scholarly journals THE RELATIONS OF THE INDIVIDUAL AMPULLÆ OF THE SEMICIRCULAR CANALS TO THE INDIVIDUAL EYE MUSCLES

1926 ◽  
Vol 8 (5) ◽  
pp. 441-449 ◽  
Author(s):  
S. S. Maxwell ◽  
O. L. Huddleston
Keyword(s):  
Mechanical Stimulation ◽  
Semicircular Canals ◽  
Mechanical Stimulus ◽  
Horizontal Canal ◽  
Eye Muscles ◽  
Reflex Effect ◽  
Strong Contraction ◽  
Rhythmic Contractions ◽  
The Individual ◽  
Stimulation Of

1. The reflex effect of direct mechanical stimulation of the exposed ampulla of the horizontal canal has been graphically recorded for each of the six extrinsic muscles of the eyeball. 2. Stimulation of a horizontal ampulla evokes a strong contraction of the homolateral rectus internus and of the contralateral rectus externus; at the same time the homolateral rectus externus and the contralateral rectus internus relax. 3. A single mechanical stimulus applied to the horizontal ampulla is sometimes followed by a nystagmus resulting from a series of rhythmic contractions of the externus and internus muscles. 4. Excitation of a horizontal ampulla gives rise to weak contractions of the superior and inferior recti and of the two oblique muscles of both eyes, simultaneously with the stronger contractions of the externus and internus respectively. 5. It is pointed out that the small simultaneous contractions of the four muscles just mentioned provide a virtual axis upon which the eyeball rotates. In other words these four act as fixation muscles. 6. It is suggested that some of the abnormal responses to horizontal rotation, seen in clinical cases, are due to the inaction of one or more of the fixation muscles.

Reflections of Efferent Activity in Rotational Responses of Chinchilla Vestibular Afferents

2002 ◽  
Vol 88 (3) ◽  
pp. 1234-1244 ◽  
Author(s):  
Meir Plotnik ◽  
Vladimir Marlinski ◽  
Jay M. Goldberg
Keyword(s):  
Rotation Axis ◽  
Semicircular Canals ◽  
Horizontal Canal ◽  
Efferent System ◽  
Type Iii ◽  
Complete Section ◽  
Viiith Nerve ◽  
Rotation Plane ◽  
Excitatory Responses ◽  
Stimulation Of

To study presumed efferent-mediated responses, we determined if afferents responded to head rotations that stimulated semicircular canals other than the organ being innervated. To minimize stimulation of an afferent's own canal, its plane was placed nearly orthogonal to the rotation plane. Otolith units were tested in a horizontal head position with the ear placed near the rotation axis to minimize linear forces. Under these circumstances, angular-velocity trapezoids (2-s ramps, 2-s plateau) evoked excitatory responses for both rotation directions. These type III responses were considerably larger in decerebrate than in anesthetized preparations. In addition to their being exclusively excitatory, the responses resembled those obtained with electrical stimulation of efferent pathways in including per-stimulus and more prolonged post-stimulus components and in being larger in irregularly discharging than in regularly discharging units. Responses, which were not seen for rotations <80°/s, grew as velocity increased between 80 and 500°/s but were seldom larger than 20 spikes/s. Complete section of the VIIIth nerve abolished type III responses, leaving conventional afferent responses intact. To study the separate contributions of canals on the two sides, responses were compared when the labyrinths were intact and when the ipsilateral or contralateral horizontal canal was mechanically inactivated. Both sides contributed to the efferent-mediated responses. That afferents could be influenced from the contralateral labyrinth was confirmed with the use of unilateral galvanic currents. Following inactivation, excitatory responses were produced by rotations exciting or inhibiting the intact horizontal canal with the responses resulting from excitatory rotations being much larger. Such a response asymmetry is consistent with a semicircular-canal origin for the type III responses. A similar asymmetry was seen in the post-stimulus responses to contralateral cathodal (excitatory) and anodal (inhibitory) galvanic currents. We conclude that the efferent system receives a sufficiently powerful vestibular input from both the ipsilateral and contralateral labyrinths to affect afferent discharge.

