摘要:

Male and female Wistar rats, aged 3 months, were massively trained (3.5 h) for a two‐way avoidance task and tested for retention (30 min) the following day. Some of them were subjected to a brief test (30 min) at 5, 10, 15, and 20 months. At 3 months, male rats scored more avoidances and a lower number of escapes, freezings, and intertrial crossings than females; in the test session, both groups improved their performance. Over time, male rats maintained the avoidance score displayed at 3 months. Female rats improved their performance at 5 and 10 months and then, at 20 months, they returned to the level attained at 3 months. These data suggest that active avoidance learning in young animals is fixed as permanent functional changes in the neuronal network of the brain which make aged rats, as well as young adult rats, able to master the task.

ISSN:1125-0003    

DOI:10.1080/11250008809386764

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Phylogenetic relationships within the Italian species of the lacertid genusPodarciswere examined by parsimony analysis of mitochondrial DNA sequences from the genes encoding the small ribosomal RNA and the phenyl transfer RNA.Lacerta viridiswas used as outgroup andTeira dugesiiwas also included in the ingroup. The 80 phylogenetically informative positions produced four most parsimonious trees, with the ItalianPodarcissplit into three groups: the first comprisedP. filfolensis, P. melisellensis. P. wagleriaria, P. muralis,andP. raffonei,the secondP. siculawith its various subspecies. The third lineage was that ofP. tiliguerta,whose relationships were resolved as more closely related to the first clade, when weighting transversion three times transitions. Bootstrap analyses on a subset of sequences representing all species herein studied, supported the results from the larger dataset. The present results are only partly in agreement with previous hypotheses based on morphology, immunology, and allozyme variation analyses.

ISSN:1125-0003    

DOI:10.1080/11250008809386765

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We report on two new Recent species of the genusDarwinula(D.aotearoaspec. nov. andD. kohangaspec. nov.) from New Zealand. Both soft part and valve morphology are described and figured. The taxonomic position of the two species within the Recent darwinulid fauna is discussed.

ISSN:1125-0003    

DOI:10.1080/11250008809386766

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1125-0003    

DOI:10.1080/11250008809386767

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1125-0003    

DOI:10.1080/11250008809386768

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1125-0003    

DOI:10.1080/11250008809386753

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor