The vestibular nerve of the chinchilla. II. Relation between afferent response properties and peripheral innervation patterns in the semicircular canals

1988 ◽  
Vol 60 (1) ◽  
pp. 182-203 ◽  
Author(s):  
R. A. Baird ◽  
G. Desmadryl ◽  
C. Fernandez ◽  
J. M. Goldberg
Keyword(s):  
Lucifer Yellow ◽  
Discharge Rate ◽  
Small Diameter ◽  
Semicircular Canals ◽  
Preceding Paper ◽  
Vestibular Nerve ◽  
Response Properties ◽  
Peripheral Innervation ◽  
Innervation Patterns ◽  
The One

1. The relation between the response properties of semicircular canal afferents and their peripheral innervation patterns was studied by the use of intra-axonal labeling techniques. Fifty physiologically characterized units were injected with horseradish peroxidase (HRP) or Lucifer yellow CH (LY) and their processes were traced to the crista. The resting discharge, discharge regularity, and responses to both externally applied galvanic currents and sinusoidal head rotations were determined for most neurons. Terminal fields were reconstructed and, as in the preceding paper, the fibers were classified as calyx, bouton, or dimorphic units. 2. To determine if the intra-axonal sample was representative, the physiological properties of the labeled units were compared with those of a sample of extracellularly recorded units. A comparison was also made between the morphology of the intra-axonal units and those labeled by extracellular injection of HRP into the vestibular nerve Most of the discrepancies between the intra-axonal and the two extracellular samples can be explained by assuming that small-diameter fibers are underrepresented in the former sample. 3. A normalized coefficient of variation (CV*), independent of discharge rate, was used to classify units as regular, intermediate, or irregular. The CV* ranged from 0.020 to 0.60. Regular units (CV* less than or equal to 0.10) outnumbered irregular units (CV* greater than or equal to 0.20) by an approximately 3:1 ratio and had higher resting discharges. 4. Calyx units were invariably irregular. The one recovered bouton unit was regular. The discharge regularity of dimorphic units was related to their epithelial location, with those found in the periphery of the crista having a more regular discharge than those located more centrally. Dimorphic units, even those with quite similar morphology, can differ in their discharge regularity. Calyx and dimorphic units, which differ in their morphology, can both be irregular. These observations imply that discharge regularity is not determined by the branching pattern of a fiber or the number and types of hair cells it contacts. 5. The galvanic sensitivity (beta*) of an afferent, irrespective of its peripheral innervation pattern, was strongly correlated with CV*. This is consistent with the notion that discharge regularity and galvanic sensitivity are causally related, both being determined by postspike recovery mechanisms of the afferent nerve terminal.(ABSTRACT TRUNCATED AT 400 WORDS)

The vestibular nerve of the chinchilla. V. Relation between afferent discharge properties and peripheral innervation patterns in the utricular macula

1990 ◽  
Vol 63 (4) ◽  
pp. 791-804 ◽  
Author(s):  
J. M. Goldberg ◽  
G. Desmadryl ◽  
R. A. Baird ◽  
C. Fernandez
Keyword(s):  
Lucifer Yellow ◽  
Small Diameter ◽  
Sampling Bias ◽  
Vestibular Nerve ◽  
Strongly Correlated ◽  
Utricular Macula ◽  
Peripheral Innervation ◽  
Physiological Properties ◽  
Innervation Patterns ◽  
Discharge Patterns

