W. Precht - Böcker

The original intent of the series Studies of Brain Function was to offer a forum to neurobiologists working in different fields to present some of their recent results in a more extensive way. What may have been or might be published in several papers appearing in different journals will thus be com­ bined in one monograph, thus making the data more easily available to a wider scientific community. It is also believed that such an attempt will provide a more comprehensive insight into one particular field of neurobiol­ ogy. Admittedly, the monograph will represent a more subjective view than that provided by a classical review article. In this monograph I am going to describe a major aspect of my research, i.e., the central processing of information arising from the receptors in the semicircular canals and otoliths of the inner ear. I shall restrict this report to those systems that are concerned with the vestibuloocular transmission, since they offer particular opportunity to study sensory-motor integration.

In review, the amount of information available on the morphological and func­ tional properties of the frog nervous system is very extensive indeed and in certain areas is the only available source of information in vertebrates. Further­ more, much of the now classical knowledge in neurobiology was originally ob­ tained and elaborated in depth in this vertebrate. To cite only a few examples, studies of nerve conduction, neuromuscular transmission, neuronal integration, sense organs, development, and locomotion have been developed with great detail in the frog and in conjunction provide the most complete holistic descrip­ tion of any nervous system. Added to the above considerations, the ease with which these animals may be maintained (both as adults and during development) and the advantage of their lower cost as compared with other vertebrate forms make the frog one of the most important laboratory animals in neurobiology. With these thoughts in mind, we decided to compile this volume. Our goal in doing so was to assemble as much as possible of the information available on frog neurobiology and to have the different topics covered by authorities in each of the fields represented. To keep the handbook restricted to one volume, we found it necessary to omit the large field of amphibian muscle neurobiology, which has already been summarized in various other publications.

Sensorimotor systems are not rigidly wired predetermined networks but rather highly plastic structures that learn and modify their entire performance in response to changes in external or internal conditions. Lesions or distortions of the system's input, which initially cause a functional disorganization, induce an active reorganization which often leads to a recovery of function. Examples of lesion-induced neural plasticity have been known for some hundred years; however, an awareness of their value as research tools is relatively new. This current interest is a consequence of rapid­ ly changing ideas concerning the nature of CNS organization. Out of these, concepts are emerging which describe neural nets as modifiable, highly dynamic, self-organizing structures. This trend is clearly reflected in this volume, which contains the proceedings of a symposium held in Bremen in July 1980 as a satellite meeting of the XXVIIIth International Congress of Physiological Sciences. The first part of this conference was devoted to some gen­ eral aspects of plasticity, discussing the current theories of functional recovery as well as morphological, neurochemical, physiological, molecular, and ontogenetic aspects. The second part dealt with lesion­ induced plasticity in specific sensorimotor systems of the spinal cord, brain stem, and cerebral cortex.