摘要:

The pretrigeminal nucleus (a structure that may be involved in vocalization) was found to stain strongly for succinic dehydrogenase in seven species of anurans (toads and frogs) representing four families and two suborders. In Xenopus laevis this nucleus seemed to be identical to the area previously found to take up testosterone in this species.

ISSN:0006-8977    

DOI:10.1159/000121811

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Correlations between progression indices of five categories of nuclei and brain centers indicate that Megachiroptera rely primarily on vision and olfaction while Microchiroptera rely primarily on audition. Among Microchiroptera, some rely more heavily on olfaction than on vision as a secondary sense, and vice-versa. There may have been compensatory effects, in the course of evolution, regarding the choice of the primary and secondary information channels.

ISSN:0006-8977    

DOI:10.1159/000121812

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The relationship between sensory specializations and behavioral specializations in two ecologically distinct species of squirrels was examined. It was predicted that the relative density of receptors in the glabrous forepaw skin of tree squirrels (Sciurus niger), which are skilled climbers and manipulate food items extensively, would be higher than that in ground squirrels (Spermophilus tridecemlineatus), which dig underground burrows. In addition to testing this prediction, several other aspects of the distribution of receptors were quantitatively examined in silver-stained material. As predicted, the relative density of receptors in the glabrous forepaw skin of tree squirrels is significantly higher than that in ground squirrels. Receptors are randomly dispersed and different classes of receptors (corpuscular vs. non-corpuscular) are intermingled in the palmar skin of both species. The proportions of the different classes of receptors do not differ among species.

ISSN:0006-8977    

DOI:10.1159/000121813

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The goal was to suggest a meaningful approach to the assessment of intelligence which may be used, for example, in correlational studies with measures of encephalization. Suggesting, as others have done, that species comparisons based on quantitative differences inherently confound intellective with nonintellective abilities, the present approach described a hierarchy of 8 basic levels of qualitatively different intellective (learning) abilities. The levels range from habituation to complex concepts. Practical procedures and strategies which, ancrease the precision of the scale were described.

ISSN:0006-8977    

DOI:10.1159/000121814

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

Previous studies have shown interhemispheric visual connections in primates to be limited to extrastriate cortex. Using the retrograde transport technique of horseradish peroxidase, we show that in the prosimian primate Galago senegalensis both striate and extrastriate cortex contribute a substantial projection to the contralateral hemisphere. Thus, the lack of an interhemispheric projection from area 17 is not a characteristic of primates and may be peculiar to only a few primate species.

ISSN:0006-8977    

DOI:10.1159/000121815

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

In a complementary neuroanatomical study by Brenowitz in 1980, it was shown that tree squirrels (Sciurus niger) have a higher relative density of mechanoreceptors in their glabrous forepaw skin than do ground squirrels (Spermophilus tridecemlineatus).The main purpose of this study was to test the prediction that tree squirrels would depend upon somatic sensory (cutaneous) input from their forepaws to a greater extent than would ground squirrels in food handling behavior. In addition, a series of more general questions about the sensory control of food handling was examined. First, using different sized food items, it was shown that food handling (rate of manipulation) is subject to sensory control, in general. Secondly, comparison of sham-operated groups with groups receiving median nerve (innervating the palmar surface) lesions showed that cutaneous input from the volar surface of the forepaw contributes to the sensory control in both species of squirrels. Thirdly, comparison of lesion effects in the two species showed that, as predicted, tree squirrels depend upon cutaneous input from their volar forepaw to a greater extent than do ground squirrels. Fourthly, by reanalyzing the above data it was shown that there is continued sensory feedback from food items rather than only an initial evaluation of them.

ISSN:0006-8977    

DOI:10.1159/000121816

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000121817

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000121818

出版商:S. Karger AG    

年代:1980

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000121819

出版商:S. Karger AG    

年代:1980

数据来源: Karger