Electrical Correlates of Ciliary Reversal in Oikopleura

1971 ◽  
Vol 55 (1) ◽  
pp. 205-212 ◽  
Author(s):  
C. P. GALT ◽  
G. O. MACKIE
Keyword(s):  
Electrical Potential ◽  
Particulate Material ◽  
The Body ◽  
Water Current ◽  
Ciliated Cells ◽  
Nervous Control ◽  
Ciliary Reversal ◽  
The Brain ◽  
Reversal Potentials ◽  
Stimulation Of

1. Reversal of the water current through the pharynx of Oikopleura is brought about by a change in the action of the cilia of the two stigmatal ciliated rings. These ‘ciliary reversals’ occur synchronously in the two ciliated rings and can be evoked by the addition of particulate material to the incoming water or by tactile or electrical stimulation of the lips. 2. Nerves run from the lips via the brain to individual ciliated cells, and it is therefore likely that the ciliated cells are under nervous control. 3. At each ciliary reversal an electrical potential can be picked up on the body surface. The same events are recorded by microelectrodes inserted into the ciliated rings. The microelectrode recordings resemble intracellular recordings, and the reversal potentials are considered to represent depolarizations of the membranes of the ciliated cells. 4. Ciliary reversals continue after removal of the brain, suggesting the existence of a peripheral pacemaker.

scholarly journals The Control of Photo-Pigmentary Responses in Eyeless Catfish

1938 ◽  
Vol 15 (3) ◽  
pp. 363-370
Author(s):  
URSULA WYKES
Keyword(s):  
Fundulus Heteroclitus ◽  
Posterior Part ◽  
Bright Light ◽  
The Body ◽  
Nervous Control ◽  
Low Frequencies ◽  
Spinal Nerves ◽  
The Brain ◽  
Photic Response ◽  
Stimulation Of

1. In common with certain other teleosts and lacertilians, eyeless Amiurus nebulosus and Fundulus heteroclitus show a pigmentary response to changes in intensity of illumination. The melanophores contract in the darkness and expand in bright light. The control of this photic response was investigated in Amiurus. 2. The contraction in darkness was not obtained in areas denervated by section of spinal nerves nor in the posterior part of the body after section of the cord. The response is therefore under the control of nervous reflexes passing through the brain. A similar melanophore contraction can be obtained by electrical stimulation of the cord at extremely low frequencies. 3. The response remained in pinealectomized animals. Photoreceptors may possibly be located in the skin or the wall of the diencephalon may be sensitive to light. 4. After hypophysectomy the response continues but the degree of melanophore expansion in bright light is diminished. The expanding hormone of the pituitary is therefore important in that it augments a melanophore response which is under nervous control.

scholarly journals Muscular Movements in Man, and their Evolution in the Infant: a Study of Movement in Man, and its Evolution, together with Inferences as to the Properties of Nerve-Centres and their Modes of Action in expressing Thought

1889 ◽  
Vol 35 (149) ◽  
pp. 23-44 ◽  
Author(s):  
Francis Warner
Keyword(s):  
Brain Area ◽  
Muscular Contraction ◽  
The Body ◽  
Brain Areas ◽  
Modes Of Action ◽  
Central Nerve System ◽  
Nerve System ◽  
The Brain ◽  
Compound Series ◽  
Stimulation Of

(1) Movement in mau has long been a subject of profitable study. Visible movement in the body is produced by muscular contraction following upon stimulation of the muscles by efferent currents passing from the central nerve-system. Modern physiological experiments have demonstrated that when a special brain-area discharges nerve-currents, these are followed by certain visible movements or contraction of certain muscles corresponding. So exact are such reactions, as obtained by experiment upon the brain-areas, that movements similar to those produced by experimental excitation of a certain brain-area may be taken as evidence of action in that area, or as commencing in discharge from that area (see Reinforcement of Movements, 35; Compound Series of Movements, 34).

Vertical banding evoked by electrical stimulation of the brain in anaesthetized green sunfish, Lepomis cyanellus, and bluegills, Lepomis macrochirus

1980 ◽  
Vol 84 (1) ◽  
pp. 149-160
Author(s):  
D. H. Bauer ◽  
L. S. Demski
Keyword(s):  
Electrical Stimulation ◽  
Transition Zone ◽  
Lepomis Macrochirus ◽  
Optic Tract ◽  
Colour Change ◽  
The Body ◽  
Lepomis Cyanellus ◽  
Green Sunfish ◽  
The Brain ◽  
Stimulation Of

