Mirror Symmetric Bimanual Movement Priming Can Increase Corticomotor Excitability and Enhance Motor Learning

What will it take for our researchers to move from wishy-washy terms like 'can' increase to will do this? I don't see that occurring until we get survivors in charge who won't fund research that doesn't directly lead to 100% recovery.  You'll have to ask your doctor to demonstrate repetitive active-passive bimanual wrist flexion and extension

Mirror Symmetric Bimanual Movement Priming Can Increase Corticomotor Excitability and Enhance Motor Learning

• Winston D. Byblow ,
• Cathy M. Stinear,
• Marie-Claire Smith,
• Lotte Bjerre,
• Brian K. Flaskager,
• Alana B. McCambridge

• Published: March 22, 2012
• https://doi.org/10.1371/journal.pone.0033882
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Abstract

Repetitive mirror symmetric bilateral upper limb may be a suitable priming technique for upper limb rehabilitation after stroke. Here we demonstrate neurophysiological and behavioural after-effects in healthy participants after priming with 20 minutes of repetitive active-passive bimanual wrist flexion and extension in a mirror symmetric pattern with respect to the body midline (MIR) compared to an control priming condition with alternating flexion-extension (ALT). Transcranial magnetic stimulation (TMS) indicated that corticomotor excitability (CME) of the passive hemisphere remained elevated compared to baseline for at least 30 minutes after MIR but not ALT, evidenced by an increase in the size of motor evoked potentials in ECR and FCR. Short and long-latency intracortical inhibition (SICI, LICI), short afferent inhibition (SAI) and interhemispheric inhibition (IHI) were also examined using pairs of stimuli. LICI differed between patterns, with less LICI after MIR compared with ALT, and an effect of pattern on IHI, with reduced IHI in passive FCR 15 minutes after MIR compared with ALT and baseline. There was no effect of pattern on SAI or FCR H-reflex. Similarly, SICI remained unchanged after 20 minutes of MIR. We then had participants complete a timed manual dexterity motor learning task with the passive hand during, immediately after, and 24 hours after MIR or control priming. The rate of task completion was faster with MIR priming compared to control conditions. Finally, ECR and FCR MEPs were examined within a pre-movement facilitation paradigm of wrist extension before and after MIR. ECR, but not FCR, MEPs were consistently facilitated before and after MIR, demonstrating no degradation of selective muscle activation. In summary, mirror symmetric active-passive bimanual movement increases CME and can enhance motor learning without degradation of muscle selectivity. These findings rationalise the use of mirror symmetric bimanual movement as a priming modality in post-stroke upper limb rehabilitation.

Figures

   

Citation: Byblow WD, Stinear CM, Smith M-C, Bjerre L, Flaskager BK, McCambridge AB (2012) Mirror Symmetric Bimanual Movement Priming Can Increase Corticomotor Excitability and Enhance Motor Learning. PLoS ONE 7(3): e33882. https://doi.org/10.1371/journal.pone.0033882

Editor: Alessio Avenanti, University of Bologna, Italy

Received: June 6, 2011; Accepted: February 23, 2012; Published: March 22, 2012

Copyright: © 2012 Byblow et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: The authors have no support or funding to report.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Repetitive transcranial magnetic stimulation (rTMS) offers promise for increasing or decreasing M1 excitability to promote recovery of motor function after stroke [1]–[9], but a practical limitation is that it requires expensive equipment, a medical environment and is contraindicated for people with a history of seizure, metal implants, cardiac pacemaker, or who are taking certain common medications [10], [11]. Compared with rTMS, transcranial direct current stimulation (tDCS) has fewer contraindications but still requires the use of medically certified electrical equipment and application by a skilled operator [12]. Motor point stimulation [13], [14] and combined peripheral nerve and TMS can enhance or suppress M1 excitability through presumed spike-timing dependent mechanisms [15]–[17] but also require expensive equipment, skilled operators, or lengthy treatment periods and also has potential contraindications. The present study explores an alternative method for increasing M1 excitability by using patterned repetitive movement, without brain or nerve stimulation per se [18], [19].

