scholarly journals The influence of kinesthetic motor imagery and effector specificity on the long-latency stretch response

2019 ◽  
Author(s):  
Christopher J. Forgaard ◽  
Ian M. Franks ◽  
Dana Maslovat ◽  
Romeo Chua
Keyword(s):  
Motor Imagery ◽  
Voluntary Control ◽  
Flexor Muscle ◽  
Important Distinction ◽  
Voluntary Response ◽  
Long Latency ◽  
Early Portion ◽  
Extensive Body ◽  
The Relationship ◽  
Stretch Response

AbstractThe long-latency “reflexive” response (LLR) following an upper-limb mechanical disturbance is generated by neural circuitry shared with voluntary control. This feedback response supports many task-dependent behaviours and permits the expression of goal-directed corrections at latencies shorter than voluntary reaction time. An extensive body of literature has demonstrated that the LLR shows flexibility akin to voluntary control, but it has never been tested whether instruction-dependent LLR changes can also occur in the absence of an overt voluntary response. The present study used kinesthetic motor imagery (Experiment 1) and instructed participants to execute a voluntary response in a non-stretched contralateral muscle (Experiment 2) to explore the relationship between the overt production of a voluntary response and LLR facilitation. Activity in stretched right wrist flexors were compared to standard “not-intervene” and “compensate” conditions. Our findings revealed that on ~40% of imagery and ~50% of contralateral trials, a partial voluntary response “leaked-out” into the stretched right wrist flexor muscle. On these “leaked” trials, the early portion of the LLR (R2) was facilitated and displayed a similar increase to compensate trials. The latter half of the LLR (R3) showed further modulation, mirroring the patterns of voluntary response activity. By contrast, the LLR on “non-leaked” imagery and contralateral trials did not modulate. We suggest that even though a hastened voluntary response cannot account for all instruction-dependent LLR modulation, the overt execution of a voluntary response in the same muscle(s) as the LLR is a pre-requisite for facilitation of this rapid feedback response.New and NoteworthyWe examined volitional modulation of the long-latency stretch response (LLR) using two novel approaches: motor imagery and the execution of contralateral movements. The LLR was only facilitated on imagery or contralateral trials when a voluntary response “leaked-out” into stretched muscle suggesting that a voluntary response in the same muscle as the LLR is a prerequisite for facilitation. Our findings also demonstrate an important distinction between the early (R2) and late (R3) portions of the LLR.

scholarly journals Influence of kinesthetic motor imagery and effector specificity on the long-latency stretch response

2019 ◽  
Vol 122 (5) ◽  
pp. 2187-2200 ◽  
Author(s):  
Christopher J. Forgaard ◽  
Ian M. Franks ◽  
Dana Maslovat ◽  
Romeo Chua
Keyword(s):  
Motor Imagery ◽  
Voluntary Control ◽  
Overt Response ◽  
Voluntary Response ◽  
Long Latency ◽  
Early Portion ◽  
Extensive Body ◽  
Long Latency Reflex ◽  
The Relationship ◽  
Wrist Flexors

The long-latency “reflexive” response (LLR) following an upper limb mechanical perturbation is generated by neural circuitry shared with voluntary control. This feedback response supports many task-dependent behaviors and permits the expression of goal-directed corrections at latencies shorter than voluntary reaction time. An extensive body of literature has demonstrated that the LLR shows flexibility akin to voluntary control, but it has not yet been tested whether instruction-dependent LLR changes can also occur in the absence of an overt voluntary response. The present study used kinesthetic motor imagery ( experiment 1) and instructed participants to execute movement with the unperturbed contralateral limb ( experiment 2) to explore the relationship between the overt production of a voluntary response and LLR facilitation. Activity in stretched right wrist flexors were compared with standard “do not-intervene” and “compensate” conditions. Our findings revealed that on ~40% of imagery and ~50% of contralateral trials, a response occurred during the voluntary epoch in the stretched right wrist flexors. On these “leaked” trials, the early portion of the LLR (R2) was facilitated and displayed a similar increase to compensate trials. The latter half of the LLR (R3) showed further modulation, mirroring the patterns of voluntary epoch activity. By contrast, the LLR on “non-leaked” imagery and contralateral trials did not modulate. We suggest that even though a hastened voluntary response cannot account for all instruction-dependent LLR modulation, the overt execution of a response during the voluntary epoch in the same muscle(s) as the LLR is a prerequisite for instruction-dependent facilitation of this feedback response. NEW & NOTEWORTHY Using motor imagery and contralateral responses, we provide novel evidence that facilitation of the long-latency reflex (LLR) requires the execution of a response during the voluntary epoch. A high proportion of overt response “leaks” were found where the mentally simulated or mirrored response appeared in stretched muscle. The first half of the LLR was categorically sensitive to the appearance of leaks, whereas the latter half displayed characteristics closely resembling activity in the ensuing voluntary period.