A pattern of dark vertical bands is a characteristic agonistic display in the green sunfish, Lepomis cyanellus and the bluegill, L. macrochirus. The rapidity with which the display can appear and disappear indicates that it is neurally controlled. Electrical stimulation of the brain was carried out in anaesthetized green sunfish and bluegills to map those regions from which this colour change can be elicited. Banding was evoked by stimulation of sites near the midline in the preoptic area, ventral thalamic-dorsal hypothalmic transition zone, the midbrain tegmentum (just dorsal to the nucleus prerotundus pars medialis), in and near the torus semicricularis, in the basal midbrain (region of the crossing tectobulbar tracts), and in the rostral basomedial medulla. A ‘transition’ zone was located basally in the middle medulla, caudal to which only paling was evoked. Areas found to be negative for evoked banding included the telencephalic lobe, the inferior lobe of the hypothalamus, the optic tract, the optic tectum, the body and valvula of the cerebellum and the caudal medulla. It is postulated that the vertical banding pattern is made up of a separate, selectively controlled system of dermal melanophores. The possible neural mechanisms controlling banding are discussed.

scholarly journals THE FUNCTION OF THE BRAIN IN LOCOMOTION OF THE POLYCLAD WORM, YUNGIA AURANTIACA

1923 ◽  
Vol 6 (1) ◽  
pp. 73-76 ◽  
Author(s):  
A. R. Moore
Keyword(s):  
Mechanical Stimulation ◽  
Sensory Stimulation ◽  
The Body ◽  
Anterior Region ◽  
Spontaneous Movement ◽  
Peripheral Stimulation ◽  
Motor Nerves ◽  
Low Threshold ◽  
The Brain ◽  
Stimulation Of

Coordinated swimming movements in Yungia are not dependent upon the presence of the brain. The neuromuscular mechanism necessary for spontaneous movement and swimming is complete in the body of the animal apart from the brain. Normally this mechanism is set in motion by sensory stimulation arriving by way of the brain. The latter is a region of low threshold and acts as an amplifier by sending the impulses into a great number of channels. When the head is cut off these connections with the sensorium are broken, consequently peripheral stimulation does not have its usual effect. If, however, the motor nerves are stimulated directly as by mechanical stimulation of the median anterior region, then swimming movements result. Also if the threshold of the entire nervous mechanism is lowered by phenol or by an increase in the ion ratios See PDF for Equation and See PDF for Equation then again peripheral stimulation throws the neuromuscular mechanism into activity and swimming movements result.

scholarly journals Joseph Lister: his contributions to early experimental physiology

2013 ◽  
Vol 67 (3) ◽  
pp. 191-198 ◽  
Author(s):  
Edward R. Howard
Keyword(s):  
Spinal Cord ◽  
Experimental Science ◽  
Spinal Cord Section ◽  
Nervous Control ◽  
Histological Studies ◽  
University College London ◽  
The Brain ◽  
Contractile Tissue ◽  
Needle Stimulation ◽  
Stimulation Of

Joseph Lister (1827–1912) acquired a lifelong interest in histology and experimental physiology while a student at University College London between 1848 and 1852. His first two publications in 1853 were histological studies of the contractile tissue of the iris and the skin. Studies of inflammation in 1855 progressed to experiments on the nervous control of arteries, using techniques of peripheral nerve division, spinal cord section and needle stimulation of the brain. This interest in nervous mechanisms led to innovative experiments on gut motility and the autonomic nervous system, from which he inferred that sympathetic nerve control was mediated via intrinsic neuronal plexuses in the gut wall, a mode of action confirmed 100 years later, in 1964–65. It is not generally known that Lister was elected FRS for this early experimental work and that his early commitment to experimental science and microscopy was the background to his later work on the development of surgical antisepsis.

Development and self-repair in hair cell epithelia

1989 ◽  
Vol 47 ◽  
pp. 792-793
Author(s):  
Jeffrey T. Corwin
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Action Potentials ◽  
Basilar Membrane ◽  
Cell Ultrastructure ◽  
Water Current ◽  
Cellular Mechanisms ◽  
Frequency Of Action Potentials ◽  
The Brain ◽  
Stimulation Of

