scholarly journals Motor cortical plasticity in response to skill acquisition in adult monkeys

2020 ◽  
Author(s):  
Ankur Gupta ◽  
Abdulraheem Nashef ◽  
Sharon Israely ◽  
Michal Segal ◽  
Ran Harel ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Skill Acquisition ◽  
Cortical Neurons ◽  
Cortical Plasticity ◽  
Task Demands ◽  
Cortical Region ◽  
Cortical Maps ◽  
Specific Outcome ◽  
Motor Cortical

SummaryCortical maps often undergo plastic changes during learning or in response to injury. In sensory areas, these changes are thought to be triggered by alterations in the pattern of converging inputs and a functional reassignment of the deprived cortical region. In the motor cortex, training on a task that engages distal effectors was shown to increase their cortical representation (as measured by response to intracortical microstimulation). However, this expansion could be a specific outcome of using a demanding dexterous task. We addressed this question by measuring the long-term changes in cortical maps of monkeys that were sequentially trained on two different tasks involving either proximal or distal joints. We found that motor cortical remodeling in adult monkeys was symmetric such that both distal and proximal movements can comparably alter motor maps in a fully reversible manner according to task demands. Further, we found that the change in mapping often included a switch between remote joints (e.g., a finger site switched to a shoulder site) and reflected a usage-consistent reorganization of the map rather than the local expansion of one representation into nearby sites. Finally, although cortical maps were considerably affected by the performed task, motor cortical neurons throughout the motor cortex were equally likely to fire in a task-related manner independent of the task and/or the recording site. These results may imply that in the motor system, enhanced motor efficiency is achieved through a dynamical allocation of larger cortical areas and not by specific recruitment of task-relevant cells.

scholarly journals Bidirectional long-term motor cortical plasticity and metaplasticity induced by quadripulse transcranial magnetic stimulation

2008 ◽  
Vol 586 (16) ◽  
pp. 3927-3947 ◽  
Author(s):  
Masashi Hamada ◽  
Yasuo Terao ◽  
Ritsuko Hanajima ◽  
Yuichiro Shirota ◽  
Setsu Nakatani-Enomoto ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Cortical Plasticity ◽  
Motor Cortical

scholarly journals Local activation of α2 adrenergic receptors is required for vagus nerve stimulation induced motor cortical plasticity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ching-Tzu Tseng ◽  
Solomon J. Gaulding ◽  
Canice Lei E. Dancel ◽  
Catherine A. Thorn
Keyword(s):  
Motor Cortex ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Cortical Plasticity ◽  
Cortical Reorganization ◽  
Cortical Motor ◽  
The Central Nervous System ◽  
Motor Cortical ◽  
Recovery Of Motor Function

AbstractVagus nerve stimulation (VNS) paired with rehabilitation training is emerging as a potential treatment for improving recovery of motor function following stroke. In rats, VNS paired with skilled forelimb training results in significant reorganization of the somatotopic cortical motor map; however, the mechanisms underlying this form of VNS-dependent plasticity remain unclear. Recent studies have shown that VNS-driven cortical plasticity is dependent on noradrenergic innervation of the neocortex. In the central nervous system, noradrenergic α2 receptors (α2-ARs) are widely expressed in the motor cortex and have been critically implicated in synaptic communication and plasticity. In current study, we examined whether activation of cortical α2-ARs is necessary for VNS-driven motor cortical reorganization to occur. Consistent with previous studies, we found that VNS paired with motor training enlarges the map representation of task-relevant musculature in the motor cortex. Infusion of α2-AR antagonists into M1 blocked VNS-driven motor map reorganization from occurring. Our results suggest that local α2-AR activation is required for VNS-induced cortical reorganization to occur, providing insight into the mechanisms that may underlie the neuroplastic effects of VNS therapy.

