scholarly journals The interaction between two trains of impulses converging on the same motoneurone

1929 ◽  
Vol 105 (738) ◽  
pp. 363-371 ◽  
Keyword(s):  
Mechanical Effect ◽  
The Other ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Afferent Pathways ◽  
Afferent Nerves ◽  
Maximal Stimulation ◽  
The Common ◽  
The Relationship ◽  
Stimulation Of

It was shown in an earlier paper (7) that if maximal stimulation of either of two different afferent nerves can reflexly excite fractions of a given flexor muscle, there are generally, within the aggregate of neurones which innervate that muscle, motoneurones which can be caused to discharge by either afferent (i. e., motoneurones common to both fractions). The relationship which two such afferents bear to a common motoneurone was shown, by the isometric method of recording contraction, to be such that the activation of one afferent, at a speed sufficient to cause a maximal motor tetanus when trans­mitted to the muscle fibres, caused exclusion of any added mechanical effect when the other afferent was excited concurrently. This default in mechanical effect was called “occlusion.” Occlusion may conceivably be due to total exclusion of the effect of one afferent pathway on the common motoneurone by the activity of the other; but facilitation of the effect of one path by the activation of the other when the stimuli were minimal suggests that, in some circumstances at least, the effect of each could augment and summate with th at of the other at the place of convergence of two afferent pathways. Further investigation, using the action currents of the muscle as indication of the nerve impulses discharged by the motoneurone units, has now given some information regarding the effect of impulses arriving at the locus of convergence by one afferent path when the unit common to both is already discharging in response to impulses arriving by the other afferent path. Our method has been to excite both afferent nerves in overlapping sequence by series of break shocks at a rapid rate and to examine the action currents of the resulting reflex for evidence of the appearance of the rhythm of the second series in the discharge caused by the first when the two series are both reaching the motoneurone.

Neuromuscular properties of the quintuply innervated flexor muscle in lobster limbs

1991 ◽  
Vol 69 (2) ◽  
pp. 477-488 ◽  
Author(s):  
T. J. Wiens ◽  
Joanne Pearce ◽  
C. K. Govind
Keyword(s):  
Active Site ◽  
Oxidative Capacity ◽  
The Other ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Electron Microscopic ◽  
Leg Muscles ◽  
Synaptic Interactions ◽  
The Common ◽  
To Receive

The flexor muscle of the lobster's walking leg was shown by enzyme histochemistry and electrophysiology to display a regional segregation of fibre types: medial fibres have a higher ATPase activity, lower oxidative capacity, and shorter membrane time constant than peripheral fibres lying near the cuticle. The muscle was confirmed to receive one inhibitory and four excitatory motor axons. As judged by the properties of their output excitatory junctional potentials (ejp's), the four excitors lie along the fast-to-slow gradient defined by the two specialized excitors of dually excited muscles. The Fα axon produces initially large ejp's which facilitate weakly or antifacilitate; they are similar to those of fast axons in other muscles. The Fρ axon at the other end of the spectrum produces strongly facilitating ejp's which are initially small, resembling those of known slow axons. The Fβ and Fγ axons show intermediate properties. The inhibitor, which is the common inhibitor of all leg muscles, innervates preferentially the more tonic muscle fibres, as does Fρ. Muscle fibres were observed to receive anywhere from one to five efferents, most receiving two to four. Serial electron microscopic observations in several regions revealed a rich supply of synaptic terminals, usually comprising a single inhibitory terminal and two or three excitatory ones. The inhibitory terminal typically has a few large synapses, each with more than one active site. Excitatory terminals, on the other hand, have many more smaller synapses, each with at least one active site. Although excitatory and inhibitory terminals were often closely juxtaposed, no synaptic interactions were observed between them.

scholarly journals Evangelical and Catholic Timespace in Work: An Argument against a Homeless Eschatology

Religions ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 199
Author(s):  
Maria Ledstam
Keyword(s):  
Empirical Study ◽  
Common Good ◽  
Ethnographic Study ◽  
The Other ◽  
Faith Based ◽  
Business As Mission ◽  
Achievable Goal ◽  
The Common ◽  
The One ◽  
The Relationship