This presentation will attempt to explain current understanding of the cellular mechanisms of normal hair cell development and the mechanisms of hair cell regeneration. Hair cells are the mechanoreceptors that transduce sound and balance stimulation of the ear and water current stimulation of the lateral line organs into electrical activity that is transmitted to the brain. Hair cells have one true cilium, the kinocilium, and 30 to 200 or more stereocilia which are modified, actin-filled microvilli, that project from the flat apical surfaces of the cells. The stereocilia are arrayed across each cell in an “organ pipe” arrangement, with a row of short stereocilia at one end and rows of increasingly taller stereocilia proceeding from that row toward the single eccentrically positioned kinocilium. That asymmetrical surface structure defines the functional polarity of each hair cell, because stimuli that mechanically bend the stereocilia array in the direction of its tall end cause a decrease in the transmembrane potential of the hair cell and increased exocytotic release of neurotransmitter from vesicles at tonically active synaptic sites in the subnuclear region. In that way the appropriately directed bending of the stereocilia causes excitation of neurons that conduct action potentials to the brain. Bending of the stereocilia in the opposite direction causes hyperpolarization of the hair cell, reduction in the exocytosis of neurotransmitter, and a resulting decrease in the frequency of action potentials conducted to the brain.In most mature organs the orientations of the stereocilia arrays of the hair cells are aligned throughout the epithelia. However, during early development of these cells their cilia bundles are oriented in a nearly random distribution. As the cells differentiate their cilia arrays grow taller and reorient, so that neighbors come into alignment. In some epithelia, such as the auditory epithelium in the cochlea of the chicken, both the number and the maximum length of the stereocilia on hair cells vary systematically along gradients related to cell position in the epithelium. This pattern of sensory cell ultrastructure correlates with the high to low pitch tuning of the basilar membrane that supports the epithelium and with the tuning of the neurons that contact the individual cells. Cells at the distal end of the chicken cochlea have less than 50 stereocilia; cells at the proximal end have over 200. The stereocilia on proximal hair cells are short (<2 microns); those on distal hair cells are long (>5 microns). The reorientation of the stereocilia arrays and their location-specific differences in stereocilia number and length all become recognizable at approximately the time when synapses form between these cells and their neurons, but experiments have shown that these processes of hair cell differentiation can occur in the absence of neurons. Several hypotheses that attempt to explain the control of differentiation in hair cells will be covered

Excitation and Inhibition of the Reflex Eye Withdrawal of The Crab Carcinus

1967 ◽  
Vol 46 (3) ◽  
pp. 475-485
Author(s):  
D. C. SANDEMAN
Keyword(s):  
Motor Neuron ◽  
Optic Tract ◽  
The Body ◽  
Motor Axon ◽  
Single Motor ◽  
Burst Length ◽  
The Brain ◽  
Cathodal Stimulation ◽  
Stimulation Of

1. Damage to the statocysts or section of the oesophageal connectives of Carcinus causes repeated ‘spontaneous’ eye withdrawals or ‘blinking’ on the damaged side. 2. When the eyes and brain are isolated from the body, repetitive blinking persists and concomitant bursts of large impulses appear in a single motor axon in the optic tract. The length of these bursts varies from 80 to 180 impulses and the interburst intervals from 5 to 60 sec. There is no obvious correlation between burst length and interburst interval. 3. The bursts are inhibited by stimulating the inside half of the ipsilateral oesophageal connective or initiated by stimulation of the oculomotor and tegumentary nerves. If stimulated with a continuous train of pulses these pathways also cause an increase or decrease in the interburst intervals. 4. The actively spiking portion of the eye-withdrawal motor neuron extends into the brain at least as far as the tegumentary/antennary neuropile. Here it is particularly sensitive to cathodal stimulation, yielding trains of spikes to maintained d.c. stimulation. This point is considered to be near the spike initiating locus for the bursts.

scholarly journals Respiratory Reflexes in the Dogfish

1959 ◽  
Vol 36 (1) ◽  
pp. 62-71 ◽  
Author(s):  
G. H. SATCHELL
Keyword(s):  
Vagus Nerve ◽  
Respiratory Rate ◽  
The Body ◽  
Tetanic Stimulation ◽  
Branchial Nerve ◽  
The Brain ◽  
Respiratory Reflexes ◽  
Normal Respiration ◽  
Stimulation Of

1. Inflation of the pharynx of a dogfish causes an inhibition of respiration manifested as a reduction in rate and amplitude. 2. Tetanic stimulation of the central end of a cut branchial nerve also inhibits respiration. 3. These inhibitory responses differ in their greater regularity and duration from the transient inhibition arising from stimulation elsewhere in the body. 4. Both normal respiration and inflation cause the discharge of receptors whose impulses pass up the vagus nerve. The pattern of firing of these receptors during an inflation corresponds to the pattern, of inhibition. 5. Brief inflations are more effective in securing inhibition if they arrive at a time when the receptors are not being caused to fire by a normal inspiration. 6. Cutting the branchial branches of the IXth and Xth nerves eliminates the pause between successive respirations and increases the respiratory rate. 7. These pauses can be made to reappear by periodically stimulating the central end of a cut branchial nerve. 8. Section of the brain between the medulla and the mesencephalon increases the sensitivity to inflation. 9. Inhibitory afferents run in all branchial branches of the IXth and Xth nerves and in the pre-spiracular branch of the VIIth nerve. 10. It is suggested that in its response to vagotomy the dogfish resembles a medullary mammal.

scholarly journals Studies in the nervous control of carbohydrate metabolism. III.—The nature of the mechanism of the nerve control