It is well known that mirror symmetric bimanual movements, with homologous muscles activated simultaneously, are more stable than any other pattern [20]–[22]. Enhanced M1 excitability and presumed GABAergic M1 disinhibition have been noted during production of mirror symmetric active-passive bimanual movement [23], [24] and may facilitate upper limb recovery after stroke by acting as a neurophysiological priming mechanism [18], [19]. Until now, there has been no direct examination of M1 excitability and inhibition immediately after repetitive active-passive bimanual movement and no examination of the immediate behavioural consequences of active-passive movement priming.

To address these issues we first examined corticomotor excitability (CME), M1 intracortical and interhemispheric inhibition and H-reflex excitability, in healthy participants before and after 20 minutes (1200 cycles) of active-passive movement made in either a mirror symmetric (MIR) pattern, or an alternating (ALT) pattern. We hypothesised that MIR but not ALT movements would facilitate corticomotor excitability within forearm flexor and extensor representations of the passive left M1. We also predicted that any difference in CME noted between patterns would be accompanied by differences in intracortical inhibition. To examine this we obtained measures of short afferent inhibition (SAI), long-latency intracortical inhibition (LICI), interhemispheric inhibition (IHI) across two experiments, and examined H-reflex excitability in a third experiment. In a separate study we examined the behavioural consequences of active-passive movement priming and hypothesised that MIR priming would facilitate motor learning. Finally we examined whether increases in CME obtained after MIR would be associated with persistent reductions in short-latency intracortical inhibition that could potentially interfere with selective voluntary muscle activation.

 

More at link.

 

 

Motor Priming in Neurorehabilitation

You'll have to ask your doctor which of these five is available right now with a protocol in their hospital.  Nothing available, call the president and ask when competence will come to the hospital.  But I also see they missed lucid dreaming.

1. (i) stimulation-based priming, 

   (ii) motor imagery and action observation, 

   (iii) sensory priming,

   (iv) movement based priming, and 

   (v) pharmacological priming.

    Motor Priming in Neurorehabilitation

   Mary Ellen Stoykov, PhD, OTR/L, and Sangeetha Madhavan, PT, PhD
   Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor  priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance.Of the numerous motor priming paradigms under investigation, only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known.Accordingly,developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation. Most importantly,an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which are delivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article, we discuss those priming paradigms that are supported by the greatest amount of evidence, including (i) stimulation-based priming, (ii) motor imagery and action observation, (iii) sensory priming,(iv) movement based priming, and (v) pharmacological priming.
   Video Abstract available.
   (seeSupplementalDigitalContent1,http://links.lww.com/JNPT/A86) for more insights from the authors.
   

Motor priming in neurorehabilitation

Maybe there is something in here but you'll have to ask your doctor for a translation into something you can do to recover.