The statocyst-oculomotor system of octopus vulgaris : extraocular eye muscles, eye muscle nerves, statocyst nerves and the oculomotor centre in the central nervous system

1984 ◽  
Vol 306 (1127) ◽  
pp. 159-189 ◽  
Keyword(s):  
Visual Information ◽  
Oculomotor System ◽  
Octopus Vulgaris ◽  
Eye Muscle ◽  
Eye Muscles ◽  
Morphological Organization ◽  
Indirect Path ◽  
Extraocular Eye Muscles ◽  
The Individual ◽  
Stimulation Of

Seven extraocular eye muscles are described in Octopus vulgaris. There are three powerful recti muscles that produce linear movements and four oblique muscles producing rotation. Some of these oblique muscles are very thin sheets passing halfway round the eyeball. The eye muscles are controlled by seven nerves, but several of these innervate more than one muscle. Stimulation of the individual nerves produces the linear and rotatory movements, or both, to be expected from the morphological organization of the muscles they innervate. Two of the nerves run only to extraocular eye muscles, the other five contain additional fibres for the iris, chromatophores or skin. Cobalt filling of the central ends of the eye muscle nerves showed that all have fibres originating in the ipsilateral anterior lateral pedal lobe which is the oculomotor centre. The two nerves whose stim ulation gave expansion of the chrom atophores of the iris were shown to contain fibres with somata in the ipsilateral anterior chromatophore lobe. Two nerves gave constriction of the pupil and proved to contain fibres with somata in an area between the posterior pedal and magnocellular lobes, demonstrating the position of a pupillary control centre. Stimulation of one nerve gave dilation of the pupil but the origin of the relevant cells remains unclear. Cobalt filling of the central ends of the macula and crista nerves of the statocyst showed the destinations of their afferent fibres in many parts of the brain, including the oculomotor centre and higher motor centres of the basal and peduncle lobes. In addition, many somata of efferent fibres to the statocyst were filled in the oculomotor centre, in the posterior lateral pedal lobe, and in the posterior pedal and magnocellular lobes. The statocyst-oculomotor system of Octopus thus includes two pathways from the statocyst equilibrium receptor organs to the motoneurons of the eyes: one direct pathway, and another indirect path via higher integrative centres where visual information about movement is combined with that coming from the statocysts. This situation points to a rem arkable convergence between the Octopus statocyst-oculomotor system and the vestibulo-ocular system of vertebrates.

scholarly journals The Nerve Net of the Actinozoa

1935 ◽  
Vol 12 (2) ◽  
pp. 119-138 ◽  
Author(s):  
C. F. A. PANTIN
Keyword(s):  
Mechanical Stimulus ◽  
Electrical Stimulus ◽  
Conducting Layer ◽  
Electrical Excitation ◽  
Sense Organs ◽  
Nerve Net ◽  
Duration Relationship ◽  
The Individual ◽  
Electrical Stimuli ◽  
Stimulation Of

1. Certain features have been supposed to characterise the nerve net. Response is said to vary with the strength of stimulus: and while conduction may occasionally take place in an all or nothing manner, yet in general conduction is supposed to take place with a decrement. To investigate these points, the responses of Calliactis parasitica to mechanical and electrical stimuli have been investigated. 2. Electrical excitation of the column of the anemone shows that a response results from a succession of stimuli and not from a single stimulus. The character of the response is independent of the strength of the individual stimuli. It depends solely upon the number of stimuli and upon the interval of time between them. All responses are highly developed facilitation phenomena. Each electrical stimulus induces a single excitation impulse in the nerve net. 3. But a mechanical stimulus is followed by the discharge of a battery of impulses from the sense organs. These increase in number and frequency with the intensity of the mechanical stimulus. A response may therefore vary with the strength of a mechanical stimulus, but only in relation to the number and frequency of impulses discharged by the sense-organs. 4. Stimulation of the intact column of the anemone shows complete conduction over its whole nerve net. Mechanical stimulation of the disc appears to show conduction with a decrement. Such a stimulus excites a battery of impulses. Each impulse is conducted without decrement, but it facilitates the entrance of succeeding impulses into adjoining sections of the disc nerve net. There is no decrement of excitation strength under any conditions in the nerve net. But there may be a numerical decrement as a battery of impulses spreads from a stimulus. 5. The nerve net is physiologically similar to ordinary nerve. A method is described for determining the strength duration relationship for the threshold of electrical excitation of the nerve net. The relation is of the usual form with a chronaxie of about 2-4σ. The nerve net has well-defined relative and absolute refractory periods: the latter is about 40-65σ. The relation of facilitation to refractory period is considered. 6. The whole nerve net of the column of the anemone acts as a conducting layer in its most simple form, directly transmitting excitation from the stimulus to the muscle. Facilitation takes place between the nerve net and its appropriate muscles. Conduction in the disc nerve net involves facilitation between parts of the nerve net in addition. 7. The true characteristics of the nerve net are diffuse conduction and the extreme development of facilitation. Diffuse conduction may be total, as in the column, or restricted, as in the disc of Calliactis. Facilitation may be between the nerve net and the muscles, or between parts of the nerve net.

