NOTICE: Posting schedule is irregular. I hope to get back to a regular schedule as the day-job allows.

Monday, January 30, 2012

The GUIDE: Brain and Brain - reprise [Full link to blog for email clients.][FT:C44]

Classic line, from classic Star Trek. "Brain and brain, what is brain?" This comes from "Spock's Brain", in which we discover that it you just connect the vocal chords, the patient can direct you in connecting the rest of the nerves!  In the interests of helping writers avoid such unscientific gaffes (and having those who know better laugh at them, at best, or stop watching/reading, at worst), I created this blog and the current project "The Lab Rats' Guide to the Brain (a guide to 'getting the science right' for writers and readers of science fiction)."

Back in the dim mists of antiquity - in other words, not quite a year ago, I started blogging The Guide, one column at a time, and posted this brief orientation to the overall structure of the brain.  To assist new readers and provide continued reference to trhe parts of the brain I figured I should reprint this blog and the "Back to the Basics" blog.  

In order to discuss the parts of the brain, I will tell people to hold their left hand at arm's length in front of their face, fingers together, palm flat and facing directly away from the face. To get the full effect, it also helps to imagine that hand in a baseball glove or catcher's mitt, but for now, just compare the hand and the picture at the right.   The thumb is the temporal lobe (light blue in the picture) and that's where a lot of the structures that process sound and help us make memory are located. Fingertips are the frontal lobes (purple). That's the control of muscle movement is located and where a lot of decision-making and "conscious thought" seems to take place. Neuroscientists call that "executive function" and it is mainly the conscious control of other brain functions. The outside edge of the hand is the parietal lobe (green). there's a lot of sensory structures there.  The forward edge of the parietal lobe is the main "somatosensory" (touch, vibration, hot, cold, pain, and position) strip and it is organized according to the different parts of the body.  Directly opposite in the frontal lobe is the "motor strip" which controls voluntary muscle movement throughout the body.  Down toward the temporal lobe are areas that handle speaking and reading. The occipital lobe (dark blue) is about where the heel of the hand would be in our model. It is almost exclusively related to vision and visual functions. However, some visual processing areas are also in the parietal lobe, since seeing quite frequently connects with hearing, speaking and reading. The cerebellum (red) and brainstem (dark green) are equivalent to the wrist - in many ways. The cerebellum coordinates muscle movement throughout the body, and the brainstem connects the brain to the body (via the spinal cord).

It seems almost as if for every function on the *outside* (surface) of the brain (we call it the "cortex" or "neocortex"), there's a structure deeper within the brain that acts as a relay, switch or preprocessing junction. By the way, we often call the deep structures "nucleus" or "ganglion", or even "fiddly bits" (with apologies to Howard Tayler), although many have their own names such as "thalamus," or "hippocampus."

Also, for those of you following this blog with interest, after the reprise of the Basics, I'll continue with diseases and disorders with Alzheimer's disease, Myasthenia Gravis, Multiple Sclerosis, ALS, deafness, blindness, paralysis and finish up with a discussion of prosthetics and bionics.  Feel free at any time to post questions.  I'll try to collect them and come back with some "mailbag" posts in a few weeks  - just write them in the comments section, or email them to Teddy at TeddRoberts dot com. I might even let the LabRats out of their cages to assist.

Until next time, take care of your brain, it's the only one you've got.

Saturday, January 28, 2012

NEWS: Failure of the Imagination. [Full link to blog for email clients.][FT:C44]

On this day in history... January 28, 1986... Space Shuttle Challenger was lost with all hands. As with the Apollo 1 fire of January 27, 1967 (and why does no-one comment on those dates), this disaster was a failure of the imagination (as spoken by astronaut Frank Borman to Congress in April, 1967) - failure to imagine that all of the conditions would conspire to cause the one-in-a-billion failure.

