摘要:

The distribution of the growth associated protein GAP-43 has been described in the brain and spinal cord of rats and other placental mammals but not marsupials. In order to provide such information, we employed a monoclonal antibody to immunostain for GAP-43 in the central nervous system of adult and developing opossums, Didelphis virginiana. The GAP-43 immunoreactivity was widely distributed in the brain of adult opossums, but it was particularly dense within specific layers of the olfactory bulb and hippocampal formation, layer I of the cerebral cortex, the bed nucleus of the stria terminalis, the nucleus accumbens, the striatum, the amygdala, the septum, the olfactory tubercle, medial parts of the preoptic area and diencephalon, the substantia nigra, the ventral tegmental area, the periaqueductal grey matter, the interpeduncular nucleus, the periventricular grey, the molecular layer of the cerebellum, the superior central nucleus, the basilar pons, the dorsal vagal and solitary nuclei, and laminae I and II of the spinal trigeminal nucleus. Immunoreactivity for GAP-43 was also present within the spinal cord, where it was densest within laminae I, II, IX, and X and within the intermediolateral cell column. In most areas of the brain and some areas of the spinal cord, an inverse correlation existed between the location of GAP-43 and myelin. Immunostaining for GAP-43 was found throughout most of the central nervous system during early development, but it decreased with age in a regionally specific manner until the adult pattern was reached. Our results suggest that the distribution of GAP-43 in opossums is similar in many respects to that reported in rats and that it is developmentally regulated.

ISSN:0006-8977    

DOI:10.1159/000113541

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The distribution of the growth associated protein GAP-43 has been described in the brain and spinal cord of rats and other placental mammals but not marsupials. In order to provide such information, we employed a monoclonal antibody to immunostain for GAP-43 in the central nervous system of adult and developing opossums, Didelphis virginiana. The GAP-43 immunoreactivity was widely distributed in the brain of adult opossums, but it was particularly dense within specific layers of the olfactory bulb and hippocampal formation, layer I of the cerebral cortex, the bed nucleus of the stria terminalis, the nucleus accumbens, the striatum, the amygdala, the septum, the olfactory tubercle, medial parts of the preoptic area and diencephalon, the substantia nigra, the ventral tegmental area, the periaqueductal grey matter, the interpeduncular nucleus, the periventricular grey, the molecular layer of the cerebellum, the superior central nucleus, the basilar pons, the dorsal vagal and solitary nuclei, and laminae I and II of the spinal trigeminal nucleus. Immunoreactivity for GAP-43 was also present within the spinal cord, where it was densest within laminae I, II, IX, and X and within the intermediolateral cell column. In most areas of the brain and some areas of the spinal cord, an inverse correlation existed between the location of GAP-43 and myelin. Immunostaining for GAP-43 was found throughout most of the central nervous system during early development, but it decreased with age in a regionally specific manner until the adult pattern was reached. Our results suggest that the distribution of GAP-43 in opossums is similar in many respects to that reported in rats and that it is developmentally regulated.

ISSN:0006-8977    

DOI:10.1159/000316253

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

In six miniaturized salamanders of the family Plethodontidae, including one of the smallest tetrapod vertebrates, Thorius pennatulus, the anatomical consequences of miniaturization for the brain were investigated. We determined (1) absolute and relative size of the brain, major parts of the brain, the tectum and tectal gray matter, (2) nerve cell size and density, and (3) the number of cells within the visual and visuomotor centers (thalamus, tectum/praetectum and tegmentum). No common compensatory strategy for the brain among the miniaturized salamanders was found. Except for the smallest species, T. pennatulus, only some of the expected compensatory processes (increase in relative size of the brain, relative size of visual centers, relative amount of gray matter or relative density of cell packing density) are found in any species, and these occur in different combinations and degrees. The most decisive factor for maximizing cell number was cell size. Miniaturized species with small cells also have many visual cells, regardless of the other factors. In contrast, the minimum number of visual neurons is found in miniaturized salamanders with large cells. It is concluded that the neuroanatomical traits investigated exert different degrees of resistance to adaptive compensatory processes. Cell size seems to be the most resistant parameter and is strictly dependent on genome size.

ISSN:0006-8977    

DOI:10.1159/000113542

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Relative brain size and the relative size of six brain regions (main olfactory bulbs, accessory olfactory bulbs, telencephalon, optic tectum, cerebellum and brain stem) in ten species of anurans from five habitats were examined to determine whether there was any evidence of adaptation in brain structure. A previously published data set was also reanalysed. Arboreal frogs have larger body-size corrected brains than frogs from other habitats. Arboreal ranid (Platymantis vitiensis) and hylid (Hyla versicolor) possess slightly larger cerebella than the ranids and hylids from other habitats. Platymantis vitiensis lacks an accessory olfactory bulb. The fully-aquatic Xenopus laevis (Pipidae) has a smaller optic tectum and cerebellum than the non-fossorial hylids and ranids. Adaptation to life underground appears to explain the modified brains of two fossorial frogs, Hemisus guineensis (Ranidae) and Rhinophrynus dorsalis (Rhinophrynidae). Both species of fossorial frogs have reduced optic tecta, larger main olfactory and smaller accessory olfactory bulbs, and larger torus semicircularis than non-fossorial species. Our data showed a strong negative correlation between the size of the optic tectum and the size of the main olfactory bulbs. We conclude that, although anuran brains are very similar across taxa in qualitative and general structure, there are some interesting, apparent adaptations, to fossorial and arboreal life.

ISSN:0006-8977    

DOI:10.1159/000113543

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A method is presented to test the relationship between a phylogenetic tree derived from brain morphology, and different hypotheses describing the evolution of a behavioral trait. This is a question of interest for evolutionary psychologists and behavioral biologists. The paper first discusses how hypotheses for behavioral evolution should be coded for such a comparison, then a triple-permutation test, originally proposed to compare independently obtained evolutionary trees, is used for the statistical assessment of each hypothesis. Non-parametric correlation coefficients computed between brain components and appropriately coded behavioral states can then be used to suggest what brain components are responsible for the development of the various states of the behavioral trait of interest. The procedure is illustrated with three different applications relating brain evolution to habitat selection in marsupials, locomotory specialization in primates, and trophic adaptation in bats.

ISSN:0006-8977    

DOI:10.1159/000113544

出版商:S. Karger AG    

年代:1995

数据来源: Karger