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.
Tags: brain, brain imaging, cerebral cortex, Homer1a, learning, memory, neural circuits, neurology, neurons, resetting brain, serial scanning 3D electron microscopy, SHY hypothesis, sleep, sleep disorders, spines, synapse, synaptic homeostasis hypothesis, synaptic scaling, wakefulness
When our curiosity is piqued, learning can be a snap and recalling the new information comes effortlessly. But when it comes to things we don’t care about—the recipe to that “delicious” holiday fruitcake or, if we’re not really into football, the results of this year’s San Diego County Credit Union Poinsettia Bowl—the new information rarely sticks.
To probe why this might be so, neuroscientists Charan Ranganath and Matthias Gruber, and psychologist Bernard Gelman, all at the University of California at Davis, devised a multi-step experiment to explore which regions of the brain are activated when we are curious, and how curiosity enhances our ability to learn and remember.
Infusing blood from younger creatures into older ones in hopes of halting—or even reversing—the aging process may sound like a macabre scene straight out of “Game of Thrones.” However, several scientific studies have shown that when older animals receive blood from younger counterparts, it improves the function of stem cells throughout the body, boosting tissue regeneration and healing. What’s not been clear is whether this activity can also rejuvenate the brain’s cognitive powers.
Let’s face it: aging is tough on the brain. The number of neural stem cells shrinks, producing fewer neurons; and many of the genes that promote brain development and neural connections become less active. To find out if young blood might hold some of the answers to this complex problem, two teams of NIH-funded researchers—one in Massachusetts and the other in California—recently turned to mice as a model system.
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