scholarly journals The influence of temporal predictability on express visuomotor responses

2020 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D. Corneil ◽  
Guy Wallis ◽  
Timothy J. Carroll
Keyword(s):  
Superior Colliculus ◽  
Onset Time ◽  
Surface Emg ◽  
Stimulus Onset ◽  
Target Motion ◽  
Target Velocity ◽  
Moving Target ◽  
Visuomotor Transformations ◽  
Shoulder Muscles ◽  
Temporal Predictability

ABSTRACTVolitional visuomotor responses in humans are generally thought to manifest 100ms or more after stimulus onset. Under appropriate conditions, however, much faster target-directed responses can be produced at upper limb and neck muscles. These “express” responses have been termed stimulus-locked responses (SLRs) and are proposed to be modulated by visuomotor transformations performed subcortically via the superior colliculus. Unfortunately, for those interested in studying SLRs, these responses have proven difficult to detect consistently across individuals. The recent report of an effective paradigm for generating SLRs in 100% of participants appears to change this. The task required the interception of a moving target that emerged from behind a barrier at a time consistent with the target velocity. Here we aimed to reproduce the efficacy of this paradigm for eliciting SLRs and to test the hypothesis that its effectiveness derives from the predictability of target onset time as opposed to target motion per se. In one experiment, we recorded surface EMG from shoulder muscles as participants made reaches to intercept temporally predictable or unpredictable targets. Consistent with our hypothesis, predictably timed targets produced more frequent and stronger SLRs than unpredictably timed targets. In a second experiment, we compared different temporally predictable stimuli and observed that transiently presented targets produced larger and earlier SLRs than sustained moving targets. Our results suggest that target motion is not critical for facilitating the expression of an SLR and that timing predictability does not rely on extrapolation of a physically plausible motion trajectory. These findings provide support for a mechanism whereby an internal timer, probably located in cerebral cortex, primes the processing of both visual input and motor output within the superior colliculus to produce SLRs.

scholarly journals The influence of temporal predictability on express visuomotor responses

2020 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D Corneil ◽  
Guy Wallis ◽  
Timothy John Carroll
Keyword(s):  
Superior Colliculus ◽  
Constant Velocity ◽  
Onset Time ◽  
Surface Emg ◽  
Stimulus Onset ◽  
Target Motion ◽  
Visuomotor Transformations ◽  
Shoulder Muscles ◽  
Temporal Predictability ◽  
Per Se

Humans are able to generate target-directed visuomotor responses in less than 100ms after stimulus onset. These "express" responses have been termed stimulus-locked responses (SLRs) and are proposed to be modulated by visuomotor transformations performed subcortically via the superior colliculus. Unfortunately, these responses have proven difficult to detect consistently across individuals. The recent report of an effective paradigm for generating SLRs in 100% of participants appears to change this. The task required the interception of a target moving at a constant velocity that emerged from behind a barrier. Here we aimed to reproduce the efficacy of this paradigm for eliciting SLRs and to test the hypothesis that its effectiveness derives from the predictability of target onset time as opposed to target motion per se. In one experiment, we recorded surface EMG from shoulder muscles as participants made reaches to intercept temporally predictable or unpredictable targets. Consistent with our hypothesis, predictably timed targets produced more frequent and stronger SLRs than unpredictably timed targets. In a second experiment, we compared different temporally predictable stimuli and observed that transiently presented targets produced larger and earlier SLRs than sustained moving targets. Our results suggest that target motion is not critical for facilitating the SLR expression and that timing predictability does not rely on extrapolation of a physically plausible motion trajectory. These findings provide support for a mechanism whereby an internal timer, probably located in cerebral cortex, primes the processing of both visual input and motor output within the superior colliculus to produce SLRs.

scholarly journals Trial-by-trial modulation of express visuomotor responses induced by symbolic or barely detectable cues

2021 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D Corneil ◽  
Guy Wallis ◽  
Timothy John Carroll
Keyword(s):  
Superior Colliculus ◽  
Target Location ◽  
Stimulus Presentation ◽  
Surface Emg ◽  
Top Down ◽  
Bottom Up ◽  
Low Contrast ◽  
Visuomotor Transformations ◽  
Shoulder Muscles ◽  
Symbolic Cues

