Time Course and Magnitude of Movement-Related Gating of Tactile Detection in Humans. III. Effect of Motor Tasks

2002 ◽  
Vol 88 (4) ◽  
pp. 1968-1979 ◽  
Author(s):  
Stephan R. Williams ◽  
C. Elaine Chapman
Keyword(s):  
Time Course ◽  
Motor Command ◽  
Passive Movement ◽  
Emg Activity ◽  
Active Movement ◽  
Potential Contribution ◽  
Backward Masking ◽  
Movement Onset ◽  
Tactile Stimuli ◽  
Tactile Detection

This study investigated the relative importance of central and peripheral signals for movement-related gating by comparing the time course and magnitude of movement-related decreases in tactile detection during a reference motor task, active isotonic digit 2 (D2) abduction, with that seen during three test tasks: a comparison with active isometric D2 abduction (movement vs. no movement) evaluated the contribution of peripheral reafference generated by the movement to gating; a comparison with passive D2 abduction (motor command vs. no motor command; movement generated by an external agent) allowed us to evaluate the contribution of the central motor command to tactile gating; and finally, the inclusion of an active “no apparatus,” or freehand, D2 abduction task allowed us to evaluate the potential contribution of incidental peripheral reafference generated by the position detecting apparatus to the results (apparatus vs. no apparatus). Weak electrical stimuli (2-ms pulse; intensity, 90% detected at rest) were applied to D2 at different delays before and after movement onset or electromyographic (EMG) activity onset. Significant time-dependent movement-related decreases in detection were obtained with all tasks. When the results obtained during the active isotonic movement task were compared with those obtained in the three test tasks, no significant differences in the functions describing detection performance over time were seen. The results obtained with the isometric D2 abduction task show that actual movement of a body part is not necessary to diminish detection of tactile stimuli in a manner similar to the decrease produced by isotonic, active movement. In the passive test task, the peak decrease in detection clearly preceded the onset of passive movement (by 38 ms) despite the lack of a motor command and, presumably, no movement-related peripheral reafference. A slightly but not significantly earlier decrease was obtained with active movement (49 ms before movement onset). Expectation of movement likely did not contribute to the results because stimulus detection during sham passive movement trials (subjects expected but did not receive a passive movement) was not different from performance at rest (no movement). The results obtained with passive movement are best explained by invoking backward masking of the test stimuli by movement-related reafference and demonstrate that movement-related reafference is sufficient to produce decreases in detection with a time course and amplitude not significantly different from that produced by active movement.

Differential Controls Over Tactile Detection in Humans by Motor Commands and Peripheral Reafference

2006 ◽  
Vol 96 (3) ◽  
pp. 1664-1675 ◽  
Author(s):  
C. Elaine Chapman ◽  
Evelyne Beauchamp
Keyword(s):  
Time Course ◽  
Index Finger ◽  
Motor Command ◽  
Electromyographic Activity ◽  
Backward Masking ◽  
Motor Tasks ◽  
Motor Commands ◽  
Tactile Stimuli ◽  
Tactile Detection ◽  
Electrical Stimuli

The purpose of this study was to determine the extent to which motor commands and peripheral reafference differentially control the detection of near-threshold, tactile stimuli. Detection of weak electrical stimuli applied to the index finger (D2) was evaluated with two bias-free measures of sensory detection, the index of detectability ( d′) and the proportion of stimuli detected. Stimuli were presented at different delays prior to and during two motor tasks, D2 abduction, and elbow extension; both tasks were tested in two modes, active and passive. For both active tasks, the peak decrease in tactile suppression occurred at the onset of electromyographic activity. The time course for the suppression of detection during active and passive D2 abduction was identical, and preceded the onset of movement (respectively, −35 and −47 ms). These results suggest that movement reafference alone, acting through a mechanism of backward masking, could explain the modulation seen with D2 movement. In contrast, tactile suppression was significantly earlier for active elbow movements (−59 ms) as compared with passive (−21 ms), an observation consistent with both the motor command and peripheral reafference contributing to the suppression of detection of stimuli applied to D2 during movements about a proximal joint. A role for the motor command in tactile gating during distal movements cannot be discounted, however, because differences in the strength and distribution of the peripheral reafference may also have contributed to the proximo-distal differences in the timing of the suppression.

