Acoustic Behavior - Neural and Comparative Bases

描述(申请人提供)：该实验室的长期目标是了解生物力学、解剖学和生理学如何使听力具有高灵敏度和方向性。由于物理限制使得声音定位和高灵敏度对于微尺度的耳朵来说是非常具有挑战性的，所以本建议将重点放在微尺度的耳朵上。蚊子是最小的能听到声音的动物之一。它们的触角连在约翰斯顿的听力器官(JOS)上，作为头上的外部附属物。JOS在功能上类似于哺乳动物的耳蜗，但更容易接近。这项工作将使用多普勒激光测振仪测量机械响应和生理记录，以测试两个天线的灵敏度。初步数据显示，这些耳朵对大带宽的声音很敏感，振动模式与以前发表的有很大不同。这些数据将导致天线振动的数学模型。初步计算表明，天线的噪声特性可能优于鼓膜的噪声特性。伊蚊并不是最小的能听到声音的昆虫。有趣的是，更小的蚊子和更大的蚊子的触角都差不多大小。这表明它们都接近声学功能的下限。比较这三个物种的耳朵可能会揭示出听觉功能的局限性。JO的30,000多个感官细胞具有独特的、高度有序的结构，暗示着音调组织和形态分级，使性能与宏观耳朵相当。蚊子的触角对重力、风和声音都有反应。将用分子标记来探测触角的基本结构和功能，以确定其机械感觉神经元之间的功能细分。这项研究与公共卫生和NIDCD的使命有关。远场粒子速度和天线耳朵在小尺寸的听觉声学中是一个相对未被探索的领域。这项工作的一个目标是揭示各种规模的听觉功能背后的基本原理。小型化是实际工程中梦寐以求的目标。这些微型耳朵的设计特点可以激励机械工程师进行仿生，并将其转化为新颖的纳米到微米尺度的定向麦克风。这些发现可能远远超出了昆虫学的好奇心。 与公共健康相关：该项目调查已知最小耳朵的听力，最终目标是提供信息，供工程师用来开发小型定向麦克风，以改进助听器。

DESCRIPTION (provided by applicant): The long-term goal of this laboratory is to understand how biomechanics, anatomy, and physiology enable hearing of high sensitivity and directional acuity. This proposal focuses on microscale ears because physical constraints make sound localization and high sensitivity extraordinarily challenging with ears of microscale dimension. Mosquitoes are among the smallest animals that hear. They possess antennae attached to Johnston's hearing organs (JOs) as external appendages on their heads. JOs are functionally analogous to the mammalian cochlea, but far more accessible. This work will use Doppler laser vibrometry to measure mechanical responses and physiological recordings to test the sensitivity of the two antennae. Preliminary data show that these ears are sensitive to sound over a large bandwidth and have modes of vibration substantially different from those published before. These data will lead to a mathematical model of antennal vibration. Preliminary calculations already indicate that antennae may have noise characteristics superior to those of tympana. The Aedes mosquito is not the smallest insect that hears. Interestingly, the antennae of even tinier midges and of even larger mosquito species are all about the same size. This suggests that they are all near the lower size limit for acoustic function. Comparing ears in these three species may reveal the limits of auditory function. The over 30,000 sensory cells of the JO have a unique and highly-ordered architecture that suggest tonotopic organization and modality fractionation enabling performance equal to macroscopic ears. Mosquito antennae respond to gravity and wind as well as to sound. The basic structure and function of antennae will be probed with molecular markers to determine functional subdivisions among its mechanosensory neurons. This research is relevant to public health and the mission of NIDCD. Far-field particle velocity and antennal ears are a relatively unexplored realm of auditory acoustics at small size. A goal of this work is to reveal the basic principles behind auditory function at all size scales. Miniaturization is coveted goal in practical engineering. The design features of these miniature ears could motivate mechanical engineers to biomimic and "translate" them into novel nano-to-microscale directional microphones. These findings potentially extend well beyond mere entomological curiosity. PUBLIC HEALTH RELEVANCE: This project investigates hearing in the smallest known ears, with the ultimate goal of providing information that engineers might use to develop small directional microphones for improved hearing aids.