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.

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.

scholarly journals Reciprocal Stimulation of Decay Between Serotonergic Facilitation and Depression of Synaptic Transmission

2008 ◽  
Vol 100 (2) ◽  
pp. 1113-1126 ◽  
Author(s):  
Sun Hee Cho Lee ◽  
Karen Taylor ◽  
Franklin B. Krasne
Keyword(s):  
Protein Kinase ◽  
Synaptic Transmission ◽  
Protein Kinase A ◽  
The Other ◽  
Command Neurons ◽  
Wide Range ◽  
History Of ◽  
Depressive States ◽  
Kinase A ◽  
Stimulation Of

Serotonin can produce multiple, contradictory modulatory effects on strength of synaptic transmission in both vertebrate and invertebrate nerve circuits. In crayfish, serotonin (5-HT) can both facilitate and depress transmission to lateral giant escape command neurons; however, which effect is manifest during application, as well as the sign and duration of effects that may continue long after 5-HT washout, may depend on history of application as well as on concentration. We report that protein kinase A (PKA) signaling is essential to the production of facilitation but depression is mediated by non-cAMP/PKA signaling pathways. However, we unexpectedly found that PKA activity is essential for the decay of depression when serotonin is washed out. This, and evidence from the effects of a variety of serotonin application regimens, suggest that facilitatory and depressive states coexist and compete and that the decay of each is dependent on stimulation by the other. A computational model that incorporates these assumptions can account for and rationalize the varied effects of a wide range of serotonin application regimens.

Inhibition of spinal afferent nerve-mediated gastric hyperemia by nicotine: role of ganglionic blockade

1993 ◽  
Vol 264 (4) ◽  
pp. H1087-H1092
Author(s):  
F. W. Leung
Keyword(s):  
Blood Flow ◽  
Afferent Nerve ◽  
Gastric Blood Flow ◽  
Doppler Flowmetry ◽  
Afferent Nerves ◽  
Vasodilatory Effect ◽  
Blocking Property ◽  
Intravenous Nicotine ◽  
Ganglionic Blocking ◽  
Stimulation Of

The hypothesis that intravenous nicotine modulates gastric spinal afferent nerve function by its ganglionic-blocking property is tested. Stimulation of the gastric spinal afferent nerves in anesthetized rats is accomplished by intragastric capsaicin irrigation. Gastric blood flow is monitored by laser-Doppler flowmetry. The increase in gastric blood flow during intragastric capsaicin irrigation is significantly reduced by 4 and 40 micrograms.kg-1.min-1 of intravenous nicotine. The inhibition appears to be specific for the spinal afferent nerves as the increase in gastric blood flow induced by electrical stimulation of the vagal afferent nerves is unaltered by these doses of intravenous nicotine. A ganglionic-blocking dose (10 mg/kg) of intraperitoneal hexamethonium also significantly attenuates the gastric vasodilatory effect of intragastric capsaicin. Intravenous nicotine (40 micrograms.kg-1.min-1) combined with intraperitoneal hexamethonium (10 mg/kg) completely abolishes the gastric vasodilatory effect of intragastric capsaicin. These data suggest that intravenous nicotine offers a specific inhibition of the gastric spinal afferent nerve-mediated hyperemia, possibly as a consequence of its ganglionic-blocking property.

Interaction between primary afferent nerves in the elicitation of reflex swallowing

1980 ◽  
Vol 239 (5) ◽  
pp. R407-R414 ◽  
Author(s):  
A. Weerasuriya ◽  
D. Bieger ◽  
C. H. Hockman
Keyword(s):  
Contralateral Side ◽  
Afferent Nerve ◽  
Reflex Response ◽  
Solitary Tract ◽  
Primary Afferent ◽  
Afferent Nerves ◽  
Primary Afferent Nerves ◽  
Adult Cats ◽  
Primary Afferent Nerve ◽  
Stimulation Of

In adult cats anesthetized with urethan, a number of observations were made that support the concept that some control over the rate of reflexly induced swallowing occurs in the intermediate network at the level of the nucleus of the solitary tract. It was shown that different nerves, e.g., the two superior laryngeal and glossopharyngeal nerves, when activated in sequence interact in such a manner as to facilitate reflex swallowing. It was also shown that the decrement in the reflex response observed to continuous stimulation of a primary afferent nerve, e.g., one superior laryngeal, can be reversed by switching the stimulation to another nerve either on the same or contralateral side. And finally, following discrete medullary lesions, it was observed that that portion of the nucleus of the solitary tract located 2 mm or more rostral to the rostralmost point of the dorsal medial sulcus appears to contain an integral component of the intermediate network that governs reflexly induced swallowing, whereas lesions restricted to the ventrolateral portion of the nucleus of the solitary tract have no effect on the reflex response.