A method for controlled mechanical stimulation of single semicircular canals

1988 ◽  
Vol 25 (2) ◽  
pp. 111-119 ◽  
Author(s):  
J.David Dickman ◽  
Paul A. Reder ◽  
Manning J. Correia
Keyword(s):  
Mechanical Stimulation ◽  
Semicircular Canals ◽  
Stimulation Of

Responses of pigeon horizontal semicircular canal afferent fibers. I. Step, trapezoid, and low-frequency sinusoid mechanical and rotational stimulation

1989 ◽  
Vol 62 (5) ◽  
pp. 1090-1101 ◽  
Author(s):  
J. D. Dickman ◽  
M. J. Correia
Keyword(s):  
Mechanical Stimulation ◽  
Semicircular Canal ◽  
Action Potentials ◽  
Transfer Functions ◽  
Semicircular Canals ◽  
Primary Afferent ◽  
Horizontal Semicircular Canal ◽  
Horizontal Canal ◽  
Best Fit ◽  
Rotational Stimulation

1. The horizontal semicircular canals of anesthetized (barbiturate/ketamine) pigeons were stimulated by rotational and by mechanical stimulation. 2. The mechanical stimulation consisted of making a small (less than 1 mm) fistula in the lateral part of the bony horizontal semicircular canal and, after inserting a probe coupled to a piezoelectric micropusher through the fistula, providing controlled indentation of the exposed membranous horizontal semicircular duct. 3. Extracellular action potentials from single horizontal semicircular canal primary afferent (HCA) fibers were recorded during sinusoidal rotational and during step, ramp, and sinusoidal mechanical stimulation. 4. The mean spontaneous discharge rate of 160 horizontal canal afferents was 86 +/- 4 (SE) spikes/s. This rate was not significantly different from that reported previously for pigeon HCA fibers recorded with the horizontal canal intact (i.e., no fistula introduced). 5. Sinusoidal mechanical indentation of the horizontal semicircular duct produced clearly entrained action potentials on 36 HCA fibers for a range of peak displacements from +/- 0.5 to +/- 30 microns. Action potentials were never modulated on afferents (n greater than 100) identified as innervating the anterior and posterior semicircular canals or the otolith organs during mechanical stimulation of the horizontal semicircular canal, even for displacements as large as 30 microns. 6. Intensity functions relating peak firing frequency (spikes per second) and peak probe displacement (micrometers) for 1.0-Hz sinusoidal mechanical stimulation were linear over the range 1.0-5.0 microns. The most sensitive units (6/36, 17%) showed response saturation as the stimulus magnitude was extended to 7 microns and beyond. 7. In 15 of 36 units, both mechanical and rotational sinusoidal stimulation (1.0 Hz) were applied to the same unit. The duct indentation magnitudes were 1.0, 2.5, 5.0, and 7.0 microns and the rotational velocities were 5, 10, and 20 deg/s. The constant of proportionality found to equate the peak response produced by rotational to that elicited by mechanical stimulation was 7.0 deg.sec-1/1.0 microns. 8. Bode plots and best-fit transfer functions of the frequency response (0.05-10.0 Hz) of 14 HCAs exposed to both mechanical and rotational stimulation were nearly identical. 9. Parameters for best-fit transfer functions, responses to step, and trapezoidal duct displacements were in excellent agreement with previous rotational studies carried out using the pigeon. 10. Although the mechanisms by which focal identation of the horizontal membranous duct produce responses have not yet been determined, primary afferent responses using this method of stimulation are directly comparable with rotatory stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Spinocervical tract neurons responsive to light mechanical stimulation of the raccoon forepaw

