When we think about human achievements, it’s amazing to consider what we’ve accomplished. We’ve sent robots to Mars, developed theories about the universe, and even mapped the human genome. Yet, understanding the human brain—the very organ behind these feats—remains a significant challenge. Scientists have been trying to unravel the complexities of the brain for centuries, and what we really need is a detailed map. This requires courageous scientists and cutting-edge technology.
Imagine if we could fully map the human brain. Such a map could unlock mysteries about mental illnesses, learning difficulties, and age-related diseases. It might help us develop new treatments or even prevent these conditions. Understanding the brain could also shed light on other scientific puzzles, like the origins of consciousness. With this knowledge, we could create smarter robots and computers.
Recognizing the importance of this quest, global efforts are underway. In the U.S., Europe, China, Japan, and various private initiatives, scientists are working to map the brain. The European Commission, for example, is funding 100 universities to create a detailed computer model of the human brain.
When we talk about mapping the brain, we’re referring to creating a “connectome”—a comprehensive catalog of all the brain’s structures and their connections. There are two types of connectomes: structural and functional. The structural connectome includes the white matter fibers connecting different brain regions and the synapses connecting neurons. This is something we can measure and observe. On the other hand, the functional connectome involves understanding how different brain regions work together, even if they’re not physically connected.
So far, we haven’t fully mapped any functional connectomes, and the only complete structural connectome is that of C. elegans, a tiny worm. Mapping this was a significant achievement, but the human brain, with its 100 billion neurons, presents a much greater challenge.
The complexity of the human brain is the first major obstacle. Scientists often start with tiny samples, about the size of a grain of sand, containing around 100,000 neurons and a billion connections. The human brain is over a million times larger, with an immense density of connections. Moreover, the brain is constantly changing, forming new neurons and connections as we grow and interact with our environment.
To tackle these challenges, the Obama administration launched the Brain Initiative in 2014, bringing together scientific institutions to better understand and treat the human mind. The Allen Institute, part of this initiative, is studying mouse brains to lay the groundwork for human brain research. Using electron microscopy, they have imaged billions of synaptic connections in a tiny piece of mouse brain.
Mapping the brain at such a high resolution is difficult. Samples must be meticulously prepared and sectioned into 25,000 slices, each just 40 nanometers wide—thinner than a human hair. These slices are then imaged using electron microscopes, generating massive amounts of data. For human brain samples, the process will need to evolve, requiring advancements in sample preparation, data storage, and less invasive technologies for studying live brains.
The Human Connectome Project, led by the NIH, is using non-invasive tools like MRI machines to study human brains. For the structural connectome, diffusion imaging tracks water movement along white matter connections. For the functional connectome, a different MRI sequence measures blood flow, which correlates with neural activity. By analyzing brain activity patterns, researchers can identify functionally connected regions.
In 2016, the Human Connectome Project released the most detailed map of the cerebral cortex, discovering 97 new brain regions and confirming 83 others. This has improved our understanding of how brain regions connect to form networks and how these networks relate to behaviors. However, more work is needed to understand how these networks are affected by illnesses and environmental factors.
The challenge of mapping the human brain is immense, pushing our technology and creativity to their limits, much like sending robots to Mars or sequencing the human genome. While significant advancements are expected in the next 10 to 20 years, it’s uncertain if we’ll ever have a complete map of every brain connection or fully understand how they produce human behaviors and emotions.
The intricate shapes of neurons are both beautiful and inspiring. Scientists and their collaborators are exploring uncharted territory, much like old explorers discovering new continents. The journey to map the human brain continues, full of promise and potential.
Using materials like clay, string, and paper, create a 3D model of the human brain. Label the different regions and their connections, representing both structural and functional connectomes. This hands-on activity will help you visualize the complexity of the brain’s network.
Choose one of the global brain mapping initiatives, such as the Human Connectome Project or the European Commission’s efforts. Research its goals, methods, and recent findings. Present your findings to the class, highlighting the initiative’s contributions to understanding the brain.
Engage in a class debate about the ethical considerations of brain mapping. Consider privacy concerns, potential misuse of data, and the impact on personal identity. This will help you critically evaluate the broader implications of scientific advancements.
Select a recent scientific article related to brain mapping. Summarize the key points, methodologies, and conclusions. Discuss how the findings contribute to the field and what challenges remain. This activity will enhance your ability to interpret scientific literature.
In groups, design a hypothetical experiment to map a specific aspect of the brain. Consider the tools and technologies you would use, the data you would collect, and the potential outcomes. Present your experimental design to the class, explaining its significance and feasibility.
Here’s a sanitized version of the provided YouTube transcript:
—
When you think about all the things humans have accomplished, it’s impressive: we’ve built and landed robots on Mars to learn more about space. We’ve developed theories about how the universe works and then validated them. We’ve sequenced the human genome to create a complete picture of our DNA. However, when it comes to understanding the minds that made these achievements possible, we still have much to learn. Scientists have been trying to navigate the complexities of our brains for hundreds of years. What would be really helpful is if we had a map. To achieve that, we need brave scientists and advanced technology.
So, how close are we to mapping the human brain? If we could create a complete map of our brain and interpret it, imagine the possibilities: it could provide insights into the causes of various mental illnesses, learning difficulties, and age-related diseases. This knowledge might help us develop treatments or prevent the onset of these conditions. A brain map could also aid in understanding other scientific mysteries, such as the origins of consciousness. Our brain is so powerful that a better understanding of its workings could lead to the creation of smarter robots and computers.
The quest for a map of the human brain is so valuable that multiple global efforts are underway. In addition to significant projects in the U.S., the European Commission is funding 100 universities to create a detailed computer model of the human brain. China and Japan have also announced projects aimed at mapping the brain, along with several private initiatives.