scholarly journals Eliciting and Recording Event Related Potentials (ERPs) in Behaviourally Unresponsive Populations: A Retrospective Commentary on Critical Factors

2021 ◽  
Vol 11 (7) ◽  
pp. 835
Author(s):  
Alexander Rokos ◽  
Richard Mah ◽  
Rober Boshra ◽  
Amabilis Harrison ◽  
Tsee Leng Choy ◽  
...  
Keyword(s):  
Event Related Potentials ◽  
Stimulus Presentation ◽  
Event Related Potential ◽  
Critical Factors ◽  
Healthy Elderly ◽  
States Of Consciousness ◽  
Long Latency ◽  
Eeg Data ◽  
Related Potentials ◽  
The Relationship

A consistent limitation when designing event-related potential paradigms and interpreting results is a lack of consideration of the multivariate factors that affect their elicitation and detection in behaviorally unresponsive individuals. This paper provides a retrospective commentary on three factors that influence the presence and morphology of long-latency event-related potentials—the P3b and N400. We analyze event-related potentials derived from electroencephalographic (EEG) data collected from small groups of healthy youth and healthy elderly to illustrate the effect of paradigm strength and subject age; we analyze ERPs collected from an individual with severe traumatic brain injury to illustrate the effect of stimulus presentation speed. Based on these critical factors, we support that: (1) the strongest paradigms should be used to elicit event-related potentials in unresponsive populations; (2) interpretation of event-related potential results should account for participant age; and (3) speed of stimulus presentation should be slower in unresponsive individuals. The application of these practices when eliciting and recording event-related potentials in unresponsive individuals will help to minimize result interpretation ambiguity, increase confidence in conclusions, and advance the understanding of the relationship between long-latency event-related potentials and states of consciousness.

scholarly journals The interaction between two trains of impulses converging on the same motoneurone

1929 ◽  
Vol 105 (738) ◽  
pp. 363-371 ◽  
Keyword(s):  
Mechanical Effect ◽  
The Other ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Afferent Pathways ◽  
Afferent Nerves ◽  
Maximal Stimulation ◽  
The Common ◽  
The Relationship ◽  
Stimulation Of

It was shown in an earlier paper (7) that if maximal stimulation of either of two different afferent nerves can reflexly excite fractions of a given flexor muscle, there are generally, within the aggregate of neurones which innervate that muscle, motoneurones which can be caused to discharge by either afferent (i. e., motoneurones common to both fractions). The relationship which two such afferents bear to a common motoneurone was shown, by the isometric method of recording contraction, to be such that the activation of one afferent, at a speed sufficient to cause a maximal motor tetanus when trans­mitted to the muscle fibres, caused exclusion of any added mechanical effect when the other afferent was excited concurrently. This default in mechanical effect was called “occlusion.” Occlusion may conceivably be due to total exclusion of the effect of one afferent pathway on the common motoneurone by the activity of the other; but facilitation of the effect of one path by the activation of the other when the stimuli were minimal suggests that, in some circumstances at least, the effect of each could augment and summate with th at of the other at the place of convergence of two afferent pathways. Further investigation, using the action currents of the muscle as indication of the nerve impulses discharged by the motoneurone units, has now given some information regarding the effect of impulses arriving at the locus of convergence by one afferent path when the unit common to both is already discharging in response to impulses arriving by the other afferent path. Our method has been to excite both afferent nerves in overlapping sequence by series of break shocks at a rapid rate and to examine the action currents of the resulting reflex for evidence of the appearance of the rhythm of the second series in the discharge caused by the first when the two series are both reaching the motoneurone.

