The angular acceleration receptor system of diverse cephalopods

1989 ◽  
Vol 325 (1227) ◽  
pp. 189-237 ◽  
Keyword(s):  
Hair Cells ◽  
Horizontal Plane ◽  
Adult Animal ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Lower Sensitivity ◽  
Receptor System ◽  
Endolymph Flow ◽  
Neutrally Buoyant ◽  
Higher Sensitivity

The system for monitoring angular acceleration is described in 59 genera of cephalopods. The dimensions are measured and volumes calculated. The volume of the statocyst is always small relative to the size of the adult animal but is smallest in animals that move fast, such as ommastrephids, loliginids and sepiids; it is larger in neutrally buoyant squids and very large in cirroctopods. In many genera the flow of endolymph is restricted by knobs, the anticristae, usually arranged on a standard plan. These reach their greatest extent in non- buoyant squids and sepiids, where some of them join to form incomplete semicircular canals in the horizontal plane, providing the lower sensitivity appropriate to rapid turning to right or left. In buoyant squids and octopods the cavity is less obstructed. The system for adjusting sensitivity is not the same in all three planes: there are not three canals as in vertebrates. In the pitching and rolling planes the channels for endolymph flow are wide, presumably providing the higher sensitivity appropriate to slower movements. Sensitivity is perhaps also adjusted by variations in the cupulae, as it is in Octopus . The crista of pelagic octopods such as Argonauta and Japetella is divided into nine sections, as in the typical benthic forms. In cirroctopods the crista is not divided in this way and indeed shows no interruption of the rows of hair cells, even at the turns. In some cirroctopods and in Vampyroteuthis there are several anticristae, an apomorphic feature that they share with the decapods; but they have perilymph- and endolymph-like octopods. In the more active cranchiid squids the anticristae are arranged on a helical course, perhaps serving to provide appropriate sensitivity during turns from the head-down position. The statocyst of Spirula differs from both sepiids and teuthids.

Some Dimensions of the Angular Acceleration Receptor Systems of Cephalopods

1984 ◽  
Vol 64 (1) ◽  
pp. 55-79 ◽  
Author(s):  
Linda Maddock ◽  
J. Z. Young
Keyword(s):  
Angular Velocity ◽  
Frequency Band ◽  
Deep Sea ◽  
Horizontal Plane ◽  
Angular Acceleration ◽  
The Body ◽  
The Other ◽  
Radius Of Curvature ◽  
Internal Radius ◽  
Neutrally Buoyant

The shapes and dimensions of the statocysts of cephalopods have been measured and compared with the semi-circular canals of vertebrates. The cavities grow much more slowly than the body as a whole, but there are knobs, anticristae, which restrict the cavity, and these grow relatively faster. This ensures that the flow of endolymph across the cupulae remains small. Where the liquid is constrained within canals the radius of curvature of the whole canal, R, is similar to that of fishes, whereas its internal radius, r, is twice as large in non-buoyant and four times as large in deep-sea buoyant cephalopods as in fishes of similar size. As in fishes the restriction is greatest in the horizontal plane, providing for operation at higher frequencies in turning about the yaw axis.The statocysts of seven species of Loligo all have similar proportions. The largest individuals of 16 genera of non-buoyant squids also have these same relative dimensions. The statocyst of Sepia is more like that of non-buoyant than of other buoyant cephalopods but yet differs significantly from that of Loligo at all sizes. On the other hand 21 genera of squids known to be neutrally buoyant are very different. Their statocysts are often larger than in the non-buoyant forms and there is less restriction of the cavity by anticristae. The greater flow of endolymph acting across the cupulae presumably provides greater sensitivity at the lower frequencies of turning of these deep-sea animals.The data suggest that the cristae of the cephalopod statocyst may operate in the frequency band where they act as angular accelerometers whereas the vertebrate semi-circular canals operate at higher frequencies as angular velocity meters.