Motor priming in neurorehabilitation

2015, Journal of neurologic physical therapy : JNPT
Mary Ellen Stoykov, PhD, OTR/L, and Sangeetha Madhavan, PT, PhD
 Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor  priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance.Of the numerous motor priming paradigms under investigation,only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known.Accordingly,developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation. Most importantly,an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which are delivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article, we discuss those priming paradigms that are supported by the greatest amount of evidence, including (i) stimulation based priming, (ii) motor imagery and action observation,(iii)sensory priming,(iv)movement based priming,and (v) pharmacological priming.
Video Abstract available.
(seeSupplementalDigitalContent1,http://links.lww.com/JNPT/A86) for more insights from the authors.
Key words:
 Motor cortex, priming, brain stimulation, Bilateral movement, Sensory stimulation
( JNPT  2015;39: 33–42)
 INTRODUCTION
Priming is defined as a change in behavior based on previous stimuli. Priming, which may occur after a single learning episode, is a type of implicit learning. The role of implicit learning in physical therapy (PT) has been the subject of recent investigation.¹⁻⁴Priming-induced learning is different from other types of implicit learning because skill-learning requires repetition.⁵Studies of priming originated in psychology, but have since been investigated in neuroscience,neurorehabilitation, and cognitive neuroscience using behavioral and brain mapping techniques. These studies, both translational and clinical, have been examining motor priming asa tool for inducing neuroplasticity and enhancing the effects of rehabilitation. Priming can be categorized as a restorative intervention that reduces impairment by targeting underlying neural mechanisms in neurological disorders.⁶Priming stimuli can be from the same modality as the accompanying task(modal specific) or from a different modality(cross-modal). An example of modal specific priming is bilateral mirror symmetrical movement(a form of movement based  priming) that is performed prior to a motor task practice and has been found to increase the rate of motor learning in neurologically healthy subjects.⁷Cross-modal priming can also be used to enhance motor learning. For example, semantic priming, reading relevant words describing an action, can produce more efficient movements in young, neurologically healthy adults compared with a control condition.⁸Although there are examples of cross-modal priming producing positive results,results from studies in the psychology literature have reported that the effects of priming are smaller with cross-modal priming as compared with priming using the same modality.⁹Initial interest in priming was fueled by popular psychology research completed several decades ago that included the isolation of memory subtypes and examination of individuals with amnesia.¹⁰Priming is an action that generates a type of implicit memory; therefore, researchers were surprised when individuals with amnesia had intact priming as this indicates that priming, unlike explicit memory, is not controlled by the medial temporal lobe. In contrast to explicit memory, priming is believed to arise from facilitated neural processing in a variety of cortical regions that are specific to the stimulus and the accompanying task. For example, the posterior cortex (extratriatal area) is implicated in perceptual priming, whereas the prefrontal cortex is implicated in conceptually based semantic priming.⁹The general theory underlying priming is that the brain,that has been primed by prior activation is generally more re-sponsive to the accompanying or subsequent training. Priming presupposes that enhanced neural activity before or duringtraining can facilitate the activation of long-term potentiation-(LTP) or long-term depression-(LTD)like mechanisms.¹¹Two proposed neural mechanisms for priming include gating and homeostatic plasticity¹²Gating occurs by disinhibition of intracortical inhibitory circuits as a result of an increase in
 calcium in the targeted cortical neurons. Gating occurs instantaneously and is achieved concurrently with motor training.¹¹Homeostatic plasticity is the ability of neurons to increase excitability after a period of low synaptic activity (and conversely, to decrease excitability after a period of high synaptic activity) and is related to changes in postsynaptic glutamate receptors.^11,12The time scale of homeostatic metaplasticity,in comparison to gating, is protracted, and hence the resting state of neurons is modulated prior tomotor training to induce synaptic plasticity. Neural mechanisms mediating motor priming vary according to priming method. However, they may produce similar effects that may include increased excitability or normalization of inhibition, which coincide with improvements in motor behavior.¹³Methods of priming the motor cortex that are most relevant to rehabilitation include (1) stimulation-based  priming¹⁴⁻²²; (2) motor imagery and action observation²³⁻²⁸;(3) manipulation of sensory input²⁹⁻³¹; (4) movement-based  priming^7,32−36; and (5) pharmacology-based priming.³⁷Stud-ies examining priming for the primary motor cortex (M1) areincreasing in number. Hence, it is important for neuroreha- bilitation professionals to be aware of the basic principles of  priming and how they influence motor training (Table 1).A search of the literature through December 2013 was performed using the search engines: PubMed, Web of Sci-ence, and Ovid. Key words used were “priming” combined with one of the following terms: “brain plasticity,” “motor recovery,” “TMS,” “rTMS,” “tDCS,” “PAS,” “PNS,” “mo-tor imagery,” “action observation,” “movement based,” “bilat-eral movements,” unilateral movements, “aerobic exercise,”“pharmacology based,” “sensory priming,” “peripheral nervestimulation,” “temporary functional deafferentation,” and “vibration.” Peer-reviewed articles were selected if they met thefollowing criteria: (1) written in English, (2) involved more than 1 human participant, and (3) included at least 1 motor performance-based outcome measure, and (4) fit the defini-tion of “priming” as described in the “Introduction” section.Papers that were cited in the selected articles, such as mecha-nistic or studies using animal models, were also included for  background information. We also included studies that cited the selected articles. The 5 priming paradigms are described later. 