This article engages with how religion and economy relate to each other in faith-based businesses. It also elaborates on a recurrent idea in theological literature that reflections on different visions of time can advance theological analyses of the relationship between Christianity and capitalism. More specifically, this article brings results from an ethnographic study of two faith-based businesses into conversation with the ethicist Luke Bretherton’s presentation of different understandings of the relationship between Christianity and capitalism. Using Theodore Schatzki’s theory of timespace, the article examines how time and space are constituted in two small faith-based businesses that are part of the two networks Business as Mission (evangelical) and Economy of Communion (catholic) and how the different timespaces affect the religious-economic configurations in the two cases and with what moral implications. The overall findings suggest that the timespace in the Catholic business was characterized by struggling caused by a tension between certain ideals on how religion and economy should relate to each other on the one hand and how the practice evolved on the other hand. Furthermore, the timespace in the evangelical business was characterized by confidence, caused by the business having a rather distinct and achievable goal when it came to how they wanted to be different and how religion should relate to economy. There are, however, nuances and important resemblances between the cases that cannot be explained by the businesses’ confessional and theological affiliations. Rather, there seems to be something about the phenomenon of tension-filled and confident faith-based businesses that causes a drive in the practices towards the common good. After mapping the results of the empirical study, I discuss some contributions that I argue this study brings to Bretherton’s presentation of the relationship between Christianity and capitalism.

The Pedal Neurons of Aplysia Punctata

1968 ◽  
Vol 48 (1) ◽  
pp. 127-140
Author(s):  
D. A. DORSETT
Keyword(s):  
Motor Neurons ◽  
The Other ◽  
Afferent Pathways ◽  
Stimulation Of

1. Three classes of neurons have been identified in the pedal ganglia of Aplysia punctata. 2. The motor neurons, which may be unipolar or bipolar, have the axon passing into one of the pedal nerves and in the case of the bipolars, the other branch entering the pedal commissure. This synapses with neurons on the opposite side, thus providing an integrative link between the ganglia. 3. The interneurons are without axons in the pedal nerves or commissure, although afferent pathways to these cells and the motor neurons occur in the pedal nerves in a variety of combinations. 4. The pathways in the ipsilateral nerves are for the most part excitatory, but inhibitory fibres occur in the posterior pedal nerve. 5. Inhibitory potentials were often obtained in the interneurons by stimulation of the pedal commissure. 6. A second type of coordinative pathway is provided by fibres which enter the CNS in one of the pedal nerves and terminate on neurons in both pedal ganglia.

Modulatory effects of nitric oxide on synaptic depression in the crayfish neuromuscular system

2000 ◽  
Vol 203 (23) ◽  
pp. 3595-3602 ◽  
Author(s):  
H. Aonuma ◽  
T. Nagayama ◽  
M. Takahata
Keyword(s):  
Nitric Oxide ◽  
Neuromuscular Transmission ◽  
Procambarus Clarkii ◽  
Synaptic Depression ◽  
Physiological Property ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Bath Application ◽  
Flexor Muscles ◽  
Stimulation Of

A characteristic physiological property of the neuromuscular junction between giant motor neurones (MoGs) and fast flexor muscles in crayfish is synaptic depression, in which repetitive electrical stimulation of the MoG results in a progressive decrease in excitatory junction potential (EJP) amplitude in flexor muscle fibres. Previous studies have demonstrated that l-arginine (l-Arg) modulates neuromuscular transmission. Since l-Arg is a precursor of nitric oxide (NO), we examined the possibility that NO may be involved in modulating neuromuscular transmission from MoGs to abdominal fast flexor muscles. The effect of a NO-generating compound, NOC7, was similar to that of l-Arg, reversibly decreasing the EJP amplitude mediated by the MoG. While NOC7 reduced the amplitude of the EJP, it induced no significant change in synaptic depression. In contrast, a scavenger of free radical NO, carboxy-PTIO, and an inhibitor of nitric oxide synthase, l-NAME, reversibly increased the EJP amplitude mediated by MoGs. Synaptic depression mediated by repetitive stimulation of MoGs at 1 Hz was partially blocked by bath application of l-NAME. Bath application of a NO scavenger, a NOS inhibitor and NO-generating compounds had no significant effects on the depolarisation of the muscle fibres evoked by local application of l-glutamate. The opposing effects on EJP amplitude of NOC7 and of carboxy-PTIO and l-NAME suggest that endogenous NO presynaptically modulates neuromuscular transmission and that it could play a prominent role at nerve terminals in eliciting MoG-mediated synaptic depression in the crayfish Procambarus clarkii.

