Activity of Lateral-Line Sense Organs in Swimming Dogfish

1972 ◽  
Vol 56 (1) ◽  
pp. 105-118
Author(s):  
B. L. ROBERTS

1. The activity of lateral-line sense organs was studied in swimming spinal dogfish by recording from filaments of the lateral-line nerve dissected in an anterior immobile part of the fish, the rest of the fish being free to move. 2. In a non-swimming fish most of the receptors were spontaneously active, discharging at 15-20 impulses/sec. 3. When the part of the body overlying the receptor was flexed, the impulse frequency was either enhanced or depressed, depending on the direction of movement. 4. In swimming spinal dogfish the sense organs discharged in bursts at the same frequency as the swimming rhythm. 5. The lateral-line receptors could provide information which would be useful in locomotory co-ordination, for the burst length, frequency, discharge frequency and number of impulses in the rhythmical discharge could all be correlated with the swimming movements.

1972 ◽  
Vol 57 (2) ◽  
pp. 435-448 ◽  
Author(s):  
B. L. ROBERTS ◽  
I. J. RUSSELL

1. The activity of efferent neurones innervating lateral-line organs on the body of dogfish was followed by recording from filaments of cranial nerve X in 41 decerebrate preparations. 2. The efferent nerves were not spontaneously active. 3. Tactile stimulation to the head and body, vestibular stimulation and noxious chemical stimulation were followed by activity of the efferent nerves. 4. In contrast, natural stimulation of lateral-line organs (water jets) did not reflexly evoke discharges from the efferent fibres. 5. Reflex efferent responses were still obtained to mechanical stimulation even after the lateral-line organs had been denervated. 6. Electrical stimulation of cranial nerves innervating lateral-lines organs was followed by reflex activity of the efferent fibres. But similar stimuli applied to other cranial nerves were equally effective in exciting the efferent system. 7. Vigorous movements of the fish, involving the white musculature, were preceded and accompanied by activity of the efferent fibres which persisted as long as the white muscle fibres were contracting. 8. Rhythmical swimming movements were accompanied by a few impulses in the efferent fibres grouped in bursts at the same frequency as the swimming movements. 9. It is concluded that the efferent neurones cannot contribute to a feedback regulatory system because they are not excited by natural stimulation of the lateral-line sense organs. The close correlation found between efferent activity and body movement suggests that the efferent system might operate in a protective manner to prevent the sense organs from being over-stimulated when the fish makes vigorous movements.


1972 ◽  
Vol 57 (1) ◽  
pp. 77-82
Author(s):  
I. J. RUSSELL ◽  
B. L. ROBERTS

1. Efferent nerve fibres innervating the lateral-line sense organs of the dogfish Scyliorhinus were stimulated with trains of stimuli while spontaneous afferent activity was monitored. 2. Significant changes in spontaneous impulse frequency could be produced when the efferent nerves were stimulated by trains of pulses at frequencies between 20-100 sec-1 lower stimulus frequencies had no visible effect. The impulse frequency decreased or was totally inhibited during the stimulus period and for 150-200 msec following it. The inhibitory effect was very variable and declined with repetitive stimulation. 3. Stimulation of the efferent nerves to inactive afferent units was followed after 500 msec by a brief low-frequency discharge.


1995 ◽  
Vol 198 (12) ◽  
pp. 2581-2591 ◽  
Author(s):  
T G Deliagina ◽  
F Ullén ◽  
M-J. Gonzalez ◽  
H Ehrsson ◽  
G N Orlovsky ◽  
...  