Yet Americans pushed onward, because freedom isn't free, and Space Exploration comes with a price. Today we face yet another failure of the imagination, because we have a generation that cannot imagine how space exploration can benefit them, as they sit in front of their TVs receiving signals from satellites in space, playing games and making facebook and twitter comments via computers that were developed to miniaturize for space applications, using cell phones with more computing power of the entirety of NASA Mission Control in 1967, surrounded by household materials such as velcro and plastics first developed for the space program. 
On a hot summer day in 1962, President John F. Kennedy, speaking at Rice University in Houston extended to this challenge to the American people:  
 ... the vows of this Nation can only be fulfilled if we in this Nation are first, and, therefore, we intend to be first. In short, our leadership in science and industry, our hopes for peace and security, our obligations to ourselves as well as others, all require us to make this effort, to solve these mysteries, to solve them for the good of all men, and to become the world's leading space-faring nation.
We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too. 
But Kennedy also forsaw the costs, the dangers, and those who would say we cannot afford to spend money on a Space effort
Surely the opening vistas of space promise high costs and hardships, as well as high reward. 
We have had our failures, but so have others, even if they do not admit them. And they may be less public.

To be sure, we are behind, and will be behind for some time in manned flight. But we do not intend to stay behind, and in this decade, we shall make up and move ahead.

The growth of our science and education will be enriched by new knowledge of our universe and environment, by new techniques of learning and mapping and observation, by new tools and computers for industry, medicine, the home as well as the school.
Unfortunately, we live in hard economic times.  We have skilled workers out of work, have lost manufacturing jobs to overseas, failed financial institutions and  loss of confidence in government.  We live in "an age of limited choices" as predicted by Niven, Pournelle and Flynn in their novel Fallen Angels.  Yet there is great promise in space effort - already by 1962 there was evidence:

And finally, the space effort itself, while still in its infancy, has already created a great number of new companies, and tens of thousands of new jobs. Space and related industries are generating new demands in investment and skilled personnel, and this city and this state, and this region, will share greatly in this growth.
You will ask "who will pay for it" and the sad truth is that future generations WILL pay the costs for whatever we do today, but what legacy do we wish to leave our sons and daughters?  A legacy of handouts and dole?  Of payouts to corrupt officials and incompetent corporations?  A legacy of despair?  Or would we rather pass on a legacy of HOPE, one that opens frontiers, provides jobs and strengthens the role of science, education and technology in our society?
It is said that all-out war will revitalize a nation's economy (but only if they win) by requiring productivity in manufacturing and technical capability.  However, a renewed commitment to Space Exploration will have the same effect - if we let it. 
  We stand at a crossroads.  How about we choose the road that leads to Space?

Thursday, January 26, 2012

The GUIDE: Hansen's Disease - The surprising neural basis of leprosy [Full link to blog for email clients.][FT:C44]

This post is partially a reprise of a blog from last spring written to coincide to my visit to the former leper colony on the island of Molokai.  It is reposted today in the context of "Neural Diseases and Disorders as Plot Devices" due to prior use in Science Fiction / Fantasy (The Chronicles of Thomas Covenant).

Leprosy – Hansen's Disease – is an infection by Mycobacterium leprae and/or Mycobacterium lepromatosis.  Despite the usual misconception, leprosy is not primarily a skin disease, nor does it result in "limbs falling off" as popular belief would have it. Leprosy is primarily a disease of the nervous system. The mycobacterium damages the sensory nerves of the periphery that lie close under the skin, first affecting tactile sense, then the fibers that transmit pain. The pale, blotchy skin lesions that have been the hallmark of leprosy from ancient times, appear as the "dermatomes" of the skin lose their neuron connections.

Dermatomes are regions of the skin that are served by a common source of "afferent" nerves ascending to the spinal and brain, and "efferent" nerves returning to the skin. Severing a single nerve will result in loss of sensation in a patch of skin from <1 to >10 cm square, depending on location on the body. Dermatomes on the fingertips are quite small, reflecting the many densely packed nerve endings that provide fine touch and sensitivity. Dermatomes over the ribs, hips and thighs are quite large, since tactile sense in those regions does not need to be as precise. Hence dermatomes are a necessary feature of the brain being able to localize *where* a sensation is coming from.

With the most common form of Hansen's Disease, the loss of sensation occurs first, and the skin lesions appear later as the dermatome loses all neural connections. A rarer variety exhibits the pale lesions, raised patches, nodules and bumps, with the numbness and sensory loss occurring much later. Ironically, the loss of neuron is due to the body's own immune system, much the same as other neuron diseases such as myasthenia gravis, multiple sclerosis (MS) and amyotropic lateral sclerosis (ALS – Lou Gehrig's Disease). Mycobacteria infect the neurons and change the outer membrane. Immune cells recognize the neurons as infected and damaged and "remove" them, resulting in the loss of neural connections between skin and brain. As more neural connections are lost, they also include the neurons returning from brain to the skin that regulate blood flow, perspiration, and other factors, resulting in the lesions normally associated with the disease.