1. The relation between the discharge properties of utricular afferents and their peripheral innervation patterns was studied in the chinchilla by the use of intra-axonal labeling techniques. Fifty-three physiologically characterized units were injected with horseradish peroxidase (HRP) or lucifer yellow CH (LY) and their labeled processes were traced to the utricular macula. For most labeled neurons, the discharge regularity, background discharge, and sensitivity to externally applied galvanic currents were determined, as were the gain (g2 Hz) and phase (phi 2 Hz) of the response to 2-Hz sinusoidal linear forces. Terminal fields were reconstructed and fibers were classified as calyx (n = 13) or dimorphic units (n = 40). No bouton units were recovered. Calyx units were confined to the striola. Dimorphic units were located in the striola (n = 8), the juxtastriola (n = 7), or the peripheral extrastriola (n = 25). 2. To determine whether the intra-axonal sample was representative, the physiological properties of labeled utricular units were compared with those of a larger sample of extracellularly recorded units. A comparison was also made between the morphology of intra-axonally labeled units and those labeled by the extracellular injection of HRP into the vestibular nerve. Most of the discrepancies between the intra-axonal and either extracellular sample can be explained by assuming that small-diameter fibers are underrepresented in the former sample. Dimorphic fibers labeled intra-axonally had more bouton endings and larger terminal trees than did those labeled extracellularly. The latter differences may reflect a sampling bias in the extracellular material. 3. Calyx units were irregularly discharging. The discharge regularity of dimorphic units was related to their macular locations. Only 1/8 dimorphic units in the striola was regularly discharging. The ratio increases to 3/7 in the juxtastriola and to 23/25 in the peripheral extrastriola. Among dimorphic units, there is a tendency for irregularly discharging afferents to have fewer bouton endings. The trend is far from perfect because it is possible to pick a subsample of dimorphic units that have similar numbers of boutons and, yet, have discharge patterns that range from regular to irregular. 4. Published morphological polarization maps can be used to predict the excitatory tilt directions of a unit from its macular location. Predictions were confirmed in 39/41 labeled afferents. 5. The galvanic sensitivity (beta *) of an afferent, irrespective of its peripheral innervation pattern or its epithelial location, was strongly correlated with a normalized coefficient of variation (CV*).(ABSTRACT TRUNCATED AT 400 WORDS)

The vestibular nerve of the chinchilla. I. Peripheral innervation patterns in the horizontal and superior semicircular canals

1988 ◽  
Vol 60 (1) ◽  
pp. 167-181 ◽  
Author(s):  
C. Fernandez ◽  
R. A. Baird ◽  
J. M. Goldberg
Keyword(s):  
Hair Cells ◽  
Afferent Fiber ◽  
Central Zone ◽  
Semicircular Canals ◽  
Peripheral Zone ◽  
Sensory Epithelium ◽  
Vestibular Nerve ◽  
Fiber Types ◽  
Peripheral Innervation ◽  
Numerous Type

1. Afferent fibers supplying the horizontal and superior semicircular canals of the chinchilla were labeled by extracellular injections of horseradish peroxidase (HRP) into the vestibular nerve. The arborizations of labeled fibers within the sensory epithelium were reconstructed from serial sections of the crista. 2. The sensory epithelium of the crista can be divided into central, intermediate, and peripheral zones of approximately equal areas. The three zones can be distinguished in normal material by the density of hair cells and by the morphology of calyx endings. 3. Labeled fibers supply either the canalicular or the utricular side of the crista. Axons seldom bifurcate below the basement membrane and they begin dividing into their terminal arborizations almost immediately upon entering the sensory epithelium. The arborizations are compact, seldom extending more than 50 micron from the parent axon. 4. Both calyx and bouton endings were labeled. Calyces can be simple or complex. Simple calyces innervate individual hair cells, whereas complex calyces supply two to three adjacent hair cells. Complex calyces are commonly found only in the central zone. Simple calyces and boutons are located in all regions of the epithelium. Calyces emerge from the parent axon or one of its thick branches. Boutons, whether en passant or terminal, are always located on thin processes. 5. Fibers were classified as calyx, bouton, or dimorphic. The first type only has calyx endings, the second only has bouton endings, and the third has both kinds of endings. Dimorphic units make up some 70% of the labeled fibers, bouton units some 20%, and calyx units some 10%. The three fiber types differ in the diameters of their parent axons and in the regions of the crista they supply. Axon diameters are largest for calyx units and smallest for bouton units. Calyx units are concentrated in the central zone of the crista, whereas bouton units are largely confined to the peripheral zone. Dimorphic units are seen throughout the sensory epithelium. 6. Calyx units are almost always unbranched and end as simple calyces or, less often, as complex calyces. The terminal arbors of bouton units consist of fine processes containing 15-80 endings. Dimorphic units vary in complexity from fibers with a single calyx and a few boutons to those with one to four calyces and more than 50 boutons. 7. The results emphasize the importance of dimorphic units, which were the most numerous type of afferent fiber labeled in this study and were the only units found to innervate all regions of the sensory epithelium.(ABSTRACT TRUNCATED AT 400 WORDS)

