Connectomics: Inside the Human Mind

Mind, soul, personality: whatever you call it, most people agree that their memories, thoughts, and perceptions reside in the brain. Yet for all its importance, the brain has been notoriously difficult to understand. The mind’s elusiveness is not for lack of trying: neuroscientists have been slicing, dicing and examining the brain for decades. Yet we still know frustratingly little about it. 


Part of the challenge in understanding the brain lies in its structure: 100 billion neurons that are connected to each other by 10,000 times as many connections, the jungle of our densely packed neural wires run millions of miles in our brains. Scientists believe it is precisely in these connections that our soul is encoded – the way we understand the world, reflect on our experiences, feel sorrow and joy, accumulate memories, and decide how and when to act. If we understood the way our neurons connect – our connectome – we would understand ourselves.

The National Institute of Health and leading researchers across America are investing millions of dollars in unveiling the human connectome. Like the human genome, the connectome is both similar and different amongst humans (it changes with our unique experiences). In fact, many in the field of connectomics compare themselves to geneticists working on decoding the human genome, but the connectome is a vastly bigger undertaking: it contains 1 million times more connections as they are letters in the human genome.

To some the effort seems hopeless. It took almost a dozen years to construct the connectome of the C. elegans worm who has only 300 neurons (compared to our 100 billion). Undeterred, Dr. Litchman’s lab at Harvard University is now tackling the significantly bigger brain of the mouse. Taking extremely thin slices off the brain of mice, Litchman’s lab takes an image of each slice and then reassembles it to draw a map of all the neurons in the brain and the points where they connect to each other.

The New York Times puts the enormity of the task at hand in perspective:

About one petabyte of computer memory will be needed to store the images needed to form a picture of a one-millimeter cube of mouse brain, the scientists say. By comparison, it takes Facebook about one petabyte of data storage space to hold 40 billion photos.

(Note: one petabyte is 1,000,000,000,000,000 bytes of data.) 

Litchman believes that it will take several years to build the connectome of the mouse; the human connectome for now remains only a dream. For an excellent introduction to the connectome and how Litchman’s lab assembles the connectome of the mouse, see this superb TED talk by Sebastian Seung (you will be blown away by the complexity of the brain):

Seung gives an incredibly intriguing test for assessing the importance of the connectome: once scientists have mapped a person's connectome, they should be able to read memories (memories are encoded in chains of synapstic connections). Perhaps not as fascinating, but certainly more profitable, one can only imagine how much Wall Street will love conectomes. With connectomes, the Street will finally make sense of everyone’s “irrational” mind and how collectively, the market moves. Whoever figures it out first will be one very rich trader.   

Ayesha and Parag Khanna explore human-technology co-evolution and its implications for society, business and politics at The Hybrid Reality Institute.

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Accretion disk surrounding a neutron star. Credit: NASA
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Caplan & Horowitz/arXiv

Diagrams illustrating the different types of so-called nuclear pasta.

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One of the study's co-authors, Matthew Caplan, a postdoctoral research fellow at McGill University, said the neutron stars would be "a hundred trillion times denser than anything on earth." Understanding what's inside them would be valuable for astronomers because now only the outer layer of such starts can be observed.

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Another possibility worth studying is that, due to its instability, nuclear pasta might generate gravitational waves. It may be possible to observe them at some point here on Earth by utilizing very sensitive equipment.

The team of scientists also included A. S. Schneider from California Institute of Technology and C. J. Horowitz from Indiana University.

Check out the study "The elasticity of nuclear pasta," published in Physical Review Letters.


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Source: Wolovick et al.

An example of the proposed geoengineering project. By blocking off the warm water that would otherwise eat away at the glacier's base, further sea level rise might be preventable.

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