大鼠听觉反应阈的测定

应用微电极技术测定了45只大鼠325根单一听神经纤维的特征频率及其阈值和调谐曲线。测得特征频率的最低值为0.58kHz,最高值为62.6kHz。敏感度最高的频带在20～50kHz,敏感度最高的阈值为6dB(SPL),其相应的频率为27.49kHz。由最低阈值连线延续到边侧的调谐曲线,便形成了大鼠整个的听反应阈曲线。该听反应阈曲线与行为测听所观察到的听力曲线近似。     

AUDITORY EXPERIENCE AND SONG DEVELOPMENT IN THE CHAFFINCH FRINGILLA COELEBS

The present paper describes the results of experiments designed to evaluate the importance of auditory-motor experience in the development of song in the Chaffinch. For this purpose a number of Chaffinches collected as nestlings or adults were deafened by extirpating the cochlea at different ages. Recordings of their song made subsequently provide the material on which the paper is based. Since the results of the experiments can only be interpreted in the light of knowledge of normal song development, the latter is described from the observation of previous workers and from some new material. Of the 20 males deafened, only three came into full song of their own accord; song was induced in the rest by the administration of testosterone phenylacetate or testosterone propionate. Songs of abnormal length were common among first-year males though males deafened when two or more years old produced song of the normal length. The song of male Chaffinches deafened as adults, that is after they had produced full song for one or more breeding seasons, was infistinguishable from that produced by intact adult males. They even went through a “plastic” song stage in which some “intermediate” themes occurred. A first-year male deafened when it had almost stabilized its song produced song that gradually deviated more and more from normal song. This indicates that the bird had not yet laid down a long-term memory of its song independent of auditory feedback. First-year male Chaffinches deafened during early spring, mid-winter and late sumer, respectively, show that the more they were deprived of the normal period of auditory-motor experience, the simpler was the song they produced in their first spring. Thus, at the time of deafening they had acquired a particular auditory-motor experience, and it is the type of element established up to that time that is incorporated into full song. Male chaffinches brought into the laboratory as nestlings and deafened when three months old produced a virtually sfyctureless song, in which the only recognizable element was a sound reminiscent of the juvenile “chirrup”. The subsong and other calls of these birds were also highly abnormal. Song development in the Chaffinch clearly starts before song as such has made its appearance. The available evidence suggests that the kind of song a male Chaffinch produces depends directly on its auditory-motor experience before deafening. There is no indication that deafening achieves its effects on the resultant song by interfering with the hormonal substrate. Relatively stable song end patterns develop in the absence of auditory feedback, so their occurrence does not necessitate the postulation of templates or preconceived patterns. Song development differs markedly from species to species.     

兔杏仁体向皮层听区的直接投射及其比较生理学意义

刺激杏仁外侧核或基底核,可在兔听区皮层观察到诱发电位,诱发电位分布在ＷｏｏｌｓｅｙＡＩ、ＡⅡ区及溴鼻沟后缘听区皮层（ＡＣＢＲＳ区）,以ＡＣＢＲＳ区反应为最大。诱发反应的潜伏期最短为２毫秒,表明杏仁向听皮层的投射可能是单突触的。形态学工作揭示,兔主要听区ＡＣＢＲＳ区电泳辣根过氧化物酶（ＨＲＰ）,杏仁外侧核及基底核都观察到逆行标记细胞,标记细胞数量以杏仁外侧核为多;ＷｏｏｌｓｅｙＡⅠ、ＡⅡ区电泳ＨＲＰ     

DROUGHT AND THE EVOLUTION OF FLOWERING TIME IN DESERT ANNUALS

Drought is often thought to stimulate flowering in desert, and sometimes in mesic, annuals. I review experimental studies of the effect of drought on flowering time in both desert and mesic annuals. No convincing experimental evidence presently exists that drought stimulates flowering in any annual plant; some experimental results suggest the opposite. The design and analysis of flowering time studies are also reviewed; most extant studies have serious flaws. Thus, a convincing demonstration of drought-stimulated flowering will require carefully designed and analyzed experiments. In light of these results, I examine several ways in which drought may affect the ecology and evolution of flowering time in desert annuals, and suggest directions for research. Several mechanisms probably contribute to phenotypic variation in flowering time and size, including water and nutrient limitation, competition, and variation in seed size and germination time. Phenotypic effects of seed traits suggest that seed and flowering time traits may not evolve independently of one another. Water stress during reproduction can influence seed traits; such maternal effects can influence the outcome of selection both on seed traits and on flowering time. The multivariate character of flowering time evolution suggests that genetic and phenotypic correlations among these traits may present important constraints on the evolution of flowering time.     

黄雀发声核团与部分听觉中枢内P物质的分布和性双态比较

用免疫组织化学方法研究P物质在雌雄黄雀发声控制核团和听觉中枢内的分布,结合计算机图像分析仪检测SP免疫阳性细胞和末梢的灰度值,并作雌雄比较。结果如下:1.在发声学习中枢嗅叶X区有大量的SP阳性神经末梢和一些神经细胞。2.在发声控制核团前脑高级发声中枢(HVc)、古纹状体栎核、发声学习中枢新纹状体巨细胞核和丘脑背内侧核外侧部内有许多的SP免疫阳性细胞。3.在发声控制中枢中脑背内侧核和延髓舌下神经核气管呜管部、听觉中枢丘脑卵圆核的壳区、中脑背外侧核壳区及中脑丘间核等有密集的SP免疫阳性神经末梢和纤维分布;雄性发声中枢内SP的分布比雌性丰富,两者有显著的差异。结果表明:SP的分布在雌雄发声中枢之间存在显著的性双态;SP广泛分布于黄雀发声控制核团和部分听觉中枢内,提示SP可能在发声控制及听觉中枢内具有重要的生理功能。     

氯霉素对大鼠睡眠和主动回避反应的影响

本文报导了氯霉素在大鼠生后7天内和鼠龄60天时给药对其成熟后的睡眠、主动回避反应以及电休克阈的影响。在新生期给药组,快眼动睡眠量显著减少,但主动回避反应成绩没有明显变化.在鼠龄60天给药组,动物的快眼动睡眠量和主动回避反应成绩均明显降低,电休克阈也降低。文中讨论了氯霉素对快眼动睡眠和脑发育的影响以及发育期快眼动睡眠与脑发育的关系。