Department of Psychology, Rutgers University, Piscataway, NJ, USA.
School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
Proc Biol Sci. 2018 Sep 26;285(1887):20181270. doi: 10.1098/rspb.2018.1270.
In birds, vocal learning enables the production of sexually selected complex songs, dialects and song copy matching. But stressful conditions during development have been shown to affect song production and complexity, mediated by changes in neural development. However, to date, no studies have tested whether early-life stress affects the neural processes underlying vocal learning, in contrast to song production. Here, we hypothesized that developmental stress alters auditory memory formation and neural processing of song stimuli. We experimentally stressed male nestling zebra finches and, in two separate experiments, tested their neural responses to song playbacks as adults, using either immediate early gene (IEG) expression or electrophysiological response. Once adult, nutritionally stressed males exhibited a reduced response to tutor song playback, as demonstrated by reduced expressions of two IEGs ( and ) and reduced neuronal response, in both the caudomedial nidopallium (NCM) and mesopallium (CMM). Furthermore, nutritionally stressed males also showed impaired neuronal memory for novel songs heard in adulthood. These findings demonstrate, for the first time, that developmental conditions affect auditory memories that subserve vocal learning. Although the fitness consequences of such memory impairments remain to be determined, this study highlights the lasting impact early-life experiences can have on cognitive abilities.
在鸟类中,发声学习使它们能够发出具有性选择的复杂歌曲、方言和与歌曲匹配的歌声。但是,有研究表明,发育过程中的压力条件会通过改变神经发育来影响歌声的产生和复杂程度。然而,迄今为止,还没有研究测试早期生活压力是否会影响发声学习的神经过程,而不是歌声的产生。在这里,我们假设发育应激会改变听觉记忆的形成和对歌曲刺激的神经处理。我们对雄性幼鸟进行了实验性的应激处理,然后在两个单独的实验中,使用即时早期基因(IEG)表达或电生理反应,测试了它们成年后的对歌曲回放的神经反应。一旦成年,营养应激的雄性对导师歌曲的回放反应就会减弱,这表现在两个 IEG( 和 )的表达减少和在尾侧中脑(NCM)和中脑(CMM)中的神经元反应减少。此外,营养应激的雄性对成年后听到的新歌曲的神经元记忆也受损。这些发现首次表明,发育条件会影响发声学习的听觉记忆。尽管这种记忆损伤的适应后果还有待确定,但这项研究强调了早期生活经历对认知能力的持久影响。