Input of hair field afferents to a descending interneuron

2021 ◽  
Author(s):  
Bianca Jaske ◽  
Gaetan Lepreux ◽  
Volker Dürr
Keyword(s):  
Joint Angle ◽  
Stick Insect ◽  
Passive Movement ◽  
Activity Level ◽  
Reach To Grasp ◽  
Movement Velocity ◽  
Before And After ◽  
Steady State Activity ◽  
Transfer Of Information ◽  
Antennal Contact

In insects the tactile sense is important for near-range orientation and is involved in various behaviors. Nocturnal insects such as the stick insect Carausius morosus continuously explore their surroundings by actively moving their antennae when walking. Upon antennal contact with objects, stick insects show a targeted front-leg movement. As this reaction occurs within 40 ms, descending transfer of information from the brain to the thorax needs to be fast. So far, a number of descending interneurons have been described that may be involved in this reach-to-grasp behavior. One of these is the contralateral ON-type velocity-sensitive neuron (cONv). cONv was found to encode antennal joint-angle velocity during passive movement. Here, we characterize the transient response properties of cONv, including its dependence on joint angle range and direction. Since antennal hair field afferent terminals were shown to arborize close to cONv dendrites, we test whether antennal hair fields contribute to the joint-angle velocity encoding of cONv. To do so, we conducted bilateral extracellular recordings of both cONv interneurons per animal before and after hair field ablations. Our results show that cONv responses are highly transient, with velocity-dependent differences in delay and response magnitude. As yet, the steady state activity level was maintained until the stop of antennal movement, irrespective of movement velocity. Hair field ablation caused a moderate but significant reduction of movement-induced cONv firing rate by up to 40 %. We conclude that antennal proprioceptive hair fields contribute to the velocity-tuning of cONv, though further antennal mechanoreceptors must be involved, too.

Wipe and flexion reflexes of the frog. II. Response to perturbations

1993 ◽  
Vol 69 (5) ◽  
pp. 1736-1748 ◽  
Author(s):  
J. L. Schotland ◽  
W. Z. Rymer
Keyword(s):  
External Load ◽  
Hind Limb ◽  
Joint Angle ◽  
Activity Level ◽  
Temporal Organization ◽  
Emg Activity ◽  
Relative Timing ◽  
Before And After ◽  
Movement Segment ◽  
Initial Movement

1. To evaluate the hypothesis that the neural control of sensorimotor transformations may be simplified by using a single control variable, we compared the movement kinematics and muscle activity patterns [electromyograms (EMGs)] of the frog during flexion withdrawal and the hind limb-hind limb wipe reflex before and after adding an external load. In addition, the flexibility of spinal cord circuitry underlying the hind limb-hind limb wipe reflex was evaluated by comparing wipes before and after removal of one of the contributing muscles by cutting a muscle nerve. 2. The kinematics of the movements were recorded using a WATSMART infrared emitter-detector system and quantified using principal-components analysis to provide a measure of the shape (eigenvalues) and orientation (eigenvector coefficients) of the movement trajectories. The neural pattern coordinating the movements was characterized by the latencies and magnitudes of EMGs of seven muscles acting at the hip, knee, and ankle. These variables were compared 1) during flexion withdrawal and the initial movement segment of the limb during the hind limb-hind limb wipe reflex in both unrestrained movements and in movements executed when a load equal to approximately 10% of the animal's body weight was attached to a distal limb segment and 2) during the initial movement segment of the wipe reflex before and after cutting the nerve to the knee flexor-hip extensor, iliofibularis. 3. Addition of the load had no discernible effect on the end-point position of the foot during either reflex. However, during the loaded flexion reflex, the ankle joint did not move until after the hip and knee joints had moved to their normal positions. This delayed flexion of the ankle was accompanied by large increases in the magnitude of EMG activity in two ankle muscles that exceeded the levels found during unrestrained movements. Significant changes in the temporal organization of the EMG pattern accompanied the change in joint angle relations during flexion withdrawal. 4. Despite the addition of an external load, all animals successfully and reliably removed the stimulus during the wipe reflex, and the relative timing of both the EMG pattern and joint angle motion was preserved. 5. Immediately after section of the nerve to a single muscle (iliofibularis), all animals successfully and reliably removed the stimulus during the wipe reflex. The relative timing of muscle activation was preserved, accompanied by a reduction in the activity level of gluteus magnus, a muscle with action reciprocal to iliofibularis.(ABSTRACT TRUNCATED AT 400 WORDS)

