The neural basis for birdsong rhythm and sequencing

描述（由申请人提供）：鸟叫是一种习得的、复杂的行为，它是在多个时间尺度上组织起来的，与人类语言的韵律和音素等方面类似。有人提出，歌曲仅在一个精细的时间尺度上通过神经回路进行编码；然而，这些研究仅限于前脑的前馈控制。本研究的总体目的是研究复发性脑干-前脑回路（BFC）如何在更广泛的范围内代表斑胸草雀歌唱的节奏方面。我假设BFC将前脑活动的必然释放与即将到来的发声命令的生成结合起来。我将在成人歌曲制作过程中，用BFC的两个关键区域的长期单单元录音来检验这一假设。首先，我将记录下前脑核RA的背侧区域，目前认为这是对歌唱时的呼吸活动进行编码的区域。其次，我将记录脑干核PAm和DM，它们都接受来自背侧RA的输入，并通过丘脑向前脑投射；目前，人们对这些亚种群中歌曲的编码方式知之甚少。我将比较这些区域中每个尖峰列车的时间与音节开始、偏移和长度。重要的是，在这个分析中，我将利用歌声时间和顺序的反复变化作为一个关键的自由度：尽管斑胸草雀的歌声是高度刻板的，但它也表现出微妙但系统的时间和顺序变化，这可能与运动代码直接相关。像这样自然发生的扰动可以揭示神经网络中特别薄弱的环节，这些环节在更严重的情况下（如疾病）更容易被破坏。人类语言中类似的时间尺度已经被确定，并与失语症（如口吃）和小脑等关键区域的损伤有关。因此，发现斑胸草雀的歌声是如何编码“韵律”的，可能会对人类语言和已知病理的生理基础有重要的见解。公开声明：伯德桑为研究大脑如何产生复杂的声音交流提供了一个令人兴奋的机会。歌曲有一个与人类语言非常相似的时间组织，但到目前为止，人们对这个组织的神经基础仍然知之甚少。目前的研究旨在研究神经回路如何编码歌曲中个体发声的节奏和顺序。因此，这项研究可能会对影响人类语言类似因素的障碍，如口吃，提供重要的见解。

DESCRIPTION (provided by applicant): Birdsong is a learned, complex behavior that is organized on multiple timescales that are analogous with aspects of human speech such as prosody and phonemes. It has been proposed that songs are encoded over neural circuits on a single fine timescale only; however, these studies have been restricted to feed forward control in the forebrain. The general aim of this research is to examine how recurrent brainstem-forebrain circuitry (BFC) represents the rhythmic aspects zebra finch song on broader scales. I hypothesize that BFC integrates corollary discharge of forebrain activity with the generation of commands for upcoming vocalizations. I will test this hypothesis with chronic, single-unit recordings in two key areas of BFC during adult song production. First, I will record from the dorsal region of forebrain nucleus RA, which is currently understood to encode the respiratory activity which accompanies song. Second, I will record from brainstem nuclei PAm and DM, both of which receive inputs from dorsal RA and project back towards the forebrain via the thalamus; currently very little is known about how song is encoded over these subpopulations. I will compare the timing of spike trains in each of these areas with syllable onsets, offsets and lengths. Importantly, I will exploit trial-to-trial variability in song timing and sequencing as a critical degree of freedom in this analysis: although zebra finch song is highly stereotyped, it also exhibits subtle but systematic variability in timing and sequencing that may be directly related to the motor code. Naturally occurring perturbations such as these could reveal especially weak links in neural networks that are more easily disrupted under more severe conditions such as a disease. Analogous timescales in human speech have been identified and are implicated in aphasias such as stuttering and lesions to key areas such as the cerebellum. Thus, the discovery of how "song prosody" is encoded in zebra finch song may reveal important insights into the physiological basis for human speech and known pathologies. Public statement: Birdsong has provided a exciting opportunity to investigate how the brain produces complex, vocal communication. Songs have a temporal organization that is very similar to human speech, but so far the neural basis of this organization remains poorly understood. The current study is aimed at how neural circuits encode the rhythm and order of individual vocalizations in song. This research may thus reveal important insights into disorders that affect similar elements of human speech, such as stuttering.