ABSTRACT
From what I have written in previous chapters, most readers should have an inkling that a medication does not necessarily have to reach the brain itself in order to change the way the brain handles information (“reconfiguring a neural network” or “switching a nerve circuit”). Many, if not most, nerves may be acted upon outside the brain (“peripherally”) in order to affect brain (“central”) function. The nerve impulses from the peripheral to the central nervous system are termed “afferent,” as opposed to “efferent.” Efferent, in this context means from the brain (and spinal cord, also part of the central nervous system [CNS]) to the peripheral nervous system (PNS).
