Physiological Correlates And Neural Mechanisms Of Vocal Communication

HD001123和HD001124是伙伴项目，共同研究灵长类和其他脊椎动物的听觉交流。这些研究的总体目标是从发育、神经机制、内分泌因素和社会背景等方面全面了解灵长类听觉交流。两种非人类灵长类动物，松鼠猴和普通绒猴是主要的研究对象，并在适当的情况下从其他物种收集额外的数据。在这个使用大脑损伤方法学的项目中，先前的工作表明，人类婴儿哭声的功能和声学等价物的产生是由位于大脑皮层额叶前中线的边缘皮质调节的，听觉皮质中的单个神经元件(颞上回)对物种特定发声的声学结构中的细微差异特别敏感，这表明在调节个体差异(声音特征)方面发挥了重要作用。该实验室的一项新举措使用免疫细胞化学来识别哭闹的婴儿和听到婴儿哭声的成年人中激活的神经元。对幼猴脑内c-fos的表达进行了研究。这一模式包括将个体分开30分钟，记录在分离过程中发出的哭声，将它们放回家中1小时，然后对它们实施安乐死，并使用免疫细胞化学对它们固定的大脑进行Fos处理。特别值得注意的是，在成年猴子身上被发现强标记的区域在婴儿身上也被强标记。尤其是前扣带回，额叶的中线皮质，甚至在1个月龄时就有大量标记细胞。这些结果表明，c-fos免疫细胞化学是一种方法，可以用同样的行为范式显示成年人大脑活跃区域的功能受累。该实验室与NINDS功能和代谢成像实验室的研究人员合作开发的脑图谱提供了识别包含大量Fos的特定结构的手段。去年开始的一项研究使用了类似的方法来识别成年听众在听到婴儿哭声时激活的神经元。对3个男性大脑的分析表明，与MacLean的边缘系统相关的结构，包括前扣带回、直回、隔区、杏仁核和海马区，都有大量Fos标记的细胞。此外，听觉皮质所在的颞上回也有丰富的标记。 使用来自雌性绒猴的MRI图像，在实验室的组织学脑图谱中识别和标记的结构也在MRI图像中被识别(与组织图谱中的图版紧密匹配)，使得在功能MRI研究中更准确地识别绒猴脑中的结构成为可能。与莫纳什大学的MTA将允许那里的研究人员使用来自该图谱的MRI图像来开发新的解剖学工具，以查看和识别绒猴大脑的结构。今年的一项新倡议将大脑中纤维束的识别添加到修订后的地图集中。这是使用与细胞结构切片相匹配的髓鞘染色切片，以及与髓鞘染色切片相匹配的DTI图像来完成的。在髓鞘染色和DTI图像中识别纤维束将首次提供绒猴大脑中纤维束的全面图像。 今年(正在进行中)一项使用c-fos免疫细胞化学的新研究正在检测松鼠猴子大脑中的区域，这些松鼠猴子在社会分离的背景下是高发声或低发声的。松鼠猴大脑中发声的通路是众所周知的，因此这将提供c-fos表达技术揭示的关于发声结构的第一个确证信息。

HD001123 and HD001124 are companion projects that together investigate auditory communication in primates and other vertebrates. The overall goal of these studies is to provide a comprehensive understanding of primate auditory communication in terms of development, neural mechanisms, endocrine factors, and social context. Two non-human primates, the squirrel monkey and common marmoset, are the main subjects of study, with additional data collected from other species where appropriate. Prior work in this project using brain lesioning methodology has shown that production of sounds that are the functional and acoustic equivalents of cry sounds in human infants are mediated by limbic cortex located along the anterior midline of the frontal lobe of the cerebral cortex, and that single neural elements in the auditory cortex (superior temporal gyrus) are particularly responsive to subtle differences in the acoustic structure of species-specific vocalizations, suggesting an important role in mediating individual differences (vocal signatures). A new initiative in the laboratory employs immunocytochemistry to identify the neurons activated in crying infants and in adults hearing infant cries. A study of c-fos expression in infant marmoset monkey brains was conducted. The paradigm involved separating individuals for 30 minutes, recording the cry sounds made during this separation, returning them to their home cage for 1 hour, then euthanizing them and processing their fixed brains for Fos using immunocytochemistry. Of particular note is that regions found to be strongly labeled in adult monkeys were also strongly labeled in infants. In particular, the anterior cingulate gyrus, midline cortex in the frontal lobe, had numerous labelled cells even at 1 month of age. These results indicate that c-fos immunocytochemistry is a method that can demonstrate functional involvement of brain regions also active in adults using the same behavioral paradigm. A brain atlas developed in this laboratory in collaboration with investigators in the NINDS Laboratory of Functional and Metabolic Imaging provided the means to identify the specific structures containing large numbers of Fos. A study begun last year used similar methods to identify the neurons activated in adult listeners upon hearing infant cries. Analysis of 3 male brains indicates that structures associated with the limbic system of MacLean, including the anterior cingulate gyrus, gyrus rectus, septum, amygdala and hippocampus, all have significant numbers of Fos-labeled cells. In addition, the superior temporal gyrus, where the auditory cortex is located, is richly labeled. Using MRI images from a female marmoset, structures identified and labeled in the lab's histological brain atlas were also identified in the MRI images (closely matched to the plates from the histological atlas), making it possible to more accurately identify structures in the marmoset brain in functional MRI studies. An MTA with Monash University will permit investigators there to use the MRI images from this atlas to develop new anatomical tools for viewing and identifying structures in the marmoset brain. A new initiative this year has added identification of fiber tracts in the brain to a revised atlas. This is being done using myelin-stained sections matched to the cell structure sections, and DTI images matched to the myelin-stained sections. Identification of fiber tracts in the myelin-stained and DTI images will provide, for the first time, a comprehensive picture of fiber tracts in the marmoset brain. A new study this year (in progress) using c-fos immunocytochemistry is examining areas in the brains of squirrel monkeys who are high- or low-vocalizers in the context of social separation. The pathways in the squirrel monkey brain for vocal production are well known, hence this will provide the first confirmatory information about vocal structures as revealed by the c-fos expression technique.