Exploring mentoring across gender, race, and generation in higher education

2019 ◽  
Vol 8 (1) ◽  
pp. 2-18 ◽  
Author(s):  
Sydney Freeman Jr ◽  
Frances Kochan
Keyword(s):  
Higher Education ◽  
Mentoring Relationships ◽  
White Female ◽  
Content Type ◽  
Mentoring Relationship ◽  
The Usa ◽  
Extensive Body ◽  
The Relationship ◽  
Practical Implications

Purpose The purpose of this paper is to examine a long-term mentoring relationship between a White female from the Traditional Generation and an African American male from the Xennial Generation, as engaged in a mentoring relationship within higher education institutions in the USA. The study investigated if, how and to what degree the differences and similarities between them influenced their mentoring relationship. Design/methodology/approach The authors used an autoethnographic approach involving extensive questioning, dialoguing, note keeping and analysis over eight months. Findings The analysis suggested that race had the greatest influence on the relationship. The primary reasons for mentoring success were similarities in family backgrounds and commonly held values. Research limitations/implications This study may not be generalizable to mentoring relationships that do not involve cultural differences in race, age or gender. Practical implications The paper offers a model for the types of strategies individuals can use in cross-racial mentoring endeavors to help build and sustain these relationships. It also includes suggestions for individuals engaged in mentoring relationships, which include gender, race or age differences, and organizations seeking to enhance diversity within their institutions. Originality/value There is not an extensive body of research on individual cross-racial, gender and generational mentoring that provides an analysis of the experience of those involved. Additionally, the model presented for examining cross-racial mentoring relationships is unique.

scholarly journals Time course of changes in the long-latency feedback response parallels the fast process of short-term motor adaptation

2020 ◽  
Vol 124 (2) ◽  
pp. 388-399 ◽  
Author(s):  
Susan K. Coltman ◽  
Paul L. Gribble
Keyword(s):  
Time Course ◽  
Motor Adaptation ◽  
Feedback Controller ◽  
Fast Process ◽  
Short Term ◽  
Early Stages ◽  
Long Latency ◽  
Stages Of Learning ◽  
Stretch Response

We investigated whether changes in the feedback stretch response were related to the proposed fast and slow processes of motor adaptation. We found that the long-latency component of the feedback stretch response was upregulated in the early stages of learning and the time course was correlated with the fast process. While some propose that the fast process reflects an explicit strategy, we argue instead that it may be a proxy for the feedback controller.

scholarly journals Coordinating long-latency stretch responses across the shoulder, elbow, and wrist during goal-directed reaching

2016 ◽  
Vol 116 (5) ◽  
pp. 2236-2249 ◽  
Author(s):  
Jeffrey Weiler ◽  
James Saravanamuttu ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Simple Form ◽  
Muscle Activity ◽  
Kinematic Redundancy ◽  
Mechanical Perturbation ◽  
Intersegmental Dynamics ◽  
Long Latency ◽  
Voluntary Behavior ◽  
Visual Targets ◽  
Perturbation Magnitude ◽  
Stretch Response