scholarly journals Responses of somatosensory area 2 neurons to actively and passively generated limb movements

2013 ◽  
Vol 109 (6) ◽  
pp. 1505-1513 ◽  
Author(s):  
Brian M. London ◽  
Lee E. Miller
Keyword(s):  
Motor Command ◽  
Accurate Estimate ◽  
Passive Movement ◽  
Efference Copy ◽  
Forward Model ◽  
Sensor Data ◽  
Active Movement ◽  
Noisy Input ◽  
Neural Discharge ◽  
Passive Movements

Control of reaching movements requires an accurate estimate of the state of the limb, yet sensory signals are inherently noisy, because of both noise at the receptors themselves and the stochastic nature of the information representation by neural discharge. One way to derive an accurate representation from noisy sensor data is to combine it with the output of a forward model that considers both the previous state estimate and the noisy input. We recorded from primary somatosensory cortex (S1) in macaques ( Macaca mulatta) during both active and passive movements to investigate how the proprioceptive representation of movement in S1 may be modified by the motor command (through efference copy). We found neurons in S1 that respond to one or both movement types covering a broad distribution from active movement only, to both, to passive movement only. Those neurons that responded to both active and passive movements responded with similar directional tuning. Confirming earlier results, some, but not all, neurons responded before the onset of volitional movements, possibly as a result of efference copy. Consequently, many of the features necessary to combine the forward model with proprioceptive feedback appear to be present in S1. These features would not be expected from combinations of afferent receptor responses alone.

Time Course and Magnitude of Movement-Related Gating of Tactile Detection in Humans. I. Importance of Stimulus Location

1998 ◽  
Vol 79 (2) ◽  
pp. 947-963 ◽  
Author(s):  
Stephan R. Williams ◽  
Jafar Shenasa ◽  
C. Elaine Chapman
Keyword(s):  
Time Course ◽  
Human Subjects ◽  
Stimulus Location ◽  
The Body ◽  
Time Dependent ◽  
Emg Activity ◽  
Dependent Manner ◽  
Perceptual Performance ◽  
Tactile Detection ◽  
The Right

Williams, Stephan R., Jafar Shenasa, and C. Elaine Chapman. Time course and magnitude of movement-related gating of tactile detection in humans. I. Importance of stimulus location. J. Neurophysiol. 79: 947–963, 1998. The time course and spatial extent of movement-related suppression of the detection of weak electrical stimuli (intensity, 90% detected at rest) was determined in 118 experiments carried out in 47 human subjects. Subjects were trained to perform a rapid abduction of the right index finger (D2) in response to a visual cue. Stimulus timing was calculated relative to the onset of movement and the onset of electromyographic (EMG) activity. Electrical stimulation was delivered to 10 different sites on the body, including sites on the limb performing the movement (D2, D5, hand, forearm and arm) as well as several distant sites (contralateral arm, ipsilateral leg). Detection of stimuli applied to the moving digit diminished significantly and in a time-dependent manner, with the first significant decrease occurring 120 ms before movement onset and 70 ms before the onset of EMG activity. Movement-related and time-dependent effects were obtained at all stimulation sites on the homolateral arm as well as the adjacent trunk. A pronounced spatiotemporal gradient was observed: the magnitude of the movement-related decrease in detectability was greatest and earliest at sites closest to the moving finger and progressively weaker and later at more proximal sites. When stimuli were applied to the distant sites, only a small (∼10%), non-time–dependent decrease was observed during movement trials. A simple model of perceptual performance adequately described the results, providing insight into the distribution of movement-related inhibitory controls within the CNS.

