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.

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.

Time Course and Magnitude of Movement-Related Gating of Tactile Detection in Humans. II. Effects of Stimulus Intensity

2000 ◽  
Vol 84 (2) ◽  
pp. 863-875 ◽  
Author(s):  
Stephan R. Williams ◽  
C. Elaine Chapman
Keyword(s):  
Stimulus Intensity ◽  
Time Course ◽  
Human Subjects ◽  
Detection Performance ◽  
Electromyographic Activity ◽  
Dependent Manner ◽  
Significant Movement ◽  
Tactile Detection ◽  
The Right ◽  
Stimulus Localization

This study examined the effect of systematically varying stimulus intensity on the time course and magnitude of movement-related gating of tactile detection and scaling in 17 human subjects trained to perform a rapid abduction of the right index finger (D2) in response to a visual cue. Electrical stimulation was delivered to D2 at five different intensities. At the lowest intensity, approximately 90% of stimuli were detected at rest (1 × P90); four multiples of this intensity were also tested (1.25, 1.5, 1.75, and 2.0 × P90). At all intensities of stimulation, detection of stimuli applied to the moving digit was diminished significantly and in a time-dependent manner, with peak decreases occurring within ±12 ms of the onset of electromyographic activity in the first dorsal interosseous (25–45 ms before movement onset). Reductions in the proportion of stimuli detected were greatest at the lowest stimulus intensity and progressively smaller at higher intensities. No shift in the timing of the decreases in performance was seen with increasing intensity. Once the weakest intensity at which most stimuli were perceived during movement had been established (2 × P90), magnitude estimation experiments were performed using two stimulus intensities, 2 × P90 (5 subjects) and 3 × P90 (3 subjects). Significant movement-related decreases in estimated stimulus magnitude were observed at both intensities, the time course of which was similar to the time course of reductions in detection performance. As stimulus intensity increased, the magnitude of the movement-related decrease in scaling diminished. A model of detection performance that accurately described the effect of stimulus intensity and timing on movement-related reductions in detection was created. This model was then combined with a previous model that described the effects of stimulus localization and timing to predict detection performance at a given stimulation site, intensity, and time during movement. Movement-related gating of tactile perception represents the end result of movement-related effects on the transmission and subsequent processing of the stimulus. The combined model clearly defines many of the requirements that proposed physiological mechanisms of movement-related gating will have to fulfill.

Respiratory and cardiovascular responses to static handgrip exercise in humans

1993 ◽  
Vol 75 (6) ◽  
pp. 2789-2796 ◽  
Author(s):  
G. A. Fontana ◽  
T. Pantaleo ◽  
F. Bongianni ◽  
F. Cresci ◽  
R. Manconi ◽  
...  
Keyword(s):  
Heart Rate ◽  
Time Course ◽  
Minute Ventilation ◽  
Muscle Tension ◽  
Maximum Voluntary Contraction ◽  
Cardiovascular Responses ◽  
Inspiratory Flow ◽  
Electromyographic Activity ◽  
Handgrip Exercise ◽  
Cardiovascular Variables

We studied the time course of respiratory and cardiovascular responses by evaluating changes in the breathing pattern, mean blood pressure (MBP), and heart rate elicited by 3 min of static handgrip at 15, 25, and 30% of the maximum voluntary contraction (MVC) in 15 healthy volunteers. Muscle tension and integrated electromyographic activity remained fairly constant during each trial. During 15% MVC bouts, initially only mean inspiratory flow increased; then, tidal volume and minute ventilation (VI) also rose progressively. No significant changes in MBP and heart rate were observed. During 25 and 30% MVC bouts, not only did mean inspiratory flow, VT, and VI increase but MBP and heart rate increased as well. A slight and delayed rise in respiratory rate was also observed. Unlike 15 and 25% MVC handgrip, 30% MVC handgrip caused a small decrease in end-tidal PCO2. Changes in the pattern of breathing occurred more promptly than those in cardiovascular variables in the majority of subjects. Furthermore, we found a positive correlation between changes in VI and those in cardiovascular variables at the end of 25 and 30% MVC trials. This study indicates that respiratory and cardiovascular responses to static handgrip exercise are controlled independently.

scholarly journals The effect of rolling massage on the excitability of the corticospinal pathway

2018 ◽  
Vol 43 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Saied J. Aboodarda ◽  
Rebecca M. Greene ◽  
Devin T. Philpott ◽  
Ramandeep S. Jaswal ◽  
Guillaume Y. Millet ◽  
...  
Keyword(s):  
Compound Muscle Action Potential ◽  
Vastus Lateralis ◽  
Femoral Nerve ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Knee Extensors ◽  
Electromyographic Activity ◽  
Muscle Action Potential ◽  
Central Excitability ◽  
Electrical Stimuli

The aim of the present study was to investigate the alterations of corticospinal excitability (motor evoked potential, MEP) and inhibition (silent period, SP) following rolling massage of the quadriceps muscles. Transcranial magnetic and femoral nerve electrical stimuli were used to elicit MEPs and compound muscle action potential (Mmax) in the vastus lateralis and vastus medialis muscles prior to and following either (i) 4 sets of 90-s rolling massage (ROLLING) or (ii) rest (CONTROL). One series of neuromuscular evaluations, performed after each set of ROLLING or CONTROL, included 3 MEPs and 1 Mmax elicited every 4 s during 15-s submaximal contractions at 10% (experiment 1, n = 16) and 50% (experiment 2, n = 10) of maximal voluntary knee extensions (MVC). The MEP/Mmax ratio and electromyographic activity recorded from vastus lateralis at 10% MVC demonstrated significantly lower values during ROLLING than CONTROL (P < 0.05). The ROLLING did not elicit any significant changes in muscle excitability (Mmax area) and duration of transcranial magnetic stimulation-induced SP recorded from any muscle or level of contraction (P > 0.05). The findings suggest that rolling massage can modulate the central excitability of the circuitries innervating the knee extensors; however, the observed effects are dependent on the background contraction intensity during which the neuromuscular measurements are recorded.

