Optimality of a Sensory Receptor Array

神经科学和神经行为学最近研究的一个隐含的假设是，通过自然选择，感觉系统已经进化到最佳的功能表现和/或能量效率。然而，事实证明，要得出功能最佳性和效率的准确定义是极其困难的，更难确定可能制约这一优化过程的不同因素的性质和相对重要性。由吉迪恩博士领导的一个多学科研究小组将开发一个理论框架，以定义和评估一个特定感觉系统的最佳性，并正在进行实验，以评估其最佳性和效率。他们正在研究的系统是板球的颈部感官系统，Acheta home ticus。这个系统的作用是作为动物听觉系统的低频近场延伸，并协调对捕食者、配偶和竞争对手产生的信号的检测、定位和识别。这个系统的感觉器由位于蟋蟀身体后部的一对天线状的“Cerci”组成，每个Cerci上覆盖着大约1000根机械感官毛发。每根毛发都附着在一个神经细胞上。该小组的工作假设是，这些感受器的生物力学和神经生理学特征对于它们所调节的感觉处理操作是优化的。研究人员将确定机械传感毛发和感受器阵列的优化程度和性质，并将确定优化发生的具体限制条件。例如，他们将确定毛发的物理结构是否与行为相关的气流信号相匹配，还将确定两个CECI上的毛发集合的全局配置是否反映了在敏感度、对噪声的稳健性和/或对具有特定行为重要性的特定类型信号的检测方面的优化，例如来自捕食者的信号。它们还将表征与生物力学、资源利用和后续处理操作的效率相关的优化限制。这些目标是通过数学分析、计算机模拟、感官结构的定量形态计量分析和神经生理学实验相结合来实现的。数学和神经科学的研究生将参与该项目，目前正在开发一门跨学科研究生水平的课程，重点是神经系统的最优化。此外，与蒙大拿州立大学的美国印第安人研究机会项目合作，本科生和大学预科阶段的美国原住民学生将进行许多实验和相关的数据分析。

An implicit hypothesis underlying much recent research in neuroscience and neuroethology is that sensory systems have evolved, through natural selection, toward optimal functional performance and/or energetic efficiency. However, it has proven extremely difficult to derive precise definitions for functional optimality and efficiency, and even more difficult to determine the nature and relative importance of different factors that might be constraining this process of optimization. A multidisciplinary group of researchers lead by Dr. Gedeon will develop a theoretical framework for defining and assessing optimality of one specific sensory system and are also carrying out experiments to assess its optimality and efficiency. The system they are studying is the cercal sensory system of the cricket, Acheta domesticus. This system functions as a low-frequency, near-field extension of the animal's auditory system, and mediates the detection, localization and identification of signals generated by predators, mates and competitors. The sense organ for this system consists of a pair of antenna-like 'cerci' at the rear of the cricket's body, each of which is covered with approximately 1000 mechanosensory hairs. Each of these hairs is attached to a single nerve cell. The group's working hypothesis is that the biomechanical and neurophysiological characteristics of these receptor organs are optimized for the sensory processing operations they mediate. The researchers will determine the extent and nature of optimization in the array of mechanosensory hairs and receptors, and will also identify specific constraints under which the optimization has taken place. For example, they will determine whether the physical structures of the hairs are matched to behaviorally relevant air-current signals and also determine if the global configuration of the ensemble of hairs on the two cerci reflects optimization with respect to sensitivity, robustness to noise, and/or to the detection of specific types of signals having particular behavioral importance, such as those from predators. They will also characterize constraints on optimization related to biomechanics, resource utilization, and efficiency of subsequent processing operations. These aims are being achieved through a combination of mathematical analysis, computer simulation, quantitative morphometric analysis of the sensory structures, and neurophysiological experiments. Graduate students in Mathematics and Neuroscience will be involved in the project, and an interdisciplinary graduate-level course is being developed that focuses on optimality in neural systems. Further, in collaboration with the American Indian Research Opportunities program at Montana State University, Native American students at the undergraduate and pre-college levels will carry out many of the experiments and associated data analysis.