From "The Lab Rat's Guide to the Brain"

(Thanks to Dr. Rob for once more giving us a chance to hear from his rats -- Amanda)

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Tedd ("Dr. Rob") Roberts

Since our last appearance, and thanks in no small part to invited guest appearances on talk shows and other discussion groups, the LabRats and I have received some emails with questions folks might like answered about science, writing, and the brain. Without further ado - a few samples from our mailbag.

"Dear Lab Monkey: Why don't you let the Rats talk more? -A. Nony Mouse"

My reply: "Dear Nony: I think you have me mistaken for Dr. Freer. Still, just for you, I will let the LabRats have their say. Do read on... - Dr. Rob."

... another...

"Hey Ratley, Do you LabRats really talk? Signed Thomas."

Ratley replies: "Doubting Thomas: You wrote to me. Are you really expecting an answer? - Ratley"

... and another letter...

"Dearest Ratface: I understand you are the kinder, gentler lab rat. Tell me, what did he mean 'too much LDS in the 60's'? - Yours, Gillian"

Ratface responds: "Squeak." Ratley steps in and translates: "Sorry Gillian, it was a lame joke, based on the Star Trek movie (#4) in which Kirk and Spock were back in the 1980's, and Kirk excused Spock's eccentricities by saying 'He was part of the free speech movement at Berkeley in the 60's. I think he did too much LDS.' Oh, and the Doc wants me to add: no offense intended to the LDS church! - (whew!) Ratley."

Okay, back to the Mail.

"Dear Dr. Rob: If humans were to develop telepathic or psychokinetic abilities, what parts of the brain would be responsible? - J.R."

Whoo-boy. Okay, that's a long one, let's table that and look at another. It'll take another whole blog post to answer that one.

"Dear LabRats: How is it possible that we can hear our own name spoken in the midst of a crowded, noisy room? - S.H."

Ah, another. Do be patient. Ratley and I will make a list and get back to these one by one.

... ah, here's a good one!

"LabRats: We sometimes hear that humans use only 10% of their brain. Is this true? - Dave F."

Ratfink says: "I'll take that one!"

Hey, 'Fink, don't startle me like that, I didn't know you were there. Okay, it's just the right size for this blog. You go ahead and answer it.

"Dear Dave:

"We hear that little bit of trivia all the time. It is, as you may have guessed, a misconception. Now, we LabRats always use 100% of our brains - well, except for maybe Ratface. Oh, and Ratso, he uses 100% of his stomach to do his thinking.

"Anyway, not to get off target, it is true that one could say that at any given time, only 10% of a humans brain is active - 5% if they are watching daytime talk shows. What it really refers to is the incredible redundancy of the human brain, plus the fact that there are specialized brain areas that are only used for particular tasks.

"Let's start with vision. There are millions of cells responsible for detecting light and sending the information to the brain. If you think of the light-sensitive retina cells (photoreceptors) like pixels in a camera or TV, you can understand why you need so many - to get the maximum fine detail in anything you look at. In fact, though, there are multiple types of photoreceptors for each "patch" of our visual field. There are 'rods' which detect black vs. white, and there are 'cones' which detect color. Further, unlike us LabRats, you humans have different color sensitivities of cones: red vs. green and blue vs. yellow. Thus for each 'pixel' of image we see, there are at least three types of retinal cells.

"Redundancy - and different functions.

"Now, take that same visual information into the brain. Before it gets there, there are 'ganglion cells' in retina that combine inputs from photoreceptors. Each ganglion cell has a donut-shaped field that represents the part of a visual scene covered by the ganglion cell. For some cells, light shining in the 'donut hole' more electrical and chemical activity in the cell, while light shining on the 'donut ring' causes less activity. Again there is redundancy and different functions. There are millions of ganglion cells covering all possible combinations of photoreceptors covering our entire visual field, and there are ganglion cells with 'on-center, off-surround' fields as described above, as well as cells with 'off-center, on-surround' functions.

"But what is it all for, and why the redundancy? Well, moving to the 'visual cortex' of the brain, combinations of inputs from retinal cells result in cells that are activated by short lines of light, and by edges. Multiple redundant copies means that there are cells for every conceivable angle of line or edge, every possible location in the visual field that our eyes can detect, as well as combining two eyes, and all those colors. Working forward into the parts of the brain called 'visual association' areas, we start to find brain cells that respond to circles, shapes, even faces!

