Perception of the Electric Organ Discharge of Conspecifics by a Weakly Electric Fish

长期以来，科学家们一直对理解感知背后的神经过程感兴趣。在人类中，这些过程和感官刺激本身往往是如此复杂，以至于对感知过程的完全理解是难以捉摸的。然而，有了更简单的动物模型，已经取得了很大的进展，其中(1)所讨论的感觉刺激是容易量化的，可以操纵的，(2)有一种方法来判断动物是否能检测到刺激，(3)负责感知的神经元的反应特性可以直接测量。电鱼提供了这样一个模型系统。扎肯博士的研究涉及一种鱼，这种鱼可以通过尾巴上的一个器官不断地产生弱电场。这个场（电器官放电，简称EOD）围绕着鱼的身体。这种动物能够在黑暗浑浊的水中导航和定位物体，通过身体表面的特殊电感受器检测电场的扭曲。排爆装置也广泛用于鱼类之间的通讯。排爆电压以近似正弦的方式变化。每个人的EOD频率都是独一无二的，男性和女性的频率相差大约一个八度。这些电感受器被调谐到鱼自己的EOD频率，而对其他频率不那么敏感。那么，鱼是如何感知异性产生的爆炸物的呢？当两条电鱼彼此靠近时，每条鱼的电感受器都会受到一个信号的刺激，这个信号是两个eod的总和。排爆信号的相互作用可能使鱼类能够探测到彼此的排爆信号。利用行为训练和神经生理学记录技术，扎肯博士正在研究如何感知这些排爆信号，以及如何从这些信号中提取有关另一条鱼存在的信息。扎肯博士的研究阐明了对生物相关刺激的感知和分析。这种理解是可以获得的，因为电鱼经常依靠电信号来探测该物种的其他成员，因为电信号很容易测量和操纵。所阐明的信号分析的基本过程应该有助于理解其他脊椎动物的感知系统。

Scientists have long been interested in understanding the neural processes underlying perception. In humans, these processes and the sensory stimuli themselves are often so complicated that a complete understanding of the perceptual process is elusive. Much progress has been made, however, with simpler animal models in which (1) the sensory stimulus in question is easily quantifiable and can be manipulated, (2) there is a way to tell if the animal can detect the stimulus, and (3) the response properties of the neurons responsible for the perception can be measured directly. Electric fish provide such a model system. Dr. Zakon's research involves a species of fish that continuously produces a weak electric field from an organ in its tail. This field (the electric organ discharge, or EOD) surrounds the fish's body. The animal is able to navigate and localize objects in dark, murky water by detecting distortions in the electric field with specialized electroreceptors on the body surface. The EOD is also used extensively in communication between fish. The EOD voltage varies in a nearly sinusoidal fashion. The EOD frequency of each individual is unique, and that of males and females differs by roughly an octave. The electroreceptors are tuned to the fish's own EOD frequency and are much less sensitive to other frequencies. How, then, does the fish perceive the EODs produced by members of the opposite sex? When two electric fish are close to each other, each fish's electroreceptors are stimulated by a signal that is the sum of the two EODs. This interaction of EOD signals probably allows the fish to detect each other's EODs. Using behavioral training and neurophysiological recording techniques, Dr. Zakon is studying how these summed EOD signals are perceived and how information about the presence of another fish is extracted from this signal. Dr. Zakon's research is elucidating the perception and analysis of a biologically relevant stimulus. This understanding can be gained because electric fish often rely on electrical signals for the detection of other members of the species and because electrical signals are easy to measure and manipulate. The underlying processes of signal analysis elucidated should be useful in understanding perceptual systems in other vertebrates.