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Human Connectome Project

The Amazing Brain: A Sharper Image of the Pyramidal Tract

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Flip the image above upside down, and the shape may remind you of something. If you think it resembles a pyramid, then you and a lot of great neuroscientists are thinking alike. What you are viewing is a colorized, 3D reconstruction of a pyramidal tract, which are bundles of nerve fibers that originate from the brain’s cerebral cortex and relay signals to the brainstem or the spinal cord. These signals control many important activities, including the voluntary movement of our arms, legs, head, and face.

For a while now, it’s been possible to combine a specialized form of magnetic resonance imaging (MRI) with computer modeling tools to produce 3D reconstructions of complicated networks of nerve fibers, such as the pyramidal tract. Still, for technical reasons, the quality of these reconstructions has remained poor in parts of the brain where nerve fibers cross at angles of 40 degrees or less.

The video above demonstrates how adding a sophisticated algorithm, called Orientation Distribution Function (ODF)-Fingerprinting, to such modeling can help overcome this problem when reconstructing a pyramidal tract. It has potential to enhance the reliability of these 3D reconstructions as neurosurgeons begin to use them to plan out their surgeries to help ensure they are carried out with the utmost safety and precision.

In the first second of the video, you see gray, fuzzy images from a diffusion MRI of the pyramidal tract. But, very quickly, a more colorful, detailed 3D reconstruction begins to appear, swiftly filling in from the top down. Colors are used to indicate the primary orientations of the nerve fibers: left to right (red), back to front (green), and top to bottom (blue). The orange, magenta, and other colors represent combinations of these primary directional orientations.

About three seconds into the video, a rough draft of the 3D reconstruction is complete. The top of the pyramidal tract looks pretty good. However, looking lower down, you can see distortions in color and relatively poor resolution of the nerve fibers in the middle of the tract—exactly where the fibers cross each other at angles of less than 40 degrees. So, researchers tapped into the power of their new ODF-Fingerprinting software to improve the image—and, starting about nine seconds into the video, you can see an impressive final result.

The researchers who produced this amazing video are Patryk Filipiak and colleagues in the NIH-supported lab of Steven Baete, Center for Advanced Imaging Innovation and Research, New York University Grossman School of Medicine, New York. The work paired diffusion MRI data from the NIH Human Connectome Project with the ODF-Fingerprinting algorithm, which was created by Baete to incorporate additional MRI imaging data on the shape of nerve fibers to infer their directionality [1].

This innovative approach to imaging recently earned Baete’s team second place in the 2021 “Show Us Your BRAINs” Photo and Video contest, sponsored by the NIH-led Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative. But researchers aren’t stopping there! They are continuing to refine ODF-Fingerprinting, with the aim of modeling the pyramidal tract in even higher resolution for use in devising new and better ways of helping people undergoing neurosurgery.

Reference:

[1] Fingerprinting Orientation Distribution Functions in diffusion MRI detects smaller crossing angles. Baete SH, Cloos MA, Lin YC, Placantonakis DG, Shepherd T, Boada FE. Neuroimage. 2019 Sep;198:231-241.

Links:

Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative (NIH)

Human Connectome Project (University of Southern California, Los Angeles)

Steven Baete (Center for Advanced Imaging Innovation and Research, New York University Grossman School of Medicine, New York)

Show Us Your BRAINs! Photo and Video Contest (BRAIN Initiative/NIH)

NIH Support: National Institute of Biomedical Imaging and Bioengineering; National Institute of Neurological Disorders and Stroke; National Cancer Institute


The Amazing Brain: Mapping Brain Circuits in Vivid Color

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Hop aboard as we fly up, down, left, and right through the information highways of the human brain! This captivating and eye-catching video was one of the winners of the 2019 “Show us Your Brain!” contest sponsored by the NIH-led Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative.

The video travels through several portions of the brain’s white matter—bundles of fiber that carry nerve signals between the brain and the body, as well as within the brain itself. Fiber colors indicate directionality: left-right fibers (red), front-back fibers (green), and top-bottom fibers (blue).

Looking from the back, we start our journey deep within the brain in the limbic system, the area that helps control emotion, learning, and memory. About three seconds in, visual fibers pop into view extending from the eyes to various brain areas into the occipital lobe (one of four major brain lobes) in the back of the brain.

About two seconds later, flying over top as the brain starts rotating, we see various fiber bundles spray upward throughout the cerebral cortex, communicating information related to language processing, short-term memory, and other functions. About halfway through the video, several green bundles emerge arching across the brain’s midline. These bundles, called the corpus callosum, house the fibers enabling communication between left and right sides of the brain. Finally, the video closes as we see many different fiber bundles lighting up all over, enabling communication between different cortical and subcortical portions of the brain through association and projection pathways.

