Adult Brains More Flexible Than Previously Thought

stemceller passed us a link to the official site for Johns Hopkins, which is reporting on some research into cognition. Generally, doctors have understood our best learning to be done at a young age, when the brain has a 'robust flexibility'. As we get older, our brain cells become 'hard-wired' along certain paths and don't move much - if at all. Or, at least, that was the understanding. Research headed by the hospital's Dr. Linden has taken advantage of 'two-photon microscopy', a new technique, to get a new picture inside a mouse's head. "They examined neurons that extend fibers (called axons) to send signals to a brain region called the cerebellum, which helps coordinate movements and sensory information. Like a growing tree, these axons have a primary trunk that runs upward and several smaller branches that sprout out to the sides. But while the main trunk was firmly connected to other target neurons in the cerebellum, stationary as adult axons are generally thought to be, 'the side branches swayed like kite tails in the wind,' says Linden. Over the course of a few hours, individual side branches would elongate, retract and morph in a highly dynamic fashion. These side branches also failed to make conventional connections, or synapses, with adjacent neurons. Furthermore, when a drug was given that produced strong electrical currents in the axons, the motion of the side branches stalled.'"

Defensive coding...

[RyanFenton]

This is kind of what I'd expect, actually. Even if an adult mind was completely plastic, as people learn of the type of experiences that will come to them, they're going to quickly learn to categorize them, and which kinds of categories tend to work with more and more experiences.

It's like as a programmer learns of which coding constructs work for which situations... they learn it becomes more important to worry about understandability rather than speed, and to code with clear structures they can pick up later if and when they need to clean up misunderstandings later. The default practice becomes a sort of robust defensive form, that requires the fewest changes over the widest plausible set of needs - while still doing the job of completely enumerating the problem set needed.

I'd expect that even with minds unhindered by age, the same sort of defensive practices programmers pick up would have analogues in most other realms of experience that mankind goes through. That would then, be easily confused with a mind unable to rapidly change, because such wide change is then rarely observed.

That said - there are more concrete bits of evidence that complicate things - such as rates of new language adoption between adults and children... but again, there's also evidence that some adults can still pick up new languages rapidly. Perhaps those same defensive practices act as a 'language censor' to 'wasting time with confusing sentence structure' - or perhaps there really is some factor of truth to the hardware limitations of an aging brain. Hard to know for sure until we get the computational nuerobiology tools in place to be able to strictly test such things... I'm really happy to see the progress so far though.

Ryan Fenton

Re:Humans

[timmarhy]

I hate this view that some how results of tests on animals don't apply to humans at all.

it's simply not true, almost every major medical advance has been tested or researched on animals like mice first.

the simple fact is mammals bodies all work in very similar ways. if you were to tell me you tested this on a FISH brain i might be more scpectical.

i already know that

[Anonymous Coward]

i'm getting older, everyone does, but media and "science" try to put in your mind that you are not capable of learning new things or think like a young man, is a trap, the truth is, you can *always* learn... pick a book, a class, and try yourself.

Re:Scary combination

[rolfwind]

It could be that there is exponentially more to remember. Back a generation ago, you had to know your name, address, a single phone number, social security number, and perhaps a few odds and ends like bank account number and/or atm number -- and you're good to go.

A generation before that list gets reduced further.

Today, how many phone numbers, email addresses, irc addresses, computer and site logins and their accompanying passwords does one have to remember? For personal, work and/or school?

Personally I welcome modern technology alleviating the burden it placed on us in the first place. People still should learn to work without a calculator -- but I don't think it's quite a disaster to forget your own phone number (kids used to have to remember only their single home number, now they'd have to remember their own number and a seperate number for each family member).

As to the topic on hand, I wouldn't be surprised if adult brains were as flexible as children -- compare to adults who have a debilitating accident and have to learn again. I think children learn faster because they have a lot less on their mind. Adults multi-task and many studies have shown that is counterproductive to efficiency. Kids have the luxury of time and lack of responsibility adults don't. Remove that, you remove a lot of stress, and the brain can focus on other things -- consciously or unconsciously.

Not really scary--it's smart.

[foreverdisillusioned]

Or maybe young people are smart enough not to clog up their brains with information that can be more easily and accurately recorded elsewhere. If all our fancy devices somehow stopped working, there would definitely be a period of confusion, but people would adapt. They'd go back to using their memories (or pen and paper.)

Technology isn't conflicting with our brain's evolution; it's extending and enhancing it. One less phone number to remember is who knows how many neurons that don't have to waste time storing and retrieving it. You might question whether young people are using this freed memory space to good use (for the love of all that's holy, I do NOT care about who won the latest reality show or what celebrities do in their spare time), but I think that it's a mistake to view this phenomenon as a fault.