Fos induction in rat brain neurons after stimulation of the hepatoportal Na-sensitive mechanism

1997 ◽  
Vol 272 (3) ◽  
pp. R913-R923 ◽  
Author(s):  
H. Morita ◽  
Y. Yamashita ◽  
Y. Nishida ◽  
M. Tokuda ◽  
O. Hatase ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Area Postrema ◽  
Vena Cava ◽  
Plasma Osmolality ◽  
Systemic Circulation ◽  
Afferent Nerve ◽  
Hypothalamic Nucleus ◽  
Nerve Activity ◽  
Afferent Nerves ◽  
Stimulation Of

Responses of hepatic afferent nerves to intraportal bolus injection of hypertonic solutions were examined in anesthetized rats. Hepatic afferent nerve activity increased in response to an intraportal injection of 0.75 M NaCl or NaHCO3 but did not respond to a similar injection of 1.5 M mannitol, 0.75 M LiCl, or 0.15 M NaCl, implying that nerves in the hepatoportal area are sensitive to increases in Na concentrations and that this leads to stimulation of hepatic afferent nerve activity. To study central activation in response to stimulation of the hepatic Na-sensitive mechanism, c-fos induction was monitored. After electrical stimulation of hepatic afferent nerves, neurons containing Fos-like immunoreactivity (Fos-li) were found in the area postrema, nucleus of the solitary tract, paraventricular hypothalamic nucleus, and supraoptic nucleus at 90 min after stimulation. Induction of Fos-li was also studied after simultaneous infusion of 0.45 M NaCl into the portal vein and distilled water into the inferior vena cava in conscious rats so as to keep the total amount of solution introduced into the systemic circulation isotonic, thus avoiding changes in mean arterial pressure, plasma osmolality, and plasma NaCl concentrations. Fos-li-containing neurons were found in the same regions in which they were found after electrical stimulation. However, few, if any, Fos-li-containing cells were found if the rats were hepatically denervated or if they received an intraportal infusion of hypertonic LiCl or mannitol. These data provide evidence for involvement of the brain stem and forebrain structures in NaCl regulatory functions induced by stimulation of the hepatoportal Na-sensitive mechanism. However, stimulation of the hepatoportal osmosensitive mechanism does not activate these central structures.

A model for predicting the age at sexual maturity for growing pullets of layer strains given a single change in photoperiod

2002 ◽  
Vol 138 (4) ◽  
pp. 441-458 ◽  
Author(s):  
P. D. LEWIS ◽  
T. R. MORRIS ◽  
G. C. PERRY
Keyword(s):  
Environmental Conditions ◽  
Sexual Maturity ◽  
Age Effects ◽  
The Other ◽  
Maximum Sensitivity ◽  
Similar Extent ◽  
Early Maturity ◽  
Long Day ◽  
Wide Range ◽  
Stimulation Of

A model is presented which will predict mean age at first egg (AFE) for pullets of laying strains reared under non-limiting environmental conditions but exposed to a single change in photoperiod during the rearing stage. An initial analysis of 12 previously reported trials involving a wide range of genotypes showed that the response to an increase in photoperiod is not simply the inverse of the response to an equal decrease in photoperiod applied at the same age. Maximum sensitivity to a reduction in photoperiod was found shortly before onset of lay, whereas maximum sensitivity to an increment in photoperiod was observed at around 10 weeks of age. Two experiments were conducted to provide further data. The first compared the effect of 3-h increases in photoperiod from 8 h to 11 h or from 11 h to 14 h with the double increment from 8 h to 14 h and also tested a reduction from 11 h to 8 h, all imposed at 17 weeks of age. AFE was advanced to a similar extent by the changes from 8 to 11 h and from 11 to 14 h (9.8 and 10.9 days respectively). Response to the double increment was not additive: AFE on this treatment was 13.3 days earlier than for constant 8 h controls. Reduction in photoperiod from 11 to 8 h at 17 weeks delayed AFE by 18.7 days compared with constant 11-h controls. In the second experiment, pullets of two strains were transferred from 8 to 16-h photoperiods and from 16 to 8 h at 5, 7, 9, 15, 17 and 19 weeks of age. Controls were kept on constant 8 and constant 16-h days. Transfer from 8 to 16-h photoperiods at 5 weeks of age had no effect on AFE. At 7 weeks there was a bimodal response with some pullets subsequently showing advanced maturity and others not. Maximum stimulation of early maturity (31 days on average for the two genotypes) was obtained at 9 weeks of age and response to stimulation declined linearly with age thereafter. The delay in AFE resulting from a reduction in photoperiod (16 to 8 h) increased linearly between 0 and 15 weeks. At 17 and 19 weeks, the response was bimodal, with some pullets maturing at the same age as long-day controls and others showing delayed maturity. Using all this evidence and some other unpublished data, a model is developed to predict AFE as a function of mean photoperiod and change in photoperiod during the rearing phase. Elements are incorporated to allow for the insensitivity of pullets younger than 50 days to an increase in photoperiod and the effect observed late in rearing when a change in photoperiod comes too late to alter AFE for the most precocious individuals in a flock. Two coefficients are required to adjust for genotype. One describes mean AFE for the genotype when reared on constant daylength and the other defines the rate at which age effects the response to a single change in photoperiod.