1989 ◽  
Vol 61 (1) ◽  
pp. 138-148 ◽  
Author(s):  
H. Hirata ◽  
B. H. Pubols
Keyword(s):  
Mechanical Stimulation ◽  
Receptive Fields ◽  
Mechanical Stimulus ◽  
Dorsal Column ◽  
Glabrous Skin ◽  
Mechanical Stimuli ◽  
The Relationship ◽  
Lemniscal System ◽  
Extracellular Activity ◽  
Stimulation Of

1. The extracellular activity of 45 antidromically identified spinocervical tract (SCT) neurons responsive to light mechanical stimulation of the glabrous surfaces of the forepaw was examined in raccoons anesthetized with pentobarbital sodium. An additional seven neurons had peripheral receptive fields (RFs) located on hairy skin of the forelimb, and three had deep RFs. 2. All recording sites were histologically verified as falling within Rexed's laminae III and IV in spinal cord segments C6-T1. Antidromic conduction velocities of the 55 neurons ranged between 8.3 and 64.2 m/s. 3. Units with glabrous skin RFs were classified according to their response to a maintained mechanical stimulus as either rapidly adapting (n = 39) or slowly adapting (n = 6). Of 11 cells tested, 2 displayed enhanced responses to noxious stimuli and were classed as multireceptive. 4. RF areas were significantly smaller on digits (range = 0.4-45.0 mm2) than on palm pads (range = 5.6-76.0 mm2), and comparable in size to RF areas previously reported in raccoon cuneate nuclear cells (32). 5. RA neurons fell into three distinct categories with respect to the relationship between instantaneous spike frequency during displacement ramp stimulation, and ramp velocity, steep functions (as defined by the value of power function exponents), flat functions, and discontinuous functions; SA neurons fell into two categories, continuous, and discontinuous. 6. The results, in conjunction with those of previous studies, lead to two major conclusions: 1) raccoon and primate spinocervicothalamic systems are more similar to each other than either is to that of the cat and 2) the ability of the raccoon SCT to convey information from the glabrous skin of the forepaw regarding characteristics of light mechanical stimuli is at least as precise as that of neurons of the dorsal column-medial lemniscal system.

Mechanical stimulation of human BON cells: Gαq involvement in 5-HT release

2001 ◽  
Vol 120 (5) ◽  
pp. A83-A83
Author(s):  
M KIM ◽  
N JAVED ◽  
F CHRISTOFI ◽  
H COOKE
Keyword(s):  
Mechanical Stimulation ◽  
Bon Cells ◽  
Stimulation Of

Use of Flexible Materials with a Novel Pressure Driven Equibiaxial Cell Stretching Device for Mechanical Stimulation of Single Mammalian Cells

2003 ◽  
Vol 773 ◽  
Author(s):  
James D. Kubicek ◽  
Stephanie Brelsford ◽  
Philip R. LeDuc
Keyword(s):  
Cell Fate ◽  
Mechanical Stimulation ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Single Cells ◽  
Complex Nature ◽  
Cellular Behavior ◽  
Cell Stretching ◽  
Stimulation Of ◽  
Pressure Driven

AbstractMechanical stimulation of single cells has been shown to affect cellular behavior from the molecular scale to ultimate cell fate including apoptosis and proliferation. In this, the ability to control the spatiotemporal application of force on cells through their extracellular matrix connections is critical to understand the cellular response of mechanotransduction. Here, we develop and utilize a novel pressure-driven equibiaxial cell stretching device (PECS) combined with an elastomeric material to control specifically the mechanical stimulation on single cells. Cells were cultured on silicone membranes coated with molecular matrices and then a uniform pressure was introduced to the opposite surface of the membrane to stretch single cells equibiaxially. This allowed us to apply mechanical deformation to investigate the complex nature of cell shape and structure. These results will enhance our knowledge of cellular and molecular function as well as provide insights into fields including biomechanics, tissue engineering, and drug discovery.

Mechanical stimulation of duck on rice phyto-morphology in rice-duck farming system

2012 ◽  
Vol 20 (6) ◽  
pp. 717-722 ◽  
Author(s):  
Zhao-Xiang HUANG ◽  
Jia-En ZHANG ◽  
Kai-Ming LIANG ◽  
Guo-Ming QUAN ◽  
Ben-Liang ZHAO
Keyword(s):  
Mechanical Stimulation ◽  
Farming System ◽  
Stimulation Of
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