Birdsong Studies Lead To a Revolution In Biology 117
Smithsonian.com covers research that began with the study of birdsong and ended by overturning the common belief that adult animals can't produce new brain cells. "Deconstructing birdsong may seem an unlikely way to shake up biology. But [Fernando] Nottebohm's research has shattered the belief that a brain gets its quota of nerve cells shortly after birth and stands by helplessly as one by one they die — a 'fact' drummed into every schoolkid's skull. [Nottebohm] demonstrated two decades ago that the brain of a male songbird grows fresh nerve cells in the fall to replace those that die off in summer. The findings were shocking, and scientists voiced skepticism that the adult human brain had the same knack for regeneration. ... Yet, inspired by Nottebohm's work, researchers went on to find that other adult animals — including human beings — are indeed capable of producing new brain cells. And in February, scientists reported for the first time that brand-new nerves in adult mouse brains appeared to conduct impulses — a finding that addressed lingering concerns that newly formed adult neurons might not function."
well ya (Score:3, Insightful)
Re:fat cells and muscle cells, too? (Score:5, Insightful)
Blasphemy! Each person only has 1 muscle cell that grows larger as they work out. /s
I learned the same things in school myself. We ere even taught that nerve cells didn't get repaired after they were damaged (to the point of dying). Oh, except in the tongue. Those were unique for some reason. And then we started learning that other nerve cells (like in the spine) did sometimes heal, but that perhaps the 'muscle memory' was lost, and learning to walk when you are an adult is much harder than it was as a child. At some point I think we may just have to say, "We don't know what we think we know, and maybe we should just start all over again." We stand on the shoulders of giants when we discover something new, but apparently sometimes it turns of those are midget's, not giant's shoulders, and we are forced to unlearn something we thought was true. Thus goes the ways of science.
Well, duh. (Score:5, Insightful)
I don't mean "duh" to the researcher -- obviously things must be tested and validated in the real world, not just postulated -- but it never made sense to me in the first place that brain cells can't regenerate. Why the hell not? What is the adaptive purpose of such a limitation? The brain consumes a huge amount of energy, much more so per-pound than any other organ in the body. That seems to imply that the brain is extremely important to the organism. Why would essentially the most important organ in the body have such a stupid limitation that it can't even recover from MINOR damage? That makes no sense.
One possible explanation for the very limited growth rate of brain cells is that if this growth rate were not tightly controlled, it could lead to "chaotic" brain tissue which could interfere with normal brain function. So general division of brain cells would not be desirable -- but I'm no neuroscientist.
Re:fat cells and muscle cells, too? (Score:2, Insightful)
Something interesting about fat cells (adipocytes)... As they swell they secrete leptin, which reduces hunger and aims to keep one at a healthy body fat level. If a person becomes fat enough that the adipocytes have to divide (probably related to maximum surface area to volume ratio), then they have more adipocytes and thus more leptin produced. But, the clincher is that losing that fat becomes more difficult, since you don't get rid of the fat cells. What happens is that each cell is forced to become unnaturally small, which lowers the amount of leptin secreted. On top of that, the more leptin that floods the leptin receptors in the brain, the more resistant to leptin the receptors become (much like a Type II Diabetic is resistant to insulin). Less leptin receptor activation causes more hunger, and thus more difficulty in losing fat. Apparently, high levels of fructose accelerate this process. (All that said, fat levels are basically a matter of calories in/out due to the laws of physics; hunger just makes it more difficult to eat less and exercise more.)
Re:fat cells and muscle cells, too? (Score:4, Insightful)
"outdated knowledge"
Isn't that a contradiction in terms? If it's wrong now, it was just as wrong when it was being taught... knowledge doesn't get "outdated". Opinions and beliefs and fashionable ideas may change... but not actual *knowledge*.
Pedantic, I know, but I get creeped out by the subtle assumption that somehow the very foundations of reality change under us as the scientific consensus shifts. This sort of abuse of language and the misidentification of beliefs, teachings and opinions with fact, is exactly why the man in the street has grown to distrust "science".
I'm pretty horrified myself if this "muscle tearing" thing is in fact incorrect - because that's what I was taught in high school gym class. It sounded stupid and abusive to me at the time - why should destroying muscle be a *good* thing? - and it was used to justify the "if it doesn't hurt you're not doing it right" idea. If it turns out that that was a flat lie all along... yeah, I'm pretty pissed off. Shouldn't we hold off making *any* such "scientific" pronouncements until we're darn sure, for good and all, that we're NOT just saying crazy wrong things?
Re:fat cells and muscle cells, too? (Score:2, Insightful)
I mean, the current accepted philosophical basis of science is Karl Popper's falsifiability criterion, which is not a monotonic logic... yet we don't have anything like a universally accepted formalisation of nonmonotonic logic [stanford.edu] to deal with this kind of situation (where something believed 'true'at time A becomes 'false' at time B when new facts emerge). There's no standard way of dealing with this in logic - much foundational work was only *started* in the 1980s and the results are still very unclear. So the formal philosophical foundations of our current scientific paradigm are a massive pile of confusion. Yet we're charging ahead using science to make sweeping technological and social changes without properly thinking them through - without even the guarantee that we CAN think them through consistently. Shouldn't that worry us a lot more than it does?
Re:well ya (Score:3, Insightful)
Re:Bird brain (Score:2, Insightful)
Re:Settled science (Score:3, Insightful)
So a scientific view that is considered the "settled" "consensus" view can change in the face of contrary evidence? That's good to know.
That's exactly correct. That's precisely how science works, and it wouldn't work any other way. When you continue to believe something in the face of contrary evidence, that's called being (1) irrational, (2) stupid, or (3) both. Had you paid attention when the teachers were trying to explain this, you wouldn't be (1), (2) or (3).
But I will add that, as noted below, just because you're (1), (2) or (3), you're only wrong, not trolling. Someone who mods a comment down just because it's wrong is both (2), and (5) an asshole. A troll would be something like my using the missing (4), inserting into in the comment in the paragraph above following the first (1) (2) (3), to say something like "or (4) religious". While accurate, it is inappropriate, and therefore a troll. So don't do it. Not even if you're (5) like me and think it's funny.
Science is a discourse, not a religion (Score:3, Insightful)