Encoding of near-range spatial information by descending interneurons in the stick insect antennal mechanosensory pathway

2013 ◽  
Vol 110 (9) ◽  
pp. 2099-2112 ◽  
Author(s):  
Jan M. Ache ◽  
Volker Dürr
Keyword(s):  
Joint Angle ◽  
Spatial Information ◽  
Strong Dependence ◽  
Movement Direction ◽  
Neural Basis ◽  
Reach To Grasp ◽  
Movement Velocity ◽  
Spatial Coordinate ◽  
Descending Interneurons ◽  
Position Sensitive

Much like mammals use their whiskers, insects use their antennae for tactile near-range orientation during locomotion. Stick insects rapidly transfer spatial information about antennal touch location to the front legs, allowing for aimed reach-to-grasp movements. This adaptive behavior requires a spatial coordinate transformation from “antennal contact space” to “leg posture space.” Therefore, a neural pathway must convey proprioceptive and tactile information about antennal posture and contact site to thoracic motor networks. Here we analyze proprioceptive encoding properties of descending interneurons (DINs) that convey information about antennal posture and movement to the thoracic ganglia. On the basis of response properties of 110 DINs to imposed movement of the distal antennal joint, we distinguish five functional DIN groups according to their sensitivity to three parameters: movement direction, movement velocity, and antennal joint angle. These groups are simple position-sensitive DINs, which signal the antennal joint angle; dynamic position-sensitive DINs, which signal the joint angle with strong dependence on movement; unspecific movement-sensitive DINs, which signal movement but not the velocity, position, or direction of movement; and ON- and OFF-type velocity-sensitive DINs. The activity of the latter two groups is increased/attenuated during antennal movement, with the spike rate increasing/decreasing linearly with antennal joint angle velocity. Some movement-sensitive DINs convey spikes to the thorax within 11 ms, suggesting a rapid, direct pathway from antennal mechanosensory to thoracic motor networks. We discuss how the population of DINs could provide the neural basis for the intersegmental spatial coordinate transfer between a touch sensor of the head and thoracic motor networks.

scholarly journals Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2690
Author(s):  
Bo Pan ◽  
Xuguang Wang ◽  
Zhenyang Xu ◽  
Lianjun Guo ◽  
Xuesong Wang
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Joint Angle ◽  
Simulation Software ◽  
Dissipated Energy ◽  
Energy Structure ◽  
Joint Angles ◽  
Crack Penetration ◽  
Before And After ◽  
The Impact

The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.

scholarly journals Analysis of physical activity level and sedentary behavior before and after stroke: A cross-sectional study

2021 ◽  
Author(s):  
João Victor de Araújo Souza ◽  
Monalisa Silva de França ◽  
Nayara Karina Ferreira Pereira ◽  
Denise Soares de Araújo ◽  
Roberta de Oliveira Cacho ◽  
...  
Keyword(s):  
Physical Activity ◽  
Analytical Study ◽  
Chronic Phase ◽  
The Elderly ◽  
Cross Sectional Study ◽  
Activity Level ◽  
Systemic Hypertension ◽  
Cross Sectional ◽  
Before And After ◽  
Regular Practice

