The fontanels get hard when the baby is between 1 and 2 years old.

Justin W.: Is each human brain unique and if so, how unique are they from other human brains?

Answer: Yes, each brain is unique.

1. Brains are unique in physical appearance. No two brains have exactly the same outside appearance. The patterns of sulci and gyri (bumps and grooves) will make each brain look different from another.

2. Each brain will have a different number of cells. Neurons probably die at different rates in different people.

3. Each person has different experiences and each brain holds unique memories. This implies that the physical structure that holds these memories must be different.

4. Every person has different behaviors and different experiences. Differences in the brain are responsible for all of these.

5. (From Neuroscientist Network member, Dr. Pat F.): Though the general circuits and connections among different parts of the brain will be fairly common among different brains, the specific connections in regard to the neurons and number of connections with each neuron will be very different for each individual, and can even change over the life of the person.

6. (From Neuroscientist Network member, Dr. Kevin L.): the apparent variation in the nervous system on the molecular level is large as well. Differences in receptor distributions, neurotransmitter and neurohomone levels and perhaps even cell adhesion molecules may all contribute to the individuality of each brain and person!

I am sure you can think of more differences between brains.

Lee: Do blind people dream?

Answer: Everyone dreams. Even the blind have "desynchronized sleep." However, during this "dream sleep" stage, people who are blind from birth do not show the rapid eye movements that sighted people have. Also, blind people have dreams that are primarily auditory, tactile or even involve taste and smell. Several scientific papers that discuss dreams in the blind:

• Visual dream content, graphical representation and EEG alpha activity in congenitally blind subjects
• The structure of laboratory dream reports in blind and sighted subjects
• Symbolism in the dreams of the blind
• Emotions in the dreams of the blind

Kel: How does Prozac work in the brain?

Answer: Prozac is a "selective serotonin reuptake inhibitor." This means that it prevents the neurotransmitter called serotonin from being taken back up into the presynaptic axonal terminal. Therefore, serotonin will stay in the synaptic cleft and work for a longer time.

For more about prozac, see:

• http://www.prozac.com/
• http://www.mentalhealth.com/drug/p30-p05.html

Jim C.: With all the money the pharmaceutical companies are pouring into treating everything from impotency to toenail fungus, is anyone trying to create a better general anaesthestic agent? What would be the characteristics of your "dream" gas?

Answer (By Dr. Chris B., member of the Neuroscientist Network): Certainly work is underway at multiple pharmaceutical companies to develop improved anesthetic gasses. However, the amount of effort, i.e., money, expended is tempered by the fact that the number of people who receive these drugs is far less than the number who might benefit from drugs to treat toenail fungus or impotence. Consequently, the potential financial return is nowhere near as great, and these companies, like all companies, are in the job of making money for their owners (shareholders).

Now, as to the ideal anesthetic gas. The properties that would be desired are these:

1. Rapid onset of effect and equally rapid offset so that patients go to sleep quickly and wake up quickly.

2. No unwanted side effects like cardiovascular depression (manifest as low blood pressure), irritation of air passages, organ toxicity (some drugs used in the past and some still in use today can cause liver and kidney damage in some situations).

3. Very potent so that you need to use very little. This is important because the more anesthetic gas you need to give the less oxygen you can give.

4. Odorless, for patient comfort.

5. Nonflammable so that there is no risk of explosion when using electrical equipment in the operating room. This is one of the reasons we no longer use ether.

6. Inexpensive

Pam S.: Is there any part of the brain that starts with the letter "z"?

Answer: Yes! An area of the brain that starts with the letter "z" is the "zona incerta."

Kim F.: What anniversary falls on September 13, 1998 and why is this an important event in the history of brain science?

Answer: September 13, 1998 marks the 150th anniversary of the date that Mr. Phineas Gage was shot through the head with an iron tamping rod. His injury and the resulting behavioral changes that he developed gave scientists information about the role of the frontal cortex.

For more information about Phineas Gage, see lobes of the brain.

Alicia E.: I saw a program on A&E about a theory that zombies were really an accident of poison. The poison was traced back to the puffer fish. A poison called tetrodotoxin. Do you have any more information on tetrodotoxin?

Answer: Yes, I have heard of the zombie/poison theory before. Tetrodotoxin is a poison from the pufferfish and its action is to block sodium channels in nerve cells.

For more about tetrodotoxin, please see:

• http://faculty.washington.edu/chudler/toxin1.html
• http://vm.cfsan.fda.gov/~mow/tet.html
• http://vm.cfsan.fda.gov/~mow/chap39.html

Erin C.: Are the cranial nerves part of the central nervous system or peripheral nervous system?

Answer: The cranial nerves are part of the peripheral nervous system.

Tami: Do infants dream?

Answer: Most probably, the answer is "Yes, infants DO dream." I say most probably, because the only way to be 100% sure that someone has dreams is to ask if he or she dreams.

As you may know, dreaming occurs in the phase of sleep called "Rapid Eye Movement" (REM) sleep. Most of the time if people are awakened during REM sleep, they will say that they were dreaming. Infants spend MORE time in REM sleep compared to adults. Therefore, although infants cannot actually tell you that they dream or not, it is likely that they spend more time dreaming than adults.

For more about sleep and dreaming, see:
http://faculty.washington.edu/chudler/sleep.html

J. Sil:Are there any animals that have ultraviolet and infrared vision?

Answer: Some snakes and fish can see infrared wavelengths of light. The bee and butterfly can see in the ultraviolet range.

For more about the sensory abilities of animals, see Amazing Animal Senses.

Lizzy: What causes "Brain Freeze?"

Answer: No one is really sure what causes brain freeze but there are a few theories. "Brain Freeze," also called an "ice cream headache," is thought to be caused by rapid cooling of the palate (upper part of mouth) which then activates nerve fibers that cause pain. Rapid cooling may affect blood vessels which change shape. This change in shape may activate nerve fibers that cause pain.

For more about Brain Freeze, see:

• http://bmj.com/cgi/content/full/314/7091/1364
• Mystery of Brain Freeze

J.S.: What is all this about nerve cells growing in adult human brains? I thought neurons did not grow in adult brains.

Answer: Recent experiments in humans have shown that new neurons DO grow in at least one area of the brain (the hippocampus). For more about this topic, please read

Changing Dogma: New Tricks for the Old Brain.

More Good News for Aging Brains

New Neurons in Neocortex? New Study Says NO!

Sarah: Do you have any information on the manatee's nervous system.

Answer: You are in luck. There is an excellent web site about the manatee brain at:

http://manateebrain.org/

Mike B.: What is PTC paper? Why do only certain people taste it?

Answer: PTC paper contains a chemical called "Phenolthiocarbamide."

For about 70% of the people in the U.S., the PTC paper tastes very bitter. The other 30% of the people say it just tastes like paper.

This ability to taste this material is genetic. The gene for tasting the chemical is DOMINANT over the one for not tasting it. For an experiment that describes the use of PTC paper, see:

Rolf: I was doing some research a few days ago and found some info and a .gif file of the first recorded EEG. Unfortunately I did not bookmark the page. Do you know where this might be located?

Answer: The page you are looking for may be the one located at:

Gavin: What is a reflex arc? The type involved when you touch a hot surface and then pull away.

Answer: The reflex arc is a concept related to muscle reflexes. The arc is made up of 1) an afferent neuron that is connected to a receptor that detects a stimulus; 2) a central processor and 3) an efferent neuron that controls a muscle.

A reflex arc that has only a single synapse (between the afferent and efferent neuron) is called a monosynaptic reflex. The knee jerk reflex is a monosynaptic reflex.

A reflex arc with multiple synapses between the afferent and efferent neurons is called a polysynaptic reflex. Limb withdrawal to a painful stimulus (flexion reflex), like in your example, is a type of polysynaptic response.

Here is the basic pathway of the flexion reflex for the foot:

1. Painful stimulus sends a message to the spinal cord where the peripheral nerve fiber (neuron #1) synapses (Synapse #1).

