I haven’t stopped to answer questions based on the Lab Rats’
Guide to the Brain for quite some time.
I have received comments in the blog, as well as in the Baen’s Bar
online community. Unfortunately I
haven’t been entirely timely in answering the ones that require more than just
a quick answer – but I do save them for later use.
So for the next several days I will work through the backlog
and answer your questions about the brain.
So without further ado…
[squeak]
What’s that, Ratley?
[squeak]
Um, yeah, I suppose I should.
[squeak]
Right. Ratley is
going to gather the other LabRats around for this. Since I still have a scientific conference
and Dragon*Con this week, I’m going to let them tackle the mail while I finish
my two presentations for the meeting.
So, I’ll just set up this automatic translator and get back to fixing
slides.
[squeak... er, excuse me.
Hi. I'm Ratley, and I'm
supervisor of the LabRats. What Speaker
seems to have forgotten is that it has traditionally been the job of the
LabRats to answer the mail. The fact
that he hasn't let us out of the lab much these past few months is one of the
reasons we've gotten so far behind in reading the mail. We each have our different areas of
expertise, so the LabRats will share the task of answering questions. For the first couple of questions, I'm going
to let Ratso answer. He's pretty smart,
even if he does prefer to spend too much time in the kitchen and talk like ...
well, a rat!]
Ratso: Yo, Ratboy, I
*resemble* dat remark! Okay, on wit' da
program heah: Chris writes: “I’m working on a story where my character
has to get used to his new super abilities.
Just how fast does the brain process?
If thoughts, movements and reflexes were to be sped up, how hard would
it be for my character to cope and learn how to use them?"
Well, Chris-boy, it's like dis – da brain is only as fast as
its parts. To understan' how fast dat
can be, ya gotta figger out how fast is each link in da chain. Da neurons, well, dey's pretty fast. Takin' the time from the first chemical
activation of a synapse to when da action potential starts is about 2
milliseconds. Action potentials (http://teddysratlab.blogspot.com/2011/02/piece-of-action-potential.html)
travel to the other end of da neuron at about 10 meters per sec. If da neuron is a *long* sensory or motor
control neuron for da body, it has a special insulatin' coating called
"Myelin" dat speeds up da action potential to about 100 meters/sec.
Once da action reaches da end of the neuron, neurotransmitter chemicals are
release to start da process all over again in da next neuron. Da chemical part takes about 2-3
millseconds.
So each link in da chain, dat is, each neuron
"synapse" takes about 5 millseconds, and it takes an action potential
less than 10 milliseconds to travel either from brain to brain area, or from
brain to hands – about 20 milliseconds to get to da feet. Dat's pretty slick, if ya ask me! Multiply dat by about 4 or 5 times for
connections between neurons and parts of brain controlling an action. I like connections. I'm a connections kind of guy myself!
So yeah, da brain can process pretty fast, almost anything
ya wanna do can be completed in about 100 milliseconds. If'n ya wants to write a story wit'
everything speeded up, ya can prob'ly get about 10 times da speed outta just
makin' the chemical and electrical connections more efficient, but like any
good exercise, ya gotta learn ta use it.
In fact, it'll be jus' like any new skill: practice, practice, Practice!
***
Ratley: Thank you, Ratso.
Perhaps you should get back to the stockroom, there's a fellow named
Guido back there saying something about kitchen supplied that fell off of a
truck?
For the next question, perhaps we should defer to our
resident master of motor skill, Nestor:
Nestor: Why thank you
old chap, that's mighty kind of you. Be
a good lad and hand me that letter then?
Ah yes. In response to “The Six
Senses (and maybe more…)” Anonymous asks:
“What about the ability to do complex tasks requiring fine motor skill,
with your hands out of sight and in all sorts of odd positions? I do that quite
often when working on cars and other mechanical things. It's like I can
"see" with my hands, often it helps if I close my eyes.”
Dear Sir:
What you are describing is commonly misnamed as "muscle
memory." A skill practiced to a
point where it becomes automatic. The
muscles move the way they are supposed to every time, you don't have to think
about it.
In reality, this should be termed "cerebellar
memory." The cerebellum is the part
of the brain most responsible for coordinating movements. It is quite heavily connected to all those
parts of the brain involved in a movement or reflex. For instance – when moving your arm, you must
move the arm muscles and joints, but you also turn your head, shift your weight
on your feet, twist slightly at the waist and often look at the movement. If you don't look, you'll probably do it ok,
but you may not be quite as accurate in the motion. Now try to move your arm while keeping the
rest of your body completely still!
Quite a bit of bother, no? That
is because the brain issues all of those commands, coordinated by the
cerebellum, and when you consciously override the reflexes, the cerebellum
requires all new programming. Sort of
like learning to raise a single eyebrow.
Soldiers and athletes understand the concept very well. Actions must be learned so well that they are
automatic – however it really is the brain learning, and not the muscles. As for your question, it's all the same,
righty-o? Because we have learned
how our muscles move while we watch them, it is right simple to imagine
those movements, then perform them with our eyes closed. You "see" with your hands because
the brain uses all of the information about movement and position and then
calls upon memory to fill in the missing pieces. All of the connections from the cerebellum to
the motor and sensory areas of the brain, plus the connections to visual and
auditory tracking centers in the brainstem provide a "map" of the
body in 3-D space. Quite amazing, if I
may say so myself.