Human cerebral cortex can produce visuomotor responses that are modulated by contextual and task-specific constraints. However, the distributed cortical network for visuomotor transformations limits the minimal response time of that pathway. Notably, humans can generate express visuomotor responses in arm muscles that are inflexibly tuned to the target location and occur 80-120ms from stimulus presentation (stimulus-locked responses, SLRs). This suggests a subcortical pathway for visuomotor transformations that might involve the superior colliculus and its downstream reticulo-spinal projections. Here we investigated whether cognitive expectations can modulate the SLR. In one experiment, we recorded surface EMG from shoulder muscles as participants reached toward a visual target whose location was unpredictable in control conditions, and partially predictable in cue conditions by interpreting a symbolic cue (75% validity). Valid symbolic cues led to earlier and larger SLRs than control conditions; invalid symbolic cues produced later and smaller SLRs than control conditions. This is consistent with a cortical top-down modulation of the putative subcortical SLR-network. In a second experiment, we presented high-contrast targets in isolation (control) or ~24ms after low-contrast stimuli, which could appear at the same (valid cue) or opposite (invalid cue) location as the target, and with equal probability (50% cue validity). We observed earlier SLRs than control with the valid low-contrast cues, whereas the invalid cues led to the opposite results. These findings may reflect bottom-up attentional mechanisms, potentially evolving subcortically via the superior colliculus. Overall, our results support both top-down and bottom-up modulations of the putative subcortical SLR network in humans.

scholarly journals Trial-by-trial modulation of express visuomotor responses induced by symbolic or barely detectable cues

2021 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D. Corneil ◽  
Guy Wallis ◽  
Timothy J. Carroll
Keyword(s):  
Superior Colliculus ◽  
Target Location ◽  
Stimulus Presentation ◽  
Surface Emg ◽  
Spatial Cues ◽  
Top Down ◽  
Low Contrast ◽  
Visuomotor Transformations ◽  
Spinal Pathway ◽  
Symbolic Cues

ABSTRACTHuman cerebral cortex can produce visuomotor responses that are modulated by contextual and task-specific constraints. However, the distributed cortical network for visuomotor transformations limits the minimal response time of that pathway. Notably, humans can generate express visuomotor responses that are inflexibly tuned to the target location and occur 80-120ms from stimulus presentation (stimulus-locked responses, SLRs). This suggests a subcortical pathway for visuomotor transformations involving the superior colliculus and its downstream reticulo-spinal projections. Here we investigated whether cognitive expectations can modulate the SLR. In one experiment, we recorded surface EMG from shoulder muscles as participants reached toward a visual target whose location was unpredictable in control conditions, and partially predictable in cue conditions by extrapolating a symbolic cue (75% validity). Valid symbolic cues led to faster and larger SLRs than control conditions; invalid symbolic cues produced slower and smaller SLRs than control conditions. This is consistent with a cortical top-down modulation of the putative subcortical SLR-network. In a second experiment, we presented high-contrast targets in isolation (control) or ~24ms after low-contrast stimuli, which could appear at the same (valid cue) or opposite (invalid cue) location as the target, and with equal probability (50% cue validity). We observed faster SLRs than control with the valid low-contrast cues, whereas the invalid cues led to the opposite results. These findings may reflect exogenous priming mechanisms of the SLR network, potentially evolving subcortically via the superior colliculus. Overall, our results support both top-down and bottom-up modulations of the putative subcortical SLR network in humans.NEW & NOTEWORTHYExpress visuomotor responses in humans appear to reflect subcortical sensorimotor transformation of visual inputs, potentially conveyed via the tecto-reticulo-spinal pathway. Here we show that the express responses are influenced both by symbolic and barely detectable spatial cues about stimulus location. The symbolic cue-induced effects suggest cortical top-down modulation of the putative subcortical visuomotor network. The effects of barely detectable cues may reflect exogenous priming mechanisms of the tecto-reticulo-spinal pathway.

scholarly journals Models for the Extrapolation of Target Motion for Manual Interception

