S- and C-start escape responses of the muskellunge (Esox masquinongy) require alternative neuromotor mechanisms

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.

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.


1998 ◽  
Vol 201 (7) ◽  
pp. 949-961 ◽  
Author(s):  
G. B. Gillis

Historically, the study of swimming eels (genus Anguilla) has been integral to our understanding of the mechanics and muscle activity patterns used by fish to propel themselves in the aquatic environment. However, no quantitative kinematic analysis has been reported for these animals. Additionally, eels are known to make transient terrestrial excursions, and in the past it has been presumed (but never tested) that the patterns of undulatory movement used terrestrially are similar to those used during swimming. In this study, high-speed video was used to characterize the kinematic patterns of undulatory locomotion in water and on land in the American eel Anguilla rostrata. During swimming, eels show a nonlinear increase in the amplitude of lateral undulations along their bodies, reaching an average maximum of 0.08L, where L is total length, at the tip of the tail. However, in contrast to previous observations, the most anterior regions of their bodies do not undergo significant undulation. In addition, a temporal lag (typically 10–15 % of an undulatory cycle) exists between maximal flexion and displacement at any given longitudinal position. Swimming speed does not have a consistent effect on this lag or on the stride length (distance moved per tailbeat) of the animal. Speed does have subtle (although statistically insignificant) effects on the patterns of undulatory amplitude and intervertebral flexion along the body. On land, eels also use lateral undulations to propel themselves; however, their entire bodies are typically bent into waves, and the undulatory amplitude at all body positions is significantly greater than during swimming at equivalent speeds. The temporal lag between flexion and displacement seen during swimming is not present during terrestrial locomotion. While eels cannot move forwards as quickly on land as they do in water, they do increase locomotor speed with increasing tailbeat frequency. The clear kinematic distinctions present between aquatic and terrestrial locomotor sequences suggest that eels might be using different axial muscle activity patterns to locomote in the different environments.


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.


1985 ◽  
Vol 53 (6) ◽  
pp. 1517-1534 ◽  
Author(s):  
G. A. Robertson ◽  
L. I. Mortin ◽  
J. Keifer ◽  
P. S. Stein

A turtle with a complete transection of the spinal cord, termed a spinal turtle, exhibits three types or “forms” of the scratch reflex: the rostral scratch, pocket scratch, and caudal scratch (21). Each scratch form is elicited by tactile stimulation of a site on the body surface innervated by afferents entering the spinal cord caudal to the transection. We recorded electromyographic (EMG) potentials from the hindlimb during each of the three forms of the scratch in the spinal turtle (see Fig. 1). Common to all scratch forms is the rhythmic alternation of the activity of the hip protractor muscle (VP-HP) and hip retractor muscle (HR-KF). Each form of the scratch displays a characteristic timing of the activity of the knee extensor muscle (FT-KE) with respect to the cycle of activity of the hip muscles VP-HP and HR-KF. In a rostral scratch, activation of FT-KE occurs during the latter portion of VP-HP activation. In a pocket scratch, activation of FT-KE occurs during HR-KF activation. In a caudal scratch, activation of FT-KE occurs after the cessation of HR-KF activation. The timing characteristics of these muscle activity patterns correspond to the timing characteristics of changes in the angles of the knee joint and the hip joint obtained with movement analyses (21). We recorded electroneurographic (ENG) potentials from peripheral nerves of the hindlimb during each of the three forms of the “fictive” scratch in the spinal turtle immobilized with neuromuscular blockade (see Fig. 4). Common to all forms of the fictive scratch is the rhythmic alternation of the activity of hip protractor motor neurons (VP-HP) and hip retractor motor neurons (HR-KF). Each form displays a characteristic timing of the activity of knee extensor motor neurons (FT-KE) with respect to the cycle of VP-HP and HR-KF motor neuron activity. The timing characteristics of these motor neuron activity patterns are similar to the timing characteristics of the muscle activity patterns obtained in the preparation with movement (cf. Figs. 1 and 4). The motor pattern for each scratch form is generated centrally within the spinal cord. In the spinal immobilized preparation, neuromuscular blockade prevents both limb movement and phasic sensory input, and complete spinal transection isolates the cord from supraspinal input.(ABSTRACT TRUNCATED AT 400 WORDS)


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.


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.


2008 ◽  
Vol 99 (5) ◽  
pp. 2408-2419 ◽  
Author(s):  
Eric D. Tytell ◽  
Avis H. Cohen

In fishes, undulatory swimming is produced by sets of spinal interneurons constituting a central pattern generator (CPG). The CPG generates waves of muscle activity that travel from head to tail, which then bend the body into wave shapes that also travel from head to tail. In many fishes, the wavelengths of the neural and mechanical waves are different, resulting in a rostral-to-caudal gradient in phase lag between muscle activity and bending. The neural basis of this phase gradient was investigated in the lamprey spinal cord using an isolated in vitro preparation. Fictive swimming was induced using d-glutamate and the output of the CPG was measured using suction electrodes placed on the ventral roots. The spinal cord was bent sinusoidally at various points along its length. First, the ranges of entrainment were estimated. Middle segments were able to entrain to frequencies approximately twice as high as those at end segments. Next, phase lags between centers of ventral root bursts and the stimulus were determined. Two halves of the cycle were identified: stretching and shortening of the edge of spinal cord on the same side as the electrode. Stimuli at rostral segments tended to entrain segmental bursting at the beginning of the stretch phase, almost 50% out of phase with previously measured in vivo electromyography data. Stimuli at caudal segments, in contrast, entrained segments at the end of stretch and the beginning of shortening, approximately the same phase as in vivo data.