scholarly journals Proteomics and the Inner Ear

2001 ◽  
Vol 17 (4) ◽  
pp. 259-270 ◽  
Author(s):  
Isolde Thalmann
Keyword(s):  
Inner Ear ◽  
Calcium Binding ◽  
Angular Acceleration ◽  
Organ Of Corti ◽  
Semicircular Canals ◽  
Frequency Discrimination ◽  
Receptor System ◽  
Perilymphatic Fistula ◽  
Proteomics Approach

The inner ear, one of the most complex organs, contains within its bony shell three sensory systems, the evolutionary oldest gravity receptor system, the three semicircular canals for the detection of angular acceleration, and the auditory system - unrivaled in sensitivity and frequency discrimination. All three systems are susceptible to a host of afflictions affecting the quality of life for all of us. In the first part of this review we present an introduction to the milestones of inner ear research to pave the way for understanding the complexities of a proteomics approach to the ear. Minute sensory structures, surrounded by large fluid spaces and a hard bony shell, pose extreme challenges to the ear researcher. In spite of these obstacles, a powerful preparatory technique was developed, whereby precisely defined microscopic tissue elements can be isolated and analyzed, while maintaining the biochemical state representative of thein vivoconditions. The second part consists of a discussion of proteomics as a tool in the elucidation of basic and pathologic mechanisms, diagnosis of disease, as well as treatment. Examples are the organ of Corti proteins OCP1 and OCP2, oncomodulin, a highly specific calcium-binding protein, and several disease entities, Meniere's disease, benign paroxysmal positional vertigo, and perilymphatic fistula.

The angular acceleration receptor system of the statocyst of Octopus vulgaris : morphometry, ultrastructure, and neuronal and synaptic organization

1987 ◽  
Vol 315 (1174) ◽  
pp. 305-343 ◽  
Keyword(s):  
Hair Cells ◽  
Angular Acceleration ◽  
Sensory Cells ◽  
Octopus Vulgaris ◽  
Afferent Neurons ◽  
Synaptic Organization ◽  
Receptor System ◽  
First Order ◽  
Small Primary ◽  
Primary Sensory Cells

The angular acceleration receptor system (crista/cupula system) of the statocyst of Octopus vulgaris has been thoroughly reinvestigated, and detailed information is presented regarding its morphometry, ultrastructure, and neuronal and synaptic organization. In each of the nine crista sections, some receptor hair cells are primary sensory cells with an axon extending from their base. Also, there are large and small secondary sensory hair cells without axons, which make afferent synapses with large and small first-order afferent neurons. The afferent synapses are of two morphologically distinct types, having either a finger-like or a flat postsynaptic process; both can be seen in the same hair cell. In addition to the afferents, there is a dense plexus of efferent fibres in each crista section, and efferent synapses can be seen at the level of the hair cells and of the neurons. The morphometric analysis of the nine crista sections shows obvious differences between the odd-numbered (C1, C3, C5, C7, C9) and the even-numbered (C2, C4, C6, C8) crista sections: they differ in length, in the number of the small primary sensory cells and in the number of the small first-order afferent neurons. Centrifugal cobalt filling of the three crista nerves revealed a disproportionate innervation of the nine crista sections: the anterior crista nerve innervates section C1 and the first half of section C2, the medial crista nerve innervates the second half of section C2, sections C3, C4, C5, and the first half of section C6, and the posterior crista nerve innervates the second half of section C6, and sections C7, C8 and C9. In each of the three crista nerves, only 25% of the total number of axons are afferent fibres, the remaining 75 % are efferent. To each of the nine crista sections a cupula is attached. In the form and size of the cupulae there is again a conspicuous difference between the odd and the even crista sections: a small widebased cupula is attached to each of the odd crista sections, whereas the even crista sections each have a large narrow-based cupula with a small area of attachment. The results are discussed with reference to their functional consequences.

