scholarly journals Time-dependent modulation of spinal excitability during action observation in the macaque monkey

2019 ◽  
Author(s):  
S.J. Jerjian ◽  
R.N. Lemon ◽  
A. Kraskov
Keyword(s):  
Pyramidal Tract ◽  
Rhesus Macaques ◽  
Action Observation ◽  
Macaque Monkey ◽  
Reach To Grasp ◽  
Hand Muscles ◽  
Spinal Circuitry ◽  
Hand Muscle ◽  
Spinal Excitability ◽  
Muscle Responses

ABSTRACTNeurons in the primate motor cortex, including identified pyramidal tract neurons projecting to the spinal cord, respond to the observation of others’ actions, yet this does not cause movement in the observer. Here, we investigated changes in spinal excitability during action observation by monitoring short latency electromyographic responses produced by single shocks delivered directly to the pyramidal tract. Responses in hand and digit muscles were recorded from two adult rhesus macaques while they performed, observed or withheld reach-to-grasp and hold actions. We found modest grasp-specific facilitation of hand muscle responses during hand shaping for grasp, which persisted when the grasp was predictable but obscured from the monkey’s vision. We also found evidence of a more general inhibition before observed movement onset, and the size of this inhibition effect was comparable to the inhibition after an explicit NoGo signal. These results confirm that the spinal circuitry controlling hand muscles is modulated during action observation, and this may be driven by internal representations of actions. The relatively modest changes in spinal excitability during observation suggest net corticospinal outflow exerts only minor, sub-threshold changes on hand motoneuron pools, thereby preventing any overflow of mirror activity into overt movement.

Properties of Primary Motor Cortex Output to Forelimb Muscles in Rhesus Macaques

2004 ◽  
Vol 92 (5) ◽  
pp. 2968-2984 ◽  
Author(s):  
Michael C. Park ◽  
Abderraouf Belhaj-Saïf ◽  
Paul D. Cheney
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Rhesus Macaques ◽  
Red Nucleus ◽  
Macaque Monkey ◽  
Emg Activity ◽  
Reach To Grasp ◽  
Distal Muscle ◽  
Forelimb Muscles ◽  
Multijoint Movements

Stimulus-triggered averaging (StTA) of electromyographic (EMG) activity from 24 simultaneously recorded forelimb muscles was used to investigate properties of primary motor cortex (M1) output in the macaque monkey. Two monkeys were trained to perform a reach-to-grasp task requiring multijoint coordination of the forelimb. EMG activity was recorded from 24 forelimb muscles including 5 shoulder, 7 elbow, 5 wrist, 5 digit, and 2 intrinsic hand muscles. Microstimulation (15 μA at 15 Hz) was delivered throughout the movement task. From 297 stimulation sites in M1, a total of 2,079 poststimulus effects (PStE) were obtained including 1,398 poststimulus facilitation (PStF) effects and 681 poststimulus suppression (PStS) effects. Of the PStF effects, 60% were in distal and 40% in proximal muscles; 43% were of extensors and 47% flexors. For PStS, the corresponding numbers were 55 and 45% and 36 and 55%, respectively. M1 output effects showed extensive cofacilitation of proximal and distal muscles (96 sites, 42%) including 47 sites that facilitated at least one shoulder, elbow, and distal muscle, 45 sites that facilitated an elbow muscle and a distal muscle, and 22 sites that facilitated at least one muscle at all joints. The muscle synergies represented by outputs from these sites may serve an important role in the production of coordinated, multijoint movements. M1 output effects showed many similarities with red nucleus output although red nucleus effects were generally weaker and showed a strong bias toward facilitation of extensor muscles and a greater tendency to facilitate synergies involving muscles at noncontiguous joints.