Now, if you will excuse me, my tail seems to be caught in a…
Oh bother!
***
Ratley: Thanks,
Nestor. We'll send the Jaws of Life in
for you, don't worry.
Sandra writes: Dear
Speaker:
My daughter's domesticated pet
rats have been vocalizing a lot lately. The other day I walked into her room
and told her it was time to get up. A rat (in the cage) poked its head out of
its sleeping hammock and said *squeak-squeak*. Later, as the two rats were out
of their cage, playing, they froze when the big black dog stepped into the
room. I sternly told the dog to leave (she's not allowed in that room) and
after the dog left, the biggest rat rushed to my side, staring at the door, and
growled and squeaked. I've never heard her (the rat) make these sounds before,
and it sounded like she was scolding the dog.I realize we humans tend to anthropomorphize our pets, but could these rats be trying to communicate? And what about the personalities these rats seem to have? For many people, rats are vermin and pests; for cats and dogs they are prey. How can these rats be so charming?
[squeak!]
Ratley: What's that,
Ratface? Cousins you say? Yes, Indeed.
They must be!
Dear Aunt Sandra – (for if the rats are our cousins, you
must be our Aunt!) – domestication of any animal is a learned process. What you are describing represents two
aspects of learning that apply to many animals.
If you have ever watched circus animals, movie dogs or the "Walrus,
Otter, Sea Lion" show at Sea World you have seen the results of what is
called "operant conditioning."
Most folks should recall reading or learning about Pavlov's experiments
in classical conditioning. Pavlov rang a
bell simultaneous with the smell/taste of food.
The dog salivated at the food stimulus, and eventually learned to
salivate at the sound of the bell alone.
In behavioral terms, we talk about an "unconditioned stimulus"
(UCS) – that is, a stimulus that produces the desired response without
learning. In the Pavlov example, smell
of food is the UCS and salivation is the response. Then there is the "Conditioned
Stimulus" (CS) – this is a stimulus (bell) that we *want* to produce the
same response as the UCS. So we present
UCS and CS together for a *lot* of repetitions – usually with the CS occurring
before the UCS. Eventually the
conditioned response (salivation) starts to occur after the bell, but before
the smell of food. Once that happens, we
call it a "conditioned response" (CR). Once our experiment begins to
look like this: CS – CR – then UCS, we have
conditioned the animal and can even omit the smell of food (UCS) and still get
salivation (CR) just by ringing the bell (CS).
Voila - Pavlov's classic experiment in behavioral conditioning, also
known as "classical conditioning."
Operant conditioning differs in that we actually teach the
animals a chain of UCS stimuli, and those stimuli require the animal to *do*
something. In the Sea World show
example, the sea lion is conditioned to know that ringing a bell means a food
reward will be given. This is classical
conditioning, but then we add a twist – now the sea lion gets a chance to
explore the bell – if it rings the bell itself, it gets a fish! This is the first essential step in operant
training, the animal makes its own response and receives a reward. To make more complex behaviors, we just train
in one preceding step at a time – before the sea lion can ring the bell, it
must climb some steps. So in this step
we have two operant phases: (1) climb steps, in order to be able to (2)
ring bell, to receive the reward. It's
just like training dogs, horses, or even people. Once enough steps are "chained"
together, our sea lion becomes the star act and appears to be behaving just
like a human – but it's only conditioning at work.
Your pet rats have become conditioned. They know which humans feed them, take them
out for exercise, and protect them from predators. This is where the second aspect of learning
comes in: dominance. Normally, dogs are
predators to rats, as are humans. Trust
me. We lab rats know all about
that! However, in caring for our
cousins, and keeping the other predators away (!) we come to recognize you
humans as the dominant creatures in our environment. As long as we remain conditioned to you, and
you protect us, we'll act submissive to you.
Now submission comes in many forms. Speaker tells us stories of working with
primates. If there's one big mean monkey
in a colony, the other monkeys are submissive, and most will not challenge the
"Alpha." However, if the Alpha
attacks a smaller monkey and a human intervenes, the lesser monkeys look
to the human as Alpha (and sometimes even the Alpha will defer to the
human). The human is the more dominant
creature and protector. In animal
behavior terms, that's usually called "mate," but is also
"companion" with the commonly domesticated animals such as dogs and
horses.
So what you are seeing is a bit of
anthropomorphization (hmm, Ratfink must have left that word lying around here)
but also a result of the conditioning and dominance hierarchy among animals.
But then again, it might just be that our cousins are a bit
smarter than you think!
***
Oops, here comes Speaker, time to get back to work.
Speaker: Thanks,
Ratley. My meetings are over, as is
Dragon*Con. There's a few more letters
in the mailbag here, and I'll try to get to those next week. I hope the answers were informative, but you
can never tell with LabRats!
Until next time….
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