Self-Organization of Firing Activities in Monkey's Motor Cortex: Trajectory Computation from Spike Signals

1997 ◽  
Vol 9 (3) ◽  
pp. 607-621 ◽  
Author(s):  
Siming Lin ◽  
Jennie Si ◽  
A. B. Schwartz
Keyword(s):  
Motor Cortex ◽  
Cortical Neurons ◽  
Arm Movement ◽  
Neuronal Firing ◽  
Neural Representation ◽  
Population Vector ◽  
Vector Method ◽  
Preferred Direction ◽  
Motor Cortical ◽  
Self Organizing

The population vector method has been developed to combine the simultaneous direction-related activities of a population of motor cortical neurons to predict the trajectory of the arm movement. In this article, we consider a self-organizing model of a neural representation of the arm trajectory based on neuronal discharge rates. A self-organizing feature map (SOFM) is used to select the optimal set of weights in the model to determine the contribution of an individual neuron to an overall movement representation. The correspondence between movement directions and discharge patterns of the motor cortical neurons is established in the output map. The topology-preserving property of the SOFM is used to analyze the recorded data of a behaving monkey. The data used in this analysis were taken while the monkey was tracing spirals and doing center→out movements. The arm trajectory could be well predicted using such a statistical model based on the motor cortex neuronal firing information. The SOFM method is compared with the population vector method, which extracts information related to trajectory by assuming that each cell has a fixed preferred direction during the task. This implies that these cells are acting along lines labeled only for direction. However, extradirectional information is carried in these cell responses. The SOFM has the capability of extracting not only direction-related information but also other parameters that are consistently represented in the activity of the recorded population of cells.

scholarly journals Deactivation of Distant Pain-Related Regions Induced by 20-day rTMS: A Case Study of Oneweek Pain Relief for Long-Term Intractable Deafferentation Pain

2014 ◽  
Vol 17;1 (1;17) ◽  
pp. E99-E105
Author(s):  
Wen-Dong Xu
Keyword(s):  
Case Report ◽  
Pain Relief ◽  
Motor Cortex ◽  
Caudate Nucleus ◽  
Cortical Plasticity ◽  
Motor Cortex Stimulation ◽  
Deafferentation Pain ◽  
Significant Difference ◽  
Stimulation Of

Background: Deafferentation pain secondary to brachial plexus avulsion, spinal cord injury, and other peripheral nerve injuries is often refractory to conventional treatments. Stimulation of the primary motor cortex (M1) has been proven to be an effective treatment for intractable deafferentation pain. The mechanisms underlying the attenuation of deafferentation pain by motor cortex stimulation remain hypothetical. Objectives: The purpose of this case report is to: (1) summarize a case in which a patient suffering chronic intractable deafferentation pain for 25 years underwent rTMS treatment over M1, (2) describe the evidence from PET imaging, and (3) reveal a possible relief mechanism with cortical plasticity. Study design: Case report. Setting: University hospital. Results: This patient had successful pain control with no transient or lasting side effects. The pain relief remained stable for at least one week. At the end of the 20-day procedure, pain relief was obtained according to the Visual Analog Scale (VAS) (-34.6%) and the McGill Pain Questionnaire (MPQ) (-31.6%). In the PET/CT scans, the glucose metabolism was significantly reduced contralaterally to the pain side in the anterior cingulate cortex (ACC), insula, and caudate nucleus. There was no statistically significant difference in any other cortical area. Limitations: Single case of a patient with long-term intractable deafferentation pain having a PET study. Conclusion: This study implies that a single session of 20 Hz rTMS over the motor cortex could reduce the pain level in patients suffering from long-term, intractable deafferentation pain. The stimulation of the M1 induces deactivation in the ACC, insula, and caudate nucleus. The changes in these pain-related regions may mirror an adaptive mechanism to pain relief after rTMS treatment. Key words: Neuropathic pain management, deafferentation pain, transcranial magnetic stimulation, motor cortex stimulation, cortical plasticity, positron emission tomography