The electrophysiological study of the responses of the isolated labyrinth of the lamprey ( Lampetra fluviatilis ) to angular acceleration, tilting and mechanical vibration

1970 ◽  
Vol 174 (1037) ◽  
pp. 419-434 ◽  
Keyword(s):  
Hair Cells ◽  
Electrophysiological Study ◽  
Mechanical Vibration ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Electric Activity ◽  
Otolith Organs ◽  
Lampetra Fluviatilis ◽  
External Canal ◽  
Activity Form

The ultrastructure of the labyrinth of Lampetra fluviatilis has recently been described by Lowenstein, Osborne & Thornhill (1968). This is now followed by an account of electrophysiological experiments in which it is shown that the elaborate shape of the cristae in the two vertical canal ampullae and the topographic arrangement of the hair cells in the sensory epithelia of the cristae makes the two semicircular canals capable of responding to angular accelerations in all planes including the horizontal, despite the absence of the horizontal (external) canal. Sequences of integrated multifibre responses from the otolith organs are presented. They show that the static responses to constant-speed tilting and to lasting deviations of the head from the normal differ in no way from those found in the gnathostome labyrinth. Frequency-synchronized impulse responses to vibration of the substrate show that the vibration sensitivity of the lamprey labyrinth resembles that found in the elasmobranchs both with respect to threshold and frequency range. It is suggested that vibration reception is localized in the sacculus and macula neglecta. This view is supported by the topographic arrangement of hair cells in the sacculus macula which is identical with that found on the vibration-sensitive sacculus macula of elasmobranchs. Rhythmic bursts of discharge activity form part of the electric activity found in the eighth nerve of the lamprey. Its origin could not be located. The functional significance of the large ciliated chambers found in the lamprey labyrinth remains obscure.

The anatomy and ultrastructure of the labyrinth of the lamprey ( Lampetra fluviatilis L.)

1968 ◽  
Vol 170 (1019) ◽  
pp. 113-134 ◽  
Keyword(s):  
Hair Cells ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Sensory Cells ◽  
Open Communication ◽  
Lampetra Fluviatilis ◽  
Sensory Ending ◽  
Sensory Hair Cell ◽  
New Type ◽  
Anatomy And Ultrastructure

The anatomy of the labyrinth of the lamprey ( Lampetra fluviatilis ) is described. The am­pullae of the two semicircular canals are each equipped with a complex three-armed sensory crista. They may be considered homologues of the ampullae of the vertical canals of the gnathostomes. However, the complexity of their cristae encourages the assumption that they may cover a spatial range of responses to angular acceleration which includes responses to accelerations in a horizontal plane controlled in the gnathostomes by the horizontal semi-circular canal. The otolith-bearing end organs are found to be located on a common macular structure. This is subdivided into an anterior horizontal, a vertical, and a posterior horizontal macula, each of which portions carries a characteristic arrangement of sensory cells. On the basis of an electronmicroscopic analysis of the orientation of the hair cells in the three main portions of the macula a revision of the homologies found in the older literature appears to be called for. It is suggested to homologize the anterior horizontal macula with the macula utriculi, the vertical macula with the macula sacculi and the posterior horizontal macula with the macula lagenae of the labyrinth of gnathostome animals. A separate sensory ending in the dorsal part of the labyrinth, the dorsal macula, may be the homologue of the macula neglecta. Ultrastructurally the end organs of the lamprey labyrinth conform with those of the gnathostome labyrinth with the exception of the presence of a new type of sensory hair cell which is equipped with a stiff kinoeilium of extraordinary length accompanied by extremely short stereocilia. This cell is found preponderantly in the vertical macula (macula sacculi). A striated organelle in the cytoplasm of the hair cells appears to be uniquely confined to the labyrinth of the lamprey. Morphologically the lamprey labyrinth differs from all other chordate labyrinths including that of its fellow cyclostome Myxine by the presence of large ciliated chambers in its centre in which long and powerful cilia maintain a permanent pattern of four endolymph vortices. The ciliated chambers are in open communication with the ampullae and with the spaces con­taining the otolith-bearing maculae. The analysis of the functional significance of the anatomical and ultrastructural findings will be described in a separate paper.

