Two-dimensional receptive Welds of midbrain lateral line units in the goldfish, Carassius auratus

We determined the receptive Welds of midbrain lateral line units in goldWsh, Carassius auratus, with a 50 Hz vibrating sphere placed at various azimuths and elevations alongside the fish and studied how responses were affected by different directions of sphere vibration. The receptive Welds of toral lateral line units, in contrast to those of primary afferent nerve fibers, did not represent the pressure gradient pattern generated by a vibrating sphere. Thus, unlike primary afferents, single toral lateral line units did not code for source location in their spatial discharge patterns. The two-dimensional receptive Welds were round, horizontally or vertically stretched, or complex. While some toral lateral line units were sensitive to the direction of sphere vibration others were not.