Central patterning and reflex control of antennular flicking in the hermit crab Pagurus alaskensis (Benedict)

1975 ◽  
Vol 63 (1) ◽  
pp. 17-32
Author(s):  
P. J. Snow
Keyword(s):  
Hermit Crab ◽  
Functional Significance ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Spike Frequency ◽  
Joint Movement ◽  
Trigger System ◽  
System A ◽  
Joint Flexion ◽  
Reflex Control

1. The effects of altering sensory input on the motoneuronal activity underlying antennular flicking have been tested. 2. Removal of the short segments of the outer flagellum results in a reduction of the number of spikes/burst in the fast flexor motoneurones A31F and A32F. 3. During a flick the delay between the burst in motoneurone A31F and the burst in motoneurone A32F is insensitive to alteration of sensory input. 4. Sensory feedback from the flexion phase of a flick is necessary for the activation of either extensor motoneurone. Evidence is presented to suggest that this feedback is primarily from joint-movement receptors at the MS-DS and DS-OF joints. 5. The results are incorporated into a model in which the patterns of flexor activity result from some specified properties of three components: a trigger system, a follower system, and the spike initiating zone of the flexor motoneurones. The trigger system determines when a flick will occur. The follower system determines the number of flexor spikes during a flick. Properties of the spike initiating zone determine the spike frequency and the timing between bursts in the flexor motoneurones. Extensor activity in the model is reflexively elicited by feedback from phasic, unidirectional receptors sensitive to joint flexion. 6. The functional significance of reflex control of extensor activity is discussed in relation to the form and proposed function of antennular flicking. It is suggested that this form of control is adapted to the function of antennular flicking because flexion at the MS-DS joint is not always necessary for the fulfilment of the fuction of a flick.

Modeling the resistance mechanism of passive knee joint flexion and extension for use in rehabilitation equipment

2021 ◽  
pp. 095441192199013
Author(s):  
Mansoor Amiri ◽  
Farhad Tabatabai Ghomsheh ◽  
Farshad Ghazalian
Keyword(s):  
Knee Joint ◽  
Sagittal Plane ◽  
Resistance Mechanism ◽  
Time Dependent ◽  
Coefficient Of Determination ◽  
Joint Movement ◽  
Elastic Coefficient ◽  
Knee Movement ◽  
Joint Flexion ◽  
Flexion And Extension

The purpose of this study was to model the resistance mechanism of Passive Knee Joint Flexion and Extension to create a similar torque mechanism in rehabilitation equipment. In order to better model the behavior of passive knee tissues, it is necessary to exactly calculate the two coefficients of elasticity of time-independent and time-dependent parts. Ten healthy male volunteers (mean height 176.4+/−4.59 cm) participated in this study. Passive knee joint flexion and extension occurred at velocities of 15, 45, and 120 (degree/s), and in five consecutive cycles and within the range of 0 to 100° of knee movement on the sagittal plane on Cybex isokinetic dynamometer. To ensure that the muscles were relaxed, the electrical activity of knee muscles was recorded. The elastic coefficient, (KS) increased with elevating the passive velocity in flexion and extension. The elastic coefficient, (KP) was observed to grow with the passive velocity increase. While, the viscous coefficient (C) diminished with passive velocity rise in extension and flexion. The heightened passive velocity of the motion resulted in increased hysteresis (at a rate of 42%). The desired of passive velocity is lower so that there is less energy lost and the viscoelastic resistance of the tissue in the movement decreases. The Coefficient of Determination, R2 between the model-responses and experimental curves in the extension was 0.96 < R2 < 0.99 and in flexion was 0.95 < R2 < 0.99. This modeling is capable of predicting the true performance of the components of passive knee movement and we can create a resistance mechanism in the rehabilitation equipment to perform knee joint movement. Quantitative measurements of two elastic coefficients of Time-independent and Time-dependent parts passive knee joint coefficients should be used for better accurate simulation the behavior of passive tissues in the knee which is not seen in other studies.

scholarly journals The emulation theory of representation: Motor control, imagery, and perception

2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush
Keyword(s):  
Motor Control ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Neural Circuits ◽  
Sensory Information ◽  
The Body ◽  
Feedback Delay ◽  
Run Off ◽  
Effects Of Feedback ◽  
The Brain

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.

The High-Energy Particle Detector (HEPD) on Board the CSES Mission

2017 ◽  
Vol 13 (S335) ◽  
pp. 365-367 ◽  
Author(s):  
Vincenzo Vitale ◽  
Keyword(s):  
Geomagnetic Field ◽  
High Energy ◽  
Low Earth Orbit ◽  
Light Nuclei ◽  
High Energy Particle ◽  
Particle Detector ◽  
Trigger System ◽  
Energy Particle ◽  
System A ◽  
Coincidence System

AbstractThe High-Energy Particle Detector (HEPD) will measure electrons, protons and light nuclei fluxes, in low Earth orbit. This detector consists of a high precision silicon tracker, a versatile trigger system, a range-calorimeter and an anti-coincidence system. It is one of the instruments on board the China Seismo-Electromagnetic Satellite (CSES). HEPD can detect multi-MeV particles trapped within the geomagnetic field. When operated at large latitudes HEPD can also detect un-trapped solar particles and low energy cosmic rays. A detailed description of the HEPD will be given.

