: brain scans. So they implemented a five-year, $40-million initiative that aims to map the brain’s communication network — the brain connections that make up the brain. It’s called the Human Connectome Project.

The group is in their third year of investigating these brain connections. The first two years were spent investigating and refining the tools they would use to do this. The next three will be spent scanning brains, analysing data and analysing the genetics of the participants.

Latest research

Using a scan called the resting state functional Magnetic Resonance Imager (fMRI), and several other tests, the researchers involved in the Human Connectome Project have started mapping these connections.

Different from most other fMRI scans, which show how blood flow changes indicating which parts of the brain are active while performing a task, the resting state test studies the brain while you aren’t doing or thinking about anything in particular. Researchers study the brain in this resting state to see how the brain works during a task or certain thought process.

The team will use the optimised methods to scan the brains of 1,200 individuals to map their connectomes. As the data from these people comes out, it will be published on the human connectome project website. They’ve already released data from the first 12 subjects, and 80 more sets of information will be released in February 2013.

The participants picked will be specially selected. For example, subjects might include sets of twins and their non-twin siblings. This will help the researchers get a better idea of how much these brain patterns are determined by genetics. To this end, they will also be collecting genetic data on all the participants, so they can map what genes create these differences.

A second human connectome team is developing new brain scanning technologies that do an even better job of analysing the connections in the brain. There’s also a group in Europe working on a project called CONNECT, and Seung has developed new ways to analyse the brain connectome on a cellular level.

Initial data from the the second human connectome team shows that these brain connections run in a pretty organised fashion, similar to the way cloth is weaved. Bundles of fibres run perpendicular to each other — some going from front to back while other connections go from the inside out.

Not everyone is sure that this data will be useful. In an October 2012 article about the Human Connectome Project in the journal Science, Greg Miller writes: “Critics contend that deciphering brain function from a circuit diagram — no matter how detailed — is like trying to figure out what a computer does by studying its wiring diagram. In both cases, the circuitry may say something about what the machine is capable of, but it’s the precise pattern of electricity coursing through it at a given time that determines what it’s actually doing.”

Mental health applications

Researchers working on connectome projects disagree. They believe that studying the brain connections will not only help us get a better grasp on how our brain works to make us who we are, but it will also reveal what goes wrong in mental health disorders like schizophrenia and depression. These diseases could be caused by changes in the brain’s connections, so getting a better understanding of how the brain works together is vitally important.

“There is huge potential for miswiring,” Seung said in the TED talk. “In truth we can’t see the brain’s wiring clearly enough to tell if this is really true. The technology to see connectomes will allow us to finally read miswiring of the brain, to see mental illnesses in the connectome.”

As data from the Human Connectome Project continues to dribble out over the next few years, researchers will have a treasure trove of information to muddle over as they contemplate how these connections make us who we are, or who we aren’t.

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