Fast ballistic arm movements triggered by visual, auditory, and somesthetic stimuli in the monkey. II. Effects of unilateral dentate lesion on discharge of precentral cortical neurons and reaction time

1983 ◽  
Vol 50 (6) ◽  
pp. 1359-1379 ◽  
Author(s):  
G. Spidalieri ◽  
L. Busby ◽  
Y. Lamarre
Keyword(s):  
Reaction Time ◽  
Motor Cortex ◽  
Cortical Neurons ◽  
Stimulus Presentation ◽  
Reference Points ◽  
Neuronal Firing ◽  
Time Interval ◽  
Cortical Cells ◽  
Before And After ◽  
Motor Cortical

Single-unit recordings from motor cortex (area 4) were obtained before and after dentate lesion in two monkeys executing fast elbow flexions and extensions in response to randomly presented visual, auditory, and somesthetic stimuli. There were no starting or ending reference points or preparatory signals. Monkeys were trained to perform movements larger than 15 degrees within 500 ms of the stimulus presentation. After electrolytic lesion of the dentate nucleus ipsilateral to the trained arm, changes in reaction time (RT) were observed. Mean daily RTs of movements triggered by light and sound were lengthened by 50-70 ms. RTs of movements triggered by somesthetic stimuli were not changed in one monkey, whereas a small increase of only 20 ms was observed in the other animal. Spontaneous firing of precentral neurons was about the same before and after dentate lesion. However, movement-related responses of cortical neurons were affected by the lesion. Whenever there was an increase in RT according to the triggering stimuli, a corresponding increase in the response time of neurons (RS) appeared. Both RS and RT increased by the same amount when movements were triggered by visual and auditory stimuli, whereas they remained about the same when somesthetic stimuli were used to trigger movements. In contrast, the time interval between the appearance of the change of neuronal firing and onset of arm displacement (RM) was not modified after the lesion. Gating of sensory conditioning inputs and modification of RT by the presentation of more than one stimulus were not abolished by dentate lesion. As a whole, the effects of dentate lesion on motor cortical neurons are consistent with the hypothesis that the neocerebellum controls the initiation of simple ballistic limb movements by controlling the discharge of motor cortex neurons. The effects could be attributed to the withdrawal of a facilitatory influence of dentate neurons on the motor cortical cells, particularly for movements triggered by teleceptive inputs.

A Temporally Asymmetric Hebbian Rule Governing Plasticity in the Human Motor Cortex

2003 ◽  
Vol 89 (5) ◽  
pp. 2339-2345 ◽  
Author(s):  
Alexander Wolters ◽  
Friedhelm Sandbrink ◽  
Antje Schlottmann ◽  
Erwin Kunesch ◽  
Katja Stefan ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Median Nerve ◽  
Cortical Excitability ◽  
Long Term Potentiation ◽  
Long Term Depression ◽  
Human Motor Cortex ◽  
Motor Cortical Excitability ◽  
Human Motor ◽  
Motor Cortical

Synaptic plasticity is conspicuously dependent on the temporal order of the pre- and postsynaptic activity. Human motor cortical excitability can be increased by a paired associative stimulation (PAS) protocol. Here we show that it can also be decreased by minimally changing the interval between the two associative stimuli. Corticomotor excitability of the abductor pollicis brevis (APB) representation was tested before and after repetitively pairing of single right median nerve simulation with single pulse transcranial magnetic stimulation (TMS) delivered over the optimal site for activation of the contralateral APB. Following PAS, depression of TMS-evoked motor-evoked potentials (MEPs) was induced only when the median nerve stimulation preceded the TMS pulse by 10 ms, while enhancement of cortical excitability was induced using an interstimulus interval of 25 ms, suggesting an important role of the sequence of cortical events triggered by the two stimulation modalities. Experiments using F-wave studies and electrical brain stem stimulation indicated that the site of the plastic changes underlying the decrease of MEP amplitudes following PAS (10 ms) was within the motor cortex. MEP amplitudes remained depressed for approximately 90 min. The decrease of MEP amplitudes was blocked when PAS(10 ms) was performed under the influence of dextromethorphan, an N-methyl-d-aspartate-receptor antagonist, or nimodipine, an L-type voltage-gated calcium-channel antagonist. The physiological profile of the depression of human motor cortical excitability following PAS(10 ms) suggests long-term depression of synaptic efficacy to be involved. Together with earlier findings, this study suggests that strict temporal Hebbian rules govern the induction of long-term potentiation/long-term depression-like phenomena in vivo in the human primary motor cortex.