Identification of two species of alpha motoneurons in cat's plantaris pool

1977 ◽  
Vol 40 (1) ◽  
pp. 16-25 ◽  
Author(s):  
D. A. Harris ◽  
E. Henneman
Keyword(s):  
Visual Inspection ◽  
Repetitive Stimulation ◽  
Ventral Root ◽  
Statistical Analyses ◽  
The Other ◽  
Small Samples ◽  
The Relationship ◽  
Decerebrate Cats ◽  
Two Populations ◽  
Stimulation Of

1. Single units of the plantaris pool were isolated in ventral root filaments of decerebrate cats and their critical firing levels (CFLs) were determined. Motoneurons of similar size, as judged by their CFLs and other criteria, were compared in firing rate (FR) during repetitive stimulation of the plantaris nerve. 2. Such units either differed very little or quite widely, suggesting that they were sampled randomly from two populations, one firing rapidly, the other slowly. The relationship between the two rates remained approximately constant, regardless of the intensity or rate of input the units received, as long as both of them discharged rhythmically. 3. In single experiments 10-15 of the smallest units in the pool (all with CFLs in the 0-8% range) were isolated and compared. Statistical analyses and visual inspection of these small samples again suggested the existence of two species of motoneurons. 4. Statistical analyses also indicated that the FRs of units in single experiments were not sampled from any one of a variety of parametric, single-modal distributions. This suggests that the data were sampled from a distribution having more than one mode, indicating the existence of separate populations or species of motoneurons among the small units of the pool (0-8% range of CFL). 5. Pooling of the normalized data from different experiments revealed a bimodal histogram, reinforcing the conclusion that there are two species of small alpha motoneurons in the plantaris pool.

scholarly journals Nervous rhythm arising from rivalry of antagonistic reflexes: Reflex stepping as outcome of double reciprocal innervation

1913 ◽  
Vol 86 (587) ◽  
pp. 233-261 ◽  
Keyword(s):  
Afferent Nerve ◽  
The Other ◽  
Present Communication ◽  
Simultaneous Stimulation ◽  
Afferent Nerves ◽  
Wide Range ◽  
Contralateral Muscle ◽  
Stimulation Of

The observations with which the present communication deals were met with in experiments continuing those on reciprocal innervation of symmetrical muscles. In my previous paper on that subject it had been reported that in regard to symmetrical extensors of the knee the ratio borne by intensity of the ipsilateral inhibition to the contralateral excitation is such that with equal stimuli to right and left symmetrical afferent nerves there is inhibitory suppression of contraction in both the muscles. In other words, under double reciprocal innervation the ipsilateral inhibition by each nerve completely overcomes the contralateral excitation of the other. It was shown that this mutual suppression holds over a wide range of the scale of intensities of stimulation. It was also shown that with quite weak stimuli a simultaneous stimulation of both nerves, stimuli being equal in intensity, often results in concurrent contraction of both muscles. Indeed, with quite weak stimuli, the effect of stimulation of each afferent nerve by itself is, in the decerebrate preparation, usually contraction of the ipsilateral as well as of the contralateral muscle. This being so, it is evident that at some point in the scale of intensities of stimulation there should be a place below which contralateral excitation is stronger than ipsilateral inhibition, whereas above it ipsilateral inhibition is stronger than contralateral excitation.

Ch.11 Plurality of obligors and of obligees, s.1: Plurality of Obligors, Art.11.1.4

2015 ◽  
Author(s):  
Meier Sonja
Keyword(s):  
The Other ◽  
The Common ◽  
The Right ◽  
The Relationship

This commentary analyses Article 11.1.4 of the UNIDROIT Principles of International Commercial Contracts (PICC) concerning the effects of defences on the relationship between the obligee and the obligors. Under Art 11.1.4, a joint and several obligor against whom a claim is made by the obligee may assert all the defences and rights of set-off that are personal to it or that are common to all the co-obligors. However, the obligor may not assert defences or rights of set-off that are personal to one or several of the other co-obligors. This commentary discusses the common defences that the obligor can assert against the obligee, along with personal defences which involve the right to avoid the contract for mistake, fraud, threat, or gross disparity.

scholarly journals EXPERIMENTS ON THE RELATION OF THE INHIBITORY TO THE ACCELERATOR NERVES OF THE HEART

1897 ◽  
Vol 2 (2) ◽  
pp. 151-179 ◽  
Author(s):  
Reid Hunt
Keyword(s):  
Mode Of Action ◽  
Inhibitory Effect ◽  
Relative Strength ◽  
The Other ◽  
Maximal Stimulation ◽  
The One ◽  
Considerable Period ◽  
Minimal Stimulation ◽  
Ventricular Beat ◽  
Stimulation Of