Author(s):  
Guobin Xia ◽  
Yong Han ◽  
Fantao Meng ◽  
Yanlin He ◽  
Dollada Srisai ◽  
...  

AbstractThe high comorbidity between obesity and mental disorders, such as depression and anxiety, often exacerbates metabolic and neurological symptoms significantly. However, neural mechanisms that underlie reciprocal control of feeding and mental states are largely elusive. Here we report that melanocortin 4 receptor (MC4R) neurons located in the dorsal bed nucleus of the stria terminus (dBNST) engage in the regulation of mentally associated weight gain by receiving GABAergic projections from hypothalamic AgRP neurons onto α5-containing GABAA receptors and serotonergic afferents onto 5-HT3 receptors. Chronic treatment with a high-fat diet (HFD) significantly blunts the hyperexcitability of AgRP neurons in response to not only hunger but also anxiety and depression-like stimuli. Such HFD-mediated desensitization reduces GABAergic outputs from AgRP neurons to downstream MC4RdBNST neurons, resulting in severe mental dysregulation. Genetic enhancement of the GABAAR-α5 or suppression of the 5-HT3R within the MC4RdBNST neurons not only abolishes HFD-induced anxiety and depression but also robustly reduces body weight by suppression of food intake. To gain further translational insights, we revealed that combined treatment of zonisamide (enhancing the GABAAR-α5 signaling) and granisetron (a selective 5-HT3R antagonist) alleviates mental dysfunction and yields a robust reversal of diet-induced obesity by reducing total calorie intake and altering food preference towards a healthy low-fat diet. Our results unveil a neural mechanism for reciprocal control of appetite and mental states, which culminates in a novel zonisamide-granisetron cocktail therapy for potential tackling the psychosis-obesity comorbidity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alyssa Maxwell ◽  
Iris Adam ◽  
Pernille S. Larsen ◽  
Peter G. Sørensen ◽  
Coen P. H. Elemans

AbstractVocal behavior can be dramatically changed by both neural circuit development and postnatal maturation of the body. During song learning in songbirds, both the song system and syringeal muscles are functionally changing, but it is unknown if maturation of sound generators within the syrinx contributes to vocal development. Here we densely sample the respiratory pressure control space of the zebra finch syrinx in vitro. We show that the syrinx produces sound very efficiently and that key acoustic parameters, minimal fundamental frequency, entropy and source level, do not change over development in both sexes. Thus, our data suggest that the observed acoustic changes in vocal development must be attributed to changes in the motor control pathway, from song system circuitry to muscle force, and not by material property changes in the avian analog of the vocal folds. We propose that in songbirds, muscle use and training driven by the sexually dimorphic song system are the crucial drivers that lead to sexual dimorphism of the syringeal skeleton and musculature. The size and properties of the instrument are thus not changing, while its player is.


Autism ◽  
2021 ◽  
pp. 136236132098795
Author(s):  
Eleanor R Palser ◽  
Alejandro Galvez-Pol ◽  
Clare E Palmer ◽  
Ricci Hannah ◽  
Aikaterini Fotopoulou ◽  
...  

Differences in understanding emotion in autism are well-documented, although far more research has considered how being autistic impacts an understanding of other people’s emotions, compared to their own. In neurotypical adults and children, many emotions are associated with distinct bodily maps of experienced sensation, and the ability to report these maps is significantly related to the awareness of interoceptive signals. Here, in 100 children who either carry a clinical diagnosis of autism ( n = 45) or who have no history of autism ( n = 55), we investigated potential differences in differentiation across autistic children’s bodily maps of emotion, as well as how such differentiation relates to the processing of interoceptive signals. As such, we measured objective interoceptive performance using the heartbeat-counting task, and participants’ subjective experience of interoceptive signals using the child version of the Body Perception Questionnaire. We found less differentiation in the bodily maps of emotion in autistic children, but no association with either objective or subjective interoceptive processing. These findings suggest that, in addition to previously reported differences in detecting others’ emotional states, autistic children have a less differentiated bodily experience of emotion. This does not, however, relate to differences in interoceptive perception as measured here. Lay abstract More research has been conducted on how autistic people understand and interpret other people’s emotions, than on how autistic people experience their own emotions. The experience of emotion is important however, because it can relate to difficulties like anxiety and depression, which are common in autism. In neurotypical adults and children, different emotions have been associated with unique maps of activity patterns in the body. Whether these maps of emotion are comparable in autism is currently unknown. Here, we asked 100 children and adolescents, 45 of whom were autistic, to color in outlines of the body to indicate how they experienced seven emotions. Autistic adults and children sometimes report differences in how they experience their internal bodily states, termed interoception, and so we also investigated how this related to the bodily maps of emotion. In this study, the autistic children and adolescents had comparable interoception to the non-autistic children and adolescents, but there was less variability in their maps of emotion. In other words, they showed more similar patterns of activity across the different emotions. This was not related to interoception, however. This work suggests that there are differences in how autistic people experience emotion that are not explained by differences in interoception. In neurotypical people, less variability in emotional experiences is linked to anxiety and depression, and future work should seek to understand if this is a contributing factor to the increased prevalence of these difficulties in autism.


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