In advanced stages, the mycobacterium attacks the cartilage and tissue around the joints, eventually damaging the bone.  The resulting shortening of bones and joints in the hand and feet gives the appearance of loss of the digits even though amputation would only occur if the digit was gangrenous.  The very severe, nonhealing lesions as well as loss of limbs results not from the disease itself, but from untreated infections that are (A) undetected due to lack of pain, and (B) impaired healing due to loss of neural control of blood and lymph flow. Untreated secondary infections can result in gangrene which in turn requires amputation; thus any limbs lost to leprosy usually result from factors other than the disease itself.

We now know that leprosy is *not* very contagious. The amount of contact required to be infected is usually only encountered by family members or caregivers.  It is likely *not* transferred via the skin or by the lesions, but by nasal secretions and mucus, much the same as influenza. There appears to be a genetic susceptibility, resulting in the disease occurring within families (as well as due to the close, repeated contact) and we now also now that >95% of humans are naturally immune.

Contrary to the Ancient Greeks who first described what we know as Hansen's disease, it is not about being "unclean." Instead, it is all about the neurons, but then, isn't everything?

Tuesday, January 24, 2012

The GUIDE: Migraine triggers [Full link to blog for email clients.][FT:C44]

Since writing my Migraines posts, I have been asked about triggers for migraines.

Many of you should be aware that migraine sufferers report many different types of triggers for their symptoms.  The most common headache triggers - eyestrain, polluted/stale/contaminated air, stress, disrupted sleep cycle - can also trigger migraines, but there are some very specific food and environmental triggers as well.

The food triggers - artificial coloring agents, cured/preserved meats, sausage, pepperoni, yeast breads, pizza, cheeses, caffeine, etc. can be found at WebMD ( which is a good start for migraine information.Understanding *why* there are specific triggers to migraines involves going back to the mechanism of what a migraine is - a reaction of the blood vessels in the brain - and the feedback loop of serotonin and histamine release that both result from and promote the vascular "spasm." 

Foods such as peanuts, sourdough, yeast breads, certain fruits... can trigger food allergies.  Even non-obvious allergies such as mold and mildew allergy can be triggered by yeast - thus resulting in increased histamine levels in the blood, triggering the vascular reaction in sensitized blood vessels in the brain. 

Preserved, cured meats contain nitrates.  In particular when those meats are fried or grilled (bacon, sausage, steak), nitrites and nitrosamines are produced, and those chemicals are also known to irritate sensitized blood vessels.  In addition, nitrosamines are metabolized by some of the same pathways as serotonin, and can lead to increased serotonin levels.

Many "stinky" or aged cheeses contain tyramine:  Bleu cheese, brie, aged cheddar, stilton, feta, gorgonzola, mozzarella, parmesan, muenster, swiss - the list goes on, and tyramine is also found in processed meats, fava/garbanzo/lima/pinto beans, avocados, raisins and fruit.  Tyramine is one of the chemicals in the pathway by which serotonin (chemical name 5-hydroxy-tryptamine) is made and broken down.  Tyramine containing foods boost the serotonin levels in the blood.

Monosodium glutamate, caffeine and aspartame (containing phenylalanine and aspartate), as well as similar chemicals, contain components of common neurotransmitter chemicals.  They can cause abnormal dilation or irritate the blood vessels as well as interact with normal brain function when levels are too high. On the other hand, if a person is used to high dietary levels, headache and migraine can occur from abstinence or lack of those chemicals:  A person who consumes 5 cups of coffee a day during the week may suffer caffeine-withdrawal headaches on the weekend.

Other environmental contaminants such as pollution, perfume, typically interact with allergy and histamine reactions of the immune system.  Chemicals such as histamine, nitrates, alcohol, and some of the neurotransmitters which dilate blood vessels are positive reinforcers of the vascular reaction that promotes a headache/migraine.  The lack of chemicals such as glutamate, aspartate, caffeine, that constrict blood vessels leads to a "rebound" dilation which acts the same ways.  Understanding that histamine and serotonin are the primary chemicals involved, and any food or reaction that increases histamine and serotonin levels will go a long way to understanding and controlling migraines.

