Expert: Amarnath.B - 2/28/2006

Question
hey Amarnath

what makes a person with no confidence, drink alcohol get buzzed and begin feeling fully confidence, do u know what part of the brain the alcohol numbs out, or what does happen to bring about this confidence

this is for school, thanks

joe

Answer
Dear Joe,

Acute and chronic alcohol consumption can have both subtle as well as dramatic effects on the brain and its functioning. The effects of alcohol on the brain can occur by both direct and indirect means. Thus, it is not really necessary that the alcohol actually reach the brain, though it does, for brain function to be modified.

Alcohol's direct action on the brain is as a depressant. It generally decreases the activity of the nervous system. One could ask how it could be a depressant if after one or two drinks a person tends to talk more and become more active. The answer is that alcohol can cause disinhibition, i.e. inhibits cells and circuits in the brain which themselves are normally inhibitory.

To understand how alcohol can effect the brain one needs to know how the brain works. The brain is composed of different regions or areas as shown. Different regions of the brain are primarily involved in different activities. For examples, the cerebellum is involved in coordination of bodily movements; the frontal cortex is primarily involved in cognitive processes; the occipital lobe contains the visual cortex; and a portion of the temporal lobe of the cortex is involved in audition. The list goes on and on.

In order for the parts to communicate with one another to achieve coordination and allow our bodies to function in a reasonable manner, the parts are connected by nerve cells also called neurons. It is estimated that there are 100 billion nerve cells in the brain so one can visualize the complexity of the inner workings of the brain.

Nerve cells communicate with one another via electrical and chemical signals. In essence signals coming from outside the body like light, sound, smells, tastes, and pressure are converted (transduced) into chemical and electrical signals which pass from one part of the body to another and from one part of the brain to another.

Once inside the brain electrical signals and chemical signals continue to be generated to allow communication between the brain parts and regions. Electrical signals generated in one neuron causes of the release of chemicals called neurotransmitters (NTs) from that neuron. These NTs in turn are then available to act at other neurons in close proximity to the first to either excite or inhibit that neuron's activity.

There are a substantial number of NTs in the brain. Four of the most important NTs with respect to alcohol are glutamate, gamma aminobutyric acid (GABA), dopamine (DA), and serotonin. Glutamate is the major excitatory NT in the brain. Ethyl alcohol acts to inhibit a subset (N- methy-D-aspartate, NMDA) of glutamate receptors, thus diminishing the excitatory actions of glutamate. GABA is the major inhibitory NT in the brain. Alcohol acts primarily at the GABAa receptor to facilitate its action, thus in essence creating enhanced inhibition. Changes in the number of both NMDA and GABA receptors and ability of these receptors to bind their NTs appear to be involved in the development of tolerance to and dependence on alcohol. The third important NT in alcohol action, Dopamine, is involved in reward processes and thus seems to be responsible for the rewarding aspects of alcohol consumption. Other things that people find rewarding such as food, sex, and other drugs of abuse also act to release DA in the brain. Serotonin also appears to play a role in reward processes and therefore seems to be important in alcohol use and abuse. In addition, serotonin is a prominent player in mood states, compulsive disorders, aggression, and effects of other drugs of abuse like methamphetamine and LSD.

Current research supports the idea that initial exposure to alcohol activates the reward pathway releasing DA in the Nucleus accumbens, which in turn sends messages to the cortex to be coded as experiences and perhaps as memories. Once coded, these experiences can influence, i.e. promote, subsequent behavior such further alcohol intake. Since these "memories" of drinking are linked to the environment in which the drinking took place, it is not surprising that the environmental cues can be important in guiding subsequent drinking behavior.

Alcohol's action on the brain produces of a number of behavioral effects. These effects are dependent upon the 1. amount of alcohol taken in, 2. the time period over which the alcohol is drunk, 3. whether other drugs are being taken at the same time, 4. the previous drinking history of the individual, 5. the physical state of the person doing the drinking, 6. the genetic background of the individual( i.e. ethnicity, gender), 7. the mood and psychological makeup of the individual and 8. the environment when alcohol is taken.

I hope this answers your question.  Please do not hesitate to contact me if there are any more queries.

God bless,

Amarnath