First in a two-part series on circadian biology and disease. Read part 2.
It’s long been known that a master clock in the hypothalamus, deep in the center of our brain, governs our bodily functions on a 24-hour cycle. It keeps time through the oscillatory activity of timekeeper molecules, much of which is controlled by a gene fittingly named Clock.
It’s also been known that the timekeeper molecules and their regulators live outside this master clock, but what exactly they do there remains mysterious. A new study reveals one surprising function: they appear to regulate the timing of brain plasticity—the ability of the brain to learn from and change in response to experiences.
“We found that a cell-intrinsic Clock may control the normal trajectory of brain development,” says Takao Hensch, PhD, a professor in the Departments of Molecular and Cellular Biology and Neurology at Harvard University and a member of the F.M. Kirby Neurobiology Center at Boston Children’s Hospital. …
One of my very favorite images in science, Dr. Wilder Penfield’s classic motor homunculus, shows how much brain real estate is devoted to controlling movement of different parts of the body. Notice the huge hands and the tiny feet. As the World Cup gets underway, soccer fan Jeffrey Holt, PhD, also a Boston Children’s Hospital neuroscientist, writes that soccer is more than just a great sport, it’s “a triumphant display of the incredible plasticity of the human brain… because the soccer player is limited by one simple rule: no hands!”
Though no one’s actually taken a look, Holt imagines that the brains of great soccer players like Cristiano Ronaldo, Lionel Messi or Neymar would have much expanded neural representation of the feet. Read more in his post on WBUR-Boston’s Cognoscenti blog.
Say you’re a scientist in a movie, and you want to find out what gives a superhero his powers. You’d investigate any special suits he wears, whether he drinks any potions and what they are, right? Real-life scientists are following the same strategy to understand a powerful group of specialized brain cells.
Parvalbumin cells (PV-cells) are a population of inhibitory neurons found throughout the cerebral cortex. While small in number and size, they have the impressive capability to synchronize the electrical activities of other brain cells and orchestrate the timing of critical periods, interludes when the brain is more “plastic” and amenable to rewiring. Abnormalities in these pivotal cells are believed to make plasticity go awry, playing an important role in autism, schizophrenia and other neurodevelopmental disorders.
“The PV-cell is vulnerable in many mental illnesses,” says Takao K. Hensch, PhD, of the F.M. Kirby Neurobiology Center at Boston Children’s Hospital and professor of molecular and cellular biology and neurology at Harvard University. “So if we can find a way to maintain its health and well-being, then we might have a way to treat neurodevelopmental disorders, even later in life.” …
If there wasn’t enough reason to be concerned about children suffering psychological and physical neglect—by their family, in foster homes, or from war or weather catastrophes—we now have three good lines of evidence that neglect harms a child’s developing brain.
But there’s also hope that some of this harm can be undone if caught in time.
When my parents told me I should walk around with my right eye patched like a pirate—on regular days, not just Halloween—I wondered if they were joking. They weren’t: those really were the doctor’s orders.
As a child, I had amblyopia, or “lazy eye”: my left eye had much poorer vision than my right eye. The eye itself was fine, but my brain wasn’t processing information coming from it. The plan was, by patching the “good” eye, to force my brain to use inputs from the amblyopic eye. …