1932 ◽  
Vol 110 (766) ◽  
pp. 158-171 ◽  
Keyword(s):  
Adrenal Gland ◽  
Carbohydrate Metabolism ◽  
Nervous Control ◽  
Parasympathetic System ◽  
Definite Answer ◽  
Set Up ◽  
The One ◽  
The Brain ◽  
Present Section ◽  
Stimulation Of

The two preceding sections have been devoted to a study of the centre which controls the level of sugar in the blood. Its location in the brain and the changes in carbohydrate metabolism resulting from its stimulation have been examined. The present section will be devoted to consideration of the results of certain experiments designed to throw light on the mechanism which is involved in this nerve control. The problems to be considered are: (1) the nerve pathway through which the centre discharges its impulses, and (2) the particular mechanism upon which these impulses primarily act. Investigation of the first of these would be greatly simplified if a definite answer could be given to the second, but, as we have seen, this is not possible, since functions of varying types located in different organs become involved. Indeed, the widespread nature of the disturbances set up by stimulation of the centre suggests the possibility that they must be due to the action of some hormone, or hormones, whose secretion into the blood is regulated by the nerve stimulus. If this be so the problem narrows itself down to finding the nerve pathway passing from the centre to the glands secreting the hormone. Two glands, the adrenal and the isles of Langerhans, have to be considered, and there is much evidence that the hor­mone which each secretes, adrenaline and insulin respectively, is under nerve control. But the nerves concerned apparently belong, in the one instance to the sympathetic (adrenal) and in the other, to the parasympathetic system (isles of Langerhans), so that the impulses resulting from piqure might act through either pathway; through the spinal cord and splanchnic nerves to the adrenal gland so as to stimulate an increased secretion of adrenaline or through the vagus so as to inhibit the secretion of insulin. In its rapidity of onset the hyperglycsemia which follows piqure resembles much more closely that which follows the injection of adrenaline than that supervening upon pancreatectomy, so that most workers who have supported the hypothesis that the nerve control acts through hormones have paid attention only to the adrenal gland. Our attention in the present paper will first of all be given to the effects of pontine decerebration on adrenalectomised animals.

Fictive swimming elicited by electrical stimulation of the midbrain in goldfish

1993 ◽  
Vol 70 (2) ◽  
pp. 765-780 ◽  
Author(s):  
J. R. Fetcho ◽  
K. R. Svoboda
Keyword(s):  
Brain Stimulation ◽  
Beat Frequency ◽  
Motor Pattern ◽  
The Body ◽  
Motor Output ◽  
Stimulus Strength ◽  
Motor Nerves ◽  
Tail Beat ◽  
The Brain ◽  
Stimulation Of

1. We developed a fictive swimming preparation of goldfish that will allow us to study the cellular basis of interactions between swimming and escape networks in fish. 2. Stimulation of the midbrain in decerebrate goldfish produced rhythmic alternating movements of the body and tail similar to swimming movements. The amplitude and frequency of the movements were dependent on stimulus strength. Larger current strengths or higher frequencies of stimulation produced larger-amplitude and/or higher-frequency movements. Tail-beat frequency increased roughly linearly with current strength over a large range, with plateaus in frequency sometimes evident at the lowest and highest stimulus strengths. 3. Electromyographic (EMG) recordings from axial muscles on opposite sides at the same rostrocaudal position showed that stimulation of the midbrain led to alternating EMG bursts, with bursts first on one side, then the other. These bursts occurred at a frequency equal to the tail-beat frequency and well below the frequency of brain stimulation. EMG bursts recorded from rostral segments preceded those recorded from caudal segments on the same side of the body. The interval between individual spikes within EMG bursts sometimes corresponded to the interval between brain stimuli. Thus, whereas the frequency of tail beats and EMG bursts was always much slower than the frequency of brain stimulation, there was evidence of individual brain stimuli in the pattern of spikes within bursts. 4. After paralyzing fish that produced rhythmic movement on midbrain stimulation, we monitored the motor output during stimulation of the midbrain by using extracellular recordings from spinal motor nerves. We characterized the motor pattern in detail to determine whether it showed the features present in the motor output of swimming fish. The fictive preparations showed all of the major features of the swimming motor pattern recorded in EMGs from freely swimming fish. 5. The motor nerves, like the EMGs produced by stimulating midbrain, showed rhythmic bursting at a much lower frequency than the brain stimulus. Bursts on opposite sides of the body alternated. The frequency of bursting ranged from 1.5 to 13.6 Hz and was dependent on stimulus strength, with higher strengths producing faster bursting. Activity in rostral segments preceded activity in caudal ones on the same side of the body. Some spikes within bursts of activity occurred at the same frequency as the brain stimulus, but individual brain stimuli were not as evident as those seen in some of the EMGs. 6. The duration of bursts of activity in a nerve was positively and linearly correlated with the time between successive bursts (cycle time).(ABSTRACT TRUNCATED AT 400 WORDS)

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