2009 ◽  
Vol 102 (3) ◽  
pp. 1491-1502 ◽  
Author(s):  
John F. Soechting ◽  
John Z. Juveli ◽  
Hrishikesh M. Rao
Keyword(s):  
Target Location ◽  
Target Motion ◽  
Target Velocity ◽  
Finger Movement ◽  
Moving Target ◽  
Initial Direction ◽  
Target Speed ◽  
On Line ◽  
Finger Motion ◽  
Target Move

Intercepting a moving target requires a prediction of the target's future motion. This extrapolation could be achieved using sensed parameters of the target motion, e.g., its position and velocity. However, the accuracy of the prediction would be improved if subjects were also able to incorporate the statistical properties of the target's motion, accumulated as they watched the target move. The present experiments were designed to test for this possibility. Subjects intercepted a target moving on the screen of a computer monitor by sliding their extended finger along the monitor's surface. Along any of the six possible target paths, target speed could be governed by one of three possible rules: constant speed, a power law relation between speed and curvature, or the trajectory resulting from a sum of sinusoids. A go signal was given to initiate interception and was always presented when the target had the same speed, irrespective of the law of motion. The dependence of the initial direction of finger motion on the target's law of motion was examined. This direction did not depend on the speed profile of the target, contrary to the hypothesis. However, finger direction could be well predicted by assuming that target location was extrapolated using target velocity and that the amount of extrapolation depended on the distance from the finger to the target. Subsequent analysis showed that the same model of target motion was also used for on-line, visually mediated corrections of finger movement when the motion was initially misdirected.

scholarly journals The superior colliculus and the steering of saccades toward a moving visual target

2017 ◽  
Author(s):  
Laurent Goffart ◽  
Aaron Cecala ◽  
Neeraj Gandhi
Keyword(s):  
Superior Colliculus ◽  
Firing Rate ◽  
Target Location ◽  
Residual Activity ◽  
Target Motion ◽  
Moving Target ◽  
Average Firing Rate ◽  
Active Population ◽  
The Future ◽  
Movement Field

ABSTRACTFollowing the suggestion that a command encoding the expected here-and-now target location feeds the oculomotor system during interceptive saccades, we tested whether this command originates in the deep superior colliculus (SC). Monkeys generated saccades to targets that were static or moving along the preferred axis, away from (outward) or toward a fixated target (inward) with a constant speed (20°/s). Vertical and horizontal motions were also tested. Extracellular activity of 57 saccade-related neurons was recorded in 3 monkeys. The movement field (MF) parameters (boundaries, center and firing rate) were estimated after spline fitting the relation between the saccade amplitude and the average firing rate of the motor burst. During radial motion, the inner MF boundary shifted in the same direction as the target motion for some neurons, not all. During vertical motion, both lower and upper boundaries were shifted upward during upward motion whereas the upper boundary only shifted during downward motions. For horizontal motions, the medial boundaries were not changed. The MF center was shifted only for outward motion. Regardless of the motion direction, the average firing rate was consistently reduced during interceptive saccades. Our study shows an involvement of the saccade-related burst of SC neurons in steering the gaze toward a moving target. When observed, the shifts of MF boundary in the direction of target motion correspond to commands related to antecedent target locations. The absence of shift in the opposite direction shows that SC activity does not issue predictive commands related to the future target location.SIGNIFICANCE STATEMENTBy comparing the movement field (MF) of saccade-related neurons between saccades toward static and moving targets, we show that the motor burst issued by neurons in the superior colliculus does not convey commands related to the future location of a moving target. During interceptive saccades, the active population consists of a continuum of neurons, ranging from cells exhibiting a shift in the center or boundary of their MF to cells which exhibit no change. The shifts correspond to residual activity related to the fact that the active population does not change as fast as the target in the visual field. By contrast, the absence of shift indicates commands related to the current target location, as if it were static.

