MECHANISMS OF ULTRASOUND DETECTION

检测超声波(频率超过20千赫)的能力并不局限于脊椎动物中的哺乳动物。取而代之的是美国沙鱼，一种(与鲱鱼有亲缘关系的)杆状鱼类可以检测到。猪耳显然参与了超声检测，但超声检测的机制尚不清楚。沙发耳具有许多脊椎动物中独一无二的特征。此外，有证据表明，椭圆体感觉上皮的支持结构可能在功能上类似于哺乳动物Corti器官的高频区。拟议的工作是对耳朵和第八神经进行详细的生理和超微结构分析，以确定超声波是如何检测到的。它还将量化美国沙鱼和其他相关物种的超声波检测能力，以更好地了解可以检测到的信号类型。生理学研究将检查每个内耳耳石内脏的反应特征，并确定参与超声检测的耳朵区域(S)。来自这些区域的神经反应将被量化。使用细胞外和细胞内技术。超微结构和形态方法将被用来了解耳朵的结构，以及超声波检测的机械适应性。马里兰大学的心理物理学研究将检查声波和超声波范围内的听力能力，并表征这些动物在噪音中检测信号的能力。这些研究还将有助于阐明超声波检测的精确机制。莫特海洋实验室(佛罗里达州萨拉索塔)的行为研究将有助于表征对回声定位声音的反应，并帮助确定哪些物种对超声波有反应。这些检查将提供一个机会，在一个非常容易接近的耳朵中检查超声波检测。该系统有可能成为研究耳朵超声区的一种模型系统。这个系统有可能有助于我们理解毛细胞系统及其神经细胞如何对超声波刺激做出反应。此外，该系统可能有助于分析哺乳动物的耳石器官如何潜在地对听力做出贡献。

The ability to detect ultrasonic sounds (frequencies over 20 kHz) is not limited to mammals among the vertebrates. Instead, American shad, a clupeid fish (related to herring) can detect. The shad ear is clearly involved in ultrasound detection, but the mechanism of ultrasound is detection is not known. The shad ear has a number of characteristics that are unique among vertebrates. Moreover, there is evidence that the support structure of the sensory epithelial of the utricle, the primary auditory endorgan in shad, may be functionally analogous to the high frequency regions of the mammalian organ of Corti. The proposed work is to do a detailed physiological and ultrastructural analysis of the ear and eighth nerve in order to determine how ultrasound is detected. It will also quantify the ultrasound detection capabilities of American shad and other-related species in order to get a better understanding of the kinds of signals that can be detected. Physiological studies will examine the response characteristics of each inner ear otolithic endorgan, and determine the ear region(s) involved with ultrasound detection. Neural responses from these regions will be quantified. Using extracellular and intracellular techniques. Ultrastructural and morphological approaches will be used to understand the structure of the ear, and the mechanical adaptations for ultrasound detection. Psychophysical studies at the University of Maryland will examine hearing capabilities at sonic and ultrasonic ranges, and characterize the ability of these animals to detect signals in noise. These studies will also help elucidate the precise mechanisms of ultrasound detection. Behavioral studies at Mote Marine Laboratory (Sarasota, Florida) will help characterize response to echolocation sounds, and help determine which species are response to ultrasound. These investigations will provide an opportunity to examine ultrasound detection in a highly accessible ear. This system has the potential of serving as a model system where ultrasonic region of the ear is amenable to investigation. This system has the potential for contributing to our understanding of how hair cell systems, and their innervating neurons, are able to respond to ultrasonic stimuli. Moreover, this system could be useful in analysis of how otolithic organs of the ear in mammals can potential contribute to hearing.