Neural maps in the electrosensory system of weakly electric fish

• The active electrosense uses multiple topographic maps of the receptor array. • Different cellular and circuit properties of the maps shape spatiotemporal tuning. • The tuning properties of the maps can be linked to specific behavioral tasks. • Topography is lost at the level of the pallium. • Nevertheless, descending projections from the pallium shape the activity of midbrain maps. The active electrosense of weakly electric fish is evolutionarily and developmentally related to passive electrosensation and the lateral line system. It shows the most highly differentiated topographic maps of the receptor array of all these senses. It is organized into three maps in the hindbrain that are, in turn, composed of columns, each consisting of six pyramidal cell classes. The cells in each column have different spatiotemporal processing properties yielding a total of 18 topographic representations of the body surface. The differential filtering by the hindbrain maps is used by superimposed maps in the multi-layered midbrain electrosensory region to extract specific stimulus features related to communication and foraging. At levels beyond the midbrain, topographic mapping of the body surface appears to be lost.