Drugs and the Brain
Introducing the Human Brain
The human brain is the most complex organ in the body. This three-pound mass of gray and white matter sits at the
center of all human activity - you need it to drive a car, to enjoy a meal, to breathe, to create an artistic masterpiece, and
to enjoy everyday activities. In brief, the brain regulates your basic body functions; enables you to interpret and respond
to everything you experience; and shapes your thoughts, emotions, and behavior.
The brain is made up of many parts that all work together as a team. Different parts of the brain are responsible for
coordinating and performing specific functions. Drugs can alter important brain areas that are necessary for life-sustaining
functions and can drive the compulsive drug abuse that marks addiction. Brain areas affected by drug abuse -
The brain stem
controls basic functions critical to life, such as heart
rate, breathing, and sleeping.
The limbic system
contains the brain's reward circuit - it links together a
number of brain structures that control and regulate our ability to feel pleasure.
Feeling pleasure motivates us to repeat behaviors such as eating - actions that
are critical to our existence. The limbic system is activated when we perform
these activities - and also by drugs of abuse. In addition, the limbic system is
responsible for our perception of other emotions, both positive and negative,
which explains the mood-altering properties of many drugs.
The cerebral cortex
is divided into areas that control specific functions. Different areas process information from
our senses, enabling us to see, feel, hear, and taste. The front part of the cortex, the frontal cortex or forebrain, is the
thinking center of the brain; it powers our ability to think, plan, solve problems, and make decisions.
How does the brain communicate?
The brain is a communications center consisting of billions of neurons, or nerve cells. Networks of neurons pass
messages back and forth to different structures within the brain, the spinal column, and the peripheral nervous system.
These nerve networks coordinate and regulate everything we feel, think, and do.