FIGURE 6

FIGURE 6

islet2B+ neurons innervate both the fin and the body axis. A subset of single neuron reconstructions color coded to indicate the axial innervation in white and the fin only innervation in pink. (A)Left, the cell has very little fin innervation and the primary afferent that enters the fin loops back out of the fin. Right, the cell has far more extensive coverage of the fin. (B)Left, a third cell is color coded for axial innervation (white), fin innervation (pink), and axial innervation under the fin (green). The inset image shows a 90 degree rotation of the same fish with the same color coding. Right, there is a substantial amount of axial innervation across all sampled fish, and the amount of axial, fin, or under the fin innervation varies across a wide range of afferent lengths. In general, the whole population has higher primary afferent lengths on the axis compared to the fin. Notably, some fish have zero to very little innervation under the fin. (C)Left, the same reconstruction in (B) is color coded for medial fin innervation (purple) and lateral fin innervation (orange). The inset again shows the same reconstruction rotated 90 degrees. Right, the number of terminals on the medial fin surface is positively correlated with the number of terminals on the axial surface under the fin (purple graph, correlation, p < 0.01). The number of terminals on the lateral fin surface shows no trend in relation to the number of terminals on the axial surface under the fin (orange graph, correlation, p > 0.05). Anterior is to the left, dorsal is up in reconstructions. In insets, medial is to the left and dorsal is up.