Optimality of a Sensory Receptor Array

最近神经科学和神经行为学研究中的一个隐含假设是，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，它已被证明是非常困难的，以获得精确的定义功能的最优性和效率，甚至更难确定的性质和相对重要性的不同因素，可能会限制这一过程的优化。Gedeon博士领导的一个多学科研究小组将开发一个理论框架，用于定义和评估一个特定感觉系统的最优性，并正在进行实验，以评估其最优性和效率。 他们正在研究的系统是蟋蟀AchetaAchticus的尾感觉系统。该系统作为动物听觉系统的低频近场延伸，并介导捕食者、配偶和竞争者产生的信号的检测、定位和识别。这个系统的感觉器官由蟋蟀身体后部的一对触角状的“尾索”组成，每个尾索覆盖着大约1000根机械感觉毛。每根毛发都附着在一个神经细胞上。该小组的工作假设是，这些受体器官的生物力学和神经生理学特征是针对它们介导的感觉处理操作而优化的。研究人员将确定机械感觉毛发和受体阵列的优化程度和性质，并确定优化发生的具体约束条件。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，并且还确定两个尾须上的毛发集合的全局配置是否反映了关于灵敏度、对噪声的鲁棒性和/或对具有特定行为重要性的特定类型的信号（例如来自捕食者的信号）的检测的优化。他们还将描述与生物力学，资源利用和后续处理操作效率相关的优化约束。这些目标是通过数学分析、计算机模拟、感觉结构的定量形态学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，并且正在开发一个跨学科的研究生课程，重点是神经系统的最优性。此外，与蒙大拿州立大学的美洲印第安人研究机会方案合作，本科和大学预科的美洲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.