The lateral line system of lampreys includes photoreceptors distributed in the skin of the tail region. These are innervated by the trunk lateral line nerves, and the afferents terminate bilaterally in the medial octavolateral nucleus, crossing the midline through the cerebellar commissure. Stimulation of the dermal photoreceptors by tail illumination initiates locomotion. The present study was performed to characterize the response to illumination in larval and adult lampreys in detail and to elucidate the neuronal pathways responsible for the activation of locomotion. In both larval and adult quiescent lampreys, the response to unilateral illumination of the tail was found to consist of an initial turn followed by rectilinear swimming. The sign and magnitude of the turning angle were not correlated with the laterality of the optic stimulus. In mechanically restrained lampreys, spinalized at the level of segments 15­20, tail illumination evoked a complex motor response in the rostral part of the body, with switches between different patterns of coordination (turns in different directions, locomotion, and turns combined with locomotion). Thus, the response to tail illumination is not a simple reflex, but includes a behavioural choice. Reticulospinal neurones play a crucial role in the initiation of locomotion in lampreys. The response to unilateral tail illumination in rhombencephalic reticular cells was studied with extracellular single-unit recordings. It was found that neurones in the middle and posterior rhombencephalic reticular nuclei were activated bilaterally. Tonic activity or slow bursts (<0.5 Hz) were evoked, in some cases lasting up to 60 s after the stimulation. The response remained bilateral after transection of one lateral line nerve and the cerebellar commissure. Afferents from one side can thus activate reticulospinal cells on both sides through a pathway outside the cerebellar commissure. This bilateral activation of reticulospinal neurones is presumably responsible for the activation of spinal locomotor networks, without any directional bias to the left or the right side, and for the rectilinear swimming observed in behavioural experiments. In the caudal part of the termination area of the lateral line nerve afferents, neurones with contralateral projections were retrogradely stained with horseradish peroxidase. These neurones appear to be likely candidates for mediating the contralateral effects of the lateral line fibres.


Author(s):  
Jennifer D. Liddicoat ◽  
B. L. Roberts

The sense organs of the lateral-line system of lower aquatic vertebrates are mechanoreceptors which respond to water movements. They are distributed over the body, usually in lines which form a definite pattern on the head and along each side of the trunk. In the Cyclostomes the sense organs project from the body surface ('free neuromasts'); in other aquatic vertebrates they are usually housed in canals which are sunk into the dermis and which open at regular intervals to the exterior, although in some teleosts and in all modern amphibia the canal system has been secondarily lost and the neuromasts are once again situated externally.


1933 ◽  
Vol 16 (4) ◽  
pp. 715-732 ◽  
Author(s):  
Hudson Hoagland

1. The lateral-line nerves of trout as well as those of catfish are found to discharge impulses spontaneously at a high frequency. 2. The frequency of nerve impulse discharge is measured as a function of the number of participating receptor groups (lateral-line sense organs). A quantitative analysis is made of the contribution to the total response made by each group of sense organs. 3. An analysis of the variability of the response is presented which makes it possible to estimate quantitatively the longitudinal extent of damage to the neuromasts due to surgical manipulation. 4. A method is described for recording the response of a single nerve fiber in the lateral-line trunk. 5. The frequency of the spontaneous discharge from the lateral-line nerve trunk when plotted as a function of temperature according to the Arrhenius equation yields a temperature characteristic of approximately 5000 calories. 6. The variability of the frequency of response as a function of temperature indicates the existence of temperature thresholds for the spontaneous activity of the neuromasts. 7. A possible basis for the spontaneous activity is considered. It is pointed out that the lateral-line system may serve as a model of the Purkinje cells of the cerebellum.


1935 ◽  
Vol 12 (3) ◽  
pp. 229-238 ◽  
Author(s):  
J. Z. YOUNG

1. The tail of larval and adult L. planeri and adult L. fluviatilis contains a photoreceptive mechanism involving an initial short sensitization period, and a latent period. 2. The impulses initiated by the photochemical change are carried in the lateral line nerves, as is shown by the facts that section of these nerves abolishes the response, whereas section of the spinal cord does not do so. 3. Motor responses are only occasionally seen after illumination of parts of the body other than the tail. These responses are apparently due to direct stimulation of the spinal cord, and can be regularly elicited if the pigment protecting the latter be removed. 4. Motor responses may follow illumination of the head, either of larvae or adults, but only after illumination periods much longer than are necessary to obtain a response from the tail. 5. The responses play a part in the normal behaviour of the animals by assisting them to bury themselves completely in the mud. 6. The stimulus of illumination of the tail simply initiates swimming movements, and there is no orientation of the animal with reference to the direction of the light. This is confirmed by the observation that, following illumination of the tail from one side, the first movement of the head may be either towards or away from the side stimulated. Further, after section of one lateral line nerve only no forced movements occur on illumination. The reaction may thus be described as a photokinesis, and does not involve any true topotaxis, its effect is to prevent the animal remaining in any illuminated area.


