The Science of Brain Mapping
Our perception of self evolves with our understanding of the brain.
Scientists know that the human brain is made of billions of big, branched cells called neurons. Working in tandem, millions of cells communicate through timed ionic impulses, firing in vast waves that impact the chemical environment of the brain itself.
Your brain is constantly relaying signals, whether you're reading an article, playing a game, or simply sleeping.
gif: Daniela Gamba, Seung Lab, Princeton University. Thanks to Tobias Navarro Schröder for advising on the propagation of neural signal waves across the brain.
Generally, one can study this beautiful network either as whole or via parts. As they say, the brain is the most complex thing in the known universe; seldom, if at all, do labs try to tackle it all.
To consider the whole brain is to study system dynamics involving populations of billions of neurons. Many researchers are making headway here by exploring functional hubs: regions of the brain linked to specific behaviors.
Understanding how neurons combine in a concerted effort to execute distinctly human capabilities requires investigation across many scales. These cells are miniscule and seeing the details with electron resolution microscopes has revealed new insights into these beautiful intricate networks.
The brain's mysterious microscopic domain is the cosmos of consciousness. The micro-monumental structures of neurons allow them to reach vast distances and touch tens of thousands of neighbors.
Charting these cells, measuring their activity, sequencing their genetics, and combining these into a single model is one of the great challenges in neuroscience and arguably of homo sapiens. We don't know when the ultimate model that facilitates our understanding of consciousness will emerge. It could be in the works right now or perhaps it will be by labs that have yet to be created. It is at least safe to say that today's fields of neuroscience will inevitably play a role in answering future questions, bringing us closer to an enriched understanding of ourselves.
The Brain's Hidden World
Cosmos of Consciousness, Daniela Gamba
The microscopic realm reveals the brain's basic components. Comprehending these basic parts informs our understanding of the system itself. Topics of study include circuits, cell classification, subcellular processes, genetics, epigenetics, and more.
As recently as the late 1800s, the brain was thought to be one singular weblike structure; unrealized was the idea that it was made of single cells. Santiago Cajal first introduced the concept that the brain contains individual neurons, earning him a Nobel Prize and a place in the hearts of neuroscientists who study the realm he introduced: cellular neuroscience.
As rivers they curve; as trees they branch. They bud like a flower with circuits aglow, growing in the breeze of thought.
It is difficult, if not impossible, to fully grasp how anything works without understanding its parts. For the past 130 years, neuroscience has seen a Cambrian explosion of fields and a subsequent manifestation of integrated study. One of these is connectomics.
Connectomics studies the network architecture and dynamics of neurons and other cells in the brain. At the micro scale, it generally integrates three areas:
- functional activity (firing patterns of neurons)
In general, to map neurons in the brain, the following sequence occurs.
- Make sure you can see the neurons. Genetically engineer neurons to express proteins that make their activity visible under a microscope.
- Record neurons doing their thing. Observe cells in the brain while an animal is doing something. Neuroscientists can now document activity from tens of thousands of cells at once.
- Image sequential cross-sections of the same volume. To map synapses, the brain must be cut in sections and imaged in high resolution. Layer by layer, a 3D image dataset will emerge.
- Reconstruct the connections among neurons. Using AI and human expertise, map the morphology of neurons to classify cells and catalog all the synapses (connections).
- Model how the brain works. When you know which cells are firing when and the connections among them, you can begin to reverse engineer functional circuits in the brain.
Pyramidal neurons closeup. Anthony Hernandez from Seung Lab reconstructions
A major bottleneck in this process is reconstructing neurons.
It takes months to generate a dataset yet years to analyze it.
This is why we build brain mapping games. Citizen science turns the act of mapping neurons into a 3D puzzle. With no neuroscience experience, people around the world have learned to solve these puzzles, thus mapping neurons and advancing the field of connectomics. Ultimately, it brings us closer to understanding the brain.
This is uncharted territory. Citizen scientists in our first project, Eyewire, discovered 6 new types of neurons in the retina and reconstructed previously unknown circuits, potentially aiding the quest for cures to vision-related disorders. From the retina to the...
Cortex. Between 2020 and 2022, a new brain mapping game will invite the world to solve puzzles alongside cutting-edge AI to reconstruct about 100,000 neurons and find 1 billion synapses. We don't know what we will uncover, except that much of it will be new and novel. If you'd like to help, you can prepare for launch by playing Eyewire as neuron-mapping skills are transferable.
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