2. Neuron (#2) in the spinal cord (an interneuron) projects to another neuron (#3) in the spinal cord (Synapse #2).

3. Neuron #3 in some cases cross over to the other side of the spinal cord; some neuron #3 stay on the same side. They all synapse on a motor neurons (#4).

4. The motor neuron sends an axon to muscles. On the side of the body that is the same as the stimulus, the result of the motor neuron is EXCITATION of the flexor muscles and INHIBITION of the extensor muscle. On the side of the body opposite to the stimulus, the result is EXCITATION of the extensor muscle and INHIBITION of the flexor muscle.

5. The result of this circuitry to the flex (withdraw) the painful limb and to extend the opposite leg for support.

It should also be mentioned that this reflex can be modified by signals from the brain. A diagram of this reflex arc is the best way to visualize this circuitry. Try to draw it out yourself.

Kate: How is the reflex pathway organized so that when light is shined in one eye the pupil in the other eye constricts?

Answer: Light into one eye causes pupil constriction of this same eye (direct response) as well as in the other eye (consensual response). Retinal ganglion cells that project to the pretectal area of the brain are responsible for these reflexes. Neurons in the pretectal area project to the Edinger-Westphal nucleus on BOTH SIDES of the brain. Neurons from the Edinger-Westphal nucleus on each side of the brain then project to the ciliary ganglion. The Edinger-Westphal nucleus on the right side projects to the ciliary ganglion on the right side and the Edinger-Westphal nucleus on the left side projects the ciliary ganglion on the left side. The ganglia then send axons to the muscle that controls pupil size.

Aaron: I was watching a segment on television about Human Growth Hormone (HGH),a substance naturally produced by the brain. Do artificial supplements of HGH really relieve the effects of aging on the brain? What are possible side effects?

Answer: The TV show on human growth hormone that you watched could have been the ABC 20/20 program. On September 25, 1998, they aired a program titled "The Fountain of Youth? Human Growth Hormone Miracle Drug or Risky Fad?" about this controversial treatment.

It is my understanding that the FDA has approved Human Growth Hormone for people who are deficient in this hormone produced by the pituitary. However, its use in normal, health people, as an anti-aging treatment is not approved. A quick search on the Internet will turn up many companies willing to sell you this product, but purchasing human growth hormone may not be worth your money.

The National Institute on Aging at the National Institutes of Health has a summary of some of these controversial treatments for aging.

Aaron: I have been wondering for some time on the neurological effects of electromagnetic fields, and if there is any explanation as to why there are high incidents of brain tumors in towns located near power stations.

Answer: The correlation between electromagnetic fields and brain cancer is somewhat inconclusive. Some studies show a correlation, others do not. I will direct you to a few resources where you can read up on this subject and you can come to your own conclusions.

1. EMF Information
2. EMF Science Review

D.S.: Do you the refractive values of the cornea and the aqueous humor?

Answer: The refractive index of the cornea = 1.376

According to http://retina.anatomy.upenn.edu/~lance/eye/humor_aqueous.html, the refractive index of the aqueous humor is either 1.3374 or 1.336.

Douglas B.: I recently observed a craniotomy and a rather important question popped up: How does the surgeon distinguish normal brain tissue from harmful tumor tissue?

Answer (By Dr. John L., neurosurgeon): There are several answers to this question. The first is that a tumor often looks different from normal brain and the surgeon can be guided by appearance. Second, the location of the tumor can be fairly well known based upon imaging studies such as MR (magnetic resonance imaging) or CT (computer tomography). By studying the relation of the tumor to identified structures (blood vessels, major sulci, etc), it is possible to have a good idea of where the tumor lies. Third, one can use intraoperative ultrasound to locate the tumor, as its sound reflective characteristics are different from the brain. Fourth, certain types of tumors are encapsulated and the boundary is quite discrete. Oher types of tumors are infiltrative and the boundaries are not discrete. When the tumor is in silent parts of the brain, one can deliberately take out surrounding tissue so as to get an adequate margin. However, the big problem with intrinsic gliomas is that they have no discrete boundaries and are widely spread through the brain before they produce any symptoms. This is why they cannot usually be cured. The tumor cells literally swim therough the brain and eventually grow to produce a recurrence.

Mik: Who discovered ribosomes?

Answer (By Neuroscientist Network Members, Dr. M.B. and Dr. Doug R.): Ribosomes, which means "body of ribose" after these organelles were found to contain the sugar ribose, were first described by Albert Claude in 1938 and were observed in animal cells which had been infected with Rous sarcoma virus. He then ascertained that noninfected cells also contained these particles and first called them microsomes (which in part they were, because ribosomes are bound to microsomes). In bacterial cells they were first described by Luria, Delbruck and Anderson in 1943.

George Palade and Keith Porter also described them around 1950 using EM when they were at Rockefeller Institute (part of reason for Palade's Nobel prize in 1974), and noticed their location on the endoplasmic reticulum (RE & RER named and disc by Porter) and free in cytoplasm.

Jill: I am wondering what kind of jobs are available for students who graduate with a Master's in Neuroscience? I am also looking for a good reference of biotechnology companies in the NorthWest.

Answer: There are some schools that offer a Master's degree in Neuroscience, but many will not admit students unless they are committed to obtaining a Ph.D. There are many job opportunities for people with a Master's degree:

• Industry - in such areas as product development and quality control Science journalism - for books, magazines or textbooks
• Teaching - it may be possible to teach at the community college level, but most teaching jobs at 4 year universities go to those people with a Ph.D. It may also be possible to get a high school teaching certificate with some additional training.
• Laboratory work - skilled technical help is always needed in research laboratories

The Pacific Northwest is a very active area for biotechnology companies. Here are a few places to give you more information such companies and about the industry:

1. http://www.wabio.com/
2. http://www.biospace.com/
3. Immunex

Jim: I heard on the radio that the brain is over 50% fat. Any truth to this? Also, is this where the term 'fat head' comes from?

Answer: I think the 50% number is a bit of an exaggeration. According to some numbers that I have found in the literature, the brain is composed of the following components:

Water                78%
Lipids               10%
Protein               8%
Carbohydrate          1%
Inorganic salts       1%
Other                 2%

Lipids are the "fats." I suppose if you ignored the water, then lipids would be slightly less than 50% of the remaining material, but I don't think this is a fair way to manipulate the numbers.

There are 3 types of brain lipids: cholesterol, glycerophospolipids and sphinoglipids. Myelin, which is the insulation around the axons of neurons, is about 80% lipid.

I am not sure where the expression "Fat Head" came from. Actually, if you know how important fats (lipids) are to the brain and rest of the nervous system, you would NOT take this expression as an insult. Fats are ESSENTIAL for the proper function and development of the brain. I suspect the expression "Fat Head" has NOTHING to do with the fat (lipid) content of the brain.

Michael S.: Can pure alcohol (ethanol, the kind you can drink) be absorbed through the skin and cause intoxication?

Answer: Ethyl alcohol (ethanol) is not absorbed through the skin very well. According to Goodman and Gilman's, The Pharmacological Basis of Therapeutics, 1985, p. 378:

"Absorption of alcohol through the human skin is negligible."

However, there are a few cases in the literature of intoxication caused by skin absorption of alcohol in INFANTS and YOUNG CHILDREN. One case involved a 1 month old infant who had her umbilical cord stump soaked in gauze pads containing ethanol. There are other reports of ethanol poisoning in children who had alcohol-soaked gauze pads applied to their skin in attempts to relieve abdominal pain. Intoxication may also occur after breathing in alcohol vapors because alcohol can be absorbed through the lungs.

E.F.: Might you be able to get some idea of how many neurons in the brain are firing by EEG? It seems one could compare an actual EEG measurement to a hypothetical maximum value given by: (# of neurons in brain) X (estimated current created by single action potential).

