摘要:

Earlier studies have shown that the negatively allometric brain-body weight association in mature mammals changes to an isometric association when body weights are adjusted for their rates of oxygen consumption. Birds are endogenous homeotherms, and so their brain weights were analyzed according to their body weights and metabolism (estimated energy supply). As expected, the brain and body weights of the 83 species of neognathid birds have a negatively allometric association. The same species, however, have a brain weight-to-estimated energy supply which cannot be separated from isometry. While passerines have bigger brains for their body weights than altricial nonpasserines, the relative brain sizes of the two avian groups cannot be separated once the metabolic rate is used to adjust the body weights. Ratites or paleognathid birds may have a different brain-to-metabolism association. Consideration of bioenergetics helps clarify brain and body weight associations.

ISSN:0006-8977    

DOI:10.1159/000118782

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Behavioral discrimination tests were used to examine spectral sensitivity and color vision in a pair of ring-tailed lemurs (Lemur catta). Sensitivity tests revealed the presence of a Purkinje shift and a photopic visual system. As measured at increment-threshold, the photopic spectral sensitivity function for the lemur has multiple peaks (at ca. 440–460, 540, and 620 nm). In color vision tests lemurs behave trichromatically in that (a) they show no evidence for a neutral point in the spectral range of 470–510 nm, and (b) they set a unique Rayleigh match (540 nm + 645 nm = 570 nm). Tests of wavelength and colorimetric purity discrimination reveal that although this prosimian has color vision, it is not an acute capacity – thresholds for these color discriminations were consistently much higher for lemurs than for normal human trichromats tested in the same situ

ISSN:0006-8977    

DOI:10.1159/000118772

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The paper considers the absolute rates at which the brain grows in different mammals and the relative rates of growth for the various subareas. It concludes that the various mammals are much more similar in the rates of growth of the brain than of the body. The rate of growth of the human brain is within the range of variation expected. Indirect evidence is presented that the different mammalian orders may differ in the relative rates of growth of the neocortex and other brain areas.

ISSN:0006-8977    

DOI:10.1159/000118773

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

A Golgi survey of the convexity cortex in the brain of the dolphin, Tursiops truncatus, has revealed many cellular characteristics which may be indicative of conservative cortical evolution. These include a high degree of pyramidalization, and an accentuation of layer II. The presence of an accentuated layer II in convexity cortex is a protoneocortical characteristic found in more ''primitive'' cortical arrangements. The growth ring concepts of cortical development outward in concentric waves from archicortical and paleocortical origins are discussed. In that context we have not been able to identify cores of hyperspecialization in the dolphin cortex corresponding to koniocortex and gigantopyramidal areas. This leads us to suggest that the cortex of the dolphin reflects a condition of the paralimbic-parinsular stage of evolutionary development. Thus, the dolphin brain may serve as a model of the theoretical mammalian archetype brain and its study may shed light on the organization of the brains of the initial ancestors of modern mammals.

ISSN:0006-8977    

DOI:10.1159/000118774

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

In the Scolopacidae, which includes the sandpipers and snipe, there is a significant enlargement of the neural apparatus subserving the behaviour of probing which is the preferred feeding strategy of this family of birds. Along with a sophisticated motor arrangement which allows fine manipulation by the tip of the bill without abduction of the mandibles, there is an obvious expansion of the forebrain area devoted to the trigeminal innervation of receptor-rich bill tip. This ''trigeminal expansion'' forms a visible bulge on the surface of the brains of the Scolopacidae but not on the brains of related shorebirds in the Charadriidae; this difference would be evident in fossil endocast material and could provide new information on the evolution of the avian brain.

ISSN:0006-8977    

DOI:10.1159/000118775

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The forebrain distribution of axons showing serotonin-like immunoreactivity was studied in the North American opossum. Serotonergic innervation of the hypothalamus was extensive, particularly within the ventromedial nucleus, the periventricular nucleus and the rostral supraoptic nucleus. Serotonergic axons were also present within the fields of Forel and zona incerta, but they tended to avoid parts of the subthalamic nucleus. In the thalamus serotonergic innervation was dense within the midline nuclei (e.g. the central, intermediate dorsal and rhomboid nuclei) and the ventral lateral geniculate nucleus, but relatively sparse in some of the nuclei more readily associated with specific functions (e.g. the ventrobasal nucleus). Serotonergic axons innervate most areas of the rostral and dorsal forebrain. Areas containing the heaviest innervation included the interstitial nucleus of the stria terminalis and the lateral septal nucleus. Serotonergic innervation of the neocortex varied markedly from region to region and within different layers of the same regions. The retrograde transport of True Blue combined with immunofluorescence for localization of serotonin revealed that serotonergic axons within the forebrain arise mainly within the dorsal raphe and superior central nuclei, but that some originate within the midbrain and pontine reticular formation and the locus coeruleus, pars alpha. Neurons of the raphe magnus and obscurus also innervate the forebrain, but few of them are serotonergic. The use of horseradish peroxidase as a retrograde marker provided evidence that raphe projections to the forebrain are topographically organized. Our results suggest that serotonergic projections to the forebrain, like those to the spinal cord, are connectionally heterogeneous.

ISSN:0006-8977    

DOI:10.1159/000118776

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The forebrain distribution of axons showing serotonin-like immunoreactivity was studied in the North American opossum. Serotonergic innervation of the hypothalamus was extensive, particularly within the ventromedial nucleus, the periventricular nucleus and the rostral supraoptic nucleus. Serotonergic axons were also present within the fields of Forel and zona incerta, but they tended to avoid parts of the subthalamic nucleus. In the thalamus serotonergic innervation was dense within the midline nuclei (e.g. the central, intermediate dorsal and rhomboid nuclei) and the ventral lateral geniculate nucleus, but relatively sparse in some of the nuclei more readily associated with specific functions (e.g. the ventrobasal nucleus). Serotonergic axons innervate most areas of the rostral and dorsal forebrain. Areas containing the heaviest innervation included the interstitial nucleus of the stria terminalis and the lateral septal nucleus. Serotonergic innervation of the neocortex varied markedly from region to region and within different layers of the same regions. The retrograde transport of True Blue combined with immunofluorescence for localization of serotonin revealed that serotonergic axons within the forebrain arise mainly within the dorsal raphe and superior central nuclei, but that some originate within the midbrain and pontine reticular formation and the locus coeruleus, pars alpha. Neurons of the raphe magnus and obscurus also innervate the forebrain, but few of them are serotonergic. The use of horseradish peroxidase as a retrograde marker provided evidence that raphe projections to the forebrain are topographically organized. Our results suggest that serotonergic projections to the forebrain, like those to the spinal cord, are connectionally heterogeneous.

ISSN:0006-8977    

DOI:10.1159/000118777

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000118778

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000118779

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000118780

出版商:S. Karger AG    

年代:1985

数据来源: Karger