Neuroethology

Abstract

Neuroethology is concerned with the analysis of the neural substrates and mechanisms that underlie animal behavior. It is the study of causal relationships between specific types of behavior and their neural substrates. Emphasis is placed on the evolutionary and comparative aspects of behavior in this young branch of behavioral physiology. Tinbergen, in The Study of Instinct (1951), introduced the term ethophysiology and stated that the analysis must be carried out from the high levels of behaviors down to the level of neurophysiology. From a broad point of view, the difference between a neuro-ethologist and a neurobiologist is that the methodology and aim of the former is based on a top-down analysis, and that of the latter on a bottom-up analysis. Analysis begins with the behavior itself, e.g., prey catching, courtship behavior, or acoustic communication, to name some highly complex and sequentially organized types of motivated behavior that occur in various phyla of different types of nervous systems. The goal of the analysis is to explain the behavior in neurobiological terms and predict its course under certain determining environmental conditions. Because of the complexity of most types of serial behavior and their underlying neural substrates, it is often advantageous to concentrate efforts on single aspects of a system or even on a single aspect of so-called simple systems, e.g., gill withdrawal in Aplysiu. Whether such analyses can still be regarded as neuroethological depends on the definition of behavior. In ethology, the term means the observable behavior of an intact organism, not the behavior of isolated or severed parts of it. A classic neuroethological example is the evasion maneuvers in noctuid moths, which are based on only two receptor cells in their tympanic organ and four kinds of interneurons in central auditory information processing of bat ultrasound. Here, a specific behavioral strategy of an organism within its ecological constraints can be explained by a relatively simple neuronal mechanism operating at the peripheral and central levels and producing an adaptive response to a meaningful stimulus.