Introduction: Stroke is a major cause of death and mortality worldwide. The sedentary lifestyle is a modifiable risk factor and the regular practice of physical activity can reduce the recurrence of stroke and its symptoms. Objective: To characterize the level of physical activity of post-stroke patients before and after the event. Methodology: This is a cross-sectional, analytical study. The population of the study consisted of patients diagnosed with stroke, in the chronic phase under treatment or that have already been discharged from the Physiotherapy School Clinic of FACISA in Santa Cruz-RN. The individuals were evaluated by the Modified Baecker Questionnaire for the Elderly (QBMI) that classifies the level of physical activity in: sedentary (-9), active (9 to 16), and athletes (+16). The normality of the variables was verified by the Shapiro-Wilk test. Wilcoxon’s test was used for comparative analysis of QBMI before and after stroke. Results: Nineteen patients participated (8 male and 11 female) with a mean age of 63 years, of these, 11 had systemic hypertension. Before, 3 were classified as sedentary (score mean: 5.34), 5 active (score mean: 12.254) and 1 athlete ( score mean: 27.04). After the stroke, 18 were classified as sedentary (score mean: 1.46) (p=0.001). Conclusion: There was a reduction in the participants’ level of physical activity, showing greater sedentariness after stroke, although physical activity is essential for secondary prevention of stroke.

The reach-to-grasp movement in Parkinson’s disease before and after dopaminergic medication

2000 ◽  
Vol 38 (1) ◽  
pp. 46-59 ◽  
Author(s):  
U. Castiello ◽  
K.M.B. Bennett ◽  
C. Bonfiglioli ◽  
R.F. Peppard
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Reach To Grasp ◽  
Dopaminergic Medication ◽  
Before And After

Unusual Step Patterns in the Free Walking Grasshopper Neoconocephalus Robustus: I. General Features of the Step Patterns

1978 ◽  
Vol 73 (1) ◽  
pp. 147-157
Author(s):  
D. GRAHAM
Keyword(s):  
Stick Insect ◽  
Before And After ◽  
Central Oscillator

The free walking step patterns of the tettigonid Neoconocephalus robustus are described and compared with the predictions of a model for walking co-ordination developed for the stick insect. Regular absences of rear leg protractions are found when the animal has walked for some minutes. The relative phasing of leg protractions before and after isolated absences suggests that an absence is created by a failure to meet all the conditions required for a protraction and that a ‘central oscillator’ maintains its intrinsic rhythm during such an absence.

scholarly journals Effect of Psychotropic Medications on Hammertoe Reconstruction Outcomes

2020 ◽  
Vol 5 (3) ◽  
pp. 247301142094413
Author(s):  
Samuel D. Maidman ◽  
Amalie E. Nash ◽  
Amanda Fantry ◽  
Shay Tenenbaum ◽  
Yahya Daoud ◽  
...  
Keyword(s):  
Short Form ◽  
Medication Use ◽  
Psychotropic Medications ◽  
Activity Level ◽  
Mood Stabilizers ◽  
Level Of Evidence ◽  
Sf 36 ◽  
Significant Difference ◽  
Patient Reported ◽  
Before And After

Background: Hammertoe deformities can seriously affect activity level and footwear. The use of prescription, mood-altering medications is very common, with some estimates as high as 25% of the population. Mood disorders, especially depression, negatively affect the results of medical and operative treatments. This study assessed the relationship of mood-altering medication use with the outcomes and complications of operative reconstruction of hammertoes. Methods: Data were prospectively collected from 116 patients who underwent hammertoe reconstruction, including demographic information, medical history, the use of mood-altering psychotropic medications (antidepressants, anxiolytics, hypnotics, and mood stabilizers), and postoperative complications. Preoperative patient-reported outcomes were measured using the visual analog scale (VAS) for pain and Short Form Health Survey (SF-36), which were repeated at 1-year follow-up. Results: A total of 36.2% of patients were taking psychotropic medications. Medication and nonmedication groups had similar pain VAS and SF-36 Physical Component Summary (PCS) scores before and after surgery. Compared with nonmedication patients, patients on psychotropic medications had significantly lower SF-36 Mental Component Summary (MCS) scores preoperatively ( P = .001) and postoperatively ( P = .006), but no significant difference in the change in MCS (ΔMCS) from preoperative to postoperative. Psychotropic medication use was associated with superficial wound infections ( P = .048), but not other complications. Conclusions: Patients taking psychotropic medications were equally likely to benefit from forefoot reconstruction as nonmedication patients. Preoperative and postoperative PCS and VAS were not significantly different between medication and nonmedication groups. Although the medication group had lower absolute MCS, they reported the same magnitude of improvement in MCS (ΔMCS) as the nonmedication group. Level of Evidence: Level II, prospective cohort study.