I thought your language on the 10% myth page as a bit misleading here: "Even if neurons are not firing action potentials." Neurons don't "fire" action potentials; the firing IS the action potential. I also take issue with your statement that non-firing neurons may still be receiving signals from other neurons. With an exception or two that I can think of (inhibition), neuronal function is an all-or-none phenomenon. Neurons are either firing in response to a stimuli, or they aren't. If the neuron doesn't fire, the stimuli isn't important.

Answer: Let me clear up some misinformation that you have. First, an estimation of the number of neurons in the brain that are firing by using the EEG will NOT be accurate. The EEG does NOT necessarily measure action potentials! Rather, the EEG is the averaged activity of thousands of neurons, some of which are not firing action potentials. This activity may be generated by postsynaptic potentials. This relates to your second comment.

You are right...firing of an action potential is what neurons do. It is ONE thing that neurons do, but NOT the only thing. Non-firing neurons receive thousands of signals from other neurons. These signals do NOT always cause an action potential! An action potential will only be generated if the neuron is depolarized above its threshold. Neuronal function is NOT all-or-none! Action potential firing IS all-or-none. The "decision" to fire an action potential is NOT all-or-none; it is based on the summation of many smaller responses (the excitatory and inhibitory postsynaptic potentials).

Furthermore, it is incorrect to state that just because a stimulus does not cause an action potential to fire it is not important. It may be part of a complex response that results in other neuronal processes (including a postsynaptic response). It may depolarize a neuron such that other postsynaptic responses cause the neuron the fire.

More about the action potential.
Do we only use 10% of our brains?

G.H.: Will having a seizure hurt the brain or destroy brain cells?

Answer (By Dr. Chris B., member of the Neuroscientist Network): Seizures can damage brain cells if they are prolonged (15-20 minutes is a number I remember being taught but I do not have a primary reference) because oxygen/glucose needs can exceed supply. Also, excitatory neurotransmitters released during seizures can be injurious if the seizure is prolonged. However, most seizures are not prolonged and do not cause damage.

Tera S.: Why do you see "stars" after you are bumped and sometimes after a sneeze or a cough?

Answer (By Dr. David P., member of the Neuroscientist Network): The "stars" are a result of a mechanical stimulation of the normally light-stimulated rods and cones in the retina. Rather than the light uncoupling rhodopsin to opsin and retinal, the bump uncouples them mechanically. Pressure caused by a sneeze or cough can also mechanically stimulate the photoreceptors. The final result is that "light spots" are seen.

Afri B.: What is sleeping gas made of?

Answer (By Dr. Chris B., member of the Neuroscientist Network): There are multiple gases that have been used for producing general anesthesia, including chloroform, ether, cyclopropane, enflurane, isoflurane, halothane, desflurane, and most recently sevoflurane. The last four drugs are the only ones still in use in the United States. These drugs are all relatively small molecules in a class called "halogenated hydrocarbons." Their basic structure is that of 1 or more carbon atoms connected to each other as well as to one or more halogen atoms (chlorine, flourine, or bromine) and with some drugs an oxygen molecule as well. The property that all of these drugs have in common is that they easily dissolve in the membranes of cells and reversibly alter their function. In particular, current evidence suggests that these drugs act on neurons in the brain to increase how tightly the neuron binds to a neurotransmitter called GABA. This neurotransmitter is responsible for inhibiting the activity of other neurons. Interestingly, other drugs like valium and perhaps alcohol have a similar mechanism.

Incidentally, most of these drugs are not gases at room temperature, they are liquids. But they evaporate very rapidly (just like rubbing alcohol or acetone (fingernail polish remover) to become gasses. Thus, to use these drugs they must be placed in a device called a vaporizer. Oxygen is then bubbled the liquid. The oxygen picks up some of the liquid and carries it away as a gas.

Tara A.: I would appreciate it if you could recommend some useful texts that I could refer to for further information on the field of neuroscience.

Answer: The ones I like are:

1. Principles of Neural Science, 4th edition, edited by E.R. Kandel, J.H. Schwartz and T.M. Jessel, New York: McGraw Hill, 2000. This is one of the best textbooks available. A shortened version of this text is also available:
   Essentials of Neural Science and Behavior, edited by E.R. Kandel, J.H. Schwartz and T.M. Jessel, Norwalk: Appleton and Lange, 1995.

2. Neuroscience: Exploring the Brain, by M.F. Bear, B.W. Connors and M.A. Paradiso, Baltimore: Williams and Williams, 2001.

3. Neurobiology, 3rd edition, by G.M. Shepherd, New York: Oxford Univ. Press, 1994.

4. Neuroscience, edited by D. Purves, G.J. Augustine, D. Fitzpatrick, L.C. Katz, A.S. LaMantia and J.O. McNamara, Sunderland: Sinauer Asso., Inc., 2001.

5. Physiology of Behavior, 6th edition, by N.R. Carlson, Boston: Allyn and Bacon, 1998.

6. The human brain : an introduction to its functional anatomy, by J. Nolte, St. Louis, MO, Mosby, 1999.

Yi W.: I would like to know what is the cause of blindness? Can it happen after birth? Can watching too much T.V., using the computer too much, and reading in dim light for a long time result in blindness?

Answer: Of course an accident that damages the eyes can cause blindness. Blindness can also be caused by brain damage after a "stroke". However, according to the National Federation of the Blind, the major causes of blindness in the United States are cataracts.

Blindness occurs more frequently in older people, but can happen in children too.

The American Academy of Ophthalmology and the American Optometric Association agree that watching too much T.V., using the computer too much, and reading in dim light for a long time do NOT cause blindness or damage the eyes. However, reading in good light will make it easier to read and will prevent eye strain and fatigue.

A. Sita: Can you tell me what deja vu is and the areas of the brain that are important for it or where I can find this information? I have spent hours searching with little luck.

Answer: Deja vu is the perception that a current "event" has happened in the past. There has not been too much research on the misunderstood topic of deja vu, but there are numerous cases of people with "temporal epilepsy" who experience sensations of deja vu. Also, electrical stimulation of the temporal lobe may cause deja vu feelings.

Deja vu is very difficult to study for several reasons. First, there are no animal models by which to study this phenomenon. Second, it is very difficult to cause feelings of deja vu and it is very difficult to study deja vu in a controlled laboratory situation. Furthermore, it may be that the mechanisms of deja vu in normal people are different than those in people with epilepsy.

It appears that there may be psychological factors (for example, stress) that may start deja vu experiences. However, deja vu is not uncommon, and it alone should not be taken as a sign of disease. For more information, see:

• What is going on in the brain when we experience deja vu? - Scientific American (2010)
• Dreamy states and psychoses in temporal lobe epilepsy: mediating role of affect.
• The deja vu experience: remembrance of things past?
• Anatomical origin of deja vu and vivid 'memories' in human temporal lobe epilepsy.
• Mental phenomena induced by stimulation in the limbic system.
• The mechanism of deja vu.

Linda F.: An episode of the "The X-Files" TV show had to do with ESP and Agent Molder mentioned a part of the brain that scientists still are not sure what it is used for. He called it "The God Center." Could you give me some information about this section of the brain and what it does?

Answer: So that's why I have been getting "God Center" questions recently! Thanks for telling me this. I don't watch the X-Files. You can tell your students not to believe everything they see on TV (or read in popular magazines).

With regard to the "God Center" of the brain....there are many areas of the brain that are involved in higher cognitive functions including the belief in God. I do not think there is one particular area of the brain that scientists can point to that would indicate where this is located. Many higher functions have multiple areas that are important...for example, memory is located in many different parts of the brain - there is NO "center." This is probably true for religious belief.

However, there was a study presented at the 1997 Society for Neuroscience meeting titled "The neural basis of religious experience." These researchers mention the temporal lobe and the amygdala as possible areas of the brain important in the belief in God and religion. There are also forms of epilepsy that cause patients to have feelings of a religious experience. Nevertheless, these areas of the brain are only PART of the whole story...these areas are probably part of a much larger "circuit."

