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.
As a graduate student in the 1980s, Bruce Yankner wondered what if cancer-causing genes switched on in non-dividing neurons of the brain. Rather than form a tumor, would those genes cause neurons to degenerate? To explore such what-ifs, Yankner spent his days tinkering with neural cells, using viruses to insert various mutant genes and study their effects. In a stroke of luck, one of Yankner’s insertions encoded a precursor to a protein called amyloid. Those experiments and later ones from Yankner’s own lab showed definitively that high concentrations of amyloid, as found in the brains of people with Alzheimer’s disease, are toxic to neural cells .
The discovery set Yankner on a career path to study normal changes in the aging human brain and their connection to neurodegenerative diseases. At Harvard Medical School, Boston, Yankner and his colleague George Church are now recipients of an NIH Director’s 2016 Transformative Research Award to apply what they’ve learned about the aging brain to study changes in the brains of younger people with schizophrenia and bipolar disorder, two poorly understood psychiatric disorders.
Credit: Michael Shribak, Marine Biological Laboratory, Woods Hole, MA
Birds do it, bees do it, and even educated fleas do it. No, not fall in love, as the late Ella Fitzgerald so famously sang. Birds and insects can see polarized light—that is, light waves transmitted in a single directional plane—in ways that provides them with a far more colorful and detailed view of the world than is possible with the human eye.
Still, thanks to innovations in microscope technology, scientists have been able to tap into the power of polarized light vision to explore the inner workings of many complex biological systems, including the brain. In this image, researchers used a recently developed polarized light microscope to trace the spatial orientation of neurons in a thin section of the mouse midbrain. Neurons that stretch horizontally appear green, while those oriented at a 45-degree angle are pinkish-red and those at 225 degrees are purplish-blue. What’s amazing is that these colors don’t involve staining or tagging the cells with fluorescent markers: the colors are generated strictly from the light interacting with the physical orientation of each neuron.
For children with autism spectrum disorder (ASD), early diagnosis is critical to allow for possible interventions at a time when the brain is most amenable to change. But that’s been tough to implement for a simple reason: the symptoms of ASD, such as communication difficulties, social deficits, and repetitive behaviors, often do not show up until a child turns 2 or even 3 years old.
Now, an NIH-funded research team has news that may pave the way for earlier detection of ASD. The key is to shift the diagnostic focus from how kids act to how their brains grow. In their brain imaging study, the researchers found that, compared to other children, youngsters with ASD showed unusually rapid brain growth from infancy to age 2. In fact, the growth differences were already evident by their first birthdays, well before autistic behaviors typically emerge.
Caption: Colorized 3D reconstruction of dendrites. Neurons receive input from other neurons through synapses, most of which are located along the dendrites on tiny projections called spines. Credit: The Center for Sleep and Consciousness, University of Wisconsin-Madison School of Medicine
People spend about a third of their lives asleep. When we get too little shut-eye, it takes a toll on attention, learning and memory, not to mention our physical health. Virtually all animals with complex brains seem to have this same need for sleep. But exactly what is it about sleep that’s so essential?
Two NIH-funded studies in mice now offer a possible answer. The two research teams used entirely different approaches to reach the same conclusion: the brain’s neural connections grow stronger during waking hours, but scale back during snooze time. This sleep-related phenomenon apparently keeps neural circuits from overloading, ensuring that mice (and, quite likely humans) awaken with brains that are refreshed and ready to tackle new challenges.