For food triggers, doctors recommend trying an "elimination diet" - go to WebMD or MyChronicMigraine for lists of foods - eliminate them *all* from your diet for 2-4 weeks, then gradually add one food from the list back into your diet each week. If migraines stop or are reduced with all trigger foods eliminated, then a trigger food is like a culprit.  If migraines return after a particular food is restored, it is likely a trigger (but not the only one), remove it for a week, then resume by adding back in other foods until you have identified the one or more foods that trigger your migraines.

Keep a food and migraine diary.  It is extremely important and will help you and your doctor identify your trigger foods.

Until next time - feed your brain... the right foods!

Sunday, January 22, 2012

REVIEW: Three for One - Extraction Point and The Case of the Displaced Detective (The Arrival and At Speed) [Full link to blog for email clients.][FT:C44]

The very first blog on this site was a book review, but I really haven't done any since.  Since so much of what is write is about the Science in Science Fiction - or Scientists Writing Fiction,  I just had to write about this trio of books by scientist-authors. 

Travis S. Taylor, Ph.D. is a rock-star of science, with multiple degrees in the physics, optics, aeronautical engineering, etc.  When John Ringo created the character of William Weaver in his novel "Through the Looking Glass," he was criticized for the unbelievability of a scientist/mountain biker/martial artist/musician/reluctant soldier.  John's counter was that the only difference between the fictional character and real-life role-model "Doc Travis" was that Taylor was more familiar with firearms than his fictional counterpart."Doc" is all that, and more, a scientist, writer, and lead guitarist/singer for a rock band - a literal "rock-star" of the SF world.

Stephanie Osborn is also "all that" - a former NASA payload flight controller, copy, teacher, ordained minister, college instructor, and writer.  Again, with multiple degrees in astronomy, physics etc., Steph would be the sort of character that would raise an eyebrow if you didn't actually know this bright, accomplished woman. Taylor and Osborn have teamed up to bring us a wild-ride novel in Extraction Point, a mystery-adventure with a strong science background. 

Dr. Reagan "Ray" Brady works for a clandestine agency that investigates mysterious occurrences.  Dr. Brady, and team - including his wife Samantha (incidentally, the leader of the investigation team), are investigating a series of crimes in which the perpetrator manages to get into and out of locked, secure places with no trace of forced entry or exit.  Further evidence has linked the same person with events that affect the advancement of science over a 300-year period.  The team begins to wonder if they are tracking a "Santa Claus" - a alien - or an "Easter Bunny" - a time-traveler; and come to the reluctant conclusion that their mysterious opponent is a "Santa Bunny" - an alien from a different time. 

Along the way, the reader is treated to some real multidimensional physics, and string / membrane / quantum theory intermixed with plenty of action and a fantastic adventure.   The writing is seamless and well-matched.  In fact, I spoke with Stephanie Osborn about the book and tried to guess which sections she wrote, vs. those written by Taylor.  I got it wrong - it is truly difficult to tell which of the authors wrote which section!  For those who may accuse the authors of writing "Mary Sue / Marty Stu" adventures (writing thinly veiled chacterizations of themselves in heroic context) I would point back to the bios of the authors above.  Is it still a "Mary Sue" when the descriptions are real? I for one welcome the depiction of scientists as heroes. 

This is a book with both science - real, accurate science! - and adventure.  I finished the book in two sittings and gave up a fair bit of sleep in the process.   Extraction Point is available in paperback print-on-demand and eBook media from Twilight Times Books.  Here's a link to the listing at Amazon's Kindle store, the eBook is a great bargain.

To continue with this trio of Science fiction fun, we turn to Stephanie Osborn's solo offerings: The Case of the Displaced Detective: The Arrival, and its close-on-the-heels sequel The Case of the Displaced Detective: At Speed. In these introductory books to a series (my understanding is that Steph is on Book 5 already) Dr. Skye Chadwick has found a way to view other realities through Project Tesseract, forming a hyperspace "windows" to worlds not too unlike our own - but with a few key differences.  Long a fan of Sherlock Holmes mysteries, Dr. Chadwick has discovered a world in which Holmes was a real, historical character, and not a product of Sir Arthur Conan Doyle's imagination.  While never explicitly stated, Project Tesseract is able to view across time, as well as hyperspace, thus Dr. Chadwick and team have chosen for their first full test to view the tragic battle of Homes and his enemy Prof. Moriarity  at Reichenbach Falls, Sweden.  However, Chadwick, a former reserve police officer cannot passively observe, but attempts to intervene, saving Holmes' life and inadvertently bringing him through the Tesseract into Chadwick's home dimension and time.