(A good reference on this topic is: J.L. Saver and J. Rabin, The Neural Substrates of Religious Experience, Journal of Neuropsychiatry, 9:498-510, 1997.)

A.K.: I have had to undergo 4 major surgeries within the last year, 3 of which used general anesthesia. Has research determined if there are lingering effects on the brain? I find that I am forgetful for quite awhile after each surgery and the longer the surgery, the longer the forgetfulness.

Does the anesthesia's effect on the brain cause the body to involuntarily twitch while at rest? This is also something I have found occurring after a general and it continues for quite some time. I would like to research this further.

Answer (By Dr. Chris B., member of the Neuroscientist Network): Several issues are relevant to your questions:

1. Mental function: First, it is important to realize that anesthesia does not occur in a vacuum, thus it is difficult to separate the effects of anesthesia from those of the surgery. For example, the "tissue injury" caused by surgery results in the release of many compounds (e.g., cytokines, leukotrienes, prostaglandins, etc.) that may affect the way we feel. Second, most people require pain medications after surgery and these drugs also have potent effects on mental function. Finally, some surgical procedures have been shown to produce brain injury with some frequency(e.g., heart surgery which requires bypass and carotid artery surgery).

However, in studies done on volunteers who had anesthesia but not surgery, normal mental function as measured by sophisticated neurobehavioral testing recovers within a few hours.

2. Twitching: General anesthetics inhibit inhibitory neurons in the spinal cord and brain even at relatively low concentrations. As a result, spinal reflexes are a little overactive in the first hours after surgery. A classic example of this is the fact that patients exhibit marked clonus (involuntary bouncing of the foot when the Achilles tendon is stretched) early in the recovery from general anesthesia. Because clonus is a sign of brain injury, it is possible that physicians may be unaware of the impact of anesthesia on clonus and think that the patient had suffered a brain injury. This is a long way of saying that muscle twitching after anesthesia that persists for a few hours is not surprising and is in fact normal. However, keep in mind that many drugs as well as bed rest can causing muscle twitching, thus cause is not always clear.

Nancy L.: How many neurons are in an insect brain?

Answer: I do not know the number of neurons in the brain of every type of insect, but I hope the number of neurons in the brain of a bee, fly and locust will help.

# of neurons in worker bee brain = 851,458
# of neurons in drone bee brain = 1,209,681
# of neurons in fly brain = 337,856
# of neurons in locust brain = 360,000

Remember, it has been estimated that the human brain has 100,000,000,000 neurons.

Reference for the number of neurons in the insect brains is: Comprehensive Insect Physiology, Biochemistry and Pharmacology, Vol. 5, edited by G.A. Kerkut and L.I. Gilbert, Pergamon Press, Oxford, 1985, p. 307.

Alex F.: How many messages are sent through an average human body in one day?

Answer: First, let me say that my answer will be an estimation only. There really isn't a fixed number of messages or action potentials that happen each day.

Second, I will make three big assumptions:

1. we will talk about the brain only
2. we will assume that the brain has 100,000,000,000 (100 billion) nerve cells (also called neurons).
3. we will assume that each neuron will fire at a rate of 1 every second.

So, 100 billion neurons firing at one per sec for 60 sec = 100 billion X 1/sec X 60 sec = 6,000,000,000,000 (6 trillion per minute)

Then, 6,000,000,000,000/min X 60 min/1 hr = 360,000,000,000,000 (360 trillion per hour)

360 trillion X 24 hours = 8,640,000,000,000,000 per day (8.6 quadrillion per day)

That's quite a lot!!!! You can check my math yourself.

Frank: How did parts of the brain get their names?

Answer: Many brain structures are named for what they actually look like. Greek and Latin words are usually used. For example, an area of the brain that is important for memory is called the hippocampus. In Greek, hippocampus means "sea horse." The structure was named hippocampus because it looked like a sea horse. Another example is a nerve called the vagus nerve. In Latin, "Vagus" means "wandering." So, the vagus nerve gets its name because it "wanders" around the body. If you are interested in learning about more names of brain structures, see my page about the origin of brain structure names at:

http://faculty.washington.edu/chudler/neuroroot.html

Jody: Would you have any good books you could suggest that would be good for parents of preschooler to read?

Answer: I have a list of books that should suit your purpose at the bottom of the on-line and off-line books and articles page. You will have to either click on the "off-line books" button or scroll all the way to the bottom of this page to get to the books (and videos). Most of these books should be in a good public library system. Two books that I highly recommend are:

1. Susan A. Greenfield, The Human Mind Explained, Henry Holt and Co., New York, 1996, pp.192. An EXCELLENT guide to the brain with plenty of pictures.
2. Anne D. Novitt-Moreno, How Your Brain Works, Ziff-Davis Press, Emeryville, 1995, pp. 170 .

Mari C.: Who are some of the famous people who have (or had) epilepsy?

Answer: According to the Florida Epilepsy Service Providers, the following people had epilepsy:

• Writers: Lord Byron, Edward Lear, Feodor Dostoevsky, Gustave Flaubert, Charles Dickens, Agatha Christie, Vachel Lindsay, Truman Capote

• Statesmen: Napoleon Bonaparte, Alexander the Great, Julius Caesar, Peter the Great

• Philosophers: Socrates, Pythagoras

• Artists: Vincent van Gogh, Leonardo da Vinci, Michelangelo

• Composers: Peter Tchaikovsky, Georg Freidrich Handel

Jake C.: When a nerve sends a pain message, does it injure the nerve.

Answer: No, a nerve is NOT usually injured when it sends a pain message. This is the normal function of some nerves. A nociceptor is a receptor for stimuli that are painful. Signals from a nociceptor are sent through nerves to the spinal cord. The actual transmission of this signal does not damage the nerve. However, sometimes the SKIN and the receptor can be injured when something painful has happened like when the skin is burned severely. One more thing - IF a nerve is injured, for example by an accident that crushes or cuts a nerve, then an abnormal pain message will sometimes be sent to the central nervous system. When this happens even after a wound is healed, it can sometimes cause "chronic pain" conditions.

Sharyn H.: Has the study by Gould & McEwen which was written up in the New York Times, about the growth of new brain cells been published yet?

Answer: Yes, this paper has been published: E. Gould, P. Tanapat, B.S. McEwen, G. Glugge and E. Fuchs, Proliferation of granule cell precursors in the dentate gyrus of adult monkeys is diminished by stress, Proc. Natl. Acad. Sci., vol. 95, pp. 3168-3171, 1998.

These researchers found that new neurons (granule cell type neurons) are added to the hippocampus in adult marmosets. Marmosets are new world primates. The addition of new neurons to the hippocampus has already been demonstrated to occur in rats and tree shrews. Stress reduced the number of new neurons. Whether these findings occur in old world primates (like rhesus monkeys) and humans remains to be determined.

What this means with regard to memory and learning is unknown at this time. The hippocampus is thought to play a role in the consolidation or transfer of short-term memories to long-term memory. However, how the addition of new neurons in the hippocampus is involved in this process is unknown. It is clear though that one of the "facts" that is always taught and that is in most textbooks, that "the number of neurons in the brain is fixed at birth," is most likely false. I think that this type of research may lead to the possible discovery of methods and techniques to grow new brain cells after injury (e.g., stroke) and repair damage to the brain and spinal cord.

^Update A new study published in the November 1998 issue of Nature Medicine describes data that show the development of NEW NEURONS in the hippocampus of adult humans!

Kelly A.: I am currently in an Anatomy course covering nerves. The instructor explained that he was told of a nerve in or near the ear that is known as the Roman Nerve - apparently applying pressure to it causes vomiting so was utilized by the ancient Romans during their gluttonous festival to allow for further ingestion. Do you have any additional info on this - perhaps the "real" name of the nerve and its location??