Transcortical reflexes and servo control of movement

1981 ◽  
Vol 59 (7) ◽  
pp. 757-775 ◽  
Author(s):  
Edward V. Evarts ◽  
Christoph Fromm
Keyword(s):  
Muscle Length ◽  
Length Change ◽  
Passive Movement ◽  
Emg Activity ◽  
Active Movement ◽  
Proprioceptive Reflexes ◽  
Afferent Inputs ◽  
Exteroceptive Reflexes ◽  
Proprioceptive Inputs

Sherrington proposed that the major role of proprioceptors is in processing afferent inputs generated by the active movements of the animal itself, and noted that the reflex effects of proprioceptive inputs are "mild." Current experimental results are consistent with the view that the major role of both segmental and transcortical proprioceptive reflexes is in small active movements and active postural stability, with muscle afferent inputs reducing "… errors of muscle length produced by fluctuating levels of motor discharge …" as stated by Goodwin and coworkers in 1978.Exteroceptive reflexes generate intense muscular responses and are of critical importance in prompt reprogramming essential for effective responses to environmental stimuli. Within the motor cortex (MI) there is a caudal region (MI/c) which receives exteroceptive cutaneous inputs and a rostral region (MI/r) which receives proprioceptive inputs. Transcortical reflexes mediated via pyramidal tract neurons (PTNs) of MI/r have properties which are analogous to segmental proprioceptive reflexes: changes of muscle length elicit PTN discharges which oppose the length change and so act to maintain stability. Furthermore, MI/r PTNs which are recruited earliest for small active movements are most sensitive to proprioceptive inputs. Data are not yet available concerning transcortical reflexes via MI/c during voluntary movement, but it is speculated that the cutaneous reflexes via MI/c might be functionally analogous to segmental cutaneous reflexes.Short-latency reflex responses also occur in postcentral (PoC) PTNs, and in this report we present results concerning the properties of PoC PTNs during active and passive movement. Caudal (area 2–5) PoC PTNs were similar to MI PTNs in that they often discharged prior to electromyogram (EMG) activity with active movement, and had different discharge frequencies with different steady state loads, but were unlike most MI PTNs in having the same changes of discharge with active and passive movement. Our finding of PoC discharge prior to movement onset, confirming that of Soso and Fetz in 1980, is discussed in connection with the concept of corollary discharge.

Active movement restores veridical event-timing after tactile adaptation

2012 ◽  
Vol 108 (8) ◽  
pp. 2092-2100 ◽  
Author(s):  
Alice Tomassini ◽  
Monica Gori ◽  
David Burr ◽  
Giulio Sandini ◽  
Maria Concetta Morrone
Keyword(s):  
Temporal Discrimination ◽  
Body Movement ◽  
Passive Movement ◽  
Active Movement ◽  
Somatosensory Processing ◽  
Action Execution ◽  
Event Time ◽  
Tactile Stimuli ◽  
Apparent Duration ◽  
Intention To Move

Growing evidence suggests that time in the subsecond range is tightly linked to sensory processing. Event-time can be distorted by sensory adaptation, and many temporal illusions can accompany action execution. In this study, we show that adaptation to tactile motion causes a strong contraction of the apparent duration of tactile stimuli. However, when subjects make a voluntary motor act before judging the duration, it annuls the adaptation-induced temporal distortion, reestablishing veridical event-time. The movement needs to be performed actively by the subject: passive movement of similar magnitude and dynamics has no effect on adaptation, showing that it is the motor commands themselves, rather than reafferent signals from body movement, which reset the adaptation for tactile duration. No other concomitant perceptual changes were reported (such as apparent speed or enhanced temporal discrimination), ruling out a generalized effect of body movement on somatosensory processing. We suggest that active movement resets timing mechanisms in preparation for the new scenario that the movement will cause, eliminating inappropriate biases in perceived time. Our brain seems to utilize the intention-to-move signals to retune its perceptual machinery appropriately, to prepare to extract new temporal information.