Book One - The Arrival - is a great exploration of "what-if" with Sherlock Holmes introduced to the Twenty-first Century.  Mixed in with the high-energy physics and hyperspace theory is a mystery worthy of Holmes, finding a spy ring on a secured military installation, detecting and preventing sabotage and updating the Victorian detective's skills.  Book Two continues the mystery, builds the relationship between Holmes and Chadwick, and explores the personality that yielded the greatest detective of (fictional) history. 

Again, these are great reads, and I finished the first volume, screaming for more.  Fortunately for me, Book Two was readily available.  I think it took me 5 days to finish, but only because my schedule was interrupted!  Two particular scenes come to memory - in the first, Osborn's history with NASA comes through as the Project Tesseract team answers a Go-NoGo checklist in a Mission Control moment familiar to fans of "Apollo 13" and "From the Earth to the Moon." In the second scene I started laughing because I saw so much of the author's background in the story - then had to explain myself to the person sitting next to me on an airplane. 

These are enjoyable books and I am eagerly awaiting the forthcoming volumes.  Osborn is very respectful of the Holmes canon, and has created a believable characterization for Holmes in the modern world.  This link is to the Amazon Kindle listing for Book One.  I highly recommend it!

Stay tuned for more of The Lab Rats' Guide to the Brain, science news and SF book reviews!

Friday, January 20, 2012

The GUIDE: The "A's" have it... [Full link to blog for email clients.][FT:C44]

I have, on many occasions, railed against "stupid movie science" in the form of getting brain science wrong, or being unimaginative regarding use of brain disorders.  As I have often said, the most misused brain disorder in TV (especially soap opera), movies and books is amnesia.  Today's blog is meant to introduce the reader (and writer) to a number of other "Axxxx" diseases that can be used with interesting consequences in fiction.

Amnesia:  Total amnesia of the sort depicted in the typical Soap-Opera head-injury scenario is rare.  Even rarer still is the fiction construct of a person living a totally different life for decades, then receiving another head injury and reverting to their original life and memories!  However, amnesia does occur, particularly with trauma or head injury, and it often encompasses about 2-3 hours before the incident, and about 1-2 days after.  The "retrograde" amnesia (forgetting past memory) is due to the fact that the normal processing of short-term to long-term memory is disrupted by injury.  The "anterograde" amnesia (inability to make new memory) is a result of swelling or infection cause pressure on the hippocampus.  With increased pressure comes decreased blood flow and decreased function.  Once the swelling goes down, the normal processes of encoding and storing memory can continue.  However, there *are* cases of surgery (deliberate or accidental), head trauma and disease that cause damage to hippocampus and produce a permanent anterograde amnesia.  I discussed such a classic case of amnesia in the epilepsy blogs last year.

Agnosia:  A special case of amnesia, agnosia results from very localized damage to the brain.  In particular, the damage occurs to the association areas of the brain that process the basic sensory information and deliver it tot he parts of the brain that make decisions and control our actions.  In the visual areas, agnosia manifests as "visual neglect" the subject ignores what is in one part of the visual field, even though the eyes and pupils react to stimulation of that part of the field, and there is evidence that *some* of the sensory information is getting through to other parts of the visual system: for example, the eyes can track a moving object through that field, and the a subject shown an embarrassing picture to that part of the field will blush and act embarrassed without being able to say why.  Neglect can apply to the body as well, a patient may not be physically aware of sensation from a limb or part of the body, even though the spinal cord, motor control, reflexes and pain reactions are intact.   Frequently the damage is to the thalamus, which relays sensory information through the brain, or to specific nerve tracts in the Parietal Lobe.

Ataxia:  Often confused with simple clumsiness, ataxia is a failure of the brain to provide coordination to movement.  Ataxia may be accompanied by tremor, rigidity or weakness, and is thus hard to diagnose differently than other diseases.  However, the key finding is the inability to coordinate the movement of more than one arm or leg at a time, clumsiness that occurs when a person stops concentrating on the movement, or the inability to stop a movement once it is started.  Ataxia usually results from damage to the cerebellum, but may also be caused by damage to deep brain nuclei or brainstem.

