The brain is a 3 pound mass of interwoven nerve cells and
one of the most magnificent and mysterious wonders of creation. It is the
supervisory center of the nervous system serving as the site of thought, emotions,
memory, and self-awareness. By means of electrochemical impulses, the
brain controls our conscious, voluntary behavior and the autonomic nervous
system through its feedback circuitry regulating the physiological functions of
the body. The blood-brain barrier provides protection against toxins, bacteria,
and other pathogens, but all psychoactive drugs are able to pass through.
The advent of eleven different brain measuring scans
allow neuroscientists to explore the structure and workings of the living
brain. There are a variety of ways to describe the different parts and
functions of the brain. In the interests of simplicity in understanding addiction,
we will use the terms "primitive" and "neo-cortex." The
primitive brain controls the autonomic system but also equips the experiencing
of our basic instinctive emotions such
as fear, hunger, anger, pleasure and lust. The neo-cortex processes information from the
primitive brain as well as conscious voluntary behavior, cognition, and memory. It
tries to make sense of the feelings and instinctive drives coming from the
primitive brain. Imagine someone craving a drink of water which originates in
the primitive brain. In response, the neo-cortex will organize a way to get it.
The primitive brain is located at the base of the skull
including the brain stem and is much smaller than the neo-cortex. One might
reason because of the major difference in size, the neo-cortex would be in
control. This is not the case. During stress we try to resist impulses to
resort to instinctive or primitive behavior often characterized by the
flight/fight syndrome. A balanced life requires healthy interaction between these two parts of the brain.
The role of the nucleus accumbens, generally described as
the pleasure / reward center, is our last consideration of the primitive brain
and is key to understanding the impact of alcohol and other drugs on the whole brain.
Although it has traditionally been studied for its role in drug addiction, it
plays an equal role in processing many other rewards such as food, sex,
gambling, and other compulsive behaviors which are now recognized as addictions. (See current definition of
addiction in Post #1)
Neurotransmitters are chemicals in the central nervous system
that transmit messages between nerve cells. Over a hundred of them help
regulate the body’s natural stimulants, painkillers, mood stabilizers, muscle
relaxants, arousal, sleep, aggression, and all other functions of the central nervous
system. Drugs increase or block the release of these naturally occurring
neurotransmitters.
Alcohol and other drugs create
sensations or effects that have a natural counterpart in the nervous
system. They trick and over stimulate
the release of the body’s natural chemicals, which then “flood” and "hijack" the
central nervous system. Drugs don’t get one intoxicated; they trigger
the release of a surplus of the body’s own chemicals at levels which are
intoxicating.
With this background, in my next post we
will begin to explore drugs of choice and what part of the brain they take
hostage.
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