Stimulus onset-to-onset time determines the dichotic temporal order threshold

2001 ◽  
Author(s):  
Harvey Babkoff ◽  
Elisheva Ben-Artzi ◽  
Leah Fostick
Keyword(s):  
Temporal Order ◽  
Onset Time ◽  
Stimulus Onset

scholarly journals Antagonist Muscle Co-Activation during Kettlebell Single Arm Swing Exercise

2021 ◽  
Vol 11 (9) ◽  
pp. 4033
Author(s):  
Ahmed Salem ◽  
Amr Hassan ◽  
Markus Tilp ◽  
Abdel-Rahman Akl
Keyword(s):  
Muscle Activation ◽  
Surface Emg ◽  
Antagonist Muscle ◽  
Arm Swing ◽  
Shoulder Muscles ◽  
Antagonist Muscles ◽  
Co Activation ◽  
Integrated Emg ◽  
Post Hoc ◽  
Electrical Muscle

The purpose of this study was to determine the muscle activation and co-activation of selected muscles during the kettlebell single arm swing exercise. To the best of our knowledge, this is the first study investigating the muscle co-activation of a kettlebell single arm swing exercise. Nine volunteers participated in the present study (age: 22.6 ± 3.8 years; body mass: 80.4 ± 9.2 kg; height: 175.6 ± 7.5 cm). The electrical muscle activity of eight right agonist/antagonist muscles (AD/PD, ESL/RA, ESI/EO, and GM/RF) were recorded using a surface EMG system (Myon m320RX; Myon, Switzerland) and processed using the integrated EMG to calculate a co-activation index (CoI) for the ascending and descending phases. A significant effect of the ascending and descending phases on the muscles’ CoI was observed. Post hoc analyses showed that the co-activation was significantly higher in the descending phase compared to that in the ascending phase of AD/PD CoI (34.25 ± 18.03% and 24.75 ± 13.03%, p < 0.001), ESL/RA CoI (34.97 ± 17.86% and 24.19 ± 10.32%, p < 0.001), ESI/EO CoI (41.14 ± 10.72% and 30.87 ± 11.26%, p < 0.001), and GM/RF CoI (27.49 ± 12.97% and 34.98 ± 14.97%, p < 0.001). In conclusion, the co-activation of the shoulder muscles varies within the kettlebell single arm swing. The highest level of co-activation was observed in the descending phase of AD/PD and GM/RF CoI, and the lowest level of co-activation was observed during the descending phase, ESL/RA and ESI/EO CoI. In addition, the highest level of co-activation was observed in the ascending phase of ESL/RA and ESI/EO CoI, and the lowest level of co-activation was observed during the ascending phase, AD/PD and GM/RF CoI. The co-activation index could be a useful method for the interpretation of the shoulder and core muscles’ co-activity during a kettlebell single arm swing.

scholarly journals The vestibular-related frontal cortex and its role in smooth-pursuit eye movements and vestibular-pursuit interactions

2006 ◽  
Vol 16 (1-2) ◽  
pp. 1-22 ◽  
Author(s):  
Junko Fukushima ◽  
Teppei Akao ◽  
Sergei Kurkin ◽  
Chris R.S. Kaneko ◽  
Kikuro Fukushima
Keyword(s):  
Eye Movements ◽  
Frontal Cortex ◽  
Smooth Pursuit ◽  
Vestibular Stimulation ◽  
Target Motion ◽  
Head Movements ◽  
Image Motion ◽  
Target Velocity ◽  
Eye Velocity ◽  
Pursuit Neurons

In order to see clearly when a target is moving slowly, primates with high acuity foveae use smooth-pursuit and vergence eye movements. The former rotates both eyes in the same direction to track target motion in frontal planes, while the latter rotates left and right eyes in opposite directions to track target motion in depth. Together, these two systems pursue targets precisely and maintain their images on the foveae of both eyes. During head movements, both systems must interact with the vestibular system to minimize slip of the retinal images. The primate frontal cortex contains two pursuit-related areas; the caudal part of the frontal eye fields (FEF) and supplementary eye fields (SEF). Evoked potential studies have demonstrated vestibular projections to both areas and pursuit neurons in both areas respond to vestibular stimulation. The majority of FEF pursuit neurons code parameters of pursuit such as pursuit and vergence eye velocity, gaze velocity, and retinal image motion for target velocity in frontal and depth planes. Moreover, vestibular inputs contribute to the predictive pursuit responses of FEF neurons. In contrast, the majority of SEF pursuit neurons do not code pursuit metrics and many SEF neurons are reported to be active in more complex tasks. These results suggest that FEF- and SEF-pursuit neurons are involved in different aspects of vestibular-pursuit interactions and that eye velocity coding of SEF pursuit neurons is specialized for the task condition.