Apraxia:  Like ataxia, apraxia results in a failure to get the body to do what the patients wills it to do.  In a typical case, it is easy for a patient to bend down, pick up a baseball that is in their way, and toss it away.  However, if the patient is told to pick up the ball, or verbally expresses the desire to throw the ball, they cannot do it.  All of the motor and sensory abilities - including coordination - are intact, but the patient cannot turn intent into action.  Damage to the premotor areas of Frontal Lobe or the associational areas of Parietal Lobe are usually involved.  Neither the motor nor sensory cortex areas are damaged, though, and all abilities remain intact.

Aphasia: When apraxia occurs within the speech centers, it is termed "aphasia." We all experience minor bouts of aphasia that occur as "tip of the tongue" phenomenon, but these are usually due to the inability to perform the appropriate memory recall of a word.  Aphasia is different, because a patient can hear the word, write the word, choose it out of a list, but cannot speak it.  It is a specific disorder of Broca's area, which sends signals to the motor cortex for diaphragm, throat, tongue and mouth to form words.  Broca's Area is in the Frontal Lobe, just below and forward of the motor cortical areas for the face and neck, and lying just over a bundle of nerve axons (the arcuate fascilus) that run from sensory association areas of the Parietal Lobe, underneath Wernicke's Area (language), Broca's Area, and terminate in the "cognition" ares of the Frontal Lobe.  Aphasia is frequently caused by damage to Broca's Area or the arcuate fasiculus.

Alexia:  Also known as visual aphasia, this is a failure of language and speech generation - in this case the failure to recognize and understand words.  Alexia is usually visual, and shows as the inability to recognize that printed or written characters represent language, i.e. "word-blindness."  There are auditory forms, but those are usually associated with obvious hearing disorders.  If the person retains the ability to speak and write words, then they have alexia without agraphia and the damage is between the visual cortex and Wernicke's area and confined to the lateral Parietal Lobe.  Damage to Wernicke's Area also causes loss of ability to write and speak coherent language.  Note the similarity to "dyslexia" and you can see how important the Wernicke/arcuate fasciculus/Broca linkage is to transforming sensory input to language.

So there, five new "A-words" to add to amnesia and spice up the plot of that new novel or movie.  The unfortunate thing, though, is that these disorders are not new, and doctors face them every day with stroke, head trauma and battlefield trauma patients.  Then again, the best stories come from real life incidents.

Thanks for reading, and tune in next time for some book reviews and a refresher on brain basics for The Lab Rats' Guide to the Brain!

Wednesday, January 18, 2012

The GUIDE: "How does the aspirin know where my pain is?" [Full link to blog for email clients.][FT:C44]

In yesterday's discussion of headache, I deliberately left out the discussion of common pain medication for headache.  If the headache is just that - a short-term disturbance of blood flow that causes an indefinite "ache" of the head, then "common" medicine is usually the best treatment.

Certainly there are rapid treatments available in the lab or hospital setting - breathing oxygen is a rapid way to cause the blood vessels in the brain to constrict, stopping the feedback loop of irritation, blood vessel dilation, inflammation and further irritation that causes the headache.  For severe cases, you need to block the serotonin and histamine release, and in very severe cases, there are other neurotransmitters and chemicals that need to be blocked...

... but headache and common body aches and pains have one feature in common, and one common treatment.  The common feature is inflammation, and the common treatment is aspirin or other Non-Steroidal Anti-Inflammatory Drugs (NSAIDs).  Damage or stress to cells of the body - whether muscles or blood vessels - results in the release of cytokines - chemical agents that act on other cells.  The common feature of cytokines is that they tend to "irritate" other cells in the body.  The body reacts by causing inflammation - swelling, increased fluid in the tissue, increased blood flow, and an increase in the immune cells entering the area.  One of the key inflammatory chemicals is arachidonic acid.  Through the pathway at the right (figure by JFD Wolff, via Wikimedia Commons), Arachidonic acid is converted to various compounds called prostaglandins and thromboxanes.  PGE2 is one of the critical agents that causes and prolongs inflammation.

The stage indicated "PGH2 synthase" is more commonly called "cylcooxygenase" or COX and there are COX-1 and COX-2 inihibitors for the two different forms of COX enzyme present.  Aspirin - acetylsalicylic acid - inhibits both COX-1 and COX-2, as do most of the NSAIDs: acetaminophen/paracetamol (Tylenol), ibuprofen (Advil), naproxen (Aleve), etc.  There are selective COX-2 inihibtors that appeared even more effective, since that COX-1 is less involved in inflammation, but the risk of cardiac side effects has removed them from the market.