Transient inhibition of primary motor cortex suppresses hand muscle responses during a reactive reach to grasp

2011 ◽  
Vol 504 (2) ◽  
pp. 83-87 ◽  
Author(s):  
David A.E. Bolton ◽  
Rupesh Patel ◽  
W. Richard Staines ◽  
William E. McIlroy
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Reach To Grasp ◽  
Hand Muscle ◽  
Muscle Responses

scholarly journals Movement initiation and grasp representation in premotor and primary motor cortex mirror neurons

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Steven Jack Jerjian ◽  
Maneesh Sahani ◽  
Alexander Kraskov
Keyword(s):  
Mirror Neurons ◽  
Primary Motor Cortex ◽  
Action Observation ◽  
Premotor Cortex ◽  
Movement Control ◽  
Population Level ◽  
Reach To Grasp ◽  
Movement Initiation ◽  
Population Activity ◽  
Spinal Circuitry

Pyramidal tract neurons (PTNs) within macaque rostral ventral premotor cortex (F5) and (M1) provide direct input to spinal circuitry and are critical for skilled movement control. Contrary to initial hypotheses, they can also be active during action observation, in the absence of any movement. A population-level understanding of this phenomenon is currently lacking. We recorded from single neurons, including identified PTNs, in (M1) (n = 187), and F5 (n = 115) as two adult male macaques executed, observed, or withheld (NoGo) reach-to-grasp actions. F5 maintained a similar representation of grasping actions during both execution and observation. In contrast, although many individual M1 neurons were active during observation, M1 population activity was distinct from execution, and more closely aligned to NoGo activity, suggesting this activity contributes to withholding of self-movement. M1 and its outputs may dissociate initiation of movement from representation of grasp in order to flexibly guide behaviour.

Direct and Indirect Corticospinal Control of Arm and Hand Motoneurons in the Squirrel Monkey (Saimiri sciureus)

1997 ◽  
Vol 78 (2) ◽  
pp. 721-733 ◽  
Author(s):  
M. A. Maier ◽  
E. Olivier ◽  
S. N. Baker ◽  
P. A. Kirkwood ◽  
T. Morris ◽  
...  
Keyword(s):  
Squirrel Monkey ◽  
Macaque Monkey ◽  
Saimiri Sciureus ◽  
Excitatory Postsynaptic Potential ◽  
Onset Latency ◽  
Implanted Electrodes ◽  
Postsynaptic Potential ◽  
Common Response ◽  
Hand Muscle ◽  
Comparable Sample

Maier, M. A., E. Olivier, S. N. Baker, P. A. Kirkwood, T. Morris, and R. N. Lemon. Direct and indirect corticospinal control of arm and hand motoneurons in the squirrel monkey ( Saimiri sciureus). J. Neurophysiol. 78: 721–733, 1997. Anatomic evidence suggests that direct corticomotoneuronal (CM) projections to hand motoneurons in the New World squirrel monkey ( Saimiri sciureus) are weak or absent, but electrophysiological evidence is lacking. The nature of the corticospinal linkage to these motoneurons was therefore investigated first with the use of transcranial magnetic stimulation (TMS) of the motor cortex under ketamine sedation in five monkeys. TMS produced early responses in hand muscle electromyogram, but thresholds were high (compared with macaque monkey) and the onset latency was variable. Second, stimulation of the pyramidal tract (PT) was carried out with the use of chronically implanted electrodes in ketamine-sedated monkeys; this produced more robust responses that were markedly facilitated by repetitive stimulation, with little decrease in latency on the third compared with the first shock. Finally, postsynaptic potentials were recorded intracellularly from 93 arm and hand motoneurons in five monkeys under general chloralose anesthesia. After a single PT stimulus, the most common response was a small, slowly rising excitatory postsynaptic potential (EPSP), either alone (35 of 93 motoneurons) or followed by an inhibitory postsynaptic potential (39 of 93). The segmental delay of the early EPSPs was within the monosynaptic range (mean 0.85 ms); however, the rise time of these EPSPs was slow (mean 1.3 ms) and their amplitude was small (mean 0.74 mV). These values are significantly slower and smaller than EPSPs in a comparable sample of Old World macaque monkey motoneurons. The results show that CM connections do exist in the squirrel monkey but that they are weak and possibly located on the remote dendrites of the motoneurons. The findings are consistent with earlier anatomic studies. Repetitive PT stimulation produced large, late EPSPs in some motoneurons, suggesting that, in this species, there are relatively strong nonmonosynaptic pathways linking the corticospinal tract to hand motoneurons.

