Neuroethology

Neuroethology is a branch of neuroscience that emphasizes the study of neural mechanisms of natural behavior. This is in contrast to other approaches to neuroscience that study the nervous system in isolation, or in the context of artificial conditions. The term itself is a combination of the words neurophysiology and ethology (Pfluger 1999).

As an example, consider the study of hearing in an echolocating bat. A species of bat may use frequency chirps to probe the environment while in flight. A traditional neuroscience study of the auditory system of the bat would involve anesthetizing it, performing a craniotomy to insert recording electrodes in its brain, and then recording neural responses to pure tone stimuli played from loudspeakers. In contrast, an ideal neuroethological study would attempt to replicate the natural conditions of the animal as closely as possible. It would involve recording from the animals brain while it is awake, producing its natural calls while performing some natural behavior such as insect capture.

Technological limitations (see below) restrict how close experiments can get to this ideal. A realistic neuroethological experiment would perhaps restrain the bat in a soft harness, but have it awake. The stimuli presented to the bat would consist of frequency sweeps (chirps) that match closely with the natural sounds produced by the bat.

Philosophy of Neuroethology
The neuroethological approach stems from the idea that animals' nervous systems have evolved to address problems of sensing and acting in certain environmental niches. For example, echolocating bats use ultrasound to navigate and hunt in darkness, while humans use sound mainly for communication. Nervous systems, therefore, are best understood in the context of the problems they have evolved to solve.

Other approaches to understanding nervous systems include the systems identification approach, popular in engineering. The idea is to stimulate the system using a non-natural stimulus with certain properties. The systems response to the stimulus may be used to analyze the operation of the system. Such an approach is useful for linear systems, but the nervous system is notoriously nonlinear, and neuroethologists argue that such an approach is limited.

This argument is supported by experiments in the auditory system. These experiments show that neural responses to complex sounds, like social calls, can not be predicted by the knowledge gained from studying the responses due to pure tones (one of the non-natural stimuli favored by auditory neurophysiologists). This is because of the non-linearity of the system.

Neuroethology and technology
Neuroethology has become more technologically feasible in recent times. The electronics required for amplifying neural signals and for transmitting them over a certain distance have enabled neuroscientists to now record from behaving animals performing activities in naturalistic environments.