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The annual cycle of spatial behavior and hippocampal volume in Sorexстатья
- Автор: Yaskin V.A.
- Сборник: Advances in the Biology of Shrews II: Special Publication of the International Society of Shrew Biologists
- Том: 1
- Глава в коллективной монографии
- Год издания: 2005
- Место издания: New York
- Первая страница: 373
- Последняя страница: 385
- Аннотация: The hippocampus is involved in the processing of spatial information on the environment, and its size is known to correlate positively with spatial ability among mammal species. Between species comparisons suggest a relationship between the amount of spatial information processed to hippocampus size. The aim of study was to find out whether seasonal and age changes of the hippocampal size may correlate also with dynamics of spatial behavior during the ontogenesis of shrews. It is known that seasonal changes in the type of spatial behavior of immature Sorex araneus transform from wide, active movements in summer to the restricted movements within the home range in autumn. Comparison between the dynamics of the hippocampus size and data on the annual dynamics of the mobility of S. araneus and S. minutus showed certain parallelism of the two parameters. The reduction in hippocampus size coincided with the shrinkage of the animal's home ranges. The morphometrical analysis has shown that width of sections of both dentate gyrus and hippocampus significantly declined from autumn to winter in S.araneus. Following winter decline a growth spurt occurred in spring. In spring the greatest increase among different brain structures was observed in the hippocampus (on 20 - 35%) in S. araneus and S. minutus. Thus, the predicted growth processes in hippocampal formation of adult animals were found. Seasonal modulation of the sex differences in the hippocampus size was also revealed: sexual dimorphism in both hippocampal volume and size of home ranges became distinct (favouring males) in the early spring when sexual maturation of the common shrews began. Home range and relative hippocampal mass was significantly higher in S. minutus than in S. araneus. Data supports a great seasonal morphological plasticity and protracted growth in behaviorally relevant brain regions. The study provides new insights into some mechanisms of Dehnel’s phenomenon in Sorex species.
- Добавил в систему: Яскин Владимир Александрович