scholarly journals Reversal of the reflex effect of an afferent nerve by altering the character of the electrical stimulus applied

1911 ◽  
Vol 83 (566) ◽  
pp. 435-446 ◽  
Keyword(s):  
Hind Limb ◽  
Electrical Stimulus ◽  
Afferent Nerve ◽  
Afferent Limb ◽  
Afferent Nerves ◽  
Reflex Effect ◽  
Extensor Muscles ◽  
Central Inhibition ◽  
Reflex Stimulation ◽  
Stimulation Of

Stimulation of an afferent limb-nerve in the decerebrate or decapitate mammal (cat, dog) gives as its reflex result flexion of that limb; during this flexion the pure extensor muscles of the limb relax under central inhibition. In the hind limb this reflex effect is observable in the isolated vasto-crureus, the main extensor muscle of the knee; that muscle if engaged in contraction relaxes when the afferent nerve is stimulated. Its elongation is the sign of the central inhibition which takes place. If the reflex stimulation be strong the muscle relaxes quickly and greatly; if the stimulation be weak the relaxation is slower and less ample. These results are easily demonstrable by using as a stimulus either faradism or mechanical stimulation such as ligation of the central stump of the afferent nerve. Usual and uniform as this result is, we find it possible in the decerebrate preparation under certain conditions to obtain reflex contraction of vastocrureus as well as reflex inhibition, and to elicit the contraction through the same afferent nerves as under other conditions so regularly elicit inhibition. The condition influencing the nature of the reflex result in this respect are (1) the strength and (2) the form of the electrical stimulus applied to the afferent nerve, and (3) the reflex state obtaining in the preparation at the time.

scholarly journals Dissociable roles for the rTPJ and dmPFC in self-other processing: a HD-tDCS study

2018 ◽  
Author(s):  
A. K. Martin ◽  
J. Huang ◽  
M. Meinzer
Keyword(s):  
Social Cognition ◽  
Episodic Memory ◽  
Mental Rotation ◽  
Congruency Effect ◽  
The Self ◽  
The Other ◽  
Self And Other ◽  
Repeated Measures Design ◽  
Wide Range ◽  
Stimulation Of

AbstractBackgroundSocial interaction relies on the integration and distinction of self and other. The dorsomedial prefrontal cortex (dmPFC) and the right temporoparietal junction (rTPJ) are two regions consistently associated with social processes. Theories of rTPJ function in social cognition include self-other distinction, self-inhibition, or embodied mental rotation, whereas the dmPFC is associated with a wide range of social functions involving understanding and encoding information pertaining to others. However, to date, no study has provided causal evidence for dissociable roles of the rTPJ and dmPFC in social cognition.Method52 healthy young adults were stratified into two studies and received either dmPFC or rTPJ anodal HD-tDCS in a sham-controlled, double-blinded, repeated measures design. Subjects completed a social cognitive battery measuring self-other processing across an implicit and explicit level one (line-of-sight) and level two (mental rotation) visual perspective taking tasks (VPT), as well as self and other encoding effects on episodic memory in order to test the self-reference effect (SRE).ResultsStimulation of the dmPFC selectively enhanced integration of the other perspective into self as indexed by an increase in congruency effect (incongruent-congruent) across both explicit VPT tasks. It also removed the SRE in episodic memory, indexed by increasing the recognition of other-encoded words and reducing the recognition of self-encoded words. Stimulation of the rTPJ resulted in improved inhibition of the self-perspective during level two VPT only, as indexed by a reduction of the congruency effect when taking the other perspective.ConclusionOur results provide the first causal evidence for dissociable roles of the dmPFC and rTPJ in social cognition. This research supports theories suggesting that rTPJ facilitates embodied mental rotation, whereas the dmPFC integrates information relevant to the other into that of the self.

Sign in / Sign up

Export Citation Format

Share Document