Dynamic maps like these are created using a 3D imaging technique called diffusion MRI tractography [1]. The technique tracks subtle pathways of water movement in the brain, and allows researchers to model the physical properties (connectional anatomy) that underlie the brain’s electrical properties (neuronal signaling). Postdoctoral researcher Ryan Cabeen and Arthur Toga, director of the University of Southern California Mark and Mary Stevens Neuroimaging and Informatics Institute, Los Angeles, used the method to study how white matter changes in developing and aging brains, as well as in brains affected by neurodegenerative or neurological disorders.

Scientific animator Jim Stanis produced the video with Cabeen and Toga. The team first created a population-averaged brain using high-quality diffusion MRI datasets from the Human Connectome Project ,and then used sophisticated computational tools to delineate each bundle manually .

The tractography technique lets scientists visualize and quantitatively analyze the brain’s wiring patterns, complementing our understanding of how the brain functions. Such methods are especially useful to learn about the organization of deep-brain areas that remain out of reach for scientists using current tools and imaging techniques.

Reference:

[1] Kernel regression estimation of fiber orientation mixtures in diffusion MRI. Cabeen RP, Bastin ME, Laidlaw DH. Neuroimage. 2016 Feb 15;127:158-172.

Links:

Arthur Toga (USC Mark and Mary Stevens Neuroimaging and Informatics Institute, Los Angeles)

Ryan Cabeen (USC Mark and Mary Stevens Neuroimaging and Informatics Institute)

qitwiki—Information about the Quantitative Imaging Toolkit (USC)

Human Connectome Project (USC)

Show Us Your Brain Contest! (BRAIN Initiative/NIH)

Brain Research through Advancing Innovative Neurotechnologies® (BRAIN) Initiative (NIH)

NIH Support: National Institute of Neurological Disorders and Stroke; National Institute of Mental Health


Cool Videos: Starring the Wiring Diagram of the Human Brain

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MRI videoThe human brain contains distinct geographic regions that communicate throughout the day to process information, such as remembering a neighbor’s name or deciding which road to take to work. Key to such processing is a vast network of densely bundled nerve fibers called tracts. It’s estimated that there are thousands of these tracts, and, because the human brain is so tightly packed with cells, they often travel winding, contorted paths to form their critical connections. That situation has previously been difficult for researchers to image three-dimensional tracts in the brain of a living person.

That’s now changing with a new approach called tractography, which is shown with the 3D data visualization technique featured in this video. Here, researchers zoom in and visualize some of the neural connections detected with tractography that originate or terminate near the hippocampus, which is a region of the brain essential to learning and memory. If you’re wondering about what the various colors represent, they indicate a tract’s orientation within the brain: side to side is red, front to back is green, and top to bottom is blue.


Big Data and Imaging Analysis Yields High-Res Brain Map

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The HCP’s multi-modal cortical parcellation

Caption: Map of 180 areas in the left and right hemispheres of the cerebral cortex.
Credit: Matthew F. Glasser, David C. Van Essen, Washington University Medical School, Saint Louis, Missouri

Neuroscientists have been working for a long time to figure out how the human brain works, and that has led many through the years to attempt to map its various regions and create a detailed atlas of their complex geography and functions. While great progress has been made in recent years, existing brain maps have remained relatively blurry and incomplete, reflecting only limited aspects of brain structure or function and typically in just a few people.

In a study reported recently in the journal Nature, an NIH-funded team of researchers has begun to bring this map of the human brain into much sharper focus [1]. By combining multiple types of cutting-edge brain imaging data from more than 200 healthy young men and women, the researchers were able to subdivide the cerebral cortex, the brain’s outer layer, into 180 specific areas in each hemisphere. Remarkably, almost 100 of those areas had never before been described. This new high-resolution brain map will advance fundamental understanding of the human brain and will help to bring greater precision to the diagnosis and treatment of many brain disorders.


Making the Connections: Study Links Brain’s Wiring to Human Traits

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The Human Connectome

Caption: The wiring diagram of a human brain, measured in a healthy individual, where the movement of water molecules is measured by diffuse tensor magnetic resonance imaging, revealing the connections. This is an example of the type of work being done by the Human Connectome Project.
Source: Courtesy of the Laboratory of Neuro Imaging and Martinos Center for Biomedical Imaging, Consortium of the Human Connectome Project

For questions about why people often think, act, and perceive the world so differently, the brain is clearly an obvious place to look for answers. However, because the human brain is packed with tens of billions of neurons, which together make trillions of connections, knowing exactly where and how to look remains profoundly challenging.

Undaunted by these complexities, researchers involved in the NIH-funded Human Connectome Project (HCP) have been making progress, as shown by some intriguing recent discoveries. In a study published in Nature Neuroscience [1], an HCP team found that the brains of individuals with “positive” traits—such as strong cognitive skills and a healthy sense of well-being—show stronger connectivity in certain areas of the brain than do those with more “negative” traits—such as tendencies toward anger, rule-breaking, and substance use. While these findings are preliminary, they suggest it may be possible one day to understand, and perhaps even modify, the connections within the brain that are associated with human behavior in all its diversity.


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