Motor cortex and corticospinal excitability in humans with a history of illicit stimulant use

2012 ◽  
Vol 113 (9) ◽  
pp. 1486-1494 ◽  
Author(s):  
Stanley C. Flavel ◽  
Jason M. White ◽  
Gabrielle Todd
Keyword(s):  
Motor Cortex ◽  
Muscle Activity ◽  
Corticospinal Excitability ◽  
Urine Drug Screen ◽  
Paired Pulse ◽  
Stimulant Use ◽  
Resting Motor Threshold ◽  
History Of ◽  
Motor Cortical

Illicit use of stimulant drugs such as methamphetamine, ecstasy, and cocaine is a current and growing problem throughout the world. The aim of the current study was to investigate the long-term effect of illicit stimulant use on human motor cortical and corticospinal circuitry. We hypothesized that individuals with a history of primarily methamphetamine and ecstasy use would exhibit altered corticospinal excitability and intracortical inhibition within motor cortex. The study involved 52 healthy adults (aged 26 ± 7 yr) comprising 26 abstinent stimulant users, 9 cannabis users, and 17 nondrug users. The experiment involved a routine urine drug screen, drug history questionnaire, neuropsychological assessment, and single- and paired-pulse transcranial magnetic stimulation (TMS) over motor cortex. EMG responses to stimulation [motor evoked potentials (MEPs)] were recorded from the contralateral first dorsal interosseus. At a given stimulus intensity, MEP area was significantly larger in abstinent stimulant users than in nondrug users during both relaxation ( P = 0.045) and muscle contraction ( P < 0.001). MEP latency was also significantly longer in abstinent stimulant users ( P < 0.009), and they exhibited significantly greater muscle activity during performance of a given task ( P = 0.004). However, resting motor threshold and the response to paired-pulse TMS were unaffected. The results suggest that abstinent stimulant users exhibit long-term changes in the excitability of motor cortical and corticospinal circuitry and muscle activity during movement. These changes may partly underlie anecdotal and objective reports of movement dysfunction in chronic stimulant users.

scholarly journals Somatosensory response properties of excitatory and inhibitory neurons in rat motor cortex

2011 ◽  
Vol 106 (3) ◽  
pp. 1355-1362 ◽  
Author(s):  
Peter D. Murray ◽  
Asaf Keller
Keyword(s):  
Motor Cortex ◽  
Receptive Field ◽  
Cortical Neurons ◽  
Inhibitory Neurons ◽  
Field Size ◽  
Spiking Neuron ◽  
Excitatory Neurons ◽  
Fast Spiking ◽  
Motor Cortical ◽  
Feedforward Inhibition

