The Physiology of a Lepidopteran Muscle Receptor

1966 ◽  
Vol 45 (2) ◽  
pp. 229-249
Author(s):  
R. DE G. WEEVERS
Keyword(s):  
Negative Feedback ◽  
Sense Organ ◽  
Great Majority ◽  
Motor Units ◽  
Contralateral Side ◽  
Ipsilateral Side ◽  
Major Function ◽  
Muscle Receptor ◽  
Spatial Facilitation ◽  
Adjacent Segments

1. When a single MRO of a caterpillar is stretched at least 32 motor units show clear reflex changes in activity. 2. The great majority of muscles are excited and the latency of the reflex differs only slightly from one muscle to another. The response has both tonic and phasic components which reflect more or less faithfully the magnitudes of the same components in the sensory discharge. 3. Muscles are affected on the contralateral side of the stimulated segment and on the ipsilateral side of adjacent segments. The reflex fields of neighbouring receptors therefore overlap; spatial facilitation produces a disproportionate increase in the overall response when two receptors are stimulated simultaneously. 4. The reflex pathway for muscles innervated by nerve 2 is shown to involve synaptic connexions in the ganglion of the segment anterior to the stimulated receptor and responding muscles. 5. The muscles most strongly excited are those which lie functionally in parallel with a stretched sense organ. It is concluded that a major function of the caterpillar MRO is to mediate a negative feedback reflex tending to stabilize bodily position independent of load.

The Physiology of a Lepidopteran Muscle Receptor

1966 ◽  
Vol 44 (1) ◽  
pp. 195-208
Author(s):  
R. DE G. WEEVERS
Keyword(s):  
Sense Organ ◽  
Sensory Stimulation ◽  
Discharge Frequency ◽  
Reflex Inhibition ◽  
Muscle Receptor ◽  
Transient Elevation ◽  
Adjacent Segments ◽  
Receptor Muscle ◽  
Stimulation Of

1. Stimulation of the pupal receptor muscle via its nerve resulted in an increased sensory discharge frequency from the MRO. 2. The extent of this excitation was similar in haemolymph and in pupal saline. 3. Stimulation of an MRO whose connexions with the C.N.S. were intact resulted in a transient reflex inhibition of the tonic discharge in the RM of the stimulated receptor. Cessation of sensory stimulation resulted in a transient elevation of RM tone in the stimulated receptor. These changes would tend to protect the sense organ during rapid stretching and would also ‘take up the slack’ when it was released. 4. A slight crossed intrasegmental RM reflex is described which would normally reinforce the ipsilateral reflex. No RM reflexes were found in adjacent segments. 5. These results are discussed in relation to the nature of the deformation occurring in the sensory dendrites, and in relation to the function of RM systems generally.

Abstract 182: Thermal Imaging as a Diagnostic Biomarker in Acute Ischemic Stroke

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Linda F Aulmann ◽  
Kira Busch ◽  
Andrea Zegelin ◽  
Thomas Eckey ◽  
Alexander Neumann ◽  
...  
Keyword(s):  
Thermal Imaging ◽  
Arterial Occlusion ◽  
Current Method ◽  
Contralateral Side ◽  
Temperature Pattern ◽  
Ipsilateral Side ◽  
Anterior Circulation ◽  
Vessel Occlusion ◽  
Clear Trend ◽  
Infrared Thermal Imaging

Purpose: With highly portable mobile infrared cameras thermal imaging during acute stroke triage has become possible. The purpose of this pilot study was to evaluate the pattern of superficial facial skin temperature in patients with acute proximal arterial occlusion of the anterior circulation compared to non-ischemic controls. We hypothesize, that temperature dysregulation in stroke with associated thermal pattern may be used to predict presence of proximal vessel occlusion. Methods: In 46 patients suffering from acute occlusion in the anterior circulation (ICA: 17, M1-MCA: 13, M2-MCA: 16) infrared thermal imaging of the face was performed before endovascular treatment. Asymmetric temperature patterns were evaluated visually. Quantitative temperature values were obtained from regions of interest (ROIs) placed symmetrically on the left and right half of on the facial thermal image. Presence and side of vessel occlusion was correlated with temperature measurements. Results: Regional facial asymmetric temperature was readily visible at 0.5°C. Temperature differences ranged from 0.5 to 1.5° C in stroke patients, and <0.5°C in controls. In 16 of 17 patients with ICA occlusion, facial asymmetric temperature was detected (in 13 lower temperatures on ipsilateral side, in 3 on the contralateral side). In 11 of 13 patients with M1-MCA occlusion, facial asymmetric temperature was detected (in 8 lower temperatures on the contralateral side, 3 on the ipsilateral side). In 15 of 16 patients with an occlusion of M2-segment, asymmetric temperature pattern was apparent, however no clear trend with regard. In 16 of 20 controls, no asymmetric temperature pattern >0.5°C was observed. Conclusion: Thermal imaging could serve as a fast point-of-care test to detect asymmetrical pattern in facial temperature as a predictor of proximal vessel occlusion in stroke. However, the current method is prone to imaging artifacts and reliability of detected asymmetry is moderate.