Answer (By Dr. Joel G., member of the Neuroscientist Network): According to our best resident anatomist, you're talking about the auricular branch of the vagus nerve (the tenth cranial nerve). Most of the vagus nerve innervates visceral organs, providing reflexive control mechanisms, but this one branch innervates the eardrum. It likely sends signals to nucleus solitarius -- which gets other vagus nerve input -- and which plays some role in regulating gut reflexes. This anatomist had heard that all it required was a tickling of the eardrum with a feather (but neither of us have tried it!) Just why this little branch of the vagus nerve goes to the eardrum is a hard question to answer.

Russell A.: If you took all the blood vessels of an average adult and laid them out how long a line would they form?

Answer: This is not exactly a neuroscience question, but it is interesting. According to The Franklin Institute Page on the Heart, the total length of all the blood vessels of the average adult is: 100,000 miles long!! By the way, the average length of all the blood vessels in a child is 60,000 miles long.

Brian G.: I am doing a project on neurons and I would like to know how are neurons different from each other.

Answer: Many people assume that all neurons are alike, but this just is not true. There are many differences between neurons.

I will divide this differences into structural (anatomical) differences and functional (physiological) differences.

Structural Differences

1. The shape of neurons can be different. Neurons can be divided into several main types: multipolar, unipolar and bipolar types of neurons. This separation refers to how many processes (dendrites and axon) each neuron has...a multipolar neuron has many dendrites, a unipolar and bipolar neuron has few. These types of neurons are described in more detail on my page on cell types. Neurons have been classified even further by giving them names based on what they look like...for example, basket cells, granule cells, pyramidal neurons, etc.
2. The size of the cell body (soma) of each neuron can be different. The diameter of a cell body can be very small (less than 10 microns) or large (about 100 microns).
3. The number of synapses a neuron makes can be small or very large (more than 1,000).
4. The number of synapses a neuron receives can be small or large.
5. The diameter of the axon of neurons can be different.
6. The type of synapse a neuron makes and receives with another neuron can be different. Synapses can occur between axon terminals and dendrites, between axon terminals and cell bodies, etc.
7. Neurons can contain different types of neurotransmitters.
8. The axon of some neurons is insulated with myelin, the axon of other neurons is not.
9. Neurons can have different numbers and different types of receptors for different neurochemicals.
10. Different types of neurons will be found in different concentrations throughout the nervous system.

Functional Differences

1. The resting membrane potential of neurons may be different from one another (generally around -65 to -70 mV).
2. The threshold level necessary to fire an action potential may be different.
3. Different neurons may have a different response to the same neurotransmitter. For example, in one neuron, dopamine may cause excitation (an excitatory postsynaptic potential) while in a different neuron, dopamine may cause inhibition (a inhibitory postsynaptic potential). Remember, it is best to think of inhibition and excitation as a property of the receptor rather than a property of the neurotransmitter.
4. Different neurons may have different conduction velocities...in other words, an action potential will travel down the axon at different speeds. This speed is determined by the diameter of the axon and by myelin wrapped around the axon. Some neurons have myelin, some do not. Myelin speeds up conduction velocity.

This is only the start of a list of differences between neurons. I am sure you could think of many more differences.

Ilana: My friend was on a rope swing and she hit her head against a tree and on the way to the hospital her mom didn't want her to fall asleep. Why cant you let someone who has had a concussion fall asleep?

Answer (By Dr. Doug J. and Dr. Chris B. members of the Neuroscientist Network): The development of bleeding and swelling caused by the bleeding, either above or below the coverings of the brain (the meninges) are among the more serious complications that can arise following head injury. The swelling caused by blood is called a hematoma. The hematoma may result from the rupture or laceration of blood vessels above or below the meninges. Hematomas may increase intracranial pressure which is not well tolerated by the brain. If not relieved as soon as possible (typically by surgical drainage), serious problems may result due to the death of brain tissue.

Loss of consciousness is one of the clinical signs observed in response to the formation of these hematomas. The loss of consciousness occurs quickly as the size of the hematoma increases. If the person who experienced the trauma is awake, it is important to keep him or her awake to observe any changes in mental status. For example, do they stay alert and oriented to their surroundings, or do they lapse in and out of consciousness. Changes in mental status are very important in diagnosing this potentially life-threatening complication. If the person was sleeping after the traumatic event and a hematoma started to develop, it would not be possible to detect the changes in mental status which would occur as the hematoma increased in size.

Another reason for keeping the person awake after head trauma is that if they fall asleep the frequency and depth of breathing may decrease. As the frequency and depth of breathing decrease, the blood vessels supplying the brain and surrounding tissues dilate as part of a reflex and the pressure inside the skull increases. While this is not a problem in the normal situation, this increase in intracranial pressure superimposed on the increased pressure caused by the hematoma may produce even more damage to the brain. Hyperventilation of the patient is one method used to limit the increase in intracranial pressure and the amount of damage caused by these hematomas before they are surgically drained.

When people have mild concussions that do not require hospital admission the usual instruction to their family is to wake them at night every few hours to make sure that they can still be aroused and thereby confirm that they are not deteriorating. There is something known as a "lucid Window" in which people initially look fine after a closed head injury but slow intracranial bleeding results in a gradual increase in intracranial pressure, decreased brain blood flow, severe neuronal injury and potentially death. Waking the person intermittantly is an attempt to catch this process before it progresses to the point of permanent injury and/or death.

Lisa.: I'm doing a project for a class that I have and I was wondering if it would be possible for you to share with me the average and starting salary of a psychobiologist or of a related field. Thanks!

Answer: Unfortunately, the starting salary for a psychobiologist is going to vary quite a bit depending on the type of position being considered. Immediately after receiving a Ph.D., many psychobiologists and people in related neuroscience disciplines, go on to complete post-doctoral fellowships. These types of jobs often do not pay very well. Salary can range from the low $20,000s to the mid $30,000s.

Some Ph.D.s may find faculty positions. These types of jobs may be teaching positions or research positions or a combination of teaching and research. Faculty positions usually start anywhere from $30,000 to $45,000. However, depending on the "deal" that a person can negotiate, it is possible to start at a salary a bit higher. If the job involves research, it is not uncommon for the Ph.D. to negotiate start-up funds to help set up the laboratory. These start-up funds can range from $10,000 up to $100,000.

Another place a new neuroscientist may find employment is in private industry. Starting salaries in industry are generally higher than those at universities. One reason that starting salaries vary so much is that different universities in different states have different salary scales. Also, the cost of living in different states may influence the amount of money a department may offer a new scientist. The Scientist (September 17, 2001) published the high and low salaries for LIFE SCIENTISTS at various stages of their career:

Liza A.: I'm trying to figure out what I want to major in, and I'm pretty certain that I want to study the brain. I understand that UCLA has a neuroscience major, but I've heard that it's better to receive a good general foundation in biology first and THEN perhaps delve into the study of the brain further in graduate school. What is your opinion on this issue?

Answer: There are several different routes that you can take on your way to become a neuroscientist. Neuroscientists come from many different backgrounds. I have some colleagues who did not go into neuroscience until after they received their Ph.D. in other disciplines. Others get their Ph.D. in neuroscience (or a related discipline) after receiving an M.D. degree.

You are right when you say a firm background in biology is important. However, I think this is important not only for the basic information that you receive, but also to make sure that it is the biological sciences that interest you.

Personally, I did not decide to go into brain research until I was a senior in college. I did not take my first biology or psychology class until I was a junior at UCLA. You see, up until this point, I wanted to be a marine biologist! The most important turning point in my studies was my experiences working in a laboratory studying the brain mechanisms of pain and analgesia. This experience was in the laboratory of Dr. John Liebeskind (who passed away this last Fall).

While in Dr. Liebeskind's laboratory, I learned what it is like to collect data, perform experiments, and write up papers. I was able to co-author a few papers and abstracts and even wrote a small grant application. I STRONGLY encourage you to volunteer (or get a work study position) in a laboratory to see if research is really what you want to do.

UCLA has a huge community of neuroscientists spread out over several departments. For more information and possibly for leads into a laboratory, try:

• UCLA School of Medicine

Toni G.: I read the Stroop effect page with the unlabelled illustration of the brain. Neither the text nor illustration indicated what the anterior cingulate was. Was it the red dot? Or the green area on the brainstem? I don't happen to have an anatomy or psychology text handy, or I'd look it up.

