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."
So now we can grow wetwear. (Score:3, Interesting)
Revolution? (Score:2, Interesting)
There was another study dating cells based on inclusion of radioisotopes left over from atmospheric nuclear weapons testing, apparently finding a very slow rate of new cell generation, measured in something like percent (or fraction thereof) per decade of the total. And their study only holds true if they correctly sorted their neurons from other cells that live in the brain (glia, blood vessels, etc). The study is actually pretty convincing, along with the Swedish BrdU study, but the rate of growth is less than stunning. The findings in birds of huge amounts of cortical growth are very cool and establish the principle that such massive growth can happen in an adult vertebrate.
What has not yet been established is what these new cells in humans might be doing, if anything. Even without new neurons, we can still be pretty flexible, by altering the strength of connections between neurons or forming entirely new connections.
Also even if the human brain does grow some new cells, the type of those cells is very important. for example, I heard a talk today from a guy with Parkinson's disease, which is a progressive disease of the cells of the substantia nigra, an area of the brain that is part of the system for controlling movement. He sure could use a few extra dopaminergic cells in his substantia nigra, but thats not happening for him, so the disease will kill him. So don't go on that brain cell massacre just yet.
Re:fat cells and muscle cells, too? (Score:2, Interesting)
Short answer: No.
If you look at the history of "modern science", from circa Newton and forward, the hard science has been separated from philosophy.
In a way you can say that the philosophers are constantly trying to catch up, and integrate the new knowledge in their world perceptions.
As a whole I do not think that is a problem. We might occationally stumble upon a field or a method that we in hindsight can see was a bad idea, for ethical reasons, but the checks and balances that is built into academia and science/science funding will soon enough learn to handle these areas (and perhaps give the philosophers a helping hand in the process).
I see philosophy as contemplative and reactive to the given facts. If we insist that all science must keep pace with philosophy, we will stifle progress enough to start a new "dark age". /Crafack
Re:Beliefs of scientists (Score:3, Interesting)
It's amazing how strong many scientists believe in certain things that are not even theories, and have a hard time changing their minds in the face of evidence to the contrary.
Why should we scientists be any different from the rest of you? We're people acting like people do, we just happen to be trying to figure things out in public. Besides, we have to believe something as a starting point so we can test an idea, and when we do have evidence, develop a theory which we can then further test to find out where we're wrong, discard that, and repeat the process. A science example of this is solar neutrinos. Despite many well designed experiments using well tested devices, only one third of the predicted amount was observed. None would be a failure, but a consistent one third? That would call for changing the theory. But they didn't. After decades someone came up with an idea of how the theory was right, but neutrinos themselves acted differently than expected. The same design was used to test the old solar neutrino theory plus the new neutrino behavior theory, and the found the solar neutrinos, oscillating between types. They didn't change their minds in the face of evidence and ended up correct.
It's also amazing how people, including us, refuse to believe something new (as opposed to just different from previous beliefs) even when well supported by evidence. A science example is the 80% positive replications of chemical transfer of learning. Even a colleague of James McConnell, the guy who started this field (and the Journal of Biological Psychology/Worm Runner's Digest), wrote in his obituary in science about this "failure", correct in his statement with respect to the field but wrong as a football bat about the theory. Scientists didn't change their minds (or come to believe something) in the face of evidence, and still haven't, and they're wrong.
Then there's conflicting theories. The two major theories of emotion are that we notice a physiological response, then attach a significance to it. The other is that we notice something, develop a cognitive response, and that causes a physiological response. Completely backwards from each other. Neither side would let go because they had plenty of evidence. After a while it came to be understood that both were right, it was emotions that occurred differently in different cases (phobias and PTSD, respectively).
And recall Einstein being interviewed when Eddington was going to measure light curvature around an eclipse to test relativity. When asked what would happen if the data were contrary to the theory, he said "then heaven help the data. The theory is correct." Eddington came back with some data and said he'd proved the theory correct and everybody believed it, and many still do. It was 70 years before a different test proved the theory correct. Subsequently, it was shown that the errors rate in the few measurements Eddington had were insufficient -- he was wrong, and so were everyone else that did and do believe his claim.
Three of these four examples are from "The Golem" by Collins and Pinch. That book very thoroughly and with references speaks to your observation but in all these different aspects, and more. It's simply the best source of examples of science being conducted as a human endeavor by plain old normal humans with human behaviors. It's instructive, illuminating and quite entertaining. And in the case of things that are correct but people continue to disbelieve, such as cold fusion, quite irritating. As a scientist that last bit, to quote Spock, "thrills me no end."