In sensory cortical networks, peripheral inputs differentially activate excitatory and inhibitory neurons. Inhibitory neurons typically have larger responses and broader receptive field tuning compared with excitatory neurons. These differences are thought to underlie the powerful feedforward inhibition that occurs in response to sensory input. In the motor cortex, as in the somatosensory cortex, cutaneous and proprioceptive somatosensory inputs, generated before and during movement, strongly and dynamically modulate the activity of motor neurons involved in a movement and ultimately shape cortical command. Human studies suggest that somatosensory inputs modulate motor cortical activity in a center excitation, surround inhibition manner such that input from the activated muscle excites motor cortical neurons that project to it, whereas somatosensory input from nearby, nonactivated muscles inhibit these neurons. A key prediction of this hypothesis is that inhibitory and excitatory motor cortical neurons respond differently to somatosensory inputs. We tested this prediction with the use of multisite extracellular recordings in anesthetized rats. We found that fast-spiking (presumably inhibitory) neurons respond to tactile and proprioceptive inputs at shorter latencies and larger response magnitudes compared with regular-spiking (presumably excitatory) neurons. In contrast, we found no differences in the receptive field size of these neuronal populations. Strikingly, all fast-spiking neuron pairs analyzed with cross-correlation analysis displayed common excitation, which was significantly more prevalent than common excitation for regular-spiking neuron pairs. These findings suggest that somatosensory inputs preferentially evoke feedforward inhibition in the motor cortex. We suggest that this provides a mechanism for dynamic selection of motor cortical modules during voluntary movements.

Associative Motor Cortical Plasticity is Modulated by the Activation History of Motor Cortex

2004 ◽  
Vol 35 (03) ◽  
Author(s):  
K Stefan ◽  
M Wycislo ◽  
V Leussink ◽  
A Schramm ◽  
M Naumann ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Cortical Plasticity ◽  
History Of ◽  
Motor Cortical

Primary motor cortical activity related to the weight and texture of grasped objects in the monkey

1992 ◽  
Vol 68 (5) ◽  
pp. 1867-1881 ◽  
Author(s):  
N. Picard ◽  
A. M. Smith
Keyword(s):  
Motor Cortex ◽  
Cortical Neurons ◽  
Grip Force ◽  
Primary Motor Cortex ◽  
Load Force ◽  
Precentral Gyrus ◽  
Surface Textures ◽  
Proprioceptive Input ◽  
Object Weight ◽  
Motor Cortical

1. Two monkeys were trained to grasp an object between the thumb and index finger and lift it to a vertical distance of 12-25 mm. Up to 12 different conditions defined by different combinations of object weights (15, 65, and 115 g) and four surface textures (oiled metal, smooth metal, fine and coarse sandpaper) were used. The apparatus was equipped to measure grip (prehensile) force, vertical (load) force, and object displacement. 2. The monkeys appropriately scaled the grip force for the weight and the coefficient of friction of the object. However, during the dynamic phase of the task (grasping and lifting), the monkeys increased the prehensile force in multiple steps, suggesting that they relied on sensory feedback from the fingers to attain an adequate grip force to lift the object rather than programming the lift in advance. 3. Single-unit activity of 248 neurons was recorded in the hand area of the primary motor cortex while the monkeys performed the task. Of 208 neurons tested for cutaneous and proprioceptive receptive fields (RFs), 96 were sensitive to cutaneous stimulation of the glabrous skin of the hand, whereas 82 received proprioceptive input from wrist and finger muscles. The concentration of neurons with cutaneous input was significantly greater in the rostral bank of the central sulcus compared with cells with proprioceptive RFs, which were more concentrated in the convexity of the precentral gyrus. 4. From the global sample, 199 cells were tested with the three object weights, and 128 of these with at least two surface textures were used in combination with the object weights. The discharge of 58/199 (29%) cells was modulated with the object weight. Cells with cutaneous (20/84, 24%) and proprioceptive (23/71, 32%) RFs were about equally responsive to the object weight. 5. A greater number of motor cortical neurons were influenced by surface texture than by object weight. Of 128 cells tested with at least two surface textures, 67 (52%) showed a modulation of their activity as a function of texture. A significantly greater proportion of neurons with cutaneous RFs (40/63, 63%) showed differential activity as a function of object texture than cells receiving proprioceptive input (21/47, 45%). 6. Weight- and texture-related neurons were not distributed equally in the rostrocaudal dimension of the motor cortex. Only 8% of texture-related cells were located in the convexity of the precentral gyrus, whereas 30% of weight-related neurons were recorded from this rostral zone.(ABSTRACT TRUNCATED AT 400 WORDS)

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