1971 ◽  
Vol 179 (1055) ◽  
pp. 157-169 ◽  

The sense organs of the body lateral-line canals of Scyliorhinus were examined with the electron microscope and shown to consist of supporting cells and two kinds of sensory cell. One type of sensory cell has the well-known structure of hair cells, bearing on its apical surface a group of stereocilia (6 to 25) associated with a single kinocilium. Each hair cell is innervated by a sensory nerve fibre and some also receive an efferent nerve supply. The second kind of sensory cell is similar in appearance, but differs at the apex in containing many vacuoles and in lacking stereocilia. There are many long microvilli and a single cilium which arises from a shallow pit. The internal structure of this cilium is variable, with the number of tubules in the outer ring ranging between 7 and 9 and with the inner pair consisting of double elements. This type of sensory cell is innervated by sensory nerve fibres and possibly by efferent fibres. The situation of the kinocilium of a hair cell in relation to the stereocilia is more variable than has been described in other hair cells while the cilium of the second sensory cell appears to bear no special relation to the microvilli. The accessory cells of the neuromast include basal and peripheral supporting cells, many of which produce a secretion, and a large secretory cell which is found at intervals at the edge of the organ. This cell has a convoluted surface and is full of vesicles.


2014 ◽  
Vol 12 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Angela M. Zanata ◽  
Priscila Camelier

Characidium samurai, a species of the family Crenuchidae apparently endemic to rio das Almas and rio Vermelho basins, Bahia, Brazil, is described. The new species is readily distinguishable from its congeners, except C. lanei, by having a dark lateral band along the head and body that is particularly broad from the rear of the head to the end of the caudal peduncle (1.5 or 2 scales wide) and by the absence of dark bars or blotches on the ventral half of the body. Characidium samurai differs from C. laneiby having the lateral band with straight borders overall (vs.lateral band with somewhat irregular borders due to blotches extending dorsally or ventrally), anal fin ii,7-8 (vs. ii,6), and 4 horizontal scale rows above the lateral line and 4 below (vs. 5/3). It further differs from congeners by a series of features, including isthmus completely covered by scales, lateral line complete with 34-37 perforated scales, 9 scales on the transversal line, 14 scale rows around the caudal peduncle, anal fin ii,7-8, and the absence of dark bars or spots on the fins, except by a faded dorsal-fin bar. The presence of pseudotympanum in four species of Characidium is discussed.


2010 ◽  
Vol 8 (4) ◽  
pp. 867-876 ◽  
Author(s):  
Akemi Shibuya ◽  
Jansen Zuanon ◽  
Maria Lúcia G. de Araújo ◽  
Sho Tanaka

The relationship between the distribution of the lateral line canals and their functionality has not been well examined in elasmobranchs, especially among Neotropical freshwater stingrays of the family Potamotrygonidae. The spatial distribution of the canals and their tubules and the quantification of the neuromasts were analyzed in preserved specimens of Potamotrygon motoro, P. orbignyi, Potamotrygon sp. "cururu", and Paratrygon aiereba from the middle Negro River, Amazonas, Brazil. The hyomandibular, infraorbital, posterior lateral line, mandibular, nasal and supraorbital canals were characterized and their pores and neuromasts quantified. The ventral canals are known to facilitate the accurate localization of prey items under the body, and our results indicate that the dorsal canals may be employed in identifying the presence of predators or potential prey positioned above the stingray's body. The presence of non-pored canals in the ventral region may be compensated by the high concentration of neuromasts found in the same area, which possibly allow the accurate detection of mechanical stimuli. The concentration of non-pored canals near the mouth indicates their importance in locating and capturing prey buried in the bottom substrate, possibly aided by the presence of vesicles of Savi.


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