The Art of Mapping Neural Connections

Sabrina Singh
5 min readOct 13, 2019
The Human Connectome Project

The brain is the most critical organ in your body, but it’s also the most complicated. The human brain contains over 100 billion neurons, that’s equivalent to the amount of stars in our universe. Neurons are used to transmit information through the body using chemical and electrical signals.

Connections between these neurons are called synapses. A synapse occurs when there’s a link between the axon of a neuron and the dendrite of another neuron. Your brain contains over 100 trillion neural connections.

These neural connections can be used to help better understand the human biology and potentially the underlying causes of mental disorders.

This is where connectomics comes in.

What is Connectomics?

Connectomics is the study of a connectome. A connectome is a complete map of your neural connections. Connectomes can also be maps of specific brain subsystems, such as the neural connections in your hippocampus. The goal of these wiring diagrams is to understand how the structure of the brain is connected to its behaviour.

The Human Connectome Project

Mapping the entire human connectome can help form additional insights into mental disorders. Currently, 450 million people suffer from mental disorders worldwide. Many conditions, such as schizophrenia, bipolar disorders, Alzheimer’s, and autism, include a biological concept of “disordered connectivity,” which means the disorder is due to an abnormality in neural connections. By using connectomics, we can compare healthy and atypical connectomes to understand the root of these disorders.

We may even be able to recover memories using connectomics. Neuroscientists believe that your stored memories are in the synapses between neurons. They hypothesize that synapses strengthen and weaken when memories form. The Brain Preservation Foundation is developing a way to persevere brains so that their connectomes can be retained, and later recover the memories encoded into the connectomes.

How do we Map the Human Connectome?

The Allen Institute for Brain Science in Seattle mapped the neural connections of a mouse brain. Five electron microscopes continuously ran for five months and collected over 100 million images of 25,000 slices of the mouse’s visual cortex. Each slice was 40 nanometers thick. By the end of their research, they collected 1.8 petabytes of data (that’s equivalent to 24 years of HD footage). Then, the institute developed a software program to assemble the images into a 3D volume and created a connectome.

Connectome of a Mouse Brain

The approach of using electron microscopy is currently being used to map the human brain, except it is taking much longer since the human brain is much more complex.

Who’s Involved?

“We have a chance to improve the lives of not just millions, but billions of people on this planet through the research that’s done in this BRAIN Initiative alone. But it’s going to require a serious effort, a sustained effort.” — Barack Obama

Barack Obama BRAIN Initiative

Currently, Obama’s BRAIN Initiative (Brain Research through Advancing Innovative Neurotechnologies) has a goal of producing dynamic pictures of the brain and understanding how individual brain cells and complex neural circuits interact at the speed of thought.

The European Commission has promised to pledge $1.3 billion over ten years to create a detailed computer model of the brain. Several private projects are also underway, creating human connectome models.

The Human Connectome Project

Frontal View of the Left and Right Hemispheres, Connected by the Corpus Callosum

The Human Connectome Project (HCP), which started on July 2009, had the goal of building a network map of a healthy human brain. Then, they would produce data sets that would help further promote research in mental disorders, including dyslexia, autism, Alzheimer’s, and schizophrenia.

The HCP data could later lead to a better understanding of how a person’s brain connectivity relates to their mental abilities, including memory, self-control, and decision making. By March 2013, HCP made these data sets available to the scientific community for free.

In the future, HCP wants to be able to pinpoint atypical connections in the connectome of those who suffer from mental disorders and fine-tune a personalized procedure of therapy or medication.

Importance of Connectomics

For a very long time, we’ve looked at mapping the brain structure, but we haven’t ever focused on the connections in the brain and their functions.

The structure of your brain is based on your experience. With the help of connectomics, we can determine if abnormalities in behaviour, learning, and pain are linked to the brain’s pathological structure.

Many neuroscientists such as Sebastian Seung believe that your connectome makes you who you are. Soon, we’ll be able to diagnose and treat neurological diseases and define death more accurately, all using connectomics.

I Am My Connectome (TED Talk by Sebastian Seung)

Challenges Facing Connectomics

The biggest challenge we face with connectomics is the complexity of the brain. Each brain has very distinct neural connections. The diversity in the structure of each minds means that scientists can’t just map one brain; they’ll have to map several.

The human brain is always changing as we continuously develop new cells and connections throughout our life. The continuous development of the brain imposes a challenge when creating a connectome. Several connectomes must be mapped to understand the abnormality in brain over time clearly.

Key Takeaways

  • Connectomics is the study of the connectome, a comprehensive map of the neural connections in the brain
  • The goal of connectomics is to understand how your brain’s physiology is connected to your behaviour
  • Connectomics can help provide insight into mental disorders including schizophrenia, Alzheimer’s, and autism
  • Obama’s BRAIN Initiative and the European Commission are currently working on developing computer models of the human brain

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