Prey Processing in Haemulid Fishes: Patterns of Variation in Pharyngeal Jaw Muscle Activity

1989 ◽  
Vol 141 (1) ◽  
pp. 359-375 ◽  
Author(s):  
PETER C. WAINWRIGHT

This study examines patterns of variation in 15 electromyographic (EMG) variables measured from recordings of pharyngeal jaw muscle activity during prey processing in four species of the perciform fish family Haemulidae. Two questions were of primary interest. (1) Are motor patterns conserved across the four species? (2) Do the fishes alter (modulate) muscle activity patterns when feeding on different prey types? The experimental design used allowed the partitioning of variance in EMG variables among species, among individuals within species, among days within individuals, among feedings within days, and among prey types. Only one variable exhibited a significant species effect, indicating that the four species used virtually the same motor pattern during prey processing. In response to three prey types differing in hardness, all four species demonstrated an ability to modulate several EMG variables that characterized the intensity of electrical activity. However, variables characterizing the relative timing of muscle activities were not influenced by prey type. A significant variance component was found among recording days and, together with the possibility of variation among experimental preparations, this raises questions about the extent of previously reported inter-individual variation in EMGs. These results support a growing data base on aquatic feeding in lower vertebrates which finds that: (1) motor patterns tend to be highly conserved among closely related taxa; (2) the ability to modulate motor patterns in response to different prey types appears to be a general property of teleost fish feeding mechanisms; and (3) variation in experimental EMG data is ubiquitous and, when unaccounted for, confounds comparisons among treatment groups.

2000 ◽  
Vol 203 (20) ◽  
pp. 3161-3176 ◽  
Author(s):  
J.R. Grubich

This study explores the evolution of molluscivory in the marine teleost family Sciaenidae by comparing the motor activity patterns of the pharyngeal muscles of two closely related taxa, the molluscivorous black drum (Pogonias cromis) and the generalist red drum (Sciaenops ocellatus). Muscle activity patterns were recorded simultaneously from eight pharyngeal muscles. Electromyographic (EMG) activity was recorded during feeding on three prey types that varied in shell hardness. Canonical variate and discriminant function analyses were used to describe the distinctness of drum pharyngeal processing behaviors. Discriminant functions built of EMG timing variables were more accurate than muscle activity intensity at identifying cycles by prey type and species. Both drum species demonstrated the ability to modulate pharyngeal motor patterns in response to prey hardness. The mean motor patterns and the canonical variate space of crushing behavior indicated that black drum employed a novel motor pattern during molluscivory. The mollusc-crushing motor pattern of black drum is different from other neoteleost pharyngeal behaviors in lacking upper jaw retraction by the retractor dorsalis muscle. This functional modification suggests that crushing hard-shelled marine bivalves requires a ‘vice-like’ compression bite in contrast to the shearing forces that are applied to weaker-shelled fiddler crabs by red drum and to freshwater snails by redear sunfish.


1993 ◽  
Vol 180 (1) ◽  
pp. 209-227 ◽  
Author(s):  
P. C. Wainwright ◽  
R. G. Turingan

Teleost fishes typically capture prey with the oral jaws and perform most types of prey- processing behavior with the pharyngeal jaw apparatus. In these fishes, the motor patterns associated with the different stages of feeding are quite distinct, and fish can modify muscle activity patterns when feeding on different prey. We examined motor pattern variation in the queen triggerfish, Balistes vetula, a versatile predator that both captures and processes prey with its oral jaws. During feeding on three prey that differed in hardness and elusiveness, three distinct patterns of behavior could be identified on the basis of patterns of muscle activity: prey capture, buccal manipulation and blowing. During prey capture by suction feeding, the retractor arcus palatini muscle (RAP) commenced activity before the levator operculi muscle (LOP). In both buccal manipulation and blowing, the RAP began activity well after the onset of activity in the LOP. Both prey capture and buccal manipulation motor patterns varied when fish fed on different prey. When capturing hard-shelled and non-elusive prey, B. vetula did not employ suction feeding but, instead, the fish directly bit parts of its prey. The motor pattern exhibited during direct biting to capture prey was different from that during suction feeding, but was indistinguishable from the pattern seen during the repeated cycles of buccal manipulation. Harder prey elicited significantly longer bursts of activity in the jaw adductor muscles than did soft prey. In spite of the involvement of the oral jaws in virtually all stages of feeding, B. vetula shows levels of variation between patterns of behavior and types of prey characteristic of previously studied teleost fishes. Thus, the coupling of capture and processing behavior patterns in the repertoire of the oral jaws does not appear to constrain the behavioral versatility of this species.


