In the present experiment, Pavlovian fear conditioning was adopted to study the effects of different early rearing environments on fear conditioning in adult rats. Weaned rats were reared in three manipulable environm...In the present experiment, Pavlovian fear conditioning was adopted to study the effects of different early rearing environments on fear conditioning in adult rats. Weaned rats were reared in three manipulable environments （enriched, social and isolated conditions）. After 8 weeks, fear conditioning （characterized by percentage of freezing） was observed and analyzed, and rats＇ weight, locomoter activity and foot-shock sensitivity were operated too. The results showed that： （1） Compared with control group, the level of conditioned fear was significantly increased in enriched group, but significantly decreased in isolated group; （2） Enriched and isolated conditions influenced rat＇s weight significantly; （3） Different rearing conditions have no effect on locomoter activity and foot-shock sensitivity. These results indicated that early enriched condition could improve the tone-evoked fear conditioning response, while isolated condition impaired the response.展开更多
IN this letter we discuss the necessary and sufficient condition of C^0 flows on closed surfaces with isolated singular points having the pseudo-orbit tracing property. According to ref. [1], on a closed surface, ever...IN this letter we discuss the necessary and sufficient condition of C^0 flows on closed surfaces with isolated singular points having the pseudo-orbit tracing property. According to ref. [1], on a closed surface, every minimal set of a C^r(r≥2) flow is trivial, but it is possible for a C^0 flow to contain non-trivial minimal sets. Thus C^0 flows on closed surfaces are more complicated than C^r(r≥2) flows.展开更多
基金National Natural Science Foundation of China(30770689)Scientific Research Fund of Hunan Provincial Education Department (05B045)National Basic Research Program of China (2002CB410803-04)
文摘In the present experiment, Pavlovian fear conditioning was adopted to study the effects of different early rearing environments on fear conditioning in adult rats. Weaned rats were reared in three manipulable environments （enriched, social and isolated conditions）. After 8 weeks, fear conditioning （characterized by percentage of freezing） was observed and analyzed, and rats＇ weight, locomoter activity and foot-shock sensitivity were operated too. The results showed that： （1） Compared with control group, the level of conditioned fear was significantly increased in enriched group, but significantly decreased in isolated group; （2） Enriched and isolated conditions influenced rat＇s weight significantly; （3） Different rearing conditions have no effect on locomoter activity and foot-shock sensitivity. These results indicated that early enriched condition could improve the tone-evoked fear conditioning response, while isolated condition impaired the response.
文摘IN this letter we discuss the necessary and sufficient condition of C^0 flows on closed surfaces with isolated singular points having the pseudo-orbit tracing property. According to ref. [1], on a closed surface, every minimal set of a C^r(r≥2) flow is trivial, but it is possible for a C^0 flow to contain non-trivial minimal sets. Thus C^0 flows on closed surfaces are more complicated than C^r(r≥2) flows.
