Neuroscience For Kids

Alcohol and the Brain

Alcohol may be the world's oldest known drug. Fermented grain, fruit juice and honey have been used to make alcohol (ethyl alcohol or ethanol) for thousands of years. The production of products containing alcohol has become big business in today's society and the consumption and abuse of alcohol has become a major public health problem. On this page, only the effects of alcohol on the brain and behavior will be discussed. For further information about other effects of alcohol, see the links at the bottom of this page.

Alcohol is a central nervous system depressant. Factors that influence how alcohol will affect a person include:

  • age
  • gender
  • physical condition
  • amount of food eaten
  • other drugs or medicines taken

The Path of Alcohol in the body

  1. Mouth: alcohol enters the body.
  2. Stomach: some alcohol gets into the bloodstream in the stomach, but most goes on to the small intestine.
  3. Small Intestine: alcohol enters the bloodstream through the walls of the small intestine.
  4. Heart: pumps alcohol throughout the body.
  5. Brain: alcohol reaches the brain.
  6. Liver: alcohol is oxidized by the liver at a rate of about 0.5 oz per hour.
  7. Alcohol is converted into water, carbon dioxide and energy.

Effects of Alcohol

In low doses, alcohol produces:

  • a relaxing effect
  • reduces tension
  • lowers inhibitions
  • impairs concentration
  • slows reflexes
  • impairs reaction time
  • reduces coordination

In medium doses, alcohol produces:

  • slur speech
  • cause drowsiness
  • alter emotions

In high doses, alcohol produces:

  • vomiting
  • breathing difficulties
  • unconsciousness
  • coma

Effects of Alcohol on the Nervous System

As mentioned above, alcohol is a central nervous system depressant. It acts at many sites, including the reticular formation, spinal cord, cerebellum and cerebral cortex, and on many neurotransmitter systems. Alcohol is a very small molecule and is soluble in "lipid" and water solutions. Because of these properties, alcohol gets into the bloodstream very easily and also crosses the blood brain barrier. Some of the neurochemical effects of alcohol are:

  • Increased turnover of norepinephrine and dopamine
  • Decreased transmission in acetylcholine systems
  • Increased transmission in GABA systems
  • Increased production of beta-endorphin in the hypothalamus

Chronic drinking can lead to dependence and addiction to alcohol and to additional neurological problems. Typical symptoms of withholding alcohol from someone who is addicted to it are shaking (tremors), sleep problems and nausea. More severe withdrawal symptoms include hallucinations and even seizures.

Chronic alcohol use can:

  • Damage the frontal lobes of the brain
  • Cause an overall reduction in brain size and increase in the size of the ventricles
  • Lead to alcoholism (addiction to alcohol) and result in tolerance to the effects of alcohol and variety of health problems
  • Cause a vitamin deficiency. Because the digestion system of alcoholics is unable to absorb vitamin B-1 (thiamine), a syndrome known as "Wernicke's Encephalopathy" may develop. This syndrome is characterized by impaired memory, confusion and lack of coordination. Further deficiencies of thiamine can lead to "Korsakoff's Syndrome." This disorder is characterized by amnesia, apathy and disorientation. Widespread disease of the brain is a feature of both Wernicke's and Korsakoff's Syndromes.

Drinking and Driving Don't Mix

The following tables are used with the permission of the Pennsylvania Liquor Control Board. They illustrate the effects of alcohol consumption on blood alcohol levels and driving skills. These data should be used only as a general reference for the effects of alcohol because body weight and other variables may influence the results. Also, some states define the limit of legal intoxication at a lower blood alcohol level (0.08%).

Calculating blood alcohol concentrations (Reference: Winek, C., in Forensic Sciences, edited by C.W. Wecht, Matthew Binder Press, New York, 1984):

Another consequence of alcohol use is Fetal Alcohol Syndrome (FAS). Inside the mother, a fetus is fed through the placenta. Because alcohol passes easily through the placenta, every time the mother drinks alcohol, the developing fetus gets a dose of alcohol. Alcohol disrupts normal brain development - THAT IS A FACT!!! Fetal exposure to alcohol can impair the development of the corpus callosum (the main connection between the right and left hemispheres of the brain), reduce the size of the basal ganglia and damage the cerebellum and cerebral cortex.

Compared to normal babies, babies born with FAS have:

  • smaller heads and brains
  • some degree of cognitive impairment
  • poor coordination
  • hyperactivity
  • abnormal facial features

Did you know?

  • Americans drink the equivalent of 500 million gallons of pure alcohol each year. (Statistic fromPrevention's Giant Book of Health Facts, 1991.)
  • Alcohol consumption by college students is linked to at least 1,400 student deaths and 500,000 unintentional injuries each year.>(Statistic from the National Institute on Alcohol Abuse and Addiction,Alcohol Alert, 58:1-4, 2002.)
  • The 18th Amendment to the US Constitution was passed in 1919 and was made effective in 1920. This started the period known as prohibition. The 18th Amendment declared that alcohol could not be manufactured, sold, imported, exported or transported in the United States. In 1933, the 21st Amendment to the Constitution was passed which repealed the 18th Amendment and made alcohol legal again

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Neuroscience For Kids

Bath Salts

"Bath salts" are a dangerous new class of synthetic drugs with no relation to the scented granules you may use to unwind in the tub. Other common street names for these drugs include "plant food," "vanilla sky," and "purple wave."