scholarly journals Regional resting state perfusion variability and delayed cerebrovascular uniform reactivity in subjects with chronic carotid artery stenosis

2018 ◽  
Vol 65 (1) ◽  
pp. 151-162
Author(s):  
Arkadiusz Szarmach ◽  
Mariusz Kaszubowski ◽  
Agnieszka Sabisz ◽  
Andrzej F Frydrychowski ◽  
Grzegorz Halena ◽  
...  
Keyword(s):  
White Matter ◽  
Carotid Artery ◽  
Temporal Lobe ◽  
Resting State ◽  
Carotid Artery Stenosis ◽  
Parietal Lobe ◽  
Contralateral Side ◽  
Artery Stenosis ◽  
Ipsilateral Side ◽  
Acetazolamide Challenge

The aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis.Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥90% on the ipsilateral side and ≤50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were carried out; the first was performed before acetazolamide administration and the second 60 minutes after injection.The differences between mean values were examined by paired two-sample t-test and alternative nonparametric Wilcoxon’s test. Normality assumption was examined using W Shapiro-Wilk test.The lowest resting-state cerebral blood flow (CBF) was observed in white matter (ipsilateral side: 18.4±6.2; contralateral side: 19.3±6.6) and brainstem (ipsilateral side: 27.8±8.5;  contralateral side: 29.1±10.8). Grey matter (cerebral cortex) resting state CBF was below the normal value for subjects of this age: frontal lobe – ipsilateral side: 30.4±7.0, contralateral side: 33.7±7.1; parietal lobe – ipsilateral side: 36.4±11.3, contralateral side: 42.7±9.9; temporal lobe – ipsilateral side: 32.5±8.6, contralateral side: 39.4±10.8; occipital lobe – ipsilateral side: 24.0±6.0, contralateral side: 26.4±6.6). The highest resting state CBF was observed in the insula (ipsilateral side: 49.2±17.4; contralateral side: 55.3±18.4). A relatively high resting state CBF was also recorded in the thalamus (ipsilateral side: 39.7±16.9; contralateral side: 41.7±14.1) and cerebellum (ipsilateral side: 41.4±12.2; contralateral side: 38.1±11.3). The highest CVR was observed in temporal lobe cortex (ipsilateral side: +27.1%; contralateral side: +26.1%) and cerebellum (ipsilateral side: +27.0%; contralateral side: +34.6%). The lowest CVR was recorded in brain stem (ipsilateral side: +20.2%; contralateral side: +22.2%) and white matter (ipsilateral side: +18.1%; contralateral side: +18.3%). All CBF values were provided in milliliters of blood per minute per 100 g of brain tissue [ml/100g/min]. Resting state circulation in subjects with carotid artery stenosis is low in all analysed structures with the exception of insula and cerebellum. Acetazolamide challenge yields relatively uniform response in both hemispheres in the investigated population.Grey matter is more reactive to acetazolamide challenge than white matter or brainstem.

The development of the retinotectal projection in Xenopus with one compound eye

Development ◽  
1975 ◽  
Vol 33 (3) ◽  
pp. 775-787
Author(s):  
Joan D. Feldman ◽  
R. M. Gaze
Keyword(s):  
Compound Eye ◽  
Contralateral Side ◽  
Compound Eyes ◽  
Stages Of Development ◽  
Ipsilateral Side ◽  
Retinotectal Projection ◽  
Xenopus Embryos ◽  
Donor Embryo

Double-nasal and double-temporal compound eyes were constructed in Xenopus embryos at stages 32 and 37/38. A particular half was removed from the host eye anlage and replaced with the opposite half-eye from the contralateral side of a donor embryo. Control operations consisted of removing a half-eye and replacing it with a similar half from the ipsilateral side of the donor embryo. Whereas in control animals, each half-eye projected its fibres to the appropriate half-tectum, in operated animals each half of the compound eye spread its optic teiminals across the entire rostrocaudal extent of the dorsal tectal surface. The area of tectal surface covered by ganglion fibre terminals was similar in operated animals mapped at successive stages of development to that previously observed in normal animals at equivalent stages. Therefore the factors responsible for the extended distribution of fibre terminals from each half of a compound eye must exist at least from mid-tadpole life, and thereafter be continuously present throughout development.