"Then we move into combining other senses, and other parts of the brain: sound, smell, touch, movement, memory, and decision making. We LabRats get to continually hear the Neuroscience student's favorite story about Grandmother Cells. That's the brain cell that is active only when it sees "Grandma's face, hears her voice, and smells her fresh-baked apple pie (with a slice of Cheddar for well-behaving LabRats). Believe it. While there may not be specific 'Grandmother Cells' in any given human's brain, there *are* brain cells tuned to respond to such high specific combinations of inputs!

So, if the Grandmother Cell is active, does that mean that we have used only one *trillionth* of our possible brain capacity?

"No.

"In the first place, the signals that activate Grandma have traveled through five widely separated brain areas for vision alone, and an equivalent number of sections for sound, smell, touch, movement (don't forget, Grandma wants a hug and a kiss before you go!). Then we had to search through memory. Is that Grandma H. or Grandma D.?

"That's another contributor to the 10% myth. The human brain has an incredible capacity for memory. With the possible exception of Ratface, the typical LabRat has billions of brain cells available for storing memory, and that's sufficient to remember where to find the cheese, the peanut butter, fruity cereal, water, electrical cords that are fun to chew... In fact, Dr. Rob has experiments that show that no matter *how* complex an environment, the rat brain can map it and remember it.

"Now in comparison, the human brain has *trillions* of brain cells in each brain area. How much more information than a mere LabRat (except for me, of course) can it store and process? As far as we can detect, no human has ever run out of storage space in the brain. Hence, humans must use only a small portion of brain resources. However, the rest of the brain is there, active, and ready to contribute at a moment's notice.

"To finish up, some of the most fascinating examples come from the field of brain imaging. MRI scanners can be set to track the flow of water or oxygen in the brain, resulting in a map of the most active brain regions. If your everyday average human lies in a scanner and listens to music, the primary and associative auditory regions light up. Sounds with an emotional or memory content may activate brain regions involved in memory. Sort of like Ratface and Heavy Metal.

"Ask them to read written music, and the visual and reading centers light up, but very little activation occurs in auditory areas. However, if you ask a professional symphony conductor to read a musical score, the brain scan lights up with brain areas involved in reading, listening, singing, memory, even the areas responsible for moving the hands and arms in conducting motions!

"Now *that* is using your brain!

"So, final answer. At any given time, sure humans only use a portion of what the brain is capable of. The rest of it gets used at other times and for other purposes. We *still* don't know the total information capacity of the LabRat brain, let alone the human one, but it is certain that it does *not* go unused!"

Thanks, Ratface. Not a bad explanation. Now I'll add one more piece of information before we let these good folks go back to their regularly scheduled blog reading...

How can we use all of our brain and *still* have room for more information? The most astounding thing is that information is both spread out among a lot of different brain cells (that redundancy again) yet still specific enough that activating only a few brain cells will get the whole bit of information back. SF writers like to call this "holographic." That's not a bad term, but not really accurate. The scientific terms are "sparse, distributed" and "associative." That last one is the key: "associative;" that means that the reason that the brain can keep holding more information is that it keeps making *associations* between new and old memory. Apart from diseases and injury, the reason why we forget is not a loss of the actual information, but a failure to come up with the appropriate associations.

So folks, keep those questions coming. Nestor is currently making a mess out of the discarded envelopes and YDR is now covered in paper link and ink. We'll try to answer some more of your questions in future guest blogs.

Oh, and thanks to the Mad Genius Club regulars for the opportunity to share my ramblings with you.

Memory and the single writer-- guest post by Doctor Tedd Roberts

*Doctor Tedd Roberts has agreed to let me do these every now and then. He would also like our readers to come up with questions. He has plans of writing a guide on the brain for writers in the future, and would like to know what our unique questions are. :) So, go ahead, comment and be unique.*


Science for the Mad Genius Writer
By Tedd Roberts


"Mrs. Smith?"

"Yes Doctor?"

"Your husband suffered a terrible head injury. He's in a coma."

"Oh, Doctor, will he be all right?"

"We'll only know once he wakes up."

…

"Ashley? It's me, Melissa!"

"Where am I? Who are you? What happened? Who am I?"