Time-dependent progression of neurogenic lower urinary tract dysfunction after spinal cord injury in the mouse model

2021 ◽  
Author(s):  
Tetsuichi Saito ◽  
Daisuke Gotoh ◽  
Naoki Wada ◽  
Pradeep Tyagi ◽  
Tomonori Minagawa ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Time Course ◽  
Time Dependent ◽  
Lower Urinary Tract Dysfunction ◽  
Emg Activity ◽  
Mrna Levels ◽  
Mechanosensitive Channels ◽  
Reduction Time ◽  
Cord Injury

This study evaluated the time-course changes in bladder and external urinary sphincter (EUS) activity as well as the expression of mechanosensitive channels in lumbosacral dorsal root ganglia (DRG) after spinal cord injury (SCI). Female C57BL/6N mice in the SCI group underwent transection of the Th8/9 spinal cord. Spinal intact mice and SCI mice at 2, 4 and 6 weeks post SCI were evaluated by single-filling cystometry and EUS-electromyography (EMG). In another set of mice, the bladder and L6-S1 DRG were harvested for protein and mRNA analyses. In SCI mice, non-voiding contractions was confirmed at 2 weeks post-SCI, and did not increase over time to 6 weeks. In 2-weeks SCI mice, EUS-EMG measurements revealed detrusor-sphincter dyssynergia (DSD), but periodic EMG reductions during bladder contraction were hardly observed. At 4 weeks, SCI mice showed increases of EMG activity reduction time with increased voiding efficiency (VE). At 6 weeks, SCI mice exhibited a further increase in EMG reduction time. RT-PCR of L6-S1 DRG showed increased mRNA levels of TRPV1 and ASIC1-3 in SCI mice with a decrease of ASIC2-3 at 6 weeks compared to 4 weeks whereas Piezo2 showed a slow increase at 6 weeks. Protein assay showed the SCI-induced overexpression of bladder BDNF with a time-dependent decrease post SCI. These results indicate that detrusor overactivity is established in the early phase whereas DSD is completed later at 4 weeks with an improvement at 6 weeks post SCI, and that mechanosensitive channels may be involved in the time-dependent changes.

Nonlinear viscosity of human wrist

1984 ◽  
Vol 52 (3) ◽  
pp. 553-569 ◽  
Author(s):  
C. C. Gielen ◽  
J. C. Houk
Keyword(s):  
Constant Velocity ◽  
Time Course ◽  
Fractional Power ◽  
Comparison Method ◽  
Mean Value ◽  
Emg Activity ◽  
Triggered Reactions ◽  
Nonlinear Viscosity ◽  
Flexor Muscles ◽  
Reflex Arc

Nonlinear viscous properties of stretch and unloading reflexes in the human wrist were examined using constant-velocity ramp stretches and releases in the range between 5 and 500 mm/s. Subjects were asked to oppose an initial flexor preload and were instructed not to intervene voluntarily when the changes in position were applied. Electromyographic (EMG) activity and net force exerted by the wrist were measured. Although subjects were instructed not to intervene to the applied stretches, even well-practiced subjects sometimes showed unintended triggered reactions, which character could be assisting or resisting. A trial comparison method was used to detect and eliminate responses contaminated by unintended reactions. Ramp stretches further loaded the preloaded flexor muscles. Responses of EMG and force increased steeply initially but after about 1-cm displacement, the slope of these responses decreased to a lower value and remained constant during the remainder of the 5-cm ramp. For higher stretch velocities, the magnitudes and slopes of the responses of EMG and force increased but less than proportionally with ramp velocity. Except for the initial transient, EMG in the loaded flexor muscles and force responses could be described by a product relationship between a linear position-related term and a low fractional power of velocity, after a correction was made for delays in the reflex arc. Mean value of the exponent in the power function of velocity was 0.3 for EMG and 0.17 for force. For higher preloads, incremental responses of force to constant-velocity stretches, plotted as a function of wrist position, shifted to higher values and the slope of increase of force with position became somewhat steeper. This upward shift of the force trace reflects a change of apparent threshold of the stretch reflex. Ramp releases shortened and unloaded the preloaded flexor muscles and stretched the initially inactive extensor muscles. Flexor EMG activity declined progressively with a time course that was independent of velocity. Extensor EMG response depended on preload. At high preloads, there was no activity except for some bursting at the highest velocities. At low preloads, EMG activity was initially absent but started part way through the ramp. The increase of activity was somewhat greater for higher ramp velocities. Force responses to shortening ramps depended on preload. At high preloads, force responses superimposed at all of the low velocities but fell to slightly lower forces at the higher velocities. At low preloads, force traces again superimposed for low velocities and at high velocities only during the initial part of the response.(ABSTRACT TRUNCATED AT 400 WORDS)

