In our four-phase fin stroke, the protraction period began after the fin ceased adduction and began to protract forward, the abduction period began as soon as the fin began to abduct more than 1 deg from its position at the termination of adduction, fin reversal occurred during the short duration after the fin ceased abducting and before it began adducting, and adduction began as soon as the fin adducted more than 1 deg from its fully abducted position. A single electrode was placed in six different muscles: three lateral muscles [arrector ventralis (ARV), abductor profundus (ABP), abductor superficialis (ABS)] and three medial muscles [arrector dorsalis (ARD), adductor profundus (ADP), adductor superficialis (ADS)] (Fig. 16.50±11.28 deg; adjusted P=0.598). Differences in fin kinematics with the loss of sensory feedback also included fin kinematics with a significantly more inclined stroke plane angle, an increased angular velocity and fin beat frequency, and a transition to the body-caudal fin gait at lower speeds. As motors, the pectoral fins are used during posture maintenance, maneuvering and braking (Higham et al., 2005), and serve as primary locomotor propulsors for many species (Walker and Westneat, 1997, 2002a,b). The role of mechanosensation in locomotion has also been studied in terrestrial animals. Muscle activity onset, duration and time of peak amplitude were calculated for six muscles that actuate the pectoral fin. How to use a word that (literally) drives some pe... Name that government! Pectoral fin kinematics before and after the loss of sensory feedback. 7; Table S3). Putative sensors have been indicated to be present in the tendons attached to the base of teleost fin rays (Pansini, 1888; Fessard and Sand, 1937; Ono, 1979), in the connective tissue associated with myotomal muscles in fishes (Ono, 1982), and in the joints and muscles associated with fins in chondrichthyans (Wunderer, 1908; Fessard and Sand, 1937; Lowenstein, 1956). For example, after the loss of sensory feedback from the wings of insects, the activity in elevator muscles increased in intensity and became more variable (Wilson and Gettrup, 1963; Pearson and Wolf, 1987), and elevators fired later in the wing phase, overlapping with the subsequent firing of depressors (Pearson and Wolf, 1987). However, after the loss of sensory feedback, the absolute duration of each fin stroke phase was significantly shorter (P<0.05). Finally, peak leading edge fin ray curvature occurred just before the fin reached maximum velocity during the downstroke and just after the fin reached maximum velocity during the upstroke. Fin beat frequency, fin beat rhythmicity, and the speed at which each fish transitioned from the pectoral to BCF gait were measured before and after the loss of fin ray sensory feedback. Delivered to your inbox! The pectoral fins of fishes perform dual and interacting roles as motors and sensors. EMG signals were amplified by a factor of 10,000, bandpass filtered from 30 Hz to 6 kHz, and notch filtered at 60 Hz using a Grass amplifier (Model 15LT, Grass Technologies, Astro-MED Inc., West Warwick, RI, USA). A single bipolar electrode was then inserted into each of the six major muscles actuating the left pectoral fin. A PCA of the 3D shape of the fin stroke trajectory was conducted in R following published methods (Olsen, 2017), and each fin stroke was treated as a unique species. © 2020 The Company of Biologists Ltd Registered Charity 277992, Pectoral fin kinematics and motor patterns are shaped by fin ray mechanosensation during steady swimming in. The portion of the fin cycle dedicated to abduction and reversal did not change after the loss of fin ray sensory feedback (P>0.05). The pectoral fin beat cycle can be divided into four main phases: a protraction period where the fin is protracted before the start of abduction, abduction (downstroke), a short reversal period where the fin is rotated about its long axis to reorient the leading edge between abduction and adduction, and adduction (upstroke) (Fig. After the loss of sensory feedback, overlap in activity between antagonistic muscles significantly increased during the protraction period (P<0.0001; Table S3). Each stroke plane angle (AP, DV and ML) was then calculated as the angle between each body axis and the corresponding projected body axis vector (see Fig. Further, a behavioral analysis of bluegill sunfish navigating a complex environment found that fish use their pectoral fins to touch obstacles and, in the absence of other sensory modalities (e.g. Definition of pectoral fin : either of the fins of a fish that correspond to the forelimbs of a quadruped Examples of pectoral fin in a Sentence Recent Examples on the Web The collar refers to the section that begins directly behind the head and ends just … One measure of fin deformation that significantly impacts the hydrodynamic performance of a flexible propulsion is camber. We hypothesized that pectoral fin ray proprioceptive feedback helps regulate the activity patterns of muscles actuating the fin, and the loss of fin ray proprioception will lead to increased variance in fin kinematics and muscle activity.
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