Similar toamphetaminesandcocaine, bath salts are stimulants, meaning that they improve mood and energy levels and make users feel more alert by increasing levels of theneurotransmitterdopamine in the brain. This increase in dopamine also means that bath salts can be addictive. Users commonly swallow, inhale, or inject the drug. The effects are felt after about 15 minutes, and users feel high for at least 4-6 hours.

The term bath salts doesn't refer to just one drug, but rather a group of chemically-related substances that are similar to the naturally-occurring stimulant cathinone, a substance derived from the khat plant. Unlike cathinone, however, bath salts aren't found in nature - they're concocted by amateur chemists.

Most often bath salts contain the chemicals mephedrone, methylone, or the tongue-twister 3,4-methylenedioxypyrovalerone (known simply as MDPV), but current estimates suggest there may be over 100 different chemicals being marketed as bath salts. That means that when you take bath salts, you don't really know what you're putting into your body, or how it's going to affect your brain.

Until recently, bath salts were legal, but only because they weren't included in current laws. But that changed when a recent spike in use caused the Drug Enforcement Agency (DEA) to take emergency action. Across the United States, poison control centers received just over 300 calls related to the drug in 2010, but more than 6,000 calls in 2011. In September of 2011, the DEA banned three of the common components of bath salts, and earlier this year a law was enacted that makes producing, selling, or possessing 28 of these substances illegal.

However, banning the drugs has been only partially effective because drug makers can avoid the law by making subtle changes to the composition of these drugs. Another trick used to avoid breaking the law is by labeling the drugs "not for human consumption."

Because bath salts are relatively new, not a lot is known about their effects. But what is known is troubling. Use of bath salts can produce life-threatening effects such as:

  • elevated heart rate (tachycardia) and blood pressure (hypertension)
  • increased body temperature (hyperthermia)
  • chest pain
  • delusions and hallucinations
  • severe agitation
  • paranoia
  • combative behavior
  • suicide
  • nausea and vomiting
  • dizziness

Nora Volkow, M.D., Director of theNational Institute on Drug Abuse, warned about the hazardous effects of bath salts last year. These drugs are particularly dangerous, she said, because their chemical composition and long-term effects are largely unknown.

/ Cocaine /

Coca Leaf / From the plant calledErythroxylon coca, cocaine is a local anesthetic and central nervous system stimulant. It can be taken by chewing on coca leaves, smoked, inhaled ("snorted") or injected. /
Coca Plant
History of Cocaine
Early Spanish explorers noticed how the native people of South America were able to fight off fatigue by chewing on coca leaves. A medical account of the coca plant was published in 1569. In 1860, Albert Neiman isolated cocaine from thecoca leafand described the anesthetic action of the drug when it was put on his tongue. Angelo Mariani, in the early 1880s produced a "medicinal" wine, called Vin Mariani, that contained 11% alcohol and 6.5 mg of cocaine in every ounce. The famous psychotherapist, Sigmund Freud, in 1884, recommended cocaine for a variety of illnesses and for alcohol and morphine addictions. Unfortunately, many of his patients went on to become addicted to cocaine! In 1886, John Pemberton developed Coca Cola, a drink that contained cocaine andcaffeine. Cocaine was REMOVED from Coca Cola in 1906 (but it still has the caffeine). The Harrison Narcotic Act in 1914 made cocaine illegal. Finally, in 1985,crack cocainewas introduced and rapidly became a major drug problem. /
Coca Wine

Crack
Effects of Cocaine on the Nervous System
A dose of between 25 to 150 mg of cocaine is taken when it is inhaled. Within a few seconds to a few minutes after it is taken, cocaine can cause:
  • a feeling of euphoria
  • excitement
  • reduced hunger
  • a feeling of strength
After this "high" which lasts about one hour, users of cocaine may "crash" into a period of depression. This crash causes cocaine users to seek more cocaine to get out of this depression and results in addiction. Withdrawal from cocaine can cause the addict to feel depressed, anxious, and paranoid. The addict may then go into a period of exhaustion and they may sleep for a very long time.
Various doses of cocaine can also produce neurological and behavioral problems like:
  • dizziness
  • headache
  • movement problems
  • anxiety
  • insomnia
  • depression
  • hallucinations
/
Cocaine

