Auditory Processing and Memory for Complex Signals

描述（由申请人提供）：口语在交流中的能力是人类物种的定义适应之一，它取决于语音信号的快速产生和感知。鸣禽是少数动物类群中最容易研究的，它们学会像人类一样发出声音信号进行社会交流。在鸣禽中，我们对斑胸草雀的了解是最先进的。本申请提出使用鸣禽前脑中听觉神经元的特性来研究用于听觉通信信号的辨别和记忆的基本神经过程。年轻的雄性斑胸草雀通过模仿的过程从成年导师那里学习发声，这类似于人类的语言习得。这些发声在成年后变得定型，并且对每个人都是独特的，为定量研究服务于这个自然交流系统的大脑过程提供了丰富的材料。利用神经生理学记录在前脑听觉区，尾内侧巢皮质（NCM），P. I。已经证明了一种神经元形式的识别记忆，这种记忆对同种声音的持续时间比对异种声音的持续时间长。这些持久的记忆区分个体同种的独特发声，这表明NCM在处理声音信号中起着特殊的作用。可以评估区分NCM神经元的声音的显著声学和时间特征，因为在这种制备中，重复呈现新的声音导致感觉反应的快速、可量化的降低。当呈现不同的声音时，响应返回到其初始高水平。这是一种刺激特异性适应的形式，让人想起哺乳动物听觉皮层的类似过程。私家侦探现在提出用先进的生理学方法，包括急性和慢性多电极记录，记录清醒斑胸草雀的NCM，以确定1）伴随特定声音信号记忆的神经反应模式的详细变化; 2）控制由音节序列组成的更复杂声音的神经处理的时间规则，如在歌曲中发生的;以及3）在与同种的实时交互期间，这种听觉识别和记忆系统的参与方式。研究结果不仅将提供一个定量描述的听觉处理的行为相关的信号在鸣禽，但也将揭示神经过程，快速的声音序列链接到可识别的听觉对象。这是解码语音和歌曲的基本步骤，因此这些研究可能为人类正常和病理性语音处理提供有用的模型。

DESCRIPTION (provided by applicant): The power of spoken language in communication is one of the defining adaptations of the human species, and it depends on the rapid production and perception of speech signals. Songbirds are the most easily studied of the few animal taxa that learn to produce vocal signals for social communication as humans do. Among songbirds, our knowledge of the zebra finch is most advanced. This application proposes to use the properties of auditory neurons in the songbird forebrain to investigate basic neural processes that serve discrimination and memory for auditory communication signals. Young male zebra finches learn their vocalizations from adult tutors through a process of imitation that resembles human speech acquisition. These vocalizations become stereotyped in adulthood and are unique to each individual, providing rich material for quantitative study of the brain processes that serve this natural communication system. Using neurophysiological recording in a forebrain auditory area, the caudo-medial nidopallium (NCM), the P.I. has demonstrated a neuronal form of recognition memory that lasts longer for conspecific than for heterospecific vocal sounds. These long-lasting memories discriminate the unique vocalizations of individual conspecifics, suggesting that NCM plays a special role in processing vocal signals. The significant acoustic and temporal features that distinguish sounds for NCM neurons can be assessed because, in this preparation, repeated presentation of a novel sound results in rapid, quantifiable decreases of the sensory response. When a different sound is presented, the response returns to its initial high level. This is a form of stimulus specific adaptation, reminiscent of similar processes described for the mammalian auditory cortex. The P.I. now proposes to record from NCM in awake zebra finches with advanced physiological methods, including acute and chronic multi-electrode recording, to determine 1) the detailed changes in neural response pattern that accompany memorization of a specific sound signal; 2) the temporal rules that govern the neural processing of more complex sounds composed of syllable sequences, as occurs in song; and 3) the way in which this auditory recognition and memory system is engaged during real-time interaction with conspecifics. The results will not only provide a quantitative description of auditory processing for behaviorally relevant signals in songbirds, but will also shed light on neural processes that link rapid sound sequences into recognizable auditory objects. This is a basic step in decoding speech, as well as song, so these studies may provide useful models for normal and pathological speech processing in humans.