1989 ◽  
Vol 141 (1) ◽  
pp. 343-358 ◽  
Author(s):  
S. M. REILLY ◽  
G. V. LAUDER

Muscle activity patterns (motor patterns) of the jaw musculature of all vertebrates studied to date (primarily fishes and amniotes) vary considerably when they feed on different types of prey. Previous data on buccal pressure patterns suggested that feeding in the aquatic salamander Ambystoma mexicanum (Shaw), is highly stereotyped. This hypothesis was tested by quantifying the motor pattern used during feeding on two prey types: earthworms and guppies. Twenty-nine variables were measured from the activity pattern of six cranial muscles in the feeding mechanism of Ambystoma mexicanum. These variables included the area under the electromyogram of each muscle, relative muscle onset times, and the amplitudes and durations of muscle bursts. Univariate and multivariate statistical analyses demonstrate that the feeding motor pattern of Ambystoma mexicanum is stereotyped and does not change with prey type, in contrast to motor patterns of other vertebrates studied to date. Individual salamanders use significantly different motor patterns from one another during feeding, but do not alter their motor pattern during feeding on different prey.


2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.


2000 ◽  
Vol 203 (7) ◽  
pp. 1241-1252 ◽  
Author(s):  
B.C. Jayne ◽  
M.W. Daggy

Although lateral axial bending is widespread for the locomotion of ectothermic vertebrates, the axial motor patterns of terrestrial taxa are known only for a limited number of species and behaviors. Furthermore, the extent to which the trunk and tail of ectothermic tetrapods have similar motor patterns is poorly documented. We therefore recorded the activity of the epaxial muscles in the trunk and tail of sand-swimming Mojave fringe-toed lizards (Uma scoparia) to determine whether this specialized behavior has features of the motor pattern that differ from those of diverse ectothermic vertebrates. Muscle activity during initial sand-swimming was a standing-wave pattern in the trunk and tail. Next, the hind limbs moved alternately and the caudofemoralis muscles and nearby axial muscle in the trunk and tail had similar long-duration electromyographic bursts, whereas the anterior trunk had shorter, more frequent electromyographic bursts. The final tail burial involved a traveling wave of posteriorly propagated axial muscle activity within localized regions of the tail. With increased temperature (from 22 to 40 degrees C), the mean frequencies of axial oscillations increased from approximately 7 to 21 Hz, and the greatest value (33 Hz) was nearly twice the maximal limb cycling frequency during running. The mean burial time at the lowest temperature (3.8 s) was nearly twice that for a 10 degrees C higher temperature. For the axial electromyograms, a decrease in temperature of 18 degrees C more than doubled the electromyographic and cycle durations, whereas the duty factors and intersegmental phase lags changed only slightly with temperature.


1997 ◽  
Vol 200 (13) ◽  
pp. 1881-1893 ◽  
Author(s):  
M Westneat ◽  
J Walker

Labriform locomotion is a widespread swimming mechanism in fishes during which propulsive forces are generated by oscillating the pectoral fins. We examined the activity of the six major muscles that power the pectoral fin of the bird wrasse Gomphosus varius (Labridae: Perciformes). The muscles studied included the fin abductors (arrector ventralis, abductor superficialis and abductor profundus) and the fin adductors (arrector dorsalis, adductor superficialis and adductor profundus). Our goals were to determine the pattern of muscle activity that drives the fins in abduction and adduction cycles during pectoral fin locomotion, to examine changes in the timing and amplitude of electromyographic (EMG) patterns with increases in swimming speed and to correlate EMG patterns with the kinematics of pectoral fin propulsion. EMG data were recorded from three individuals over a range of swimming speeds from 15 to 70 cm s-1 (1­4.8 TL s-1, where TL is total body length). The basic motor pattern of pectoral propulsion is alternating activity of the antagonist abductor and adductor groups. The downstroke is characterized by activity of the arrector ventralis muscle before the other abductors, whereas the upstroke involves nearly synchronous activity of the three adductors. Most EMG variables (duration, onset time, amplitude and integrated area) showed significant correlations with swimming speeds. However, the timing and duration of muscle activity are relatively constant across speeds when expressed as a fraction of the stride period, which decreases with increased velocity. Synchronous recordings of kinematic data (maximal abduction and adduction) with EMG data revealed that activity in the abductors began after maximal adduction and that activity in the adductors began nearly synchronously with maximal abduction. Thus, the pectoral fin mechanism of G. varius is activated by positive work from both abductor and adductor muscle groups over most of the range of swimming speeds. The adductors produce some negative work only at the highest swimming velocities. We combine information from pectoral fin morphology, swimming kinematics and motor patterns to interpret the musculoskeletal mechanism of pectoral propulsion in labrid fishes.


