Meeting Abstract
Proprioceptive feedback, the sense of movement and position of one’s body elements in space, is critical to the motor performance of many animals. The pectoral fins of fishes are highly innervated by the sensory system and perform dual roles as propulsors and sensors. Fish control the shape of their fins to maintain efficient propulsion in an unstable environment, which suggests that proprioceptive feedback is needed to complete these complex and precise movements. The objective of this study is to examine how the loss of proprioception impacts pectoral fin muscle activity patterns and kinematics of labriform swimmers. To determine how pectoral fin proprioceptive feedback is used in labriform swimming, we performed bilateral transections of all sensory nerves that innervate the pectoral fins of the princess parrotfish (Scarus taeniopterus) and examined the effects on fin kinematics and activity patterns of the muscles used to actuate the fin. The loss of sensory feedback resulted in bilaterally asymmetric fin movements, increased fin beat frequency, and a transition to the body-caudal fin gait at lower speeds. However, pectoral fin rhythmicity remained the same or increased after the loss of sensory feedback. In general, the order of muscle activation during the fin stroke did not change after transection. After the loss of sensory feedback, the duration of each muscle’s activity relative to cycle duration increased and the relative lag between the onsets of activity decreased between muscles. The resultant increase in overlap of activity between abductor and adductor muscle pairs may stiffen the fin to enhance control after sensory loss. These results indicate that proprioceptive feedback is critical for the performance of typical pectoral fin motor patterns and kinematics.