Topical Review: Vision and Gait in Older Adults: A Clinician’s Perspective

2021 ◽  
pp. 95-106
Keyword(s):  
Sensory Integration ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Management Plan ◽  
Vision Impairment ◽  
Evidence Based ◽  
Care Providers ◽  
Risk Of Falling ◽  
Human Function ◽  
The Impact

Gait is an important human function, and vision is the dominant sensory input used during gait. Vision aids pathfinding decisions and provide ongoing sensory feedback to maintain appropriate balance and prevent falls. Eye care providers who wish to effectively address the impact of vision impairment on the risk of falling will customize their management plan based on specific impairments. This article provides an overview of normal sensory integration as it applies to gait, with an emphasis on vision. It also presents an evidence-based review of visual dysfunctions that cause falls, as well as strategies to reduce falls in adults with visual impairment, with emphasis on patients over age 65.

How do inositol and glucose modulate feeding in Manduca sexta caterpillars?

2000 ◽  
Vol 203 (8) ◽  
pp. 1299-1315 ◽  
Author(s):  
J.I. Glendinning ◽  
N.M. Nelson ◽  
E.A. Bernays
Keyword(s):  
Manduca Sexta ◽  
Functional Significance ◽  
Sensory Input ◽  
Sugar Alcohol ◽  
Inhibitory Effects ◽  
Neural Recordings ◽  
Behavioral Studies ◽  
Aversive Taste ◽  
Taste Cells

Many species of caterpillar possess taste cells that respond exceptionally vigorously to the sugar alcohol myo-inositol. We examined the functional significance of these inositol-sensitive taste cells in Manduca sexta caterpillars through an integrated series of electrophysiological and behavioral studies. Neural recordings from all the gustatory chemosensilla revealed that M. sexta have only two pairs of inositol-sensitive taste cells, which respond strongly and selectively to myo-inositol, and two pairs of sugar-sensitive taste cells, which respond relatively weakly to sugars (glucose and sucrose). Behavioral studies established that myo-inositol incites feeding and counteracts the inhibitory effects of aversive taste stimuli (e.g. caffeine) on feeding, but does not promote increased consumption once feeding has been initiated. In contrast, glucose and sucrose did not produce any robust effects on feeding. We failed to obtain any evidence of sensory inhibition between taste cells that responded to myo-inositol and caffeine, indicating that myo-inositol counteracts the inhibitory effects of caffeine on feeding through a central gustatory mechanism. We conclude that sensory input from the inositol-sensitive taste cells, but not the sugar-sensitive taste cells, plays an important role in regulating feeding in M. sexta.

Potters Make Shorter Pots Under Conditions of Reduced Sensory Input

Perception ◽  
2018 ◽  
Vol 47 (8) ◽  
pp. 860-872
Author(s):  
Mounia Ziat ◽  
Min Park ◽  
Brian Kakas ◽  
David A. Rosenbaum
Keyword(s):  
Visual Feedback ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Perception And Action ◽  
Behavioral Research ◽  
Control Hypothesis ◽  
Clay Pots ◽  
Do So

Although people have made clay pots for millennia, little behavioral research has explored how they do so. We were specifically interested in potters’ use of auditory, haptic, and visual feedback. We asked what would happen if one or two of these sources of feedback were removed and potters tried to create pots of a given height, stopping when they thought they had reached that height. We asked students in a pottery class to build simple clay vessels either when they had full sensory feedback (in the control condition for all participants) or when they had reduced input from one modality (in Experiment 1) or two modalities (in Experiment 2). Participants were asked to stop building the vessels when they thought the vessels were 5 in. high. We found that participants produced shorter vessels when one or more forms of sensory feedback was reduced. The degree of shortening did not depend on the type or number of reduced sensory channels. The results are consistent with a control hypothesis where potters must have learned how to use sensory feedback from the modalities to help them control their ceramic creations. The results help highlight the importance of the intimate connections between perception and action.

Measurement of the Arc of Digital Flexion and Joint Movement Ranges

1995 ◽  
Vol 20 (6) ◽  
pp. 836-840 ◽  
Author(s):  
J. D. ARBUCKLE ◽  
D. A. McGROUTHER
Keyword(s):  
Healthy Subjects ◽  
Video Recording ◽  
Similar Technique ◽  
Joint Movement ◽  
Joint Angles ◽  
Full Extension ◽  
Male And Female ◽  
Full Flexion ◽  
Joint Flexion ◽  
Prognostic Importance

Dynamic digital flexion was examined by video recording healthy subjects making a fist. The are of the fingertip sweep from full extension to full flexion was replayed frame by frame and plotted. A similar technique was employed to measure the MP, PIP and DIP joint angles throughout digital flexion. Graphs were plotted of MP against PIP, and PIP against DIP flexion. These results were related to a theoretical 45° line. The fingertip appears to sweep through an elliptical pathway when flexing, rather than an equiangular curve. Graphs of joint flexion showed that male and female fingers flex in a similar fashion, as do the index and little finger. Graphs of PIP against DIP flexion suggest some limiting mechanism of either the extensor or flexor system. These graphs give useful insights into the complex mechanisms of dynamic digital flexion, and may be of diagnostic and prognostic importance.

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