More at link.

The effect of priming on outcomes of task-oriented training for the upper extremity in chronic stroke: A systematic review and meta-analysis

I guess you'll have to start guessing what the hell priming is. 

 The effect of priming on outcomes of task-oriented training for the upper extremity in chronic stroke: A systematic review and meta-analysis

  Neurorehabilitation and Neural Repair (NNR) , Volume 34(6) , Pgs. 479-504.

NARIC Accession Number: J84038.  What's this?
ISSN: 1545-9683.
Author(s): da Silva, Erika S. M.; Ocamoto, Gabriela N.; dos Santos-Maia, Gabriela L. ; Padovez, Roberta F. C. M. ; Trevisan, Claudia ; de Noronha, Marcos A.; Pereira, Natalia D. ; Borstad, Alexandra ; Russo, Thiago L..
Publication Year: 2020.
Number of Pages: 26.

Abstract: 

Study determined the effects of priming on task-oriented training on upper-extremity outcomes (body function and activity) in chronic stroke. The PubMed, CINAHL, Web of Science, EMBASE, and PEDro databases were searched for relevant studies. Outcome data were pooled into categories of measures considering the International Classification Functional (ICF) classifications of body function and activity. Means and standard deviations for each group were used to determine group effect sizes by calculating mean differences (MDs) and 95-percent confidence (95%CI) intervals via a fixed effects model. Thirty-six studies with 814 patients undergoing various types of task-oriented training were included in the analysis. Of these studies, 17 were associated with stimulation priming, 12 with sensory priming, 4 with movement priming, and 3 with action observation priming. Stimulation priming showed moderate-quality evidence of body function. Only the Wolf Motor Function Test (time) in the activity domain showed low-quality evidence. However, gains in motor function and in use of extremity members were measured by the Fugl-Meyer Assessment (UE-FMA). Regarding sensory priming, moderate-quality evidence and effect size were found for the UE-FMA, corresponding to the body function domain (MD 4.77, 95%CI 3.25-6.29), and for the Action Research Arm Test, corresponding to the activity domain (MD 7.47, 95%CI 4.52-10.42). Despite the low-quality evidence, the study found an effect size (MD 8.64, 95%CI 10.85-16.43) in movement priming. Evidence for action observation priming was inconclusive. The findings suggest that combining priming and task-oriented training for the upper extremities of chronic stroke patients can be a promising intervention strategy.
Descriptor Terms: INTERVENTION, LIMBS, LITERATURE REVIEWS, MOTOR SKILLS, REHABILITATION SERVICES, STROKE, TASK ANALYSIS, THERAPEUTIC TRAINING.


Can this document be ordered through NARIC's document delivery service*?: Y.
Get this Document: https://journals.sagepub.com/doi/full/10.1177/1545968320912760.

Citation: da Silva, Erika S. M., Ocamoto, Gabriela N., dos Santos-Maia, Gabriela L. , Padovez, Roberta F. C. M. , Trevisan, Claudia , de Noronha, Marcos A., Pereira, Natalia D. , Borstad, Alexandra , Russo, Thiago L.. (2020). The effect of priming on outcomes of task-oriented training for the upper extremity in chronic stroke: A systematic review and meta-analysis.  Neurorehabilitation and Neural Repair (NNR) , 34(6), Pgs. 479-504. Retrieved 8/19/2020, from REHABDATA database.

Cortical priming strategies for gait training after stroke: a controlled, stratified trial

And your doctor will 100% guarantee that HIT will not cause a stroke?

Do you really want to do high intensity training?