Emergency Room Visits due to Cocaine and Heroin

Image courtesy of theOffice of National Drug Control Policy / Deathcaused by too much cocaine (an overdose) is not uncommon. Cocaine can cause large increases in blood pressure that may result in bleeding within the brain. Constriction of brain blood vessels can also cause a stroke. An overdose of cocaine can cause breathing and heart problems that could result in death. This is what killed the University of Maryland basketball player, Len Bias, in 1986. Comedian John Belushi also died from a cocaine/heroin overdose in 1982.
Cocaine is highly "reinforcing": when it is given to animals, they will give it to themselves. In fact, if animals are given the choice, they will put up with electrical shocks and give up food and water if they can get cocaine.
Cocaine acts by blocking the reuptake of the neurotransmitters dopamine, norepinephrine and serotonin in the brain. Therefore, these neurotransmitters stay in the synaptic cleft for a longer time. Research has also shown that cocaine can also cause the release of dopamine from neurons in the brain.
Cocaine can also affect the peripheral nervous system. These effects include constriction of blood vessels, dilation of the pupil and irregular heart beat.
The Brain on Cocaine

These two images of the brain are positron emission tomography (PET) scans of a normal person (picture on the left) and of a person on cocaine (picture on the right). The PET scan shows brain function by seeing how the brain uses glucose, the energy source for neurons. In these scans, theredcolor shows high use of glucose,yellowshows medium use andblueshows the least use of glucose. Notice that many areas of the brain of the cocaine user do not use glucose as effectively as the brain of the normal person. This can be observed by the lower amounts of red in the right PET scan.
Image courtesy of theNational Institute on Drug Abuse; used with permission.

e:homeexploremdma (ecstasy)

Neuroscience For Kids

Ecstasy

The American Heritage Dictionary defines ecstasy as "intense joy or delight." Despite its peppy name, the illegal drug ecstasy can damage nerve cells in the brain. Ecstasy, also known as 3,4methylenedioxymethamphetamine or "MDMA" for short, is a stimulant related to the drugs mescaline andamphetamine.Other names for MDMA are "Adam," "XTC," "Doves" or just "E."

MDMA was first synthesized and patented in 1914 by the German drug company called Merck. Scientists thought that this drug could be used as an appetite suppressant. In the 1970s, MDMA was given to psychotherapy patients because it helped them open up and talk about their feelings. This practice was stopped in 1986 when animal studies showed that ecstasy caused brain damage.

Some users say they take ecstasy because it lowers their inhibitions and relaxes them. MDMA is also said to increase awareness and feelings of pleasure and to give people energy. However, some people report side effects after taking MDMA such as headaches, chills, eye twitching, jaw clenching, blurred vision and nausea. Some doses of MDMA can cause dehydration, hyperthermia and seizures. The effects of MDMA send some people to the emergency room (see graph on right). Unlike the drugLSD, MDMA in low doses does not cause people to hallucinate. Ecstasy gained national attention when it was the drug of choice at club parties, called "raves." In asurvey taken in 2005, 3.0% of 12th graders, 2.6% of 10th graders and 1.7% of 8th graders reported that they had used MDMA at least once within the year.

MDMA appears to have several effects on the brain. MDMA can:

  • cause the release of the neurotransmitter called serotonin.
  • block the reuptake of serotonin by the synaptic terminal that releases it.
  • deplete the amount of serotonin in the brain.

Data suggest that MDMA may be toxic to the brain. Dr. George Ricaurte, an associate professor of neurology at Johns Hopkins University, analyzed brain scans of people who had used ecstasy. The study included people who had used ecstasy an average of 200 times over five years. Although the behavior of these people appeared normal, brain scans showed that the drug had damaged their brains. In fact, those who used the drug more often had more brain damage than less frequent users. Moreover, memory tests of people who have taken ecstasy as compared to non-drug users have shown that the ecstasy users had lower scores.

Specifically, the drug damaged cells that release the neurotransmitter called serotonin. Using an imaging technique called positron emission tomography (PET), Ricaurte noted a 20-60% reduction in healthy serotonin cells in the drug users. Damage to these cells could affect a person's abilities to remember and to learn.

At this point, scientists do not know if this damage is permanent, or if those damaged cells will replace themselves. Also, it is not known if this loss of cells affects behavior or the ability to think. Ricaurte is conducting other studies to gauge ecstasy's effect on mood, memory, cognition, and behaviors such as eating and sleeping. In 2003,German researchersused PET scans to study the brains of current and past users of ecstasy. This research demonstrated that ecstasy users had lower levels of serotonin activity in several brain areas. However, ecstasy users who stopped using the drug 20 weeks before the scan showed some recovery in serotonin function.

Information from brain scans of people is valuable, but it is difficult to control the different variables when using human subjects. Perhaps some of the students didn't report their drug use accurately. Maybe they didn't remember how many times they had used ecstasy. To be able to control the variables more carefully in a study, Ricaurte looked for help from animal experiments. In an article published inThe Journal of Neuroscience(June 15, 1999), Ricaurte compared the data from monkeys who were given ecstasy dissolved in a liquid twice a day for four days to other monkeys who received the same liquid WITHOUT the ecstasy twice a day for four days. The study showed that the monkeys who were given ecstasy had damage to the serotonin-containing nerve cells. This damage was still visible seven years later!. Areas that were especially affected were the frontal lobe of the cerebral cortex, an area in the front part of the brain that is used in thinking, and the hippocampus, an area deep in the brain that helps with memory. Although damage was still observed seven years later, it was less severe than when it was observed two weeks after drug use. This suggests that some regrowth could have occurred, but that it is far from complete.