Phase-dependent reversal of reflexes mediated by the thoracocoxal muscle receptor organ in the crayfish, Pacifastacus leniusculus

1986 ◽  
Vol 55 (4) ◽  
pp. 689-695 ◽  
Author(s):  
P. Skorupski ◽  
K. T. Sillar
Keyword(s):  
Motor Neurons ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Motor Output ◽  
Dependent Manner ◽  
Muscle Receptor ◽  
Reflex Pathways ◽  
Receptor Organ ◽  
Positive And Negative Feedback ◽  
Central Excitability

Both negative feedback, resistance reflexes and positive feedback, assistance reflexes are mediated by the thoracocoxal muscle receptor organ (TCMRO) in the crayfish, depending on the central excitability of the preparation. In this paper we present evidence that the velocity-sensitive afferent T fiber of the TCMRO may elicit either resistance or assistance reflexes in different preparations. In preparations displaying assistance reflexes, the S and T fibers of the TCMRO exert reciprocal effects on leg motor neurons (MNs). The S fiber excites promotor MNs (negative feedback) and inhibits remotor MNs, the T fiber excites remotor MNs (positive feedback) and inhibits promotor MNs. During reciprocal motor output of promotor and remotor MNs, reflexes mediated by the TCMRO are modulated in a phase-dependent manner. The TCMRO excites promotor MNs during their active phases (negative feedback) but inhibits them during their reciprocal phases. Remotor MNs are excited by the TCMRO during their active phases (positive feedback). It is proposed that depolarizing central inputs that occur in the S and T fibers at opposite phases of the motor output cycle (21) facilitate the output effects of each afferent in alternation, effectively mediating a phase-dependent shift between the effects of one afferent and the other. The implications of central modulation of reflex pathways and the possible functions of positive and negative feedback reflexes during locomotion are discussed.

Role of the Oculomotor Vermis in Generating Pursuit and Saccades: Effects of Microstimulation

1998 ◽  
Vol 80 (4) ◽  
pp. 2046-2062 ◽  
Author(s):  
R. J. Krauzlis ◽  
F. A. Miles
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Transition Point ◽  
Contralateral Side ◽  
Movement Behavior ◽  
Visually Guided ◽  
Ipsilateral Side ◽  
Oculomotor Vermis ◽  
Eye Velocity

Krauzlis, R. J. and F. A. Miles. Role of the oculomotor vermis in generating pursuit and saccades: effects of microstimulation. J. Neurophysiol. 80: 2046–2062, 1998. We studied the eye movements evoked by applying small amounts of current (2–50 μA) within the oculomotor vermis of two monkeys. We first compared the eye movements evoked by microstimulation applied either during maintained pursuit or during fixation. Smooth, pursuitlike changes in eye velocity caused by the microstimulation were directed toward the ipsilateral side and occurred at short latencies (10–20 ms). The amplitudes of these pursuitlike changes were larger during visually guided pursuit toward the contralateral side than during either fixation or visually guided pursuit toward the ipsilateral side. At these same sites, microstimulation also often produced abrupt, saccadelike changes in eye velocity. In contrast to the smooth changes in eye velocity, these saccadelike effects were more prevalent during fixation and during pursuit toward the ipsilateral side. The amplitude and type of evoked eye movements could also be manipulated at single sites by changing the frequency of microstimulation. Increasing the frequency of microstimulation produced increases in the amplitude of pursuitlike changes, but only up to a certain point. Beyond this point, the value of which depended on the site and whether the monkey was fixating or pursuing, further increases in stimulation frequency produced saccadelike changes of increasing amplitude. To quantify these effects, we introduced a novel method for classifying eye movements as pursuitlike or saccadelike. The results of this analysis showed that the eye movements evoked by microstimulation exhibit a distinct transition point between pursuit and saccadelike effects and that the amplitude of eye movement that corresponds to this transition point depends on the eye movement behavior of the monkey. These results are consistent with accumulating evidence that the oculomotor vermis and its associated deep cerebellar nucleus, the caudal fastigial, are involved in the control of both pursuit and saccadic eye movements. We suggest that the oculomotor vermis might accomplish this role by altering the amplitude of a motor error signal that is common to both saccades and pursuit.