2004 ◽  
Vol 91 (5) ◽  
pp. 2380-2384 ◽  
Author(s):  
Paul S. G. Stein ◽  
Susan Daniels-McQueen

Agonist motor neurons usually alternate between activity and quiescence during normal rhythmic behavior; antagonist motor neurons are usually active during agonist motor neuron quiescence. During an antagonist deletion, a naturally occurring motor-pattern variation, there is no antagonist activity and no quiescence between successive bursts of agonist activity. Motor neuron recordings of normal fictive rostral scratching in the turtle displayed rhythmic alternation between activity and quiescence for hip flexors, knee flexors, and knee extensors. Knee-flexor activity occurred during knee-extensor quiescence. During a hip-extensor deletion, a variation of rostral scratching, rhythmic hip-flexor bursts occurred without intervening hip-flexor quiescence. There were 3 distinct patterns of knee motor activity during the cycle before or after a hip-extensor deletion. In most cycles, there was knee flexor-extensor rhythmic alternation. In some cycles, termed knee-flexor deletions, there was no knee-flexor activity and rhythmic knee-extensor bursts occurred without intervening knee-extensor quiescence. In other cycles, termed knee-extensor deletions, there was no knee-extensor activity and rhythmic knee-flexor bursts occurred without intervening knee-flexor quiescence. The concept of a module refers to a population of motor neurons and interneurons with similar activity patterns; interneurons in a module coordinate agonist and antagonist motor neuron activities, either with excitation of agonist motor neurons and interneurons, or with inhibition of antagonist motor neurons and interneurons. Previous studies of hip-extensor deletions support the concept of a rhythmogenic hip-flexor module. The knee-related deletions described here support the concept of rhythmogenic knee-flexor and knee-extensor modules linked by reciprocal inhibition.


CRANIO® ◽  
2019 ◽  
pp. 1-7 ◽  
Author(s):  
Roberta Valentino ◽  
Iacopo Cioffi ◽  
Stefano Vollaro ◽  
Roberta Cimino ◽  
Roberta Baiano ◽  
...  

2002 ◽  
Vol 205 (14) ◽  
pp. 2005-2016 ◽  
Author(s):  
Melina E. Hale

SUMMARYThe startle response is a model system for examining the neural basis of behavior because of its relatively simple neural circuit organization and kinematic pattern. In fishes, the two primary types of startle behavior differ in their initial movements. In the C-start type of startle, the fish bends into a C shape, while the S-start involves an S-shaped body bend. Although considerable research has focused on determining how the C-start is generated neurally, S-start neurobiology has not been examined. I quantify the kinematics and electromyographic patterns of the initial movements of the C-start and S-start behaviors of the muskellunge (Esox masquinongy)to test three hypotheses for how the S-start is generated. (i) The S-start is generated by the same motor neural circuit as the C-start, but passive bending of the tail causes the body to take on an S shape. (ii) The S-start is generated by the same motor neural circuit as undulatory swimming. (iii) The S-start is generated by an independent neural mechanism from that used either in the C-start or in undulatory swimming. Results from kinematics and muscle activity patterns support the third hypothesis. In the muskellunge, the S-start is a high-performance startle behavior with peak angular velocity and peak angular acceleration of its initial bending comparable with those of the C-start and higher than would be expected for undulatory swimming. The S-start motor pattern, however, is distinct from the C-start motor pattern in having simultaneous muscle activity anteriorly on one side of the body and posteriorly on the opposite side. In contrast, the C-start is characterized by simultaneous unilateral muscle activity along the full length of the body. Alternative models are proposed for S-start neural circuit organization involving reticulospinal and local control of muscle activity.


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