The long-latency stretch response (muscle activity 50–100 ms after a mechanical perturbation) can be coordinated across multiple joints to support goal-directed actions. Here we assessed the flexibility of such coordination and whether it serves to counteract intersegmental dynamics and exploit kinematic redundancy. In three experiments, participants made planar reaches to visual targets after elbow perturbations and we assessed the coordination of long-latency stretch responses across shoulder, elbow, and wrist muscles. Importantly, targets were placed such that elbow and wrist (but not shoulder) rotations could help transport the hand to the target—a simple form of kinematic redundancy. In experiment 1 we applied perturbations of different magnitudes to the elbow and found that long-latency stretch responses in shoulder, elbow, and wrist muscles scaled with perturbation magnitude. In experiment 2 we examined the trial-by-trial relationship between long-latency stretch responses at adjacent joints and found that the magnitudes of the responses in shoulder and elbow muscles, as well as elbow and wrist muscles, were positively correlated. In experiment 3 we explicitly instructed participants how to use their wrist to move their hand to the target after the perturbation. We found that long-latency stretch responses in wrist muscles were not sensitive to our instructions, despite the fact that participants incorporated these instructions into their voluntary behavior. Taken together, our results indicate that, during reaching, the coordination of long-latency stretch responses across multiple joints counteracts intersegmental dynamics but may not be able to exploit kinematic redundancy.

scholarly journals Modulation of long-latency afferent inhibition by the amplitude of sensory afferent volley

2017 ◽  
Vol 118 (1) ◽  
pp. 610-618 ◽  
Author(s):  
Claudia V. Turco ◽  
Jenin El-Sayes ◽  
Hunter J. Fassett ◽  
Robert Chen ◽  
Aimee J. Nelson
Keyword(s):  
Nerve Stimulation ◽  
Sensory Nerve ◽  
Sensory Afferents ◽  
Afferent Inhibition ◽  
Afferent Fibers ◽  
Long Latency ◽  
Afferent Volley ◽  
Sensory Nerve Action ◽  
Sensory Fibers ◽  
The Relationship

Long-latency afferent inhibition (LAI) is the inhibition of the transcranial magnetic stimulation (TMS) motor-evoked potentials (MEP) by the sensory afferent volley following electrical stimulation of a peripheral nerve. It is unknown how the activation of sensory afferent fibers relates to the magnitude of LAI. This study investigated the relationship between LAI and the sensory nerve action potentials (SNAP) from the median nerve (MN) and the digital nerves (DN) of the second digit. LAI was obtained by delivering nerve stimulation 200 ms before a TMS pulse delivered over the motor cortex. Experiment 1 assessed the magnitude of LAI following stimulation of the contralateral MN or DN using nerve stimulus intensities relative to the maximum SNAP (SNAPmax) of that nerve and two TMS intensities (0.5- and 1-mV MEP). Results indicate that MN LAI is maximal at ~50% SNAPmax, when presumably all sensory afferents are recruited for TMS of 0.5-mV MEP. For DN, LAI appears at ~50% SNAPmax and does not increase with further recruitment of sensory afferents. Experiment 2 investigated the magnitude of LAI following ipsilateral nerve stimulation at intensities relative to SNAPmax. Results show minimal LAI evoked by ipsilateral MN and no LAI following ipsilateral DN stimulation. Implications for future studies investigating LAI include adjusting nerve stimulation to 50% SNAPmax to obtain maximal LAI. Additionally, MN LAI can be used as a marker for neurological disease or injury by using a nerve stimulation intensity that can evoke a depth of LAI capable of increasing or decreasing. NEW & NOTEWORTHY This is the first investigation of the relationship between long-latency afferent inhibition (LAI) and the sensory afferent volley. Differences exist between median and digital nerve LAI. For the median nerve, LAI increases until all sensory fibers are presumably recruited. In contrast, digital nerve LAI does not increase with the recruitment of additional sensory fibers but rather is present when a given volume of sensory afferent fibers is recruited (~50% of maximum sensory nerve action potential). This novel data provide practical guidelines and contribute to our understanding of the mechanisms underlying LAI.

scholarly journals The Relationship between Motor Imagery Ability and Change of Performance

2016 ◽  
Vol 31 (2) ◽  
pp. 221-225
Author(s):  
Kazuya UMENO ◽  
Kouichi NAKAMURA
Keyword(s):  
Motor Imagery ◽  
Imagery Ability ◽  
The Relationship
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