The time-course of ion and water transport across decapitated sunflowers for 32 h after detopping

1970 ◽  
Vol 48 (9) ◽  
pp. 1625-1631 ◽  
Author(s):  
D. G. Sobey ◽  
L. B. MacLeod ◽  
D. S. Fensom
Keyword(s):  
Time Course ◽  
Passive Movement ◽  
The Other ◽  
Ion Concentration ◽  
Culture Solution ◽  
Time Axis ◽  
Normal Functioning ◽  
Water Culture ◽  
Diurnal Cycles ◽  
Exudation Rate

Sunflowers growing in water culture solution containing only six ions (K+, Na+, Ca2+, Mg2+, Cl−, and NO3−) were decapitated and the exudate was allowed to accumulate in vinyl tubes. Measurements of biopotential, exudation rate, and ion concentration in the exudate and the nutrient medium were made at 4-h intervals during the 32-h period after detopping. The exudation rate, fluxes for each ion, biopotentials, and Δ E values for each ion were plotted on a time axis. With the fluxratio equation, chloride, nitrate, and potassium were observed to be entering actively, whereas for the other cations the gradient inward was passive. The active or passive movement for each ion and the diurnal cycles in exudation and ion fluxes changed as time after detopping increased. These changes might be accounted for in terms of the effects of detopping which remove the supply of energy compounds necessary for the normal functioning of the root.

Time Course of Determination of Movement Direction in the Reaction Time Task in Humans

2001 ◽  
Vol 86 (3) ◽  
pp. 1195-1201 ◽  
Author(s):  
Martin Sommer ◽  
Joseph Classen ◽  
Leonardo G. Cohen ◽  
Mark Hallett
Keyword(s):  
Reaction Time ◽  
Motor Cortex ◽  
Time Course ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Movement Direction ◽  
Movement Onset ◽  
Thumb Movement

The primary motor cortex produces motor commands that include encoding the direction of movement. Excitability of the motor cortex in the reaction time (RT) task can be assessed using transcranial magnetic stimulation (TMS). To elucidate the timing of the increase in cortical excitability and of the determination of movement direction before movement onset, we asked six right-handed, healthy subjects to either abduct or extend their right thumb after a go-signal indicated the appropriate direction. Between the go-signal and movement onset, single TMS pulses were delivered to the contralateral motor cortex. We recorded the direction of the TMS-induced thumb movement and the amplitude of motor-evoked potentials (MEPs) from the abductor pollicis brevis and extensor pollicis brevis muscles. Facilitation of MEPs from the prime mover, as early as 200 ms before the end of the reaction time, preceded facilitation of MEPs from the nonprime mover, and both preceded measurable directional change. Compared with a control condition in which no voluntary movement was required, the direction of the TMS-induced thumb movement started to change in the direction of the intended movement as early as 90 ms before the end of the RT, and maximum changes were seen shortly before the end of reaction time. Movement acceleration also increased with maxima shortly before the end of the RT. We conclude that in concentric movements a change of the movement direction encoded in the primary motor cortex occurs in the 200 ms prior to movement onset, which is as early as increased excitability itself can be detected.

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