Inputs from regularly and irregularly discharging vestibular nerve afferents to secondary neurons in the vestibular nuclei of the squirrel monkey. II. Correlation with output pathways of secondary neurons

1987 ◽  
Vol 58 (4) ◽  
pp. 719-738 ◽  
Author(s):  
S. M. Highstein ◽  
J. M. Goldberg ◽  
A. K. Moschovakis ◽  
C. Fernandez
Keyword(s):  
Spinal Cord ◽  
Vestibular Nucleus ◽  
Preceding Paper ◽  
Vestibular Nuclei ◽  
Vestibular Nerve ◽  
Antidromic Activation ◽  
Mean Values ◽  
Postsynaptic Potentials ◽  
The Mean ◽  
Vestibular Nerve Afferents

1. Intracellular recordings were made from secondary neurons in the vestibular nuclei of barbiturate-anesthetized squirrel monkeys. Monosynaptic excitatory postsynaptic potentials (EPSPs) evoked by stimulation of the ipsilateral vestibular nerve (Vi) were measured. An electrophysiological paradigm, described in the preceding paper (26), was used to determine the proportion of irregularly (I) and regularly (R) discharging Vi afferents making direct connections with individual secondary neurons. The results were expressed as a % I index, an estimate for each neuron of the percentage of the total Vi monosynaptic input that was derived from I afferents. The secondary neurons were also classified as I, R, or M cells, depending on whether they received their direct Vi inputs predominantly from I or R afferents or else from a mixture (M) of both kinds of Vi fibers. The neurons were located in the superior vestibular nucleus (SVN) or in the rostral parts of the medical or lateral (LVN) vestibular nuclei. 2. Antidromic activation or reconstruction of axonal trajectories after intrasomatic injection of horseradish peroxidase (HRP) was used to identify three classes of secondary neurons in terms of their output pathways: 1) cerebellar-projecting (Fl) cells innervating the flocculus (n = 26); 2) rostrally projecting (Oc) cells whose axons ascended toward the oculomotor (IIIrd) nucleus (n = 27); and 3) caudally projecting (Sp) cells with axons descending toward the spinal cord (n = 13). Two additional neurons, out of 21 tested, could be antidromically activated both from the level of the IIIrd nucleus and from the spinal cord. 3. The Vi inputs to the various classes of relay neurons differed. As a class, Oc neurons received the most regular inputs. Sp neurons had more irregular inputs. Fl neurons were heterogeneous with similar numbers of R, M, and I neurons. The mean values (+/- SD) of the % I index for the Oc, Fl, and Sp neurons were 34.7 +/- 24.7, 51.9 +/- 30.4, and 61.8 +/- 18.0%, respectively. Only the Oc neurons had a % I index that was similar to the proportion of I afferents (34%) in the vestibular nerve (cf. Ref. 26). 4. The commissural inputs from the contralateral vestibular nerve (Vc) also differed for the three projection classes. Commissural inhibition was most common in Fl cells: 22/25 (88%) of the neurons had Vc inhibitory postsynaptic potentials (IPSPs) and 1/25 (4%) had a Vc EPSP. In contrast, Vc inputs were only observed in approximately half the Oc and Sp neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

CONFINEMENT OF QUARKS AND GLUONS II

1995 ◽  
Vol 10 (22) ◽  
pp. 3155-3167 ◽  
Author(s):  
KAZUHIKO NISHIJIMA
Keyword(s):  
Quantum Chromodynamics ◽  
Preceding Paper ◽  
Asymptotic Freedom ◽  
Color Confinement ◽  
The One

It is shown that color confinement is a consequence of BRS invariance and asymptotic freedom of quantum chromodynamics. BRS invariance is exploited to define color confinement, and asymptotic freedom is utilized to prove it. The proof presented in this paper is an extension of the one in the preceding paper.

scholarly journals Effects of weir geometry on scour development in the downstream of Piano Key Weirs

