Considering all the recent advances in mapping the complex circuitry of the human brain, you’d think we’d know all there is to know about the brain’s basic anatomy. That’s what makes the finding that I’m about to share with you so remarkable. Contrary to what I learned in medical school, the body’s lymphatic system extends to the brain—a discovery that could revolutionize our understanding of many brain disorders, from Alzheimer’s disease to multiple sclerosis (MS).
Researchers from the National Institute of Neurological Disorders and Stroke (NINDS), the National Cancer Institute (NCI), and the University of Virginia, Charlottesville made this discovery by using a special MRI technique to scan the brains of healthy human volunteers . As you see in this 3D video created from scans of a 47-year-old woman, the brain—just like the neck, chest, limbs, and other parts of the body—possesses a network of lymphatic vessels (green) that serves as a highway to circulate key immune cells and return metabolic waste products to the bloodstream.
Research shows that the roots of autism spectrum disorder (ASD) generally start early—most likely in the womb. That’s one more reason, on top of a large number of epidemiological studies, why current claims about the role of vaccines in causing autism can’t be right. But how early is ASD detectable? It’s a critical question, since early intervention has been shown to help limit the effects of autism. The problem is there’s currently no reliable way to detect ASD until around 18–24 months, when the social deficits and repetitive behaviors associated with the condition begin to appear.
Several months ago, an NIH-funded team offered promising evidence that it may be possible to detect ASD in high-risk 1-year-olds by shifting attention from how kids act to how their brains have grown . Now, new evidence from that same team suggests that neurological signs of ASD might be detectable even earlier.
The 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.
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 . 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.
This past weekend, I attended a scientific meeting in New York. As often seems to happen to me in a hotel, I tossed and turned and woke up feeling not very rested. The second night I did a bit better. Why is this? Using advanced neuroimaging techniques to study volunteers in a sleep lab, NIH-funded researchers have come up with a biological explanation for this phenomenon, known as “the first-night effect.”
As it turns out, the first night when a person goes to sleep in a new place, a portion of the left hemisphere of his or her brain remains unusually active, apparently to stay alert for any signs of danger. The new findings not only provide important insights into the function of the human brain, they also suggest methods to prevent the first-night effect and thereby help travelers like me in our ongoing quest to get a good night’s sleep.