Hydrostatic pressure effects on vestibular hair cell afferents in fish and crustacea

2003 ◽  
Vol 13 (4-6) ◽  
pp. 235-242
Author(s):  
Peter J. Fraser ◽  
Stuart F. Cruickshank ◽  
Richard L. Shelmerdine
Keyword(s):  
Hydrostatic Pressure ◽  
Hair Cells ◽  
Signal To Noise Ratio ◽  
Angular Acceleration ◽  
Pressure Effects ◽  
Sensory Cells ◽  
Associated Gas ◽  
Piston Mechanism ◽  
New Finding ◽  
Resting Activity

Following the discovery of a hydrostatic pressure sensor with no associated gas phase in the crab, and the knowledge that several systems of cells in culture show long term alterations to small changes in hydrostatic pressure, we show here that vestibular type II hair cells in a well known model system (the isolated elasmobranch labyrinth), are sensitive to hydrostatic pressure. This new finding for the vertebrate vestibular system may provide an explanation for low levels of resting activity in vertebrate hair cells and explain how fish without swim bladders sense hydrostatic cues. It could have implications for humans using their balancing systems in hypobaric or hyperbaric environments such as in aircraft or during space exploration. Although lacking the piston mechanism thought to operate in crab thread hairs which sense angular acceleration and hydrostatic pressure, the vertebrate system may use larger numbers of sensory cells with resultant improvement in signal to noise ratio. The main properties of the crab hydrostatic pressure sensing system are briefly reviewed and new experimental work on the isolated elasmobranch labyrinth is presented.

scholarly journals A case series shows independent vestibular labyrinthine function after major surgical trauma to the human cochlea

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Stefan K. Plontke ◽  
Torsten Rahne ◽  
Ian S. Curthoys ◽  
Bo Håkansson ◽  
Laura Fröhlich
Keyword(s):  
Case Series ◽  
Vestibular Function ◽  
Semicircular Canals ◽  
Vestibular Evoked Myogenic Potentials ◽  
Head Impulse Test ◽  
Surgical Trauma ◽  
Cochlear Function ◽  
Receptor System ◽  
Tertiary Referral Center ◽  
Significant Difference

Abstract Background The receptors for hearing and balance are housed together in the labyrinth of the inner ear and share the same fluids. Surgical damage to either receptor system was widely believed to cause certain permanent loss of the receptor function of the other. That principle, however, has been called into question because there have been anecdotal reports in individual patients of at least partial preservation of cochlear function after major surgical damage to the vestibular division and vice versa. Methods We performed specific objective vestibular function tests before and after surgical trauma (partial or subtotal cochlear removal) for treatment of intracochlear tumors in 27 consecutive patients in a tertiary referral center. Vestibular function was assessed by calorics (low-frequency response of the lateral semicircular canal), vestibulo-ocular reflex by video head impulse test (vHIT) of the three semicircular canals, cervical and ocular vestibular evoked myogenic potentials (cVEMP, saccule and oVEMP, utricle). Preoperative and postoperative distributions were compared with paired t-tests. Results Here we show that there was no significant difference between pre- and post-operative measures for all tests of the five vestibular organs, and that after major surgical cochlear trauma, the vestibular receptors continue to function independently. Conclusions These surprising observations have important implications for our understanding of the function and the surgery of the peripheral auditory and vestibular system in general and open up new possibilities for the development, construction and evaluation of neural interfaces for electrical or optical stimulation of the peripheral auditory and vestibular nervous system.

scholarly journals Efferent Influences on the Afferent Activity from the Octopus Angular Acceleration Receptor System

1985 ◽  
Vol 119 (1) ◽  
pp. 251-264
Author(s):  
R. WILLIAMSON
Keyword(s):  
Angular Acceleration ◽  
Stimulus Level ◽  
Gradual Decrease ◽  
Afferent Activity ◽  
Receptor System ◽  
Stimulus Response ◽  
Electrophysiological Recordings ◽  
Level Of Activity ◽  
Sinusoidal Oscillations ◽  
Stimulation Of