scholarly journals Trunk Muscle Activity in One- and Two-Armed American Kettlebell Swing in Resistance-Trained Men

2019 ◽  
Vol 03 (01) ◽  
pp. E12-E18
Author(s):  
Vidar Andersen ◽  
Marius Fimland ◽  
Atle Saeterbakken
Keyword(s):  
Muscle Activation ◽  
Surface Emg ◽  
Contralateral Side ◽  
Trunk Muscle ◽  
Rectus Abdominis ◽  
Erector Spinae ◽  
Oblique Muscle ◽  
Ipsilateral Side ◽  
External Oblique ◽  
The One

AbstractThe aim of the study was to compare the one-armed vs. two-armed American kettlebell swing on trunk muscle activation. Fifteen resistance-trained men performed ten repetitions of both exercises using a 14-kg kettlebell. Surface EMG from the erector spinae, rectus abdominis and external oblique muscles were collected on both sides of the trunk. The erector spinae activation during the one-armed swing was 14–25% higher on the contralateral compared to the ipsilateral side in both exercises (Cohen’s d effect size [ES]=0.41–0.71, p ˂ 0.001–0.034). Further, the contralateral side was 14% more activated during the two-armed swing compared to the ipsilateral side during the one-armed swing (ES=0.43, p=0.009). For the rectus abdominis muscle, the two-armed swing induced higher activation of the rectus abdominis compared to the one-armed swing on both the contralateral (40%, ES=0.48, p=0.040) and ipsilateral side (59%, ES=0.83, p=0.002). There were no differences for the external oblique muscle (p=0.495–0.662). In conclusion, the trunk activation patterns of the two exercises were different, which could be explained by different biomechanics in the two exercises, and could thus have complimentary effects. We recommend that both unilateral and bilateral execution of the American kettlebell swing is included over time.

scholarly journals Proximal Femoral Asymmetry in Japanese Patients before Total Hip Arthroplasty

10.29007/ms33 ◽  
2019 ◽  
Author(s):  
Maximilian C. M. Fischer ◽  
Kunihiko Tokunaga ◽  
Masashi Okamoto ◽  
Klaus Radermacher
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Healthy Subjects ◽  
Preoperative Planning ◽  
Contralateral Side ◽  
Morphological Parameters ◽  
Neck Length ◽  
Ipsilateral Side ◽  
Femoral Length ◽  
Side Asymmetry

Templating is an important and established step in the preoperative planning process of total hip arthroplasty (THA) in order to select the size and position of the implant. In severely arthritic cases, the unaffected contralateral side is sometimes used as a reference to reconstruct morphological parameters of the planned implantation (ipsilateral) side, for example the femoral offset, the leg length or the antetorsion. Recent studies have shown that a significant side-to-side asymmetry of important proximal femoral parameters already exists in healthy subjects questioning the validity of the contralateral side as a reference. However, if preoperative asymmetry is larger than asymmetry in healthy subjects, preoperative planning can still make use of the contralateral side to target a postoperative result within the range of physiological asymmetry. Therefore, the specific objective of this study was to quantify the preoperative side-to-side asymmetry of five important morphological parameters of the proximal femur. Significant side-to- side differences between the ipsilateral side and the contralateral side were detected for the antetorsion, the offset, the neck length and the femoral length. The antetorsion is significantly higher for the ipsilateral side whereas offset, neck length and femoral length are significantly smaller. Mean and maximum difference in antetorsion is almost twice as high for the THA patients in comparison to healthy subjects. The same trend can be observed for the femoral length, less pronounced also for the caput-collum-diaphyseal angle. The comparison of proximal femoral side-to-side differences for subjects before THA and healthy subjects leads to the conclusion that contralateral templating can be a reasonable basis for THA planning of severely arthritic hips if the contralateral side shows no signs of osteoarthritis or developmental dysplasia.

scholarly journals Effects of Impactor Size on Biomechanical Characteristics of Spinal Cord in Hemicontusion Injury Model Using Finite Element Analysis