"Oh, no!"

…

It's a familiar theme, amnesia as a plot device. Overused, trite, cliché, yes; but also terribly *mis*-used.

Hi, the bloggers of the Mad Genius Club have asked me to contribute a series on the science behind science fiction/fantasy. I don't claim to be a Mad Genius, nor am I necessarily a Mad Scientist – a bit upset at times, but not truly Mad! Bwahahahaha! (I think we can safely save that label for Dr. Freer.) However, I am a writer, and I have over 70 "stories" in print, although they are all scientific articles in professional journals. My field is neuroscience, the physiology and pharmacology (mechanics and chemicals) of the brain, and I am currently employed as a faculty member at a medical school.



What? Oh, yeah. This is Ratley, an intelligent lab rat. Actually that's LabRat, they insist on the capitals. Ratley and his friends will help me with these blogs.

So, on to today's topic: SF/F clichés regarding the brain with particular emphasis on amnesia.

Amnesia is little understood by the lay public. The most common experience of amnesia is the soap-opera scene with which this column opened. But what is amnesia, and how does it *really* happen?

OK, classroom time.



What? I said, class…



OK, if you insist,*you* tell them.

[Ahem. OK, y'all, I got the stuffy Doc out of the way. As the Doc said, I'm Ratley, and I've *experienced* amnesia in the lab. Let me tell ya, it ain't no picnic. Amnesia means "without memory," and there's two typical types – retrograde amnesia, meaning a loss of memory from the past. The other kind is called anterograde amnesia and it means loss of memory "forward" into the future. I've had 'em both, and they result when a part of the brain that processes memory ain't workin'. ]

Excuse me, Ratley?



Are you going to explain what you mean by "future" memory? Shouldn't you tell them that anterograde amnesia is a lack of ability to make *new* memories?



I will, thanks.

In fact, anterograde amnesia is the most common form of amnesia, even though the retrograde form (poor Ashley, above) is better known. Imagine, trying to remember a phone number but never quite managing it; reading the same newspaper over and over again, never recalling the previous read; or never being able to remember where you'd left your keys, your car, your kids, your wife…

How can this be, how can it happen? Well, let's start by looking at how amnesia happens.

Take Ratley for instance.



Not literally, calm down, please! I'm just giving an example!

When Ratley said he had experienced amnesia, he means that in the lab, scientists use a chemical to temporarily put part of the brain to sleep, causing amnesia – which type depends on the brain area affected. In humans, amnesia usually results from damage to the brain. Oh, but not just any damage! It has to be specific type of damage and specific areas of the brain. Damage can be a traumatic head injury: Ashley's tragic soap-opera car crash, or the angsty teen's headfirst dive into an empty swimming pool. Damage to specific brain areas can also occur due to epilepsy, stroke, tumor, hemorrhage, infection (meningitis or encephalitis) or drug interactions.



Yes, Ratley, just like Ratface. See folks, Ratface did a bit too much LDS in the 60's. He's harmless – really – but not all there.

And what are those brain areas? Well, in scientist language, they are the pre-frontal and frontal cortex (for retrograde amnesia); hippocampus, medial temporal lobe and diencephalon (for anterograde amnesia). Traumatic injury, tumor and stroke can affect any of these areas; infection and hemorrhage are most likely to involve the frontal and prefrontal cortex, while epilepsy and drugs are most likely to affect the hippocampus, temporal lobe and diencephalon.



Yes, I know. Go ahead. Ratley wants to show you how to tell the brain areas apart.

[ Oh, sorry about that. Okay, humans. You've got those big hands with nice opposable thumbs. So, unhand that mouse and keyboard! Now, place your index fingers on your temples, yes, the soft areas at the side of the forehead. Feel that? It is the most direct access to your brain except from the inside. From your fingers to the center of your forehead is frontal cortex. If you draw a line between your forefingers across the top of your head – that's the prefrontal cortex. Move your fingers straight back until they are directly in front of your ears – that's the medial temporal lobe and hippocampus. Move the fingers below and behind the ears – straight in from there at the center, bottom of the brain is the brain stem, also known as the diencephalon.

[What about the other areas, the top of the head, the back, the base of the skull? You humans just *love* to make movies where the bad guy hits the hero on the top or back of the skull with the butt of a gun – he (or she) loses consciousness and wakes up in the hospital with amnesia. Silly humans. Listen to the rat, now: it's not gonna happen that way.