Electrophysiological recordings were made from afferent units of the octopus angular acceleration receptor system during the electrical stimulation of efferent axons to this system. Of the afferent units examined, 93% changed their activity in response to stimulation of the efferent axons. During efferent stimulation 77% of the afferent units decreased their activity. The magnitude of the inhibition and the time to maximum response were frequency dependent, with most units showing an increase in inhibition with increase in efferent stimulation frequency. The poststimulus recovery from inhibition was of two types: either a gradual increase in activity to the pre-stimulus resting level of activity (Fig. 3) or a rapid increase in activity to a level above the pre-stimulus level, i.e. a postinhibitory rebound or facilitation, and then a gradual decline to the resting level of activity (Fig. 4). During long periods of efferent stimulation (<40 s) the inhibition was not maintained. During stimulation of the efferent axons 16% of the afferent units increased their activity. The post-stimulus response consisted of either a gradual decrease in activity to the pre-stimulus level of resting activity or a rapid increase in activity followed by a gradual decrease to the resting level of activity (Fig. 6). During long periods of efferent stimulation the excitation increased to a plateau level which was maintained for the duration of the stimulus period (Fig. 7). Sinusoidal oscillations of the statocyst evoked bursts of afferent activity in time with the movement. The magnitude of these bursts could be decreased or increased by stimulation of the efferent axons (Fig. 8). It is proposed that two populations of efferents are present in the octopus statocyst, one inhibitory and the other excitatory, and that both types of efferent affect single afferent units.

Sensorimotor aspects of high-speed artificial gravity: II. The effect of head position on illusory self motion

2003 ◽  
Vol 12 (5-6) ◽  
pp. 283-289
Author(s):  
Fred W. Mast ◽  
Nathaniel J. Newby ◽  
Laurence R. Young
Keyword(s):  
Healthy Subjects ◽  
Horizontal Plane ◽  
High Speed ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Head Position ◽  
Artificial Gravity ◽  
Axis Of Rotation ◽  
Self Motion

The effects of cross-coupled stimuli on the semicircular canals are shown to be influenced by the position of the subject's head with respect to gravity and the axis of rotation, but not by the subject's head position relative to the trunk. Seventeen healthy subjects made head yaw movements out of the horizontal plane while lying on a horizontal platform (MIT short radius centrifuge) rotating at 23 rpm about an earth-vertical axis. The subjects reported the magnitude and duration of the illusory pitch or roll sensations elicited by the cross-coupled rotational stimuli acting on the semicircular canals. The results suggest an influence of head position relative to gravity. The magnitude estimation is higher and the sensation decays more slowly when the head's final position is toward nose-up (gravity in the subject's head x-z-plane) compared to when the head is turned toward the side (gravity in the subject's head y-z-plane). The results are discussed with respect to artificial gravity in space and the possible role of pre-adaptation to cross-coupled angular accelerations on earth.

Functions of separate sensory receptors of nonauditory labyrinth of the cat

1962 ◽  
Vol 202 (6) ◽  
pp. 1211-1220 ◽  
Author(s):  
Kenneth E. Money ◽  
John W. Scott
Keyword(s):  
Intact Animal ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
The Other ◽  
Sensory Receptors ◽  
Vestibular Tests ◽  
Normal Orientation ◽  
Angular Displacements ◽  
Vertical Semicircular Canals

A technique for plugging individual semicircular canals of cats was developed, and it was established that the plugging of a semicircular canal completely blocked its receptivity without influencing the functions of the other vestibular receptors. It was found that cats with all six semicircular canals plugged were lacking all sensitivity to angular acceleration, but they retained normal responses to linear acceleration. Results of several vestibular tests led to the conclusion that the vertical semicircular canals initiate corrections for fast angular displacements from the normal orientation when the displacements are about horizontal axes and that the otoliths initiate corrections for slow angular displacements about horizontal axes. In tests of single horizontal canals, the durations of postrotatory nystagmus were the same after rotations in opposite directions. It was concluded that in the intact animal both horizontal semicircular canals contribute equally to reception of angular acceleration in both directions.

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