Model Systems in Neuroethology

通过研究一种特殊的动物物种--所谓的“冠军物种”，已经取得了许多突破性的发现。例如，我们对人类大脑中神经元如何发送信号的基本了解来自对鱿鱼巨大神经的研究，而允许人类神经和肌肉之间交流的分子(乙酰胆碱受体)的发现来自对电鳗的研究。在这里，研究人员将使用类似的方法研究星鼻鼹鼠及其近亲，以了解分子和大脑组织水平上的触觉。星鼻鼹鼠的鼻子末端有一组特有的星形触角；触角的触摸可以感知和定位食物。星鼻鼹鼠的触觉是所有哺乳动物中最发达的。令人惊讶的是，在哺乳动物(和人类)的皮肤中产生触摸信号的分子仍然没有被发现。初步研究表明，星鼻鼹鼠的恒星中含有大量这样的分子，这可能会在理解触摸信号是如何产生方面取得突破。除了这个目标之外，研究人员还将调查大脑中的空间是如何专门用于处理最重要的输入的。这一点很重要，因为熟练的行为(如演奏乐器或在电脑上打字)需要很大的脑区。这在较高的大脑水平(如大脑新皮质)是很好理解的，但关于大脑通路(脑干和丘脑)的较低区域是如何为熟练行为分配空间的，我们知之甚少。了解触摸的分子和触摸在大脑中的处理方式是一个基本目标，这将使研究人员了解哺乳动物和人类的正常和异常情况。此外，这种独特的动物还可以作为向学生和公众教授生物学和感官的工具。这些研究将为教学提供引人注目的工具，并将为学员提供广泛的接触行为神经生物学的机会，从行为学到解剖学，再到单细胞记录和分子生物学。对星鼻鼹鼠的研究将探索鼻子上独特的“触觉中心凹”的组织和表现。恒星的这一小块区域用于高敏锐度触摸，在大脑中的比例过高，这为更好地理解与行为上重要的身体部位相关的大脑映射提供了机会。此外，感受器致密的皮肤有助于利用生物信息学识别感觉神经元中介导触摸的分子。另一方面，东方鼹鼠具有特殊的嗅觉能力和相关行为，这将使人们更好地了解动物如何定位气味并跟踪气味踪迹。因为所有哺乳动物都有共同的大脑组织和功能的基本特征，所以这些发现将帮助我们理解神经系统如何处理感觉信息的一般原理。更具体地说，星鼻鼹鼠在理解大脑图谱以及初级传入和代表行为重要皮肤表面的中枢神经系统区域之间的关系方面具有优势。这是我们理解正常和不正常的大脑组织和发育的基础。

Many groundbreaking findings have been made by studying a specialized animal species - a so-called "champion species." For example, our basic understanding of how neurons in human brains send signals came from studies of the giant nerves of squid, whereas discovery of the molecule (the acetylcholine receptor) that allows communication between nerves and muscles in humans came from studies of the electric eel. Using a similar approach here the researchers will study star-nosed moles and their relatives to understand the sense of touch at both the molecular and brain organization levels. Star-nosed moles have a characteristic star-shaped set of tentacles at the end of their snout; food is sensed and located by touch of the tentacles. Star-nosed moles have the most developed sense of touch of any mammal species. Surprisingly, the molecules that generate touch signals in the skin of mammals (and humans) remain undiscovered. Preliminary investigations show that star-nosed moles have great numbers of these molecules in their star, which may allow for a breakthrough in understanding how touch signals are generated. In addition to this goal, the researchers will investigate how space in the brain is devoted to processing the most important inputs. This is important because skilled behaviors (such as playing a musical instrument or typing on a computer) require large brain territories. This is well understood at the higher brain levels (such as the cerebral neocortex) but little is known about how space in lower areas of the brain pathways (the brainstem and thalamus) is divided up for skilled behaviors. Understanding both the molecules of touch and the way touch is processed in brains is a basic goal that will inform researchers about both normal and abnormal conditions in mammals and humans generally. In addition, the unique animals serve as vehicles for teaching about biology and senses to both students and the public. These investigations will provided compelling vehicles for teaching and will provide trainees with broad exposure to behavioral neurobiology ranging from behavior, to anatomy, to single-cell recordings and molecular biology. Studies of star-nosed moles will explore the organization and representation of the unique "tactile fovea" on the nose. This small area of the star, used for high acuity touch, is over-represented in the brain, providing an opportunity for better understanding brain mapping related to behaviorally important body parts. In addition, the receptor-dense skin is useful for identifying the molecules that mediate touch in sensory neurons using bioinformatics. Eastern moles, on the other hand, have exceptional olfactory abilities and related behaviors that will allow for better understanding of how animals localize odorants and follow scent trails. Because all mammals share basic features of brain organization and function, findings will help us to understand general principles of how nervous systems process sensory information. More specifically, the star-nosed mole has advantages for understanding brain mapping and the relationship between primary afferents and areas of the central nervous system that represent behaviorally important skin surfaces. This is fundamental to our understanding of normal and abnormal brain organization and development.