2020 ◽  
Author(s):  
Alireza Mosalman Yazdi ◽  
S. Abbas Hoseini ◽  
Sohrab Nazari ◽  
Nosratollah Amanian
Keyword(s):  
Discharge Rate ◽  
Scour Depth ◽  
Scour Hole ◽  
Weir Height ◽  
The One ◽  
Rectangular Model

Abstract Scouring in the downstream of all weirs, including Piano Key Weirs (PKWs), can have major safety implications. Since the research on downstream scouring of PKWs is very limited, and the weir geometry is also known to have an impact on downstream scouring, this study investigated scouring in the downstream of PKWs with rectangular and trapezoidal geometries and two different heights. The scour hole measurements showed that in both rectangular and trapezoidal models, scour hole parameters increased both with the increase in discharge rate and the increase in weir height. Under similar discharge conditions, the scour depth downstream from the rectangular model was greater than that downstream from the trapezoidal model. The dimensionless maximum scour depth, the distance of maximum scour depth from the weir toe, and the scour hole length for the trapezoidal PKW were, on average, 6, 13, and 11% lower than the corresponding ones for the rectangular PKW, respectively. However, these differences decreased with the increase in falling height. For both weir geometries, the maximum scour depth was aligned with the outlet keys. In addition, the maximum scour depth under the outlet keys was 13% greater than the one under the inlet keys.

Electronic and structural study of hexagonal TiC nanowires: ab initio study

BIBECHANA ◽  
2018 ◽  
Vol 16 ◽  
pp. 7-14 ◽  
Author(s):  
Puspa Raj Adhikari ◽  
Om Prakash Upadhyay ◽  
Gopi Chandra Kaphle ◽  
Anurag Srivastava
Keyword(s):  
Density Functional ◽  
Small Diameter ◽  
Hexagonal Structure ◽  
Density Of State ◽  
Electronic Density ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The One ◽  
The Impact ◽  
Bulk Structures

Nanowire are the one-dimensional nanostructure with the diameter order of one to few hundred nanometre. These structure shows unique properties other than their bulk structures. In this article, a qualitative first principle discussion of TiC nanowire is reported, indicating the impact of DFT based GGA relativistic corrections on its electronic properties. Here, we analyse   the Titanium Carbide (TiC) nanowire of hexagonal structure periodic in Z-direction with the density functional theory (DFT). The GGA with RBBE Correlation analysis of this material shows the metallic characteristics in its bulk but the electronic density of  state shows that the hybridization state are different from their bulk when the material is analysed in nanostructure form. Three structures of hexagonal TiC nanowire directed in (1,1,1) plane were analysed to explore diameter (4-18) Å dependent comparative study of electronic, stabilizing and optical property which shows unique different result counterparts to its bulk. Hexagonal TiC nanowire were found to be semiconducting with narrow band gap (0.21-0.34) eV in small diameter while metallic in higher diameter. They are comparable stables as their bulk for higher structure. Similarly, for the same investigation, the structures are cross checked by surface atom passivation to verify the reliability of the result that we found.BIBECHANA 16 (2019) 7-14

scholarly journals Experimental researches in electricity: Twelfth series

1843 ◽  
Vol 4 ◽  
pp. 49-52
Keyword(s):  
Electric Discharge ◽  
Physical State ◽  
Charged Particles ◽  
Preceding Paper ◽  
The Other ◽  
Electric Conduction ◽  
The One ◽  
Experimental Researches ◽  
Inductive Charge ◽  
Perfect Conduction