Answer: I see your problem. You followed the link on my Stroop effect page to the "Jay's Brain" page on the the Stroop effect. The picture of the brain you are having trouble with is on his page, but I can explain it to you. By the way, your questions are quite good...the text and/or picture SHOULD have been labelled by the authors of this page - you are quite right.

The RED spot on the picture points to the anterior cingulate gyrus (also called anterior cingulate cortex). The GREEN spot located near the brainstem is actually in the 4th ventricle for some reason....I have no idea why!! I have a similar picture on my site that labels the cingulate gyrus (the anterior cingulate gyrus is just the "anterior" or front part of the gyrus). This picture can be found at: http://faculty.washington.edu/chudler/sagittal.html

B. Aus.: I am very interested in your suggestions for an 8th grade science fair project. Any ideas or suggestions would be greatly appreciated. I am especially interested in brain topics.

Answer: I think a science fair project related to the nervous system would be a great idea. Last year I visited a science fair and I did NOT see any projects related to the brain.

I would suggest that you start by looking over the experiments and activities on my page: http://faculty.washington.edu/chudler/experi.html

Many of these experiments are demonstrations rather than science fair projects, but with a little thinking on your part, you could turn one of these ideas into a project. Look over the experiments on this page and you should find something that interests you.

Several people: I have heard that we use only 10% of our brain. Is this true?

Answer: I am asked this question many times. So many times in fact, that I have created a separate page called:

Shannon R.: I am doing an essay on how the memory of a human changes as they grow older, but am not quite sure were to start. Is there any information that proves that your memory improves or gets worse as you grow older? I was also wondering which part of the brain controls your memory. Are there any other websites that may help me?

Answer: As with many questions about the brain, there are no simple answers. As people get older, there are definite changes in behavior including changes in sleep habits, movement patterns and mental function. There is a great amount of variation between people of the effects of age on mental function. It is apparent that many intellectual functions (including memory) do change in people, but that this change does not necessarily decrease their quality of life.

Data show that changes in the brain later in life may include:

1. Reduced brain weight
2. Reduced level of protein in the brain
3. Reduced number of neurons in the brain (especially in cerebral cortex)
4. Reduced levels of enzymes that produce the neurotransmitters dopamine and norephinephrine.
5. Reduced number of receptors for dopamine, norepinephrine and acetylcholine.

However, as I said, there is a wide range in changes that occur. NOT all older people have memory problems. On the other hand, as people get older, there is more and more "chance" of neurological disorders that include memory problems. For example, Alzheimer's disease is rarely seen in young people.

With regard to your question about where memory is located, this is also a difficult question. There seem to be several areas of the brain that play a role in memory including the cerebral cortex and hippocampus and other subcortical areas. To read more about memory, here are some good articles that you can find on the Internet:

1. http://www.epub.org.br/cm/n01/memo/memory.htm

Also, if you want to find out some more about Alzheimer's disease, go to my Neurological Disorders page.

What is the hardest tissue in the human body? What are 3 suggestions for good brain health?

Answer: Sounds like a homework question. The answers to your questions are on two of my web pages.

Go to: The Tooth and Brain Fitness

Darren W.: Could you compare and contrast the Brain and the reflex nervous system, but the only problem is that i need it for tomorrow please help me!!

Answer: Sounds like another homework question. I think the best way to help you is to tell you about a few places on the WWW were you can get your own answer. Try:

1. Neuroscience for Kids Page on Reflexes

I was wondering if you could tell me when do our brains stop developing and connecting neurologically? Are we still able to improve brain power later in life? When does the window of opportunity for math close and can we continue to develop math/logical thinking?

Answer (By Dr. Jim C., member of the Neuroscientist Network): This is a somewhat difficult question to answer simply, because we need to do much more research to answer these questions more precisely. Different parts of our brains develop at different rates, some starting early before we are born and other regions starting after we are born. Also, different aspects of the development of our brain end at different times. If we look at the development of connections between nerve cells (called synapses), then one of the latest regions of our brains to stop forming synapses is the prefrontal cortex, the outer region of the brain directly behing your forehead. Here the process of synapse formation goes on into mid-teen years. But it may surprise you that more synapses does not always mean a better functioning brain. In many brain regions, an overabundance of synapses are usually formed during the first few years of life before a "pruning or cutting back" of synapses occurs to reach a relatively stable number.

If we look at the development of the insulation that helps nerve fibers conduct information faster between nerve cells (called myelin), then there are other regions of the brain that are thought not to be completely myelinated until the mid-20's!.

There is no doubt that we can continue to improve our brain power later in life. Part of the basis for learning and memory processes in the brain are considered to be represented by changes in the structure as well as function of the nerve cells involved in the activity. These structural changes are due to the forming and reforming of connections between nerve cells as indicated by changes in the structure of individual nerve cells: their sending parts (axons) and their receiving parts (dendrites). Nearly all mental abilities, including math and logical reasoning can be maintained, perhaps not as quickly for someone in their 70's or 80's, but just as researchers are finding that physical activities help the body stay healthy, mental activities also have great benefit for keeping the brain healthy.

In the not-so-distant future, I suspect that newer techniques of brain imaging that are being used will help us to better understand the structural and biochemical changes that underly the formation of memories and learning as we develop our mental capacities through school years and adulthood.

From Fernando P.: I'm a Psychology teacher in the last level of a secondary school. The next year students will be studying Medicine, Biology or Psychology. Or they'll stop studying. Next month I'll begin the subject about the Nervous System. What do you think it's really important to teach them about this subject, more important than all the fastidious classifications and scientific names? How to speak them about the dynamics of the Nervous System and the Brain? Can you give me any sugestions? Thank you and congratulations for your work. I deeply appreciate it.

Answer: I think that every instructor will have a different answer to your question. However, I will give you my own suggestions about how to approach these students.

It is my belief that an introductory class in neuroscience (or psychobiology or physiological psychology) should be approached by a teacher in much the same way that a fisherman prepares to go fishing. The fisherman is the teacher and the fish are the students.

A fisherman must have the correct tools: a fishing rod, hooks, line and bait. A teacher must have the correct tools: the basic knowledge of the subject matter and the methods to relay this knowledge to the students. I consider the "bait" that the teacher uses to be critical...the teacher must use the correct bait to maintain the interest of the student. The goal of the fisherman and the teacher of an introductory class is similar. The fisherman wants to hook the fish and reel it in. The teacher of the introductory neuroscience class should want to "hook the students" - to make the students want more; to make the students want to take another class that explores the subject matter in more detail. Whenever a lesson can be applied to the students' everyday experience or can be reinforced with "hands-on" demonstrations or activities, the bait is made even more attractive.

In the introductory class, it is impossible to cover the all aspects of the nervous system. I share your view that there are many names, pathways and other vocabulary that can get students distracted. However, I believe that learning of some new vocabulary is essential before you can engage students in meaningful discussion of the nervous system. The basic planes of sections and directions should be discussed immediately. This subject can be a bit dry and boring, but it can be made more interesting by demonstrations.

I would then go on to the very basics of the nervous system: the neuron, the action potential and the synapse. Again, using many demonstrations and activities to illustrate concepts. It is also necessary for you to lay out the framework of the nervous system by introducing the names of various structures of the nervous system.

Following the synapse, you might want to discuss neurochemistry, drug effects and altered states of consciousness. This may be especially relevant to many of your students who may be thinking of experimenting with drugs.

The senses can be a favorite area of study for many students. Students can use themselves as test subjects to investigate touch, taste, smell, hearing and vision. The senses offer you many possibilities for in-class experiments. My favorite is the blind spot test - when an image disappears into students' blind spots, the expression on their faces is priceless.

