Peripheral and central processing of lateral line information.

The lateral line is a hydrodynamic sensory system that allows fishes and aquatic amphibians to detect the water motions caused, for instance, by conspecifics, predators or prey. Typically the peripheral lateral line of fishes consists of several hundred neuromasts spread over the head, trunk, and tail fin. Lateral line neuromasts are mechanical low-pass filters that have an operating range from <1 Hz up to about 150 Hz. Within this frequency range, neuromasts encode the duration, local direction, amplitude, frequency, and phase of a hydrodynamic stimulus. This paper reviews the peripheral and central processing of lateral line information in fishes. Special attention is given to the coding of simple and complex hydrodynamic stimuli, to parallel processing, the roles of the various brain areas that process hydrodynamic information and the centrifugal (efferent) control of lateral line information. The review argues that in order to fully comprehend peripheral and central lateral line information processing, it is imperative to do comparative studies that take into account the ecology of fishes, meaning that natural stimulus and noise conditions have to be considered.