An outstanding characteristic of the nervous system is that neurons make
selective functional contacts. Each neuron behaves as if it recog- nizes
the neurons with which it associates and rejects associations with
others. The specific interneuronal relationships that result define the
innate neuronal circuits that determine the functioning of this system.
The purpose of this volume is to present some approaches to the problem
of neuronal recognition. The volume has been somewhat arbitrarily
divided into three sections. In the first section, the overrid- ing
theme is the degree of specificity of neuronal recognition. How specific
is specific? Is the specificity so precise that the neurites of one
neuron will only make synaptic contact with a unique target neuron? If
less precise, within what range? Are the rules for specification that
are operative in the embryo still operative at the same level of
precision when connections regenerate in the mature organism? Are they
still operative in dissociated tissue grown in culture? The second
section of this volume contains reviews of morphologi- cal studies of
synaptogenesis and biochemical studies of synaptic com- ponents. Can the
morphology of developing cellular contacts provide clues about
selectivity? Can the chemical components of synaptic junc- tions be
isolated and characterized? Do they include resolvable compo- nents that
mediate neuronal recognition? The third section contains studies seeking
to identify the existence of specific molecules that might mediate
cellular recognition. A major question here is whether molecules of this
type even exist.