Selectivity and excitability of upper-limb muscle activation during cervical transcutaneous spinal cord stimulation in humans

2021 ◽  
Author(s):  
Roberto M. de Freitas ◽  
Atsushi Sasaki ◽  
Dimitry G. Sayenko ◽  
Yohei Masugi ◽  
Taishin Nomura ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Upper Limb ◽  
Spinal Cord Stimulation ◽  
Muscle Activation ◽  
Anterior Neck ◽  
Hand Muscles ◽  
Ia Afferents ◽  
Arm Muscles ◽  
Muscle Responses ◽  
Transcutaneous Spinal Cord Stimulation

Cervical transcutaneous spinal cord stimulation (tSCS) efficacy for rehabilitation of upper-limb motor function was suggested to depend on recruitment of Ia afferents. However, selectivity and excitability of motor activation with different electrode configurations remains unclear. In this study, activation of upper-limb motor pools was examined with different cathode and anode configurations during cervical tSCS in 10 able-bodied individuals. Muscle responses were measured from six upper-limb muscles simultaneously. First, post-activation depression was confirmed with tSCS paired pulses (50 ms interval) for each cathode configuration (C6, C7, and T1 vertebral levels), with anode on the anterior neck. Selectivity and excitability of activation of the upper-limb motor pools were examined by comparing the recruitment curves (10-100 mA) of first evoked responses across muscles and cathode configurations. Our results showed that hand muscles were preferentially activated when the cathode was placed over T1 compared to the other vertebral levels, while there was no selectivity for proximal arm muscles. Furthermore, higher stimulation intensities were required to activate distal hand muscles than proximal arm muscles, suggesting different excitability thresholds between muscles. In a separate protocol, responses were compared between anode configurations (anterior neck, shoulders, iliac crests, and back), with one selected cathode configuration. The level of discomfort was also assessed. Largest muscle responses were elicited with the anode configuration over the anterior neck, while there were no differences in the discomfort. Our results therefore inform methodological considerations for electrode configuration to help optimize recruitment of Ia afferents during cervical tSCS.

Role of Primate Magnocellular Red Nucleus Neurons in Controlling Hand Preshaping During Reaching to Grasp

2001 ◽  
Vol 85 (4) ◽  
pp. 1461-1478 ◽  
Author(s):  
Peter L. E. Van Kan ◽  
Martha L. McCurdy
Keyword(s):  
Task Performance ◽  
Motor Behavior ◽  
Red Nucleus ◽  
Reaching Movements ◽  
Emg Activity ◽  
Reach To Grasp ◽  
Spinal Circuitry ◽  
A Minor ◽  
Hand Preshaping

Reaching to grasp is of fundamental importance to primate motor behavior and requires coordinating hand preshaping with limb transport and grasping. We aimed to clarify the role of cerebellar output via the magnocellular red nucleus (RNm) to the control of reaching to grasp. Rubrospinal fibers originating from RNm constitute one pathway by which cerebellar output influences spinal circuitry directly. We recorded discharge from individual forelimb RNm neurons while monkeys performed a reach-to-grasp task and two tasks that were similar to the reach-to-grasp task in trajectory, amplitude, and direction but did not include a grasp. One of these, the device task, elicited reaches while holding a handle, and the other, the free-reach task, elicited reaches that did not require any specific hand use for task performance. The results demonstrate that coordinated whole-limb reaching movements are associated with large discharge modulations of RNm neurons predominantly when hand use is included. Therefore RNm neurons can at best only make a minor contribution to the control of reaching movements that lack hand use. We evaluated relations between the discharge of individual RNm neurons and electromyographic (EMG) activity of forelimb muscles during the reach-to-grasp task by comparing times of peak RNm discharge to times of peak EMG activity. The results are consistent with the view that RNm discharge may contribute to EMG activity of both distal and proximal muscles during reaching to grasp especially digit extensor and limb elevation muscles. Relations between the discharge of individual RNm neurons and movements of the metacarpi-phalangeal (MCP), wrist, elbow, and shoulder joints during individual trials of task performance were quantified by parametric correlation analyses on a subset of neurons studied during the reach-to-grasp and free-reach tasks. The results indicate that MCP extensions were consistently preceded by bursts of RNm discharge, and strong correlations were observed between parameters of discharge and the duration, velocity, and amplitude of corresponding MCP extensions. In contrast, relations between discharge and movements of proximal joints were poorly represented, and RNm discharge was not related to the speed of limb transport. Based on our data and those of others, we hypothesize that cerebellar output via RNm is specialized for controlling hand use and conclude that RNm may contribute to the control of hand preshaping during reaching to grasp by activating muscle synergies that produce the appropriate MCP extension at the appropriate phase of limb transport.

