Pinaud Raphael, Terleph Thomas A
Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA.
J Biosci. 2008 Mar;33(1):145-55. doi: 10.1007/s12038-008-0030-y.
Songbirds rely on auditory processing of natural communication signals for a number of social behaviors,including mate selection,individual recognition and the rare behavior of vocal learning - the ability to learn vocalizations through imitation of an adult model,rather than by instinct. Like mammals,songbirds possess a set of interconnected ascending and descending auditory brain pathways that process acoustic information and that are presumably involved in the perceptual processing of vocal communication signals. Most auditory areas studied to date are located in the caudomedial forebrain of the songbird and include the thalamo-recipient field L (sub fields L1,L2 and L3),the caudomedial and caudolateral mesopallium (CMM and CLM,respectively) and the caudomedial nidopallium (NCM). This review focuses on NCM,an auditory area previously proposed to be analogous to parts of the primary auditory cortex in mammals. Stimulation of songbirds with auditory stimuli drives vigorous electrophysiological responses and the expression of several activity-regulated genes in NCM.Interestingly,NCM neurons are tuned to species-specific songs and undergo some forms of experience-dependent plasticity in-vivo . These activity-dependent changes may underlie long-term modifications in the functional performance of NCM and constitute a potential neural substrate for auditory discrimination. We end this review by discussing evidence that suggests that NCM may be a site of auditory memory formation and/or storage.
鸣禽的许多社会行为都依赖于对自然交流信号的听觉处理,包括配偶选择、个体识别以及罕见的发声学习行为——即通过模仿成年个体的发声来学习发声,而非依靠本能。与哺乳动物一样,鸣禽拥有一套相互连接的听觉脑的上行和下行通路,这些通路处理声学信息,并且可能参与发声交流信号的感知处理。迄今为止,大多数已研究的听觉区域位于鸣禽的大脑内侧尾状前脑,包括丘脑接受区L(L1、L2和L3亚区)、内侧尾状和外侧尾状中脑皮质(分别为CMM和CLM)以及内侧尾状巢皮质(NCM)。本综述聚焦于NCM,这是一个先前被认为类似于哺乳动物初级听觉皮层部分区域的听觉区域。用听觉刺激对鸣禽进行刺激会在NCM中引发强烈的电生理反应以及几种活动调节基因的表达。有趣的是,NCM神经元对特定物种的歌声具有调谐能力,并且在体内会经历某种形式的经验依赖性可塑性变化。这些依赖于活动的变化可能是NCM功能性能长期改变的基础,并构成听觉辨别潜在的神经基质。我们通过讨论表明NCM可能是听觉记忆形成和/或存储位点的证据来结束本综述。