scholarly journals Time for Action: Neural Basis of the Costs and Benefits of Temporal Predictability for Competing Response Choices

2021 ◽  
pp. 1-17
Author(s):  
Inga Korolczuk ◽  
Boris Burle ◽  
Jennifer T. Coull ◽  
Kamila Śmigasiewicz
Keyword(s):  
Motor Cortex ◽  
Onset Time ◽  
Incorrect Response ◽  
Response Conflict ◽  
Cortical Inhibition ◽  
Costs And Benefits ◽  
Neural Basis ◽  
Response Hand ◽  
Temporal Predictability ◽  
Choice Complexity

Abstract The brain can anticipate the time of imminent events to optimize sensorimotor processing. Yet, there can be behavioral costs of temporal predictability under situations of response conflict. Here, we sought to identify the neural basis of these costs and benefits by examining motor control processes in a combined electroencephalography–EMG study. We recorded electrophysiological markers of response activation and inhibition over motor cortex when the onset-time of visual targets could be predicted, or not, and when responses necessitated conflict resolution, or not. If stimuli were temporally predictable but evoked conflicting responses, we observed increased intertrial consistency in the delta range over the motor cortex involved in response implementation, perhaps reflecting increased response difficulty. More importantly, temporal predictability differentially modulated motor cortex activity as a function of response conflict before the response was even initiated. This effect occurred in the hemisphere ipsilateral to the response, which is involved in inhibiting unwanted actions. If target features all triggered the same response, temporal predictability increased cortical inhibition of the incorrect response hand. Conversely, if different target features triggered two conflicting responses, temporal predictability decreased inhibition of the incorrect, yet prepotent, response. This dissociation reconciles the well-established behavioral benefits of temporal predictability for nonconflicting responses as well as its costs for conflicting ones by providing an elegant mechanism that operates selectively over the motor cortex involved in suppressing inappropriate actions just before response initiation. Taken together, our results demonstrate that temporal information differentially guides motor activity depending on response choice complexity.

Use of a Shoulder Rest for Playing the Violin Revisited: An Analysis of the Effect of Shoulder Rest Height on Muscle Activity, Violin Fixation Force, and Player Comfort

2019 ◽  
Vol 34 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Laura M Kok ◽  
Jim Schrijvers ◽  
Marta Fiocco ◽  
Barend van Royen ◽  
Jaap Harlaar
Keyword(s):  
Muscle Activity ◽  
Anterior Part ◽  
Activity Patterns ◽  
Deltoid Muscle ◽  
Surface Emg ◽  
Emg Activity ◽  
Linear Regression Models ◽  
Upper Trapezius ◽  
Shoulder Muscles ◽  
Rest Condition

AIMS: For violinists, the shoulder rest is an ergonomic adaptation to reduce musculoskeletal load. In this study, we aimed to evaluate how the height of the shoulder rest affects the violin fixation force and electromyographic (EMG) activity of the superficial neck and shoulder muscles. METHODS: In professional violinists, four different shoulder rest heights during five playing conditions were evaluated. Outcome variables included the jaw-shoulder violin fixation force and bilateral surface EMG of the upper trapezius (mTP), sternocleidomastoid (mSCM), and left anterior part of the left deltoid muscle (mDTA). Playing comfort was subjectively rated on a visual analogue scale (VAS). Linear regression models were estimated to investigate the influence of the shoulder rest height on muscle activity and violin fixation force as well as the muscle activity of the five evaluated muscles on violin fixation force. RESULTS: 20 professional violinists (4 males, 16 females, mean age 29.4 yrs) participated in this study. The shoulder rest condition had a significant effect on playing comfort (p<0.001), with higher shoulder rest conditions associated with decreased subjective playing comfort. The mean violin fixation force for each shoulder rest condition ranged between 2.92 and 3.39 N; higher shoulder rests were related to a higher violin fixation force (p<0.001). CONCLUSION: In this study, violin fixation force and muscle activity of the left mDTA increased while playing with an increasing height of the shoulder rest. As the shoulder rest influences muscle activity patterns and violin fixation force, adjustment of the shoulder rest and positioning of the violin need to be carefully optimized.

Sign in / Sign up

Export Citation Format

Share Document