So, the aspirin doesn't need to know where the pain is, it just needs to block this one reaction that is present wherever pain occurs.  Overall, NSAIDs are the most effective relief of inflammation-related pain that we have - and it (aspirin) all started as willow tree bark.

See you next time!


Graphic borrowed with permission (the APPROPRIATE way to handle internet content) from Howard Taylor's Schlock Mercenary website.

Since I post science information that is supplemented from material found online, anyone with an accusation of copyright infringement could have my site blocked and all content removed - even though I've sent over a year writing my book!  There is no protection of free speech, no due process and no recourse in SOPA/PIPA.  It may be defeated by the Supreme Court, but the process will take years and too much damage could result.  Better to never let it get out of Congress.

Please join in telling the U.S. Congress not to pass the SOPA and PIPA bills. [Full link to blog for email clients.][FT:C44]

Tuesday, January 17, 2012

The GUIDE: Migraine [Full link to blog for email clients.][FT:C44]

Oh.  The PAIN!

Headaches occur at a minimum of once per week in persons living in industrialized society.  They can be simply a slight pain induced by too much reading, polluted (or stale) air, food triggers, not enough sleep or allergic reaction.  It is tempting to refer to all severe headaches as "Migraines", especially if they occur with regularity.  However, not all headaches are migraines, and not all migraines are the same.

Let's start with some definitions and descriptions.  First, headaches are really neural in that they don't mean that the cells of the brain are acting in any manner different from normal.  Instead, headaches are a vascular problem.  Metabolic imbalances cause tiny blood vessels to expand, the increased blood flow causes changes in other blood vessels and in brain activity.  In addition, there is release of the neurotransmitter serotonin, and its close chemical sibling: histamine.  Those chemicals cause further reaction of the blood vessels, leading to the sensations we know as a headache.

The involvement of histamine means that there are many ways of triggering headaches - sinus congestion, allergy, food reactions, excess carbon dioxide in the atmosphere, etc.  The CO2 involvement is one reason why breathing oxygen relieves headaches - high CO2 causes blood vessels to dilate (get larger) increasing blood flow in the brain to higher than normal levels, while high O2, low CO2 causes those same vessels to constrict and reduce blood flow to normal levels.

All of these causative factors lead to the same sensation: discomfort and perceived pressure in the forehead area, behind the eyes.  The brain itself does not have the nerve endings that signal pain in the rest of the body, so the sensation of pain is really one of pressure, and it results from the "cognitive" areas of the brain trying to find a way to represent the chemical changes that result from the unusual blood flow patterns.

Migraine starts the same way, but adds a new components, because migraines really do involve a change in the electrical activity of the brain.  To start with, the majority of migraine sufferers report a "prodrome" or "aura" before the pain sets in.  This aura is quite frequently associated with visual changes - light sensitivity, flashing, pulsing, tunnel vision, blurring, spots or even temporary blindness.  In this manner, the aura of a migraine is quite similar to that preceding an epileptic seizure (see prior blogs on Seizures and Epilepsy), but is most often visual and does not spread or involve other senses.  The aura signals the initial "irritation" of the blood vessels that supply the brain, but the migraine pain itself comes from the later reaction in which neuron activity is suppressed by what is called "spreading cortical depression."  No, this doesn't mean depression in the clinical sense, but that brain activity is in fact suppressed and only the strongest (and most noticeable) signals can be processed.  The video above illustrates the spreading depression in the orange band that starts in the visual cortex and spreads up and forward to include the Parietal, and even the Frontal Lobes of the brain.

The interesting parallels between migraine and seizure continue, but migraines are not epileptic in nature.  Seizures do involve some element of cortical depression, reduction in normal brain activity is necessary to set up the abnormal synchronous activity of an epileptic seizure.  After the seizure passes, there can be spreading cortical depression.  However, the synchronous activity does not occur in migraine, only the spreading depression, and that appears to result from the serotonin and histamine release from the cells lining the blood vessels.  Still, some seizure medicines (sumatriptan - Imitrex) can be useful in treating migraines in that they can limit the spreading cortical depression by altering neural response to serotonin.  Preventative medication for migraines often involves blood pressure/calcium blocker medicines such as Verapamil that can reduce the "irritation" of blood vessels.  Injection of very small amounts of botulinum toxin (Botox) into the blood vessels that most frequently react to induction of a migraine can also reduce the "irritability" and reduce the frequency of migraines. 