Other favorites of many students are the higher cognitive functions: language, thought, memory. Still other students find sleep and emotion fascinating - and they are! Many students may have relatives who have neurological diseases - this is a good chance to relate what is known about such disorders with a student's personal experience. It depends on how much time you have to teach. It is probably not possible to cover every topic. However, for each different topic, use as many demonstrations and experiments that you can.

My suggestion to you is to be like a fisherman. Use the best bait that you have - with skill, practice and a little luck you will hook many fish.

From Dave M.: Many students are making college selection choices now and few know what the professional life of a scientist is like. One question you may help my students with - Can you suggest ways that students might identify colleges or universities that will prepare them well for a profession in neuroscience, or science in general?

Should students be involved in research? while in high school? as an undergraduate in college?

What are the benefits / problems with doing this?

How might one arrange to do research in a lab similar to yours?

Certainly if the opportunity to become involved in research while in high school is there, I would encourage students to participate. As undergraduates at the university, students will find many more opportunities to get into the laboratory. Often there are advertisements posted around the university for lab assistants and many departments keep lists of lab jobs.

The skills necessary to perform neuroscience research are varied. Some skills are very technical requiring advanced training. However, many opportunities for undergraduates exist in laboratories performing behavioral experiments. As an undergraduate (junior and senior years) at UCLA, I worked in the laboratory of Dr. John Liesbeskind and was able to co-author 2 papers published in scientific journals. It wasn't until this time that I decided to pursue a career in Neuroscience.

From John M.: I'm interested in the "holographic" theory of memory and how the brain/neurons store, recall and can be re-trained to respond in new ways with practice. How does desire, purpose, emotions, and interactions with people (the instructor) make learning more or less successful? What gets people "ready" to learn?

1. When an animal is stressed or aroused, chemicals (hormones) in the body are released. If these "stress" hormones are given to an animal immediately after training, then the animal will remember the training better than if the hormones were not given.

2. Injection of drugs that affect a variety of neurochemical systems can influence memory.

3. Both Drs. LeDoux and McGaugh have hypothesized that a brain structure called the amygdala has a role in the effects that emotion has on memory: injection of drugs into the amygdala or destruction of the amygdala can influence "emotional memory."

4. Dr. McGaugh has performed fascinating experiments with human subjects comparing the memories of subjects shown emotional scenes with the memories of subjects shown unemotional scenes. These experiments were highlighted in a PBS special called Pieces of Mind and I would highly recommend visiting this site for more information.

1. Would an "emotionally-charged" training session result in enhanced learning and memory of the material you present?
2. Would a stressful training session help (or hurt) learning and memory?
3. What is the role of attention in memory and learning and how can you make use of this in training?

Perhaps we will soon be able to answer some of these questions by applying basic science research to real life situations.

From Carolyn P.: Dr. Chudler, can you describe the type of research you are conducting in your laboratory?

Answer: I currently have 3 research interests:

1. The mechanisms by which the basal ganglia (the caudate nucleus, putamen, globus pallidus) process somatosensory, auditory and visual information. An understanding of how the basal ganglia process sensory information may shed light on how the nervous system responds to environmental cues and how organisms make use of these cues to make appropriate behavioral responses. Moreover, this line of research may lead to data concerning the etiology of Parkinson's Disease, and provide information leading to potential treatments for this debilitating disorder. (for more information on conditions such as Parkinson's disease, see Neurological Disorders.

2. The role of the cerebral cortex in pain and nociception. The role of the cerebral in pain is poorly understood. The neurobiology of pain is very difficult to study because it is a very complex behavior. Pain is "multidimensional":
   • Pain has a sensory component - where is the pain, how much pain, etc.
   • Pain has a motivational/affective component - it stirs emotions and increases drive to reduce pain.
   • Pain has a cognitive component - you learn from pain and it draws your attention. The goal of this research is to devise treatment for people with chronic and acute pain. For more about pain, see the International Association for the Study of Pain home page.

3. My last research interest is in the response of the nervous system to peripheral nerve injury. I hope that this line of research will lead to therapies and treatments for patients who have sustained damage to various nerves.

From Carol M.: A report earlier this year (1997) suggests that ibuprophen, a common anti-inflammatory drug, reduces one's risk of developing Alzheimer's disease. Any comments on this study?

Answer: The recent paper concerning the role of anti-inflammatory drugs to reduce the risk of Alzheimer's Disease (AD) suggests a new treatment strategy to control this devastating degenerating brain disorder. At this time, the cause and cure for AD are unknown.

For those of you with access to a medical school library, this paper can be found in the journal called Neurology, volume 48, pages 626-632, 1997.

This study was based on the hypothesis that inflammatory processes in the brain have a role in the generation of AD. This is NOT a new hypothesis - rather, there are several prior papers that advance this theory...for example:

1. Aisen-P-S., Inflammation and Alzheimer disease. Mol-Chem-Neuropathol. 1996 May-Aug. 28(1-3). P 83-8.
2. Thal-L-J.,Potential prevention strategies for Alzheimer disease. Alzheimer-Dis-Assoc-Disord. 1996 Fall. 10 Suppl 1. P 6-8.
3. McGeer-P-L. McGeer-E-G.The inflammatory response system of brain: implications for therapy of Alzheimer and other neurodegenerative diseases. Brain-Res-Brain-Res-Rev. 1995 Sep. 21(2). P 195-218.
4. McGeer-P-L. McGeer-E-G. Anti-inflammatory drugs in the fight against Alzheimer's disease. Ann-N-Y-Acad-Sci. 1996 Jan 17. 777. P 213-20.
5. Wong-P-T. McGeer-P-L. McGeer-E-G. Decreased prostaglandin synthesis in postmortem cerebral cortex from patients with Alzheimer's disease. Neurochem-Int. 1992 Sep. 21(2). P 197-202.

However, this new study is the first to look at such a large population of subjects and to examine them over a long period of time. Briefly, these researchers found that in a long-term study that people who take non-steroidal anti-inflammatory drugs like ibuprofen appear to have a less risk for developing AD.

This is an exciting finding because it provides data to confirm the hypothesis regarding a role of inflammation in the generation of AD and suggests that drugs to target the inflammatory process may reduce the symptoms of AD and prevent the development of AD.

These results are still preliminary and caution must be used in the interpretation of the results. The link between inflammation and AD still needs further research. Moreover, these researchers found that aspirin, also an anti-inflammatory drug, did not reduce the risk of AD. Also, the experiment design of these study was one of correlation. The most important thing that I remember from my statistics classes was that "correlation does not mean causation." In other words, just because one thing correlates with another does not mean that one thing CAUSES the other. I hope that clinical and experimental testing will resolve this issue.

The possible side effects of anti-inflammatory drugs must also be considered. These include altered kidney function and peptic ulcers. Moreover, there may be unwanted drug interactions between anti-inflammatory drugs and AD drugs that produce side effects.

Regardless of these concerns, this recent paper gives hope that new effective treatments and even a possible cure for AD are just around the corner.

For more information about Alzheimer's Disease, see the Neurological Disorders Page.

From Bill H.: I am a sophomore in High School I am interested in becoming a biologist and have a few questions. I am particularly interested in genetics. What would be some of the best colleges for me to attend. Do you know if the University of Nebraska has a good program in biology?

I will complete science courses in biology, chemistry and physics before I graduate. I will also complete math courses in geometry, algebra and introductory calculus. Are there any other courses that I should try to take to prepare myself to major in biology in college.

There are so many decisions that go into selecting a college that I will not make a specific recommendation. This is a decision that is best decided by you with help from your parents and perhaps your teachers. However, let me point out that for further information about the University of Nebraska Department of Biology, see:

1. University of Nebraska at Omaha Dept. of Biology

From Renita C.: A few years ago, I ran across an article in Harper's about an anatomist that had done some holographic work on the brains of salamanders. I was wondering if you'd heard of this man's work? It has to be almost twenty years old. I've forgotten his name, I believe it was Paul something. He is or was located in Bloomington Indiana, affiliated with the university there. I spoke with his wife, Jane. (yes, I actually tracked down a celebrity), she'd told me she'd assisted her husband with his work at that time. I didn't get to speak with the doctor himself and was wondering if there were follow up studies with his work. It dealt with memory and the restoration of function to parts of the brain that had been destroyed due to injury. Have you heard anything?

