The Anatomical Substrate for Telencephalic Function

ISBN-13: 9783540512295 / Angielski / Miękka / 1989 / 110 str.

C. Leonardus Veenman; Dagmar Crzan; Helene Kern

Opis

The basic thesis for this study was that the telencephalon is needed to make decisions in new situations. Subsidary hypotheses were that the telencephalon consists of: (a) a sensorimotor system which generates motor activity from sensory input and (b) a selection system which makes choices from possible motor programs. It was postulated that the selection system should fulfil the following requirements: be accessible for past and present events, have the capacity to process this information in a nondetermined way with a possibility for ordering, and have access to motor-affecting systems (the sensorimotor system). The ability of the selection system to correlate information in a nonpredetermined way was considered most important. In short: The selection system should be able to associate any information in any combination, and have the capability for internal control of neuronal activity and external selection of motor programs (see Fig. IA. ) Xenopus laevis was chosen as a subject, since it has a relatively simple tel- encephalon, with characteristics that it shares with "primitive" species of different vertebrate classes, and because it is easy to maintain as a laboratory animal. The main method used was the determination of connections with HRP. The pallium was in the focus of attention, since it was considered to be the core of the selection system. Immunohistochemistry was used as an additional parameter to compare Xenopus laevis forebrain with those of other vertebrates.

Spis treści

1 Introduction: Theoretical Basis for Telencephalic function.- 1.1 Telencephalic function.- 1.2 Dual Sensorimotor and Selection System.- 1.3 Position of the Pallium.- 1.4 Working Hypotheses.- 1.5 Choice of Animal.- 1.5.1 Scientific Grounds.- 1.5.2 Practical Grounds.- 1.6 Methods Employed.- 2 Methods and Results: Study of Prosencephalic Connectivity and Structural Organization.- 2.1 Extra-experimental Procedures.- 2.2 Experimental Procedures.- 2.2.1 Preparation.- 2.2.2 Horseradish Peroxidase Determination.- 2.2.3 General Histological Techniques.- 2.3 Horseradish Peroxidase Labeling.- 2.4 Display of the Forebrain and Injection Sites.- 2.4.1 Nissl Stain.- 2.4.2 Reconstructions.- 2.4.3 Cross Sections.- 2.4.4 Locations of the Injection Sites.- 2.5 Horseradish Peroxidase Injections in the Pallium (1-12).- 2.5.1 Description of the Format.- 2.5.2 Descriptions of the HRP Transport (Injections 1–12).- 2.6 Horseradish Peroxidase Injections in Extrapallial Telencephalic Areas (13–16).- 2.6.1 Description of the Format.- 2.6.2 Descriptions of the HRP Transport (Injections 13–16).- 2.7 Horseradish Peroxidase Injections in Extratelencephalic Regions (17–22).- 2.7.1 Description of the Format.- 2.7.2 Descriptions of the HRP Transport (Injections 17–22).- 3 Methods and Results: Electron Microscopic Study of HRP-Labeled Elements.- 3.1 Preparation of the Electron Microscopic Material.- 3.2 Electron Microscopic Material.- 3.3 Conclusions.- 4 Methods and Results: Distributions of Opioids, Substance P, and Serotonin.- 4.1 Immunohistochemistry.- 4.2 Distributions.- 4.2.1 Substance P and Opioids.- 4.2.2 Serotonin.- 4.3 Conclusions.- 5 Discussion: Hodological, Functional, and Comparative Concepts.- 5.1 Connectivity of the Telencephalon.- 5.1.1 Input Systems to the Pallium.- 5.1.2 Intrinsic Connections of the Pallium.- 5.1.3 Efferents of the Pallium.- 5.1.4 Efferents and Afferents of the Striatum.- 5.1.5 Dual Information Processing System of the Telencephalon.- 5.1.5.1 Pallium and Striatum Complex.- 5.1.5.2 Amygdaloid Complex.- 5.1.5.3 Position of the Pallium in Relation to Other Prosencephalic Structures.- 5.2 Midline Crossing Connections.- 5.2.1 Basis for Left-Right Interactions.- 5.2.2 Commissures.- 5.2.3 Bilateral Projections.- 5.2.4 Conclusions.- 5.3 Function of the Pallium.- 5.3.1 Mechanism of Association.- 5.3.2 Synaptic Triad.- 5.3.3 Pallial-Striatal Interactions.- 5.3.4 Conclusions and Implications.- 5.4 Comparisons with Other Vertebrates.- 5.4.1 Comparison with Other Amphibians.- 5.4.2 Comparison with Fishes.- 5.4.3 Comparison with Reptiles.- 5.4.4 Comparison with Birds.- 5.4.5 Comparison with Mammals.- 5.5 Conclusions.- 6 Summary.- References.