Physiological Correlates And Neural Mechanisms Of Vocal Communication

HD001123和HD001124是合作项目，共同研究灵长类动物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、内分泌因素和社会环境等方面全面了解灵长类动物的听觉交流。两种非人类灵长类动物，松鼠猴和普通狨猴，是研究的主要对象，并在适当情况下从其他物种收集额外数据。该项目先前使用脑损伤方法的工作表明，人类婴儿哭声的功能和声学等效声音的产生是由位于大脑皮层额叶前中线的边缘皮层介导的，并且听觉皮层（颞上回）中的单个神经元素对物种特异性发声的声学结构的细微差异特别敏感。表明在调节个体差异（声音特征）中起重要作用。实验室的一项新举措是利用免疫细胞化学来识别哭泣的婴儿和听到婴儿哭声的成年人体内激活的神经元。研究了c-fos在狨猴幼脑中的表达。该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，将它们送回家中的笼子1小时，然后对它们实施安乐死，并使用免疫细胞化学处理它们固定的大脑。特别值得注意的是，在成年猴子身上发现的被强烈标记的区域在婴儿身上也被强烈标记。特别是，在1个月大的时候，前额叶中线皮层的前扣带回就有大量的标记细胞。这些结果表明，c-fos免疫细胞化学是一种可以使用相同的行为范式来证明成年人活跃的大脑区域的功能参与的方法。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含有大量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边缘系统相关的结构，包括扣带前回、直回、中隔、杏仁核和海马，都有显著数量的fos标记细胞。此外，听觉皮层所在的颞上回也被充分标记。

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.