Effects of Ambulation and Nondependent Transfers on Vital Signs in Patients Receiving Norepinephrine

2017 ◽  
Vol 26 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Rosario Arcaya Nievera ◽  
Ann Fick ◽  
Hilary K. Harris
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Physical Therapy ◽  
Arterial Pressure ◽  
Low Dose ◽  
Vital Signs ◽  
Activity Level ◽  
Significant Difference ◽  
Before And After ◽  
Norepinephrine Dose

Purpose To assess the safety of mobilizing patients receiving low-dose norepinephrine (0.05 μg/kg per min) by examining mean arterial pressure and heart rate before and after activity with parameters set by the physician. Background Norepinephrine is a peripheral vasoconstrictor administered for acute hypotension. During activity, blood flows to the periphery to supply muscles with oxygen, which may oppose the norepinephrine vasoconstriction. The safety of mobilizing patients receiving norepinephrine is unclear. Methods Heart rate, mean arterial pressure, norepinephrine dose, and activity performed were extracted retrospectively from charts of 47 cardiothoracic surgery patients during the first patient transfer to chair or ambulation with norepinephrine infusing. Mean arterial pressure and heart rate were compared before and after physical therapy (paired t tests). Differences among norepinephrine doses and physical activity levels were evaluated (Kruskal-Wallis test). Results Forty-one of the 47 patients (87%) tolerated the activity within safe ranges of vital signs. The change in patients’ mean arterial pressure from before to after activity was not significant (P = .16), but a significant increase in heart rate occurred after activity (P < .001). A Kruskal-Wallis test showed no significant difference in the norepinephrine dose and activity level (χ2 = 6.34, P = .17). No instances of cardiopulmonary or respiratory arrest occurred during any physical therapy sessions. Conclusions Infusion of low-dose norepinephrine should not be considered an automatic reason to keep patients on bed rest.

Inter-Rater Reliability for Hand Activity Level (HAL) and Force Metrics

2002 ◽  
Vol 46 (13) ◽  
pp. 1037-1040 ◽  
Author(s):  
Marissa L. Ebersole ◽  
Thomas J. Armstrong
Keyword(s):  
Weighted Kappa ◽  
Threshold Limit Value ◽  
Activity Level ◽  
Peak Force ◽  
Observational Method ◽  
Limit Value ◽  
Analysis Process ◽  
Automotive Assembly ◽  
Before And After ◽  
Trained Observers

Observational rating methods are used frequently in ergonomic job analysis because they are less costly and time consuming than other methods. The ACGIH recently published a threshold limit value (TLV) for repetitive work. This TLV suggests the use of one such observational method developed by Latko et al. (1997) for rating Hand Activity Level (HAL) and peak force. One criticism of Latko's method is the unknown reliability and consistency of the raters during the analysis process. Latko suggests the use of two or more trained observers to increase this consistency. This study analyzed 410 jobs at an automotive assembly plant using 2 observers recording initial and final ratings. A weighted kappa was calculated for the HAL and peak force before and after discussion. Before discussion, HAL reliability was rated as moderate and peak force as fair. After discussion, both HAL and peak force kappa values were rated as good.

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