Comparison of Muscle Activity during Use of Computer Pointing Devices in Cad Operators

2000 ◽  
Vol 44 (37) ◽  
pp. 633-636 ◽  
Author(s):  
Pat Tittiranonda ◽  
Bernard Martin ◽  
Stephen Burastero
Keyword(s):  
Muscle Activity ◽  
Index Finger ◽  
Neck Muscles ◽  
Electromyographic Activity ◽  
Flexor Digitorum Superficialis ◽  
Upper Trapezius ◽  
Extensor Indicis Proprius ◽  
Significant Difference ◽  
Experimental Mouse ◽  
Flexor Digitorum

This study examined the use of four different computer pointing devices on surface electromyographic activity of the index finger, forearm and shoulder/neck muscles among CAD operators in the workplace. Subjects were randomly assigned to use their own mouse, a trackball, a joystick mouse or an experimental mouse. Results showed that there was a statistically significant difference in muscle load for the upper trapezius, extensor indicis proprius, and extensor carpi ulnaris across pointing devices for CAD operations. The flexor digitorum superficialis muscle load remained relatively constant when all pointing devices were compared.

Scrutinizing integrative effects in a multi-stimuli detection task

2012 ◽  
Vol 25 (0) ◽  
pp. 100 ◽  
Author(s):  
Mario Pannunzi ◽  
Alexis Pérez-Bellido ◽  
Alexandre Pereda Baños ◽  
Joan López-Moliner ◽  
Gustavo Deco ◽  
...  
Keyword(s):  
Signal Detection Theory ◽  
Compound Stimulus ◽  
Detection Task ◽  
Sensory Stimuli ◽  
Tactile Stimuli ◽  
Auditory Detection ◽  
Theoretical Hypothesis ◽  
Multisensory Enhancement ◽  
Tactile Detection ◽  
Level Of Processing

The level of processing at which different modalities interact to either facilitate or interfere with detection has been a matter of debate for more than half a century. This question has been mainly addressed by means of statistical models (Green, 1958), or by biologically plausible models (Schnupp et al., 2005). One of the most widely accepted statistical frameworks is the signal detection theory (SDT; Green and Swets, 1966) because it provides a straightforward way to assess whether two sensory stimuli are judged independently of one another, that is when the detectability (d′) of the compound stimulus exceeds the Pythagorean sum of the d′ of the components. Here, we question this logic, and propose a different baseline to evaluate integrative effects in multi-stimuli detection tasks based on the probabilistic summation. To this aim, we show how a simple theoretical hypothesis based on probabilistic summation can explain putative multisensory enhancement in an audio-tactile detection task. In addition, we illustrate how to measure integrative effects from multiple stimuli in two experiments, one using a multisensory audio-tactile detection task (Experiment 1) and another with a unimodal double-stimulus auditory detection task (Experiment 2). Results from Experiment 1 replicate extant multisensory detection data, and also refuse the hypothesis that auditory and tactile stimuli integrated into a single percept, leading to any enhancement. In Experiment 2, we further support the probabilistic summation model using a unimodal integration detection task.

The Temporal Course of Visual Pattern Encoding: Effects of Pattern Goodness

1983 ◽  
Vol 35 (4) ◽  
pp. 607-633 ◽  
Author(s):  
Edmund S. Howe ◽  
Cynthia J. Brandau
Keyword(s):  
Processing Time ◽  
Time Course ◽  
Short Term Memory ◽  
Experimental Situation ◽  
Stimulus Display ◽  
Backward Masking ◽  
Display Time ◽  
Pattern Goodness ◽  
Temporal Course ◽  
Encoding Effects

Subjects typically display superior reproduction of good (redundant, symmetrical) visual patterns compared with poor ones. This pattern goodness effect could conceivably involve encoding processes, short-term memory processes, or response processes. The present experiments explored the time course of wholistic encoding of Garner dot patterns as a function of tachistoscopic exposure time, delay of backward masking, and post-mask shadowing. Within the specific framework of additive factors theory, Experiment I showed: (a) equal rates of encoding for all patterns since comparable slopes were obtained for the recall X processing time functions; and (b) superior absolute recall for good patterns since different intercepts were obtained. Experiment II demonstrated that when degree of encoding was initially equalized for all patterns, the rate of extraction of further information remained constant over available processing time and was unaffected by pattern goodness, slopes and intercepts for good versus poor patterns then being equal. Experiment III confirmed that, given some fixed duration of available processing time, information is abstracted at the same rate for all pattern regardless of the ratio stimulus display time to delay of mask onset. Experiment IV indicated that maintenance rehearsal normally occurs in the present experimental situation, and that very good patterns are somewhat less disrupted by shadowing over a three-second interval. While STM is thus implicated in the pattern goodness effect it does not follow that STM constitutes a complete explanation of the intercept differences reported here. Empirical evidence of response bias toward production of good patterns, however, was not found. It was shown that very good patterns are highly familiar and nameable, and proposed that they do consequently have an early encoding advantage.

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