Neuronal basis of source localisation and the processing of bulk water flow with the fish lateral line

Fish perceive local water motions and local pressure gradients with their mechanosensory lateral line. The sensory units of the lateral line are the neuromasts that are distributed across the surface of the animal. Water motions are received and transduced into neuronal signals by neuromast hair cells. The information is then conveyed by afferent nerve fibers to the fish brain and processed by lateral line neurons in distinct nuclei of the brainstem, cerebellum, midbrain, and forebrain. The present review introduces the peripheral morphology of the lateral line and describes physiological work, thereby focussing on recent studies that have investigated what kind of sensory information is provided by dipole sources and bulk water flow, and how fish use and process this flow information.