scholarly journals Re-emergence of hand-muscle representations in human motor cortex after hand allograft

2009 ◽  
Vol 106 (17) ◽  
pp. 7197-7202 ◽  
Author(s):  
Claudia D. Vargas ◽  
Antoine Aballéa ◽  
Érika C. Rodrigues ◽  
Karen T. Reilly ◽  
Catherine Mercier ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Upper Limb ◽  
Magnetic Stimulation ◽  
Cortical Representation ◽  
Human Motor Cortex ◽  
Hand Muscles ◽  
Right Hand ◽  
Hand Muscle ◽  
The Right

The human primary motor cortex (M1) undergoes considerable reorganization in response to traumatic upper limb amputation. The representations of the preserved arm muscles expand, invading portions of M1 previously dedicated to the hand, suggesting that former hand neurons are reassigned to the control of remaining proximal upper limb muscles. Hand allograft offers a unique opportunity to study the reversibility of such long-term cortical changes. We used transcranial magnetic stimulation in patient LB, who underwent bilateral hand transplantation 3 years after a traumatic amputation, to longitudinally track both the emergence of intrinsic (from the donor) hand muscles in M1 as well as changes in the representation of stump (upper arm and forearm) muscles. The same muscles were also mapped in patient CD, the first bilateral hand allograft recipient. Newly transplanted intrinsic muscles acquired a cortical representation in LB's M1 at 10 months postgraft for the left hand and at 26 months for the right hand. The appearance of a cortical representation of transplanted hand muscles in M1 coincided with the shrinkage of stump muscle representations for the left but not for the right side. In patient CD, transcranial magnetic stimulation performed at 51 months postgraft revealed a complete set of intrinsic hand-muscle representations for the left but not the right hand. Our findings show that newly transplanted muscles can be recognized and integrated into the patient's motor cortex.

CHARACTERIZATION OF FINGER ISOMETRIC FORCE PRODUCTION WITH MAXIMUM POWER OF SURFACE ELECTROMYOGRAPHY

2009 ◽  
Vol 21 (03) ◽  
pp. 193-199 ◽  
Author(s):  
Wensheng Hou ◽  
Xiaoying Wu ◽  
Jun Zheng ◽  
Li Ma ◽  
Xiaolin Zheng ◽  
...  
Keyword(s):  
Surface Electromyography ◽  
Force Production ◽  
Neuromuscular Control ◽  
Maximum Power ◽  
Ar Model ◽  
Force Level ◽  
Hand Muscles ◽  
Significant Difference ◽  
Target Force ◽  
Hand Muscle