[Next exercise, put your thumbs directly in front of your ears and lace your other fingers over the top of your head. That's the sensory and motor areas – controlling all sense of touch, position and pain, and moving the various muscles of the body. From there to the back of the skull is visual area, responsible not only for sight, but also interpreting what you see. Run your fingers down from top, center of your head, to the very back the skull. Feel that slight dimple? That bony area right below it protects the cerebellum, responsible for coordinating all of the muscles involved in any movement. ]

Thanks, Ratley!

So, in our story brave Ashley foils the terrorist, gets cold-cocked at the base of his skull for his troubles, and wakes up with amnesia, right? Well, no. He might wake up with some coordination problems, blurred vision or possibly "agnosia" a specific type of amnesia for words or faces, but not full scale retrograde amnesia.

What about that mysterious alien parasite that "wraps itself around the cerebral cortex" and takes over its host, leaving total amnesia in its path?



No, Ratley, I know what you're going to say, but I'm *not* talking about Ratfink!

Leaving aside the fact that there is no *room* for such a parasite without sacrificing so much brain tissue that the host is clearly impaired in more than just memory, the description is not specific enough to suggest any particular type of amnesia. No, the more likely result will be pressure on the other parts of the brain causing the hapless host to stop thinking and breathing well before any amnesia could set in.

On the other hand, just about any surgery on the brain carries risk of damage to neighboring area. Anterograde amnesia is a common side effect, although retrograde amnesia is rarer. In fact, to get total retrograde amnesia requires trauma – massive infection, crushing injury to the central-to-frontal part of the skull, concussive blast injury. Anything less is unlikely to give total amnesia. Oh, sure, falling off a horse and hitting your head on a curb will likely cause a bit of amnesia – certainly for the 10 minutes or so immediately preceding the injury – but not the total "Who am I?" kind. Typically the amnesia lasts as long as the brain swelling that accompanies the concussion (about 24-48 hours) but usually only extends to memories from a few hours to a few months prior to the accident.

So, how *do* you incorporate brain damage and/or amnesia into a plot? Ratley?

[First, keep it simple. If the big dumb hero takes a glancing blow to the head, he's not gonna have total amnesia and lead a complete second life for 20 years. Keep it simple, and keep it short. Give the big dummy amnesia for the day leading up to the accident, and only lasting a few days to a week. However, you *can* leave the actual events of the accident permanently forgotten.

[Second, avoid the obvious. Instead of giving the dude full amnesia, consider an alternative.

[Doc?]

Right, Ratley. Alternatives to amnesia might be: (1) agnosia– inability to remember faces or the names of common objects, (2) aphasia - the inability to speak certain words or names (we also call this the "tip of the tongue" phenomenon), or (3) neglect – an apparent inability to consciously notice objects that occur in particular places in our field of vision.

Back to you, Ratley.

[Thanks, Doc.

[Third, remember that total retrograde amnesia is *rare*. Instead of amnesia, give your character vision, hearing or coordination problems. There's a bunchaton of other stuff that happens after head injury.

[Fourth, keep in mind the differences in those different types of amnesia: give a human anterograde amnesia and they may not remember that they had the exact same conversation 15 minutes ago, but they can still remember the name of their 10th grade crush. Likewise, retrograde amnesia still leaves the ability to make new memories.

[Ah, excuse me a sec…

[HEY RATFACE! The cheese is over THERE!

[Ah, sorry about that, maybe Doc needs to finish this while I go help Ratface.]

So, folks, Ratley's final point is to keep the perspective. Amnesia typically means loss of memory for facts. Skills such as reading, riding a bike, speaking a foreign language, complex logic puzzles – those memories are processed and stored in a different manner and not subject to the same injuries as amnesia. Just like Ratface can't remember where he left the cheese just now, he still remembers how to run mazes and get under Ratley's fur.

Finally, don't be too stuck on the rules (or clichés). Try something new, or figure out a way to let your protagonist function with just a partial injury. If you want help, don't hesitate to contact an expert –



- Or a LabRat! In fact, many scientists would be flattered to help out an author.

Until next time, be kind to your brain; for now, it's the only one you have!