Meeting Abstract
Fishes use median and paired fins to control their body movements. Although fin kinematics are being studied in a variety of species, little is known of the sensorimotor control of fins. Fish fins are equipped with a neural organization that allows for coordination of two pairs of fins (pectoral and pelvic) and multiple median fins, which offers a rich opportunity to address how the brain and spinal cord control and modulate motor patterns. Here, we combine genetic tools with imaging in larval and juvenile zebrafish to examine the sensory architecture of the fin fold and the sensory and motor innervation of the later developing dorsal and anal fins. The larval fin fold is innervated by the mechanosensory Rohon Beard (RB) neurons, which exhibit diverse arborization patterns. RB somata are often located several segments anterior to the innervated tissue. While all RB cells innervate the trunk body wall, some cells also arborize into the dorsal, ventral or both fin folds. In juvenile zebrafish, sensory innervation of the dorsal and anal fins is provided by dorsal root ganglion (DRG) neurons. Each fin ray is innervated by multiple DRG cells whose somata are located in body segments adjacent to the innervated area. Spinal motor neurons arborize extensively in the serially organized median fin muscles with dense innervation mainly along the base of the fin. Unlike axial motor innervation, fin motor axons appear to extend to multiple fin muscles along the anteroposterior axis of the fin. Investigating patterns of sensorimotor innervation of the median fins will help us understand sensorimotor strategies for fin actuation and multifin coordination. Funding: US Office of Naval Research, Department of Defense. N00014-18-1-2673.