2020 ◽  
Vol 10 (12) ◽  
pp. 4097
Author(s):  
Batbayar Khuyagbaatar ◽  
Kyungsoo Kim ◽  
Temuujin Batbayar ◽  
Yoon Hyuk Kim
Keyword(s):  
Spinal Cord ◽  
Finite Element ◽  
Infinite Horizon ◽  
Experimental Studies ◽  
Contralateral Side ◽  
Cervical Region ◽  
Fe Model ◽  
New York University ◽  
Ipsilateral Side ◽  
Cord Injury

A cervical hemicontusion spinal cord injury (SCI) produces forelimb deficits on the ipsilateral side of the injury while sparing the function of the limbs on the contralateral side of the injury, allowing for the evaluation of experimental therapeutics for functional recovery. Although the effects of contusion force on the functional and behavioral outcomes were adequately described in previous experimental studies, the size of the impactor tip also had significant effects on the extent of the lesion on the contralateral side of the injury in the hemicontusion rat model. However, studies regarding the effects of impactor size on the spinal cord for the hemicontusion model are limited. In this study, a finite element (FE) model of the rat cervical spinal cord was developed to investigate the effects of impactor size in the hemicontusion SCI model on the stress, strain, and displacement of the spinal cord for the New York University (NYU) and Infinite Horizon (IH) impactors. The impactor tip diameters of 1.2 mm and 1.6 mm with high impact loading resulted in the highest stresses and strains in the right (ipsilateral) side of the spinal cord. Thus, impactor tip diameters between 1.2 mm and 1.6 mm would be convenient to use in the rat hemicontusion SCI models for the cervical region without damaging the left (contralateral) side of the spinal cord. Our findings provide an insight into SCI mechanisms in the rat cervical hemicontusion model.

scholarly journals Musculoskeletal Ultrasonography Assessment of Functional Magnetic Stimulation on the Effect of Glenohumeral Subluxation in Acute Poststroke Hemiplegic Patients

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chengyuan Yang ◽  
Ping Chen ◽  
Wenjie Du ◽  
Qingmei Chen ◽  
Huilin Yang ◽  
...  
Keyword(s):  
Upper Limb ◽  
Magnetic Stimulation ◽  
Contralateral Side ◽  
Control Group ◽  
Ipsilateral Side ◽  
Limb Function ◽  
Lesser Tuberosity ◽  
Upper Limb Function ◽  
The Difference ◽  
Musculoskeletal Ultrasonography

Background. Glenohumeral subluxation (GHS) is common in patients with acute hemiplegia caused by stroke. GHS and upper limb function are closely related. Objective. Using musculoskeletal ultrasonography (MSUS) to objectively evaluate the efficacy of functional magnetic stimulation (FMS) in the treatment of GHS in acute hemiplegic patients after stroke. Methods. The study used prospective case control study. Stroke patients with GHS were recruited and assigned to control group and FMS group. Control group received electrode stimulation at the supraspinatus and deltoid muscles of the hemiplegic side, while FMS group was stimulated at the same locations. Before and after treatment, the distances of the acromion-greater tuberosity (AGT), acromion-lesser tuberosity (ALT), acromiohumeral distance (AHD), supraspinatus thickness (SST), and deltoid muscle thickness (DMT) in patients’ bilateral shoulder joint were measured by MSUS, respectively. Meanwhile, Fugl-Meyer Assessment (FMA) was used to evaluate the improvement of upper limb function. Results. 30 patients were recruited. After FMS treatment, there was a significant decrease in the difference value between ipsilateral side and contralateral side of AGT [t=8.595, P<0.01], ALT [t=11.435, P<0.01], AHD [t=8.375, P<0.01], SST [t=15.394, P<0.01], and DMT [t=24.935, P<0.01], and FMA score increased [t=-13.315, P<0.01]. Compared with control group, FMS group decreased more significantly in the difference value between ipsilateral side and contralateral side of AGT [t=2.161, P<0.05], ALT [t=3.332, P<0.01], AHD [t=8.768, P<0.01], SST [t=6.244, P<0.01], and the DMT [t=3.238, P<0.01], and FMA score increased more significantly in FMS group [t=7.194, P<0.01]. Conclusion. The study preliminarily shows that the MSUS can objectively and dynamically evaluate the treatment effect of GHS in hemiplegic patients. Meanwhile, compared with control group, the FMS is more effective and has fewer side effects, and the long-term effect of FMS is worth further study. This trial is registered with ChiCTR1800015352.

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