When we refer to a map of the human brain, we specifically mean creating something called a “connectome”—a comprehensive catalog of all the brain’s structures and their connections. There are two types of connectomes: structural and functional. The structural connectome consists of the white matter fibers that connect different brain regions and the synapses that connect neurons. This is measurable and observable. In contrast, the functional connectome relates to the coordination and function across brain regions, identifying areas that work together without direct physical connections.
Currently, we have not fully mapped any functional connectomes, and the only complete structural connectome mapped is that of *C. elegans*, a tiny nematode. Although mapping that connectome was a significant achievement, it remains a complex organism. The challenge of mapping the human brain is exponentially greater, as humans have around 100 billion neurons.
This vast complexity is the first major obstacle scientists face. They must start small, often studying samples the size of a grain of sand, which contain about 100,000 neurons and form approximately one billion connections. The human brain is over a million times larger than this sample, highlighting the immense density of connections in such a small space. Additionally, the brain is constantly changing, complicating the study further. As we grow, our brains develop new neurons and connections based on our interactions with the environment, and they continue to change as we age.
To address these challenges, the Obama administration initiated the Brain Initiative in 2014, uniting several scientific institutions to better understand and treat the human mind. As part of this coalition, the Allen Institute is analyzing mouse brain samples to catalog and connect various cell types, laying the groundwork for similar work on the human brain. Using electron microscopy, the team has imaged billions of tiny synaptic connections in a cubic millimeter of mouse neocortex.
Mapping the brain at this resolution is challenging, as many factors must align perfectly. Scientists must prepare samples meticulously, sectioning them into 25,000 slices just 40 nanometers wide. For context, a strand of hair is five times thicker than that. These slices are then distributed across six electron microscopes for imaging, a process that took about five months to complete. The resulting data amounts to approximately two petabytes, or 2 million gigabytes, from just one millimeter of brain tissue.
To work with larger human brain samples, the process will need to evolve, as it will ultimately yield the largest data set ever collected. Significant advancements in sample preparation, sectioning, and data storage will be necessary. We will also need less invasive technologies to study live human brains. To create a comprehensive map, we must analyze more than just one brain; we need to study a diverse range of brains, including those of different ages and genders.
The Human Connectome Project, led by the NIH, is currently using non-invasive tools to study human brains. The primary tool is an MRI machine. For the structural connectome, diffusion imaging is employed to observe the movement of water along white matter connections. For the functional connectome, a different MRI sequence is used to measure blood flow in the brain, which is believed to correlate with neural activity. By analyzing patterns of brain activity over time, researchers can identify functionally connected brain regions.
The Human Connectome Project has made significant strides, releasing the most detailed map of the cerebral cortex to date in 2016, which included the discovery of 97 new brain regions and the confirmation of 83 others. We now have a better understanding of how different brain regions connect to form networks and how these networks relate to various behaviors. However, more work is needed to understand how these networks are affected by illnesses and environmental factors.
This challenge is immense and will push our technology and creativity to their limits, much like the achievements of sending robots to Mars and sequencing the human genome. So, how close are we to mapping the human brain? The biggest barriers to creating a detailed human connectome are technological. In my scientific lifetime, progress has been exponential, so I wouldn’t be surprised if we see significant advancements in the next 10 to 20 years. However, I am not entirely convinced that we will ever have a complete map of every connection in the human brain or fully understand how they interact to produce all human behaviors, cognitive abilities, and emotions.
The intricate shapes of neurons are beautiful and inspiring. We and our collaborators are among the first to observe such detail at this scale in the brain, akin to the old explorers discovering new continents. We are mapping uncharted territory.
For more episodes of “How Close Are We,” check out this playlist. Don’t forget to subscribe and return to Seeker for more episodes. Thank you for watching.
—
This version maintains the core content while removing any informal language and ensuring clarity.
Brain – The organ in the body that serves as the center of the nervous system, responsible for processing sensory information and controlling bodily functions. – The human brain is capable of processing complex thoughts and emotions, making it a central focus in neuroscience studies.
Connectome – A comprehensive map of neural connections in the brain, often referred to as the brain’s wiring diagram. – Scientists are working on creating a detailed connectome to better understand how different regions of the brain communicate with each other.
Neurons – Specialized cells in the nervous system that transmit information through electrical and chemical signals. – Neurons communicate with each other through synapses, forming intricate networks that underlie all brain functions.
Mapping – The process of identifying and charting the locations and functions of various components within the brain. – Brain mapping techniques have advanced significantly, allowing researchers to pinpoint areas responsible for specific cognitive tasks.
Technology – The application of scientific knowledge for practical purposes, especially in industry, including tools and devices used in neuroscience research. – Advances in imaging technology have revolutionized our ability to study the brain’s structure and function in real-time.
Consciousness – The state of being aware of and able to think about one’s own existence, sensations, and thoughts. – Understanding the neural basis of consciousness remains one of the most challenging questions in neuroscience.
Diseases – Disorders or malfunctions in the body, often affecting the brain and nervous system, that can impair normal functioning. – Neurodegenerative diseases like Alzheimer’s and Parkinson’s are major areas of research in the field of neuroscience.
Research – The systematic investigation into and study of materials and sources to establish facts and reach new conclusions. – Ongoing research in neuroscience is crucial for developing new treatments for brain-related disorders.
Imaging – The use of various techniques to visualize the internal structures of the brain, aiding in diagnosis and research. – Functional MRI is a popular imaging technique that allows scientists to observe brain activity by measuring changes in blood flow.
Networks – Interconnected groups or systems, particularly referring to the complex web of neurons and synapses in the brain. – The brain’s networks are responsible for integrating information from different sensory modalities to produce coherent perceptions.