The object of the present series of researches is to examine how far the principal general facts in electricity are explicable on the theory adopted by the author, and detailed in his last memoir, re­lative to the nature of inductive action. The operation of a body charged with electricity, of either the positive or negative kind, on other bodies in its vicinity, as long as it retains the whole of its charge, may be regarded as simple induction , in contradistinction to the effects which follow the destruction of this statical equilibrium, and imply a transit of the electrical forces from the charged body to those at a distance, and which comprehend the phenomena of the electric discharge . Having considered, in the preceding paper, the process by which the former condition is established, and which consists in the successive polarization of series of contiguous particles of the interposed insulating dielectric; the author here proceeds to trace the process, which, taking place consequently on simple induction, terminates in that sudden, and often violent interchange of electric forces constituting disruption , or the electric discharge. He investigates, by the application of his theory, the gradual steps of transition which may be traced between perfect insulation on the one hand, and perfect conduction on the other, derived from the varied degrees of specific electric relations subsisting among the particular substances interposed in the circuit: and from this train of reasoning he deduces the conclusion that induction and conduction not only depend essentially on the same principles, but that they may be regarded as being of the same nature, and as differing merely in degree. The fact ascertained by Professor Wheatstone, that electric conduction, even in the most perfect conductors, as the metals, requires for its completion a certain appreciable time, is adduced in corrobo­ration of these views; for any retardation, however small, in the transmission of electric forces can result only from induction; the degree of retardation, and, of course, the time employed, being proportional to the capacity of the particles of the conducting body for retaining a given intensity of inductive charge. The more perfect insulators, as lac, glass and sulphur, are capable of retaining electri­city of high intensity; while, on the contrary, the metals and other excellent conductors, possess no power of retention when the in­tensity of the charge exceeds the lowest degrees. It would appear, however, that gases possess a power of perfect insulation, and that the effects generally referred to their capacity of conduction, are only the results of the carrying power of the charged particles either of the gas, or of minute particles of dust which may be present in them: and they perhaps owe their character of perfect insulators to their peculiar physical state, and to the condition of separation under which their particles are placed. The changes produced by heat on the conducting power of different bodies is not uniform; for in some, as sulphuret of silver and fluoride of lead, it is increased; while in others, as in the metals and the gases, it is diminished by an augmentation of temperature.

scholarly journals Weight structures vs.t-structures; weight filtrations, spectral sequences, and complexes (for motives and in general)

2010 ◽  
Vol 6 (3) ◽  
pp. 387-504 ◽  
Author(s):  
M.V. Bondarko
Keyword(s):  
Preceding Paper ◽  
Spectral Sequences ◽  
Motivic Cohomology ◽  
Adjacent Structures ◽  
Unramified Cohomology ◽  
Homological Functor ◽  
Stable Homotopy Category ◽  
Weight Structure ◽  
The One ◽  
Weight Structures

AbstractIn this paper we introduce a new notion ofweight structure (w)for a triangulated categoryC; this notion is an important natural counterpart of the notion oft-structure. It allows extending several results of the preceding paper [Bon09] to a large class of triangulated categories and functors.Theheartofwis an additive categoryHw⊂C. We prove that a weight structure yields Postnikov towers for anyX∈ObjC(whose 'factors'Xi∈ObjHw). For any (co)homological functorH:C→A(Ais abelian) such a tower yields aweight spectral sequenceT : H(Xi[j]) ⇒H(X[i + j]); Tis canonical and functorial inXstarting fromE2.Tspecializes to the usual (Deligne) weight spectral sequences for 'classical' realizations of Voevodsky's motivesDMeffgm(if we considerw = wChowwithHw=Choweff) and to Atiyah-Hirzebruch spectral sequences in topology.We prove that there often exists an exact conservative weight complex functorC→K(Hw). This is a generalization of the functort:DMeffgm→Kb(Choweff) constructed in [Bon09] (which is an extension of the weight complex of Gillet and Soulé). We prove thatK0(C) ≅K0(Hw) under certain restrictions.We also introduce the concept of adjacent structures: at-structure isadjacenttowif their negative parts coincide. This is the case for the Postnikovt-structure for the stable homotopy categorySH(of topological spectra) and a certain weight structure for it that corresponds to the cellular filtration. We also define a new (Chow)t-structuretChowforDMeff_⊃DMeffgmwhich is adjacent to the Chow weight structure. We haveHtChow≅ AddFun(Choweffop,Ab);tChowis related to unramified cohomology. Functors left adjoint to those that aret-exact with respect to somet-structures are weight-exact with respect to the corresponding adjacent weight structures, and vice versa. Adjacent structures identify two spectral sequences converging toC(X,Y): the one that comes from weight truncations ofXwith the one coming fromt-truncations ofY(forX,Y∈ObjC). Moreover, the philosophy of adjacent structures allows expressing torsion motivic cohomology of certain motives in terms of the étale cohomology of their 'submotives'. This is an extension of the calculation of E2of coniveau spectral sequences (by Bloch and Ogus).

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