The experiments described in Part IV of this paper show that in whatever manner the problem of the relation of the vagus to the accelerators is approached, whether the accelerators are stimulated during a stimulation of the vagus, or the vagus during a stimulation of the accelerators, or both are stimulated simultaneously, either for a short or for a longer period, the result is the same, viz., the effect upon the rate of the heart is determined entirely by the relative strength of the stimuli applied to the two nerves. If the stimuli are of approximately the same strength, as judged by the effect of stimulating the nerves separately, the rate of the heart is but slightly affected; if the stimulus applied to the vagus is the stronger, the heart is slowed; if it is weaker, the heart is accelerated. In all cases the result of stimulating the two nerves simultaneously is approximately the algebraic sum of the results of stimulating them separately; sometimes the inhibitory effect slightly predominates, but not more frequently than does the accelerator effect. Moreover, the two nerves may be stimulated simultaneously for a considerable period of time without either completely overcoming the effect of the other. Thus as far as their effect upon the rate of the ventricular beat is concerned, the vagus and accelerator nerves seem to be purely antagonistic; the statement that a minimal stimulation of the one can completely overcome a maximal stimulation of the other is undoubtedly incorrect, and the hypotheses as to the mode of action of these nerves upon the heart, based upon this statement, lose their chief support.

Homology of chromosomes of the X genomes in common and Uruguayan dallisgrass, Paspalum dilatatum

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 950-953 ◽  
Author(s):  
Byron L. Burson
Keyword(s):  
Chromosome Pairing ◽  
Chromosome Numbers ◽  
The Other ◽  
Paspalum Dilatatum ◽  
Intraspecific Hybridization ◽  
The Common ◽  
Complete Sets ◽  
The Relationship ◽  
Metaphase I

Two biotypes of dallisgrass, Paspalum dilatatum Poir., designated common and Uruguayan, have chromosome numbers and genome formulas of 2n = 5x = 50 (IIJJX) and 2n = 6x = 60 (IIJJXX), respectively. The relationship between the X genomes in these two biotypes is unknown, and each was arbitrarily assigned the letter X to designate an unknown genome. This study was undertaken to determine the relationship between the X genomes in these two biotypes. Because both biotypes are apomicts and cannot be crossed, a sexual intraspecific F1 hybrid (2n = 45) between sexual yellow-anthered (2n = 4x = 40; IIJJ) and common dallisgrass biotypes was crossed with Uruguayan dallisgrass. This F1 hybrid has complete sets of the I and J genomes but only 5 of the 10 chromosomes of the X genome from common dallisgrass. Two hybrids were recovered. One had 52 and the other had 53 chromosomes, which associated at metaphase I as 22 bivalents + 8 univalents and 23 bivalents + 7 univalents, respectively. Twenty bivalents represent pairing of members of the I and J genomes, and those in excess of 20 represent pairing between members of the two X genomes. The remaining members of the X genome from the Uruguayan biotype were present as univalents at metaphase I. This demonstrates that those chromosomes of the X genome from the common biotype that were present are homologous to members of the X genome of the Uruguayan biotype. Both hybrids are aposporous facultative apomicts with some sterility.Key words: meiosis, intraspecific hybridization, chromosome pairing, genome relations, apomixis.

scholarly journals Evolution of the YouTube Personas Related to Survival Horror Games

2021 ◽  
Vol 6 (2) ◽  
pp. 54-68
Author(s):  
Francesco Toniolo
Keyword(s):  
Emotional Reactions ◽  
The Other ◽  
The Common ◽  
The One ◽  
The Relationship

The indie survival horror game genre has given rise to some of the most famous game streamers on YouTube, especially titles like Amnesia: The Dark Descent (Frictional Games 2010), Slender: The Eight Pages (Parsec Productions 2012), and Five Nights at Freddy’s (Scott Cawthon 2014). The games are strongly focused on horror tropes including jump scares and defenceless protagonists, which lend them to displays of overemphasised emotional reactions by YouTubers, who use them to build their online personas in a certain way. This paper retraces the evolution of the relationship between horror games and YouTube personas, with attention to in-game characters and gameplay mechanics on the one hand and the practices of prominent YouTube personas on the other. It will show how the horror game genre and related media, including “Let’s play” videos, animated fanvids, and “creepypasta” stories have influenced prominent YouTuber personas and resulted in some changes in the common processes of persona formation on the platform.

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