Finger's action has been controlled by both intrinsic and extrinsic hand muscles. Characterizing the finger action with the activations of hand muscles could be useful for evaluating the neuromuscular control strategy of finger's motor functions. This study is designed to explore the correlation of isometric fingertip force production and frequency-domain features of surface electromyography (sEMG) recorded on extrinsic hand muscles. To this end, 13 subjects (five male and eight female university students) have been recruited to conduct a target force-tracking task. Each subject is required to produce a certain level of force with either the index or middle fingertip to match the pseudo-random ordered target force level (4N, 6N, or 8N) as accurate as possible. During the finger force production process, the sEMG signals are recorded on two extrinsic hand muscles: flex digitorum superficials (FDS) and extensor digitorum (ED). For each sEMG trail, the power spectrum is estimated with the autoregressive (AR) model and from which the maximum power is obtained. Our experimental results reveal three findings: (1) the maximum power increases with the force level regardless of the force producing finger (i.e. index or middle) and the extrinsic hand muscle (i.e. FDS or ED). (2) The sEMG maximum power of index finger is significantly lower than that of the middle finger under the same force level and extrinsic hand muscle. (3) No significant difference can be found between the maximum powers of FDS and ED. The results indicate that the activations of the extrinsic muscles are affected by both the force level and the force producing finger. Based on our findings, the sEMG maximum power of the extrinsic hand muscles could be used as a key parameter to describe the finger's actions.

scholarly journals The Effects of Motor Cortical Stimulation on the Excitability of Spinal Motoneurons in Man

1975 ◽  
Vol 2 (3) ◽  
pp. 245-253 ◽  
Author(s):  
S.H. Milner-Brown ◽  
J.P. Girvin ◽  
W.F. Brown
Keyword(s):  
Stretch Reflex ◽  
Direct Evidence ◽  
Pyramidal Tract ◽  
Single Pulse ◽  
H Reflex ◽  
Cortical Stimulation ◽  
Spinal Motoneurons ◽  
Hand Muscles ◽  
Stimulus Current ◽  
Contralateral Hand

SUMMARY:The pyramidal tract and particularly the direct corticomotoneuronal components (DCM) have become increasingly important in the higher primates. Minimal single pulse precentral stimulation in man evokes EMG discharges from the contralateral hand muscles with a latency of 18-21 milliseconds. The excitability changes produced by such cortical stimulation on the upper limb H-reflex has been observed to include a short duration early facilitation probably corresponding to the DCM input and a later, longer lasting facilitation mediated by the same and probably other corticofugal projections. Potentiation of the H-reflex in the upper limbs by means of postcentral excitation required much higher single pulse stimulus intensities and the changes in excitability produced on the spinal motoneurons could have been explained by physical extension of the stimulus current to the precentral region. Isometric contraction potentiated the H-reflex produced by combinations of precentral cortical and peripheral nerve stimulation but no direct evidence was found to support a possible transcortical basis for the V2 stretch reflex.

scholarly journals RELATIONSHIP BETWEEN THE STRENGTH OF ARM AND HAND MUSCLES TO PASSING RESULTS FOR AEK MEN'S volley ball NEW NABARA VC YEAR 2020

2021 ◽  
Vol 1 (2) ◽  
pp. 140-147
Author(s):  
Yusran Rizki
Keyword(s):  
Muscle Strength ◽  
Significant Relationship ◽  
Male Athletes ◽  
Male Athlete ◽  
Hand Muscles ◽  
Tests And Measurements ◽  
Hand Grip ◽  
Hand Muscle ◽  
The Relationship ◽  
Descriptive Method

The research objective in this thesis is to determine how much the relationship between arm muscle strength and hand muscle strength on the passing results of men's volleyball volleyball Aek Nabara Barumun VC in 2020. The location of this research was conducted at Aek Nabara Barumun VC Volleyball Club. Data collection was started from 18 December - 27 December 2020. The sample of this study was male athletes who had been selected from the population with purposive sampling, totaling 10 people. The method used in this research is descriptive method with tests and measurements. The research instruments used were arm muscle strength using push-ups, hand muscle strength using a hand grip, and passing tests to the wall. The results of the study can be concluded that: (1) There is a significant relationship between arm muscle strength and volleyball passing results in male athlete Aek Nabara Barumun VC in 2020 (tcount> ttable = 5.398> 2.262). (2) there is a significant relationship between hand muscle strength and volleyball passing results in male athlete Aek Nabara Barumun VC in 2020 (tcount> ttable = 6,782> 2,262). (3) there is a significant relationship between arm muscle strength and muscle strength hand on the results of the results of passing over volleyball in the male athlete Aek Nabara Barumun VC in 2020 (Fcount> Ftable = 32 <4.46).

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