Birdsong Studies Lead To a Revolution In Biology

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."

Comments

Thank god!

[Anonymous Coward]

Drink up, fellas!

Re:Thank god!

[dbet]

It's a bit of a myth that brain cells are killed when you drink. They are simply impaired.

So, don't drink because it's now safer, drink because it makes you better looking, funnier, and completely impervious to insults.

So now we can grow wetwear.

[paradxum]

This is actually very awesome as we have slowly made use of mice/rat brain cells as computing devices. This adds a whole new level, Just imagine a self-repairing/expanding computer... hmmmm maybe that's not such a good idea.

Re:So now we can grow wetwear.

[Maxo-Texas]

Op: Computer, please calculate the optimum trajectory to venus.

chee chee chee... working

Optimal path... CHEESE.

Op: Grr... Computer, please calculate the best stock to buy.

chee chee chee... working

Optimal stock... CHEESE.

Bird brain

[oldhack]

The new brain cells are still bird brain cells.

fat cells and muscle cells, too?

[panthroman]

I learned that nerve, fat, and muscle cells didn't change in number during life*. Seems that's not true about neurons. Apparently also not true about fat cells ("If excess weight is gained as an adult, fat cells increase in size about fourfold before dividing and increasing the absolute number of fat cells present.") Anyone know the scoop on muscle cells?

* - Supposedly weight gain was due to the individual adipocytes getting larger, like a microcosmic obesity. And strength gain was due to more actin and myocin in each myocyte, like a micrcosmic bodybuilder.

Re:fat cells and muscle cells, too?

[LeadLine]

I don't know where you studied, but as far as I know, you create tiny rips in your muscles when you work out and new cells are grown to bridge the tear.

Re:fat cells and muscle cells, too?

[__aasqbs9791]

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.

Re:fat cells and muscle cells, too?

[Hurricane78]

No. That it outdated knowledge and is actually an overworking of your muscles. I know that it's stated again, and again, and again, by people who seem to be experts by all standards. Yet there is proper proof that it's not the right way to get stronger, and actually creates scar tissue. So you might get bigger muscles, but not really stronger ones! The strength comes from the tissue that did *not* rupture,and was allowed to grow.

So it's better to lift a lighter weight more often, than a heavier one just a couple of times.

Re:fat cells and muscle cells, too?

[lennier]

"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?

Well, duh.

[pclminion]

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:Well, duh.

[DynaSoar]

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.

I am, and you're right in nearly every detail. I'd only add:

- New growth would consume energy that the very hungry brain would prefer not to waste that way.

- Brain function develops by strengthening some of its connections, but losing far more. You're born with 4 times the connections you die with. There's no need for new cells in terms of function.

- It actually is in repair that 'chaotic' growth occurs. Neurons are notoriously stupid when it comes to regrowing back in the same place. Severed nerve trunks try to grow back together but get tangled and miss connection, make incorrect connections, or simply turn back on themselves in a tangled "stump neuroma". Some (but not all) of this occurs because the 'interneurons' that act as the telephone poles to the neural wires also get damaged and/or die.

- There's good progress made in getting neurons to regrow and reattach properly, using techniques of treating the cut nerves with certain things and/or using host stem cells. I'm not fully up on the details, but I will be once I read a copy of my son's dissertation; he defended it last month and is just finishing the revisions. I do know that in some cases even severed spinal cords could grow back correctly enough for partial function if treated soon enough with a particular substance. That substance is a common food additive, so phase 1 clinical trials might be skipped. The hope is an injectable treatment would be available to emergency workers which, if the testing bears out the initial studies, would give people with severed nerves more than half their original function in more than half the cases.

Re:Thank Cliff!

[dsginter]

In an episode of "Cheers," Cliff Clavin, the trivia-spouting, quirky, irksome mama's boy mailman is seated at the bar describing the buffalo theory to his buddy, Norm Peterson, the beer loving heavyweight bar stool sitting perpetual patron.

Cliff expounds his "Buffalo Theory" to Norm:
Well, you see, Norm, it's like this. A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it's the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members.

In much the same way, the human brain can only operate as fast as the slowest brain cells. Now, as we know, excessive intake of alcohol kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine.

And that, Norm, is why you always feel smarter after a few beers.

Utter bullshit

[Anonymous Coward]

Take a june bug, large and green...tie a string to it's leg and let him fly in circles. At the point where he starts to BLUR, that must be the speed of light. Figure the scale based on RPMs, etc the usual way.

SO: Speed of light: 34 mph!

Seriously: this standard stood for something like 700 years. Science: imperfect.

Wikipedia: Speed of light, history

Physics.virginua.edu: Speed of light

Worsleyschool: Measuring the speed of light

Early, scientific attempts to measure speed of light were very... Well... scientific. And quite accurate. In 1021 an Iraqi physicist realized that light has finite, variable speed that is slower in denser bodies.

In 1629-1667 there were several tries to measure how long it takes for light to move two miles. They all however got to the conclusion that it couldn't be measured because light's speed was so high and human reaction speed could not keep up

In late 1600s astronomers tried to find out the speed of light by observing the moons of Jupiter. They finally got pretty close to the actual value.