JAMES L. MCGAUGH Understanding of the nature and functions of
neurotransmitter systems in the brain has increased enormously in recent
decades. Lack of knowledge required us, not too long ago, to use the
adjective "putative" when discussing transmitters. Such caution is no
longer essential (at least for a number of transmitters). Impressive
progress has been achieved in understanding the pharmacology,
biochemistry and anatomy of transmitter systems. There has, however,
been relatively less progress in understanding the functioning of brain
transmitters in regulating and mediating behavior. A simple and
certainly correct explanation for this is, of course, that understanding
of neurotransmitter functions requires prior detailed knowledge of basic
pharmacology, biochemistry and anatomy. Beyond that, it now seems likely
that progress in understanding the functions of brain neurotransmitters
will proceed only as we examine the interactions of neurotransmitter
systems in regulating behavioral functions. This premise is, of course,
suggested by the findings of studies of the chemical neuroanatomy of the
brain: Neurotransmitter systems are influenced by other neurotransmitter
systems and, in tum, influence the same as well as other systems. No
system works alone. The chapters in this book explicitly examine the
interactions of neurotransmitter systems involved in the regulation of
cognitive processes. The facts and interpretations offered provide
compelling support for the premise that cognitive processes are
orchestrated by interactions among neurotransmitter systems. And, they
offer promise that understanding of such interactions will be of
critical importance in the develop- ment of treatments for brain
diseases affecting cognitive functioning.