Because Andrew Marr blames high-intensity training for his stroke. 

Can too much exercise cause a stroke?

The latest here:

 

Cortical priming strategies for gait training after stroke: a controlled, stratified trial

• Sangeetha Madhavan,
• Brice T. Cleland,
• Anjali Sivaramakrishnan,
• Sally Freels,
• Hyosok Lim,
• Fernando D. Testai &
• Daniel M. Corcos 

Journal of NeuroEngineering and Rehabilitation volume 17, Article number: 111 (2020) Cite this article

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Abstract

Background

Stroke survivors experience chronic gait impairments, so rehabilitation has focused on restoring ambulatory capacity. High-intensity speed-based treadmill training (HISTT) is one form of walking rehabilitation that can improve walking, but its effectiveness has not been thoroughly investigated. Additionally, cortical priming with transcranial direct current stimulation (tDCS) and movement may enhance HISTT-induced improvements in walking, but there have been no systematic investigations. The objective of this study was to determine if motor priming can augment the effects of HISTT on walking in chronic stroke survivors.

Methods

Eighty-one chronic stroke survivors participated in a controlled trial with stratification into four groups: 1) control–15 min of rest (n = 20), 2) tDCS–15 min of stimulation-based priming with transcranial direct current stimulation (n = 21), 3) ankle motor tracking (AMT)–15 min of movement-based priming with targeted movements of the ankle and sham tDCS (n = 20), and 4) tDCS+AMT–15 min of concurrent tDCS and AMT (n = 20). Participants performed 12 sessions of HISTT (40 min/day, 3 days/week, 4 weeks). Primary outcome measure was walking speed. Secondary outcome measures included corticomotor excitability (CME). Outcomes were measured at pre, post, and 3-month follow-up assessments.

Results

HISTT improved walking speed for all groups, which was partially maintained 3 months after training. No significant difference in walking speed was seen between groups. The tDCS+AMT group demonstrated greater changes in CME than other groups. Individuals who demonstrated up-regulation of CME after tDCS increased walking speed more than down-regulators.

Conclusions

Our results support the effectiveness of HISTT to improve walking; however, motor priming did not lead to additional improvements. Upregulation of CME in the tDCS+AMT group supports a potential role for priming in enhancing neural plasticity. Greater changes in walking were seen in tDCS up-regulators, suggesting that responsiveness to tDCS might play an important role in determining the capacity to respond to priming and HISTT.

Trial registration

ClinicalTrials.gov, NCT03492229. Registered 10 April 2018 – retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03492229.

Background

Many stroke survivors experience chronic gait impairments. After rehabilitation, 36% of stroke survivors cannot walk independently [1] and walk ~ 50% slower than age-matched peers [2], which is well below the speed required for safe community ambulation (1.06 m/s) [3]. Walking endurance is also markedly reduced after stroke [4]. Reduced walking speed and endurance are major barriers for community participation [4, 5] and are associated with decreased physical activity [6] and quality of life [7, 8]. Gait rehabilitation has focused on development of interventions to restore ambulatory capacity, and there is a critical need to maximize benefits of current walking training interventions.

Because of its clinical and home accessibility, treadmill training has long been utilized as an effective and feasible method of walking training for post-stroke individuals [9]. Recent studies have explored high-intensity interval training (HIIT) as a way to reduce training time and volume while maximizing intensity [10]. HIIT involves alternating periods of walking at a high intensity and recovery intensity. Speed-based HIIT (HISTT) is one type of HIIT designed to improve an individual’s walking speed by training at the maximum tolerated treadmill belt speed. HISTT leads to greater improvements in overground walking speed than progressive treadmill training in chronic [11, 12] and sub-acute [13] stroke. The effectiveness of HISTT at improving clinical gait and neurophysiological outcomes post-stroke has not been thoroughly investigated.

