Learning about learning
Yearning for learning
New neurons
Brains 'n sweat
Sprouting brain cells
Stem cells
School's open: Learn carefully
26 Aug 1999. School's back in session. Time to clean some erasers and reformat the hard disk, sharpen some pencils and drag out that metric ruler.

The new school season got The Why Files to wondering about the science of learning. What's new in the study of neurons -- the brain cells that are the source of intelligence, learning and memory -- not just in kids, but in adults too?

If you're curious about what makes us curious, crank up that new browser, and dive into The Why Files guide to yearnin' and learnin', version 2.0.

Need neurons?
When your computer memory gets stuffed, you can buy a bigger hard disk. But when your own memory wet-ware gets sluggish, your options are severely limited. Some people swear by a good jolt of caffeine, but when it comes to actually replacing the wet-ware inside your brain, well, almost any neurological textbook will say that an adult mammal's brain does not replace damaged or dead neurons -- period.

That's odd because other organs are constantly being replenished. Shed skin cells are continually replaced by newly divided ones. Blood cells live for a few weeks, then die off and are recycled.

'56 Chevy


But scientists have long held that neurons have steadfastly refused to divide in mature mammals. And despite the talk-show gabble that blames memory declines in aging baby-boomers on dying brain cells, there's reason to think that adding neurons could backfire. Who's to say the new cells would be wired right? Instead of helping you remember the truth -- that you and the spousal unit eloped in a turquoise-and-black '56 Chevy -- a miswired new neuron might cause you to remember splitting the scene in a hot pink Nash Metropolitan convertible.

Nash Metropolitan Beyond the tactless idea of eloping in a hot pink economy car, there's considerable evidence that adult mammalian brains cannot grow replacement neurons. Many common brain diseases, for example, including stroke and Alzheimer's, do their damage by killing off brain cells that are never replaced.


neuron small
Undaunted by this gloomy news, we aging Why Filers managed to dredge up some encouraging discoveries in the neurology labs.

  • According to a discovery reported this year, human brains actually do create new neurons -- in a place vital to processing of new memories.

  • Simple exercise stimulates neurons to grow in rats.

  • Scientists have identified in humans a "spare-part" brain cell that could eventually become the basis for replacing burned-out neurons.
While we can still remember what we're talking about, what's all this about new neurons?

The Why Files
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