Collaborative Research: Mechanisms of Sound Source Localization Underlying an Ancestral Mode of Vertebrate Hearing

定位声音来源的能力使动物能够发现猎物，避开捕食者，并与其他动物交流，因此是许多物种生存的基础。虽然数十年的行为、生理和神经解剖学研究揭示了陆地动物用来定位声音的物理线索和神经机制，但鱼类作为现存最古老的脊椎动物群体使用的机制仍然是一个谜。总而言之，这些实验将研究鱼类利用的声音定位的机制，这些机制可能形成了脊椎动物最近的听力和声音定位模式的进化基础。在整个项目中，Sisneros博士和Forlano博士将培训和指导研究生和本科生，并在星期五港实验室(FHL)就所支持的研究进行年度公开演讲。作为这项研究计划不可或缺的一部分，Sisneros博士和Forlano博士将在每年夏天在FHL接待GK-12教师，他们将在那里参加实地和实验室实验。研究人员还将与他们所在机构的教师一起制定教学计划、学生项目和一个教育网站。这项研究将采取综合的行为、解剖学和大脑激活方法来确定鱼类是否与其他被研究的脊椎动物在根本上相似，并使用双耳信息(来自两只耳朵的信息)来定位声音，或者根本不同，并仅基于单耳(单耳)信息实现稳健的定位。需要检验的中心假设是，双耳整合对于学员声源定位是必不可少的。为了验证这一假设，研究人员将1)通过在系统地单侧或双侧移除每个内脏的耳石(球囊、球囊、椭圆囊)之前和之后在已建立的声音回放范例中测试动物来确定声音定位行为需要哪些内耳内耳内脏，2)通过用不同的荧光标记的葡聚糖胺示踪剂分别或以双重或三重组合整体标记每个内脏来表征来自所有三个内脏的内耳传入到后脑中已知听觉处理区域的同侧和对侧投射，以及3)表征在完整动物和那些经历了系统性内脏移除的动物中由受控听觉定向刺激所产生的大脑激活模式，使用c-Fos作为神经激活的标志物。所有原始、处理和合并的数据的复制数字文件将由两名研究人员存储在本地和云中，并将在发布后两年内公开提供。

The ability to locate the source of sounds enables animals to detect prey, avoid predators and communicate with others and is thus basic to survival in many species. While decades of behavioral, physiological and neuroanatomical research have revealed the physical cues and neural mechanisms that terrestrial animals use to localize sound, the mechanisms used by fish, the oldest living vertebrate group, remain a mystery. Collectively, these experiments will investigate the mechanisms of sound localization utilized by fish that likely formed the evolutionary foundation for more recent modes of vertebrate hearing and sound localization. Throughout the project, Drs. Sisneros and Forlano will train and mentor both graduate and undergraduate students and give annual public lectures regarding the supported research at the Friday Harbor Labs (FHL). As an integral part of this research program, Drs. Sisneros and Forlano will host GK-12 teachers every summer at FHL where they will participate in field and laboratory experiments. The researchers will also develop lesson plans, student projects and an educational website with the teachers at their home institutions. The investigation will take an integrated behavioral, anatomical, and brain activational approach to determine whether fish are fundamentally similar to other studied vertebrates, and use binaural information (information from both ears) to localize sound, or are fundamentally different, and achieve robust localization on the basis of monaural (single-ear) information alone. The central hypothesis to be tested is that binaural integration is essential for sound source localization in midshipman. To test this hypothesis, the investigators will 1) determine which inner ear endorgans are required for sound localization behavior by testing animals in an established sound playback paradigm before and after systematic unilateral or bilateral removal of each endorgan's otolith (saccule, lagena, utricle), 2) characterize the ipsilateral and contralateral projections of inner ear afferents from all three endorgans to known auditory processing regions in the hindbrain by bulk labeling each endorgan separately or in double or triple combination with different fluorescent-labeled dextran amine tracers, and 3) characterize the brain activation patterns resulting from controlled auditory directional stimulation in intact animals and in those that have undergone systematic endorgan removal, using c-Fos as a marker for neural activation. Duplicate digital files of all raw, processed and consolidated data will be stored locally and in the cloud by both researchers and will be made publically available within two years following publication.