From Renita C.: My questions have to do with nerve agents. I work with quite a few chemicals and recently came in contact with something that might have had a temporary effect on my parasympathetic nervous system. I was wondering if you could point me to some other resources that could help with antidotal treatment based on symptom alone, when one is unaware of the chemical with which one has come in contact. Like if something is slowing the heartbeat it could be hormonally stimulated, or it could be a toxin. Well this "blixit" could be the universal antidote in that situation. Is there any reference aside from the good old pharmacology textbooks and warning labels MSDS etc.

Answer: Of course the first thing to do if you are having health problems is to see a physician. The physician may be able to refer you to a toxicologist or environmental health specialist who can be of more assistance.

As far as finding out more about toxins, neurotoxins, and the autonomic nervous system there are several good sources:

1. Neurotoxins - this is a page that I have developed for the Neuroscience for Kids - this page describes many neurotoxins. I also have created a brief discussion of the autonomic nervous system.
2. ToxFAQs: Hazardous Substance Fact Sheets

From Kim E.: You know the old acronym for remembering the cranial nerves, about "on old Olympus towering tops a Finn and German viewed some hops." Well, I was wondering if you had another acronym?

Answer: You have listed the most well known mnemonic device for the 12 cranial nerves. This type of mnemonic is called an acrostic. I have updated this mnemonic because the eighth cranial nerve is now better known as the vestibulocochlear nerve rather than the auditory nerve. Instead I purpose the follow mnemonic: "On old Olympus towering top a famous vocal German viewed some hops." There is one other well known mnemonic for these nerves, however, it is somewhat "X-rated"...the first 5 words are Oh, Oh, Oh, to, touch,...I will not repeat the complete mnemonic here...you will have to ask someone else.

Another mnemonic for the cranial nerves concerns whether they are only sensory, only motor or both sensory and motor. The acrostic for this is: "Some Say Marry Money, But My Brother Says Big Business Matters More." The first letter of each word signifies whether the particular cranial nerve is sensory only (S); motor (M); or both sensory and motor (B). So, the "S" in the word "Some" means that the first cranial nerve (the olfactory nerve) is sensory only; the "S" in the word "Say" means that the second cranial nerve (the optic nerve) is sensory only...etc.

One more mnemonic for the first two cranial nerves only is "You have one nose and two eyes"...therefore, cranial nerve I is the olfactory and cranial nerve II is the optic. Of course, this only helps for the first two nerves.

See "Neuroscience for Kids" on the cranial nerves for more information.

From Barbara W.: I teach fourth grade and plan to do a unit in the Fall on the brain. Would it be okay if my students wrote questions to you here? Also, I teach college education courses, one on constructivism. I would appreciate receiving some information on what happens in the brain when we pull together previous experiences and new information to create new concepts. Thanks for your help.

Answer: Glad to hear that you will be doing a unit on the brain with your fourth grade class. I would prefer that your students address questions directly to me at my email address: chudler@u.washington.edu

Your question about using experiences (memories?) and new information to create new ideas is intriguing. Unfortunately, scientists are only beginning to understand some of the basic mechanisms involved with learning and memory. I hope that I will have a better answer for you when more is known about the neural mechanisms of memory and learning.

From Sachin A.: I'm currently getting a B.S. in neuroscience and philosophy at Texas Christian U. I definitely know that I want to have a career in academic medicine involving neuroscience research with non-human primates, plus teaching neuroscience to med/grad students. This means getting both an MD(without residency) and a Ph.D. Can you tell me about the MSTP program at Univ. of Wash, and of any current neuroscience research involving non-human primates at U of Wash that you may know of?

There are several departments on campus that use non-human primates neuroscience research. The UW is home of one of the Regional Primate Research Centers. (Sorry, no home page for them that I know.) Many of the investigators who belong the Regional Primate Research Center also have affiliations with other departments such as:

1. Department of Biological Structure
2. Neurobiology and Behavior
3. Department of Psychology

I would suggest you browse these department pages to see the current research of the faculty.

Good luck with your studies.

From Gurumurthy. S.: I am currently doing my postgraduation in Computer Science and Eng. at Indian Institute of Tech. I did my Bachelor of Engineering in Computer Science. I am very much interested in Neural Networks and in modeling the brain using computers. I have not got much exposure to Neuroscience, which I think would help me very much. I intend to do a Ph.D. in Neuroscience. Could you please tell me where I could do it and what must I do for it?

From Rachael F.: I will be teaching a neuroscience course to 12^th grade students this spring. I want them to follow NeuroLab going into space in March 1998. I contacted what I thought was the good link at NASA but don't think this is going to help. Are there any experiments that would be possible for us to conduct while Neurolab is in space?

Answer: There are a few Web sites for the 1998 Space Shuttle "NeuroLab":

1. NeurOn

From Joseph F.: I am currently studying Neurosci at the undegrad level. I am perplexed at what I am going to do with my education. I assume I will obtain an M.D./Ph.D. in Neurosci. I am interested in the development of virtual tech. I want to also have the capability of a neurosurgeon, for its obvious role in the interfacing of VR with people. What will I call myself? What will I be? How do I study something we haven't developed? How do I develop it and what do I study to do so.

Answer: Some of the most innovative work in the life sciences is being done by utilizing new technologies in medicine. There are even some groups that are pursuing the use of virtual reality within the realm of neurosurgery.

An M.D./Ph.D. program is probably the best way to go to get into this field. It would also be best to ask people at the medical schools you are interested in about the type of training you will receive. You may also want to consider bioengineering departments that have projects that focus on this type of work. You may be able to participate in an ongoing project while you are still in school.

From Amanda W.: I'm interested in pursuing a career in Neuroscience. What Universities do you feel offer a superior degree program in the field? I also wondered if you knew of any research programs in Houston that might be in need of be willing to take on an inexperienced undergraduate student?

Answer: According to a US News and World Report list, the following graduate schools were ranked best for neuroscience:

1. Harvard University (MA)
2. Stanford University (CA)
3. Johns Hopkins University (MD)
4. University of California San Francisco
5. Duke University (NC)
5. Massachusetts Institute of Technology
5. Washington University (MO)
5. Yale University (CT)
9. Columbia University (NY)
10. University of California San Diego

Personally, I would add to this list: University of Washington; University of Minnesota; Washington University; University of California (Los Angeles and Berkeley Campuses).

Concerning research programs in the Houston area - I would suggest that you look over the programs offered at:

1. Baylor College of Medicine (Division of Neuroscience)

These two WWW pages contain information about the research going on at these universities and a short description of the faculty. If you see a program that interests you, then contact the people involved in the lab. You never know if they will need someone to help out.

From Allan N.: Can a person be very smart with a little brain? What is the largest human brain known?

Answer: Well, it depends on how little. An average brain weighs about 3 pounds (1,300-1,400 gm) The smallest known human brain in a normal person is from a 46 year old man - this brain weighed only 1 pound 8 oz. (680 grams). The largest brain known is from a 30 yr. old man - this brain weighed 5 pound, 1.1 oz (2,300 gm). These statistics come from the Guinness Book of World Records. However, there is no relationship between the size of a person's brain and how smart they are. See the page on brain size for more information on this topic.

From Marc M.: In our 6th grade science class we are studying electricity. Don't natural electric impulses send the messages given off by the brain to the rest of the body?

Answer: Yes, you are right. The nervous system works using an "electrochemical" process. Read more about this at my page about action potentials at:

http://faculty.washington.edu/chudler/ap.html

and about the differences between the brain and a computer at:

http://faculty.washington.edu/chudler/bvc.html

For other neuroscience question/answer pages, see:

1. Ask Dr. Universe
2. Mad Scientist's Network - Neuroscience