by Tom Ray

1. Why are there so many different neurotransmitter receptors in the brain?
   
2. What is the functional role of each, and how are they organized in the brain?
   
3. How are the activities of these transmitter systems and their interactions associated with mental states?

In short, what is the chemical architecture of the brain and the mind that emerges from it? The answers to these questions should ultimately provide a firmer basis for understanding mental illness and developing treatments.

The pharmacological approach to these questions is to develop compounds that bind selectively at receptors, and activate or block them, and use them as probes to receptor function. When the molecular mechanisms of action of a drug are known, they can be correlated with the behavioral effects in animals or the subjective reports of humans, to understand the mental correlates of their underlying biological effects. When used in this way, pharmacology is a means of exploring the chemical organization of the brain and mind.

Peter Kramer's book "Listening to Prozac" introduced the pharmacological approach to the general public. The title "Listening to Prozac" means that we learned something new about the nature of the human mind by observing the effects of prozac.

Prozac was developed to treat depression, but when it was prescribed to large numbers of people, it was discovered that it also changed personality (from timid to self-confident). Before this unplanned experiment, it was not known that such aspects of personality were under chemical influence. By listening to prozac, we learned something about the chemical organization of the human mind.

Although pharmacology is generally thought of as a branch of medicine that uses chemicals to treat illness, pharmacology can also be used as a method of probing living systems to understand how they are organized and how they function.