Migraines typically last from 4-72 hours and are accompanied by extreme light sensitivity, nausea, blurred vision, fatigue, hypersensitivity to sound and yes - short-term psychological depression.  However, it is very easy to call any severe headache a "migraine" even when that is not the case.  Allergic rhinitis - i.e. a "stuffy nose" and sinus congestion can trigger headaches that react to pressure in the sinus cavities that surround the nose and sit adjacent to the olfactory bulb - the "smell" center of the brain.  The proximity of sinus to the Frontal Lobe means the pressure gets translated to the brain, and the neurons react with activity that signals pain.

And yet, migraines may very well have an allergic component.  A well-known trigger for migraine is certain foods and food additives.  Nitrites in cooked/preserved meats, artificial coloring agents, phenylalanine in artificial sweetener, food allergens such as tomato or nuts, and surprisingly - yeast breads.  The reason is because any trace of food allergy (or mold allergy, in the case of yeast) can cause the histamine increase leading to migraine.

I did mention, though, that not all "migraines" are in fact the classic migraine described here.  "Cluster headaches" - so named because the headaches occur in "clusters" that frequently occur at the same time each day, with pain in the same area of face and/or head, and occur for weeks or even months at a time -  vary from migraines and conventional headaches because it appears that they *do* involve some unusual brain cell activity.  Cluster headaches are not preceded by auras, and the pain is quite often confined to one side of the face and head.  They are still treated with some of the same drugs as headaches and migraines, as well as a few specific drugs to disrupt the activity of the neurons that trigger the headache.  If these treatment options fail, the docs need to take a look inside the head - not to see if there is anything missing, but to look for unusual blood vessel formation or something that might be causing pressure.

Headache is all about blood pressure and blood flow, since this Guide is all about brain disorders at plot devices, it is important to consider what could cause headaches and migraines to stop or start - and that comes down to anything that disrupts blood flow.  Physical head injury, hormonal changes (puberty, pregnancy, menopause), blood loss, allergy, surgery - all of these could trigger the onset, or mark the cessation of a lifetime of headaches.  Don't forget the debilitating effects - imagine if during his Labours, Hercules had needed go lie down for 3 days to allow a migraine to pass!  Then again, a headache-ridden Theseus may have welcomed the dark and dank Labyrinth and slain the minotaur if only for access to a refuge from sun and sea!

Tomorrow, to complement this blog will be a short article on pain medication.  Thanks for reading!

- s2la 

Monday, January 16, 2012

NEWS: The Return [Full link to blog for email clients.][FT:C15]*

OK, I've been slacking long enough.  The previous six months have seen a flurry of activity in the day job, including grant proposal *re*-submissions, scientific manuscripts sent in, revised, edited, and revised again, plus three major scientific meeting presentations, a bunch of family trips and one SF convention.

So it's a new year and we need to get this show on the road again - literally - I will be participating in Stellarcon, DeepSouthCon50, LibertyCon and Dragon*Con this year, with a possible on RavenCon.  I'm taking my appeal for accuracy of Science in Science Fiction to the cons and am pleased to participate in any serious or humorous panels that draw on scientific knowledge and background.

Put simply, SF cons are *FUN* and I enjoy them.  If you are attending any of these cons, drop by the panels or the Bar Fly Central (Baen's Barflies) and say hi!

So, for a reintroduction to this blog, I highly suggest clicking on the Tab above: "What is the Lab Rats' Guide to the Brain" which is a "sticky" post that combines many aspects of my prior posts "Back to Basics" and "Brain and Brain, what is Brain?"

My plan for this reboot is to start with today's introduction, jump right back to our discussion of brain disorders with the next several posts on Migraines, The Flurry of A's (Amnesia, Agnosia, Apraxia, Ataxia and Aphasia) and Hansen's Disease, then catch new readers up with a reprise of Brain and Brain and Back to Basics.


*For Baen's Bar  followers, I am posting this to "Baen's Bar" conference to let you know that the blog is back.  Regular mirroring of the blog will still occur in "Sarah's Diner" conference as before.