Connectomics: Making Maps Of The Brain In Your Head

In the recent decades, connectomics (the study of connections in the nervous system) has established itself as a branch of neuroscience, focusing on the neuronal connections in the brain. As part of this undertaking, the Human Connectome Project (HCP) was launched in 2009 and has gained much traction in the neuroscience community. This project aims to map out a matrix to represent all possible anatomical connections between the neural networks in the brain. In less scientific words, this project aims to understand how the parts of the brain communicate with each other. This task uses very technical methods to analyse these structures, including many MRI (magnetic resonance imaging) techniques to observe the brain at a macroscopic level, to Brainbow to observe individual neurons.

Brainbow [Source]

Gaining Significance

The reason why connectomics have gained so much attention is becuase it allows mathematical models to be made of reality, and also allows the management of big data. More interestingly, it promises to allow a deeper understanding of how the neural networks in the brain can affect behaviour.

These networks might even provide an explanation to certain psychiatric disorders. Currently, psychiatric disorders are believed to result from genetic anomalies to hormonal imbalances. However, connectomics allow for another perspective, that the disorder results from faulty wiring in the brain. This is not to say that people are born with faulty wiring and therefore have psychiatric disorders, but it might provide an explanation to how some of the experiences resulting from these disorders might occur, or even how certain disorders are seemingly linked.

Challenging Data

Camillo Golgi and Santiago Ramón y Cajal [Source]

In 1906, Camillo Golgi and Santiago Ramón y Cajal were jointly awarded a Nobel Prize for using the Golgi staining method to identify the neural structures and how they worked. While that was a groundbreaking discovery, 110 years later (to today), the HCP aims to look at neurons on both the macroscopic and microscopic level. Even to the scale of 2,000,000,000,000 (that’s 12 0’s!) of the neuronal level.

Osmium Impregnation Technique in Mapping A 3-D Image of A Neuron. [Source]

One of the methods used in the mapping, called the osmium impregnation technique

 starts by filling a chunk of the brain with a metal called osmium. This chunk is embedded into a hard plastic to be sliced by a diamond blade to 1/1000 of the thickness of hair. Each 2-D section is then stacked up to form a 3-D image of the neuron. What makes this task tedious is that 33,333 of these sections have to be stacked to even form 1 cubic millimeter of a 3-D image. Even more challenging, each human brain is uniquely different. Even twins reared in similar households can have structurally different brains! The amount of labour required to map the entirety of the brain will take supercomputers and large amounts of storage to store all the information, so it will probably be a few more decades before we can make a Von Neumann machine (a machine so complex that it could behave autonomously).

Towards A Hope-Filled Tomorrow

There are many challenges that have to be overcome with the HCP, and this task might not yield immediate results because of the amount of work that needs to go into it. Even so, while we can reasonably say that we’re nowhere close to constructing artificial intelligent beings with connectomics, this undertaking will provide profound insights into the workings of the brain in the coming years, such as in the networks of the brain regions and how they affect behaviour. Many hopeful scientists believe that the HCP will turn out just as successfully as the Human Genome Project and that we will eventually be able to fully comprehend the workings of the most complex organ known, the brain.