Re:Scary combination

[Belial6]

I agree. The other thing that people forget is that children often have access to vastly superior resources. Take for example the classic example of children learning languages easier than adults. When people point that out, they generally fail to notice that children tend to learn their language via total immersion and virtually everyone around them is happy to be a 24/7 personal tutor on the language. While most children can get by in their first language by 2 or 3 years only, they tend not to be what we would call fluent until 5 or 6. Give me a couple of full time language tutors and 5 years of total immersion with no need to remember my native tongue, and I will learn the new language too.

Ron Paul???

[pixelfood]

Why is this article tagged with 'ronpaul' and 'ronpaulisanazi'? I thought this was slashdot, not digg. Why don't we just tag the article with 'omgiphonejailbreak' and '10waystoimproveyourwebsite' while we're at it?

bullshit?

[foreverdisillusioned]

Even a casual glance at immunology from a layman's perspective reveals your statement to be utter bullshit; there are many, many diseases and afflictions that are species specific, sometimes highly so.

He stated that it's "not true" that animal tests don't apply to humans at all (true), that almost every major medical advance has been tested or researched on animals like mice first (true, at least since the mid-twentieth century), and that mammal bodies work in very similar ways (true).

What you said is also true--that despite the huge similarities there are also significant differences--but that doesn't make his statement "bullshit"... perhaps merely "incomplete."

I support your point in general, especially because brains is obviously one of the organs in which humans differ the most, but I don't think that gives you the right to call a bunch of essentially truthful statements "bullshit."

Re:Adults can learn...

[CrazedWalrus]

I think you're right. I think adults tend to be reluctant to learn new things for a few reasons:

• Fatigue. Most adults are overworked, and many tend to avoid taking on any extra effort beyond what's required to get to the next day. Gratuitous learning of a foreign subject matter tends to be difficult, so is about the last thing they want to do when they get home from a hard day at work.
• Divided attention, or excessive multitasking. Again, a matter of not enough cycles to go around. I find that it's a sheer joy to me if I can spend an hour or two and really concentrate on something. Usually I can't do so without interruption or another obligation getting in the way.
• Information layering. By the time people are adults, they've built a stack of information that suits them well. The last thing they want to do is start over from the bottom. To use an analogy: Each successive level of math builds on the principles established in previous levels. By the time you're a Physicist using Calculus, why in the hell would you want to go back and learn a new way to add numbers when the one you know works just fine?
• 
  
  Granted, most of this comes back to lack of effort, but in most cases, the decision to not put forth the effort is very understandable. It doesn't mean that adults can't learn. It just means they're too busy, have too many distractions and demands on their time, are happy with their current methods, or are simply too damn tired.

Just hand waiving

[tgv]

That kind of conclusion is totally unwarranted. To begin with, the mice were not 70 years old. No, don't laugh! Either mouse neurons age as fast as the mice themselves do, which implies that (the processes in) their neurons differ fundamentally from ours, or these neurons age the way we do, but then they were studying two year old neurons, which I thought used to be considered pretty young.

Second, the observation that learning and memorizing becomes more difficult with age is pretty solid. If our neurons maintain their plasticity, these people should explain how a plastic brain stops learning.

Concluding: the observations are probably true, the conclusions were just made to draw attention and get more funding (aging is a big topic for funds these days). Such is the sad state of science.

PS I hold a post-doc in neurocognition.

Re:Not true

[Z00L00K]

Actual truth is that as an adult you become more habit-bound than as a kid, but that doesn't stop you from learning new things. As a kid you are all over testing boundaries but as an adult you skip that part and strive forward in the direction you found were the most ideal when you were a kid. What's ideal for one person may not be for another and depending on the environment and the stimulus received as a kid you get preferences.

And this is also one reason why it may be good for a person to change job now and then to not grow stale in one environment. It may be good to not change too often but if the job stops to develop a person it will result in that the person having the job will get bound to the job and unable to accept changes or the person will change job.

It's important for people to take on challenges now and then - even if failing it's a learning experience. If failing all the time - it's just meaning that this person is attempting things that always are too hard or that that particular person hasn't the ability to know his/her own limits.

Re:Adults can learn...

[LionKimbro]

Let me add: "reward systems."

If an adult speaks a second language poorly, people go, "Oh, what an idiot... Will you please just speak in your native tongue?!"

But if a child learning a language speak it poorly, people go, "Wow! You're learning so quickly! You're really doing a great job!" They'll smother the child with attention.

Kids also find other kids who are basically forced to learn to speak a language, and are learning at the same skill level, and so on.