Cortical priming with neurostimulation or movement is a promising adjuvant therapy to enhance effects of motor rehabilitation [14]. The premise behind neural priming is that the brain retains its capacity to reorganize after stroke, and priming may improve the effect of associated motor training by correcting the imbalance in interhemispheric inhibition observed post-stroke and facilitating long-term potentiation and depression like mechanisms [14]. One clinically translatable type of cortical priming is non-invasive transcranial direct current stimulation (tDCS). After stroke, tDCS has been used to correct interhemispheric imbalance in two primary ways: 1) anodal tDCS, in which the anode is placed over the ipsilesional hemisphere to increase ipsilesional cortical excitability and 2) cathodal tDCS, in which the cathode is placed over the contralesional hemisphere to decrease contralesional cortical excitability. Anodal tDCS has been shown to upregulate corticomotor pathways and improve motor learning and function [14,15,16]. Although cathodal tDCS has also shown beneficial effects, suppressing the contralesional hemisphere may be maladaptive in individuals with limited neural resources in the ipsilesional hemisphere [16, 17]. These findings support the role of tDCS to potentially enhance the effects of other types of motor training [15]. Movement-based priming, another priming technique, often involves the performance of a repetitive movement, such as wrist flexion and extension, prior to performance of motor training [18]. Like tDCS, movement-based priming may also increase corticomotor excitability (CME) and enhance the effects of motor training [18, 19]. Thus, movement-based priming is also a potential adjuvant to enhance the effects of HISTT, and combining tDCS and movement-based priming may yield greater benefits than either type of priming in isolation.

Despite the potential benefits of tDCS and movement-based priming, there have been no systematic investigations on the effects of motor priming on HISTT-induced improvements in walking. Our lab recently found that a single session of HISTT paired with tDCS and movement priming increases excitability of the ipsilesional hemisphere and decreases excitability of the contralesional hemisphere, supporting the potential efficacy of priming for enhancing HISTT [20]. In this controlled trial with stratification, our objective was to determine if motor priming can augment the effects of HISTT. As it is critical that the optimal priming technique be paired with gait rehabilitation, we compared the effects of three types of priming techniques on 4-weeks of HISTT: tDCS, movement-based priming, and both combined. Based on pilot data, we hypothesized that tDCS and movement-based priming would enhance the effects of HISTT on walking speed with corresponding changes in CME and combining both types of priming would lead to even greater improvement.

 

Motor priming in neurorehabilitation

Only 6 pages and 4.5 years old and I am absolutely positive that your doctor knows nothing about this.  So you are on your own to figure out how this might help you recover. Our fucking failures of stroke associations are doing nothing with this, they do nothing for survivors.

Motor priming in neurorehabilitation

 Mary Ellen Stoykov, PhD, OTR/L, and Sangeetha Madhavan, PT, PhD
Priming is a type of implicit learning wherein a stimulus prompts achange in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor  priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance.Of the numerous motor priming paradigms under investigation, only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known.Accordingly, developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation.  Most importantly,an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which aredelivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article, we discuss those priming paradigms that are supported by the greatest amount of evidence, including (i) stimulation-based priming, (ii) motor imagery and action observation,(iii)sensory priming,(iv)movement based priming,and (v) pharmacological priming.
VideoAbstractavailable.
(seeSupplementalDigitalContent1,http://links.lww.com/JNPT/A86) for more insights from the authors.
Key words:
 Motor cortex, priming, brain stimulation, Bilateral movement, Sensory stimulation
(
 JNPT
 2015;39: 33–42)
INTRODUCTION
P
riming is defined as a change in behavior based on previous stimuli. Priming, which may occur after a single learning episode, is a type of implicit learning. The role of implicit learning in physical therapy (PT) has been the subject of recent investigation.
1
−
4
Priming-induced learning is
Department of Occupational Therapy, Rush University Medical Center,Chicago,Illinois(M.E.S.);and Department of PhysicalTherapy, University of Illinois in Chicago (S.M.).This manuscript was funded, in part, by a training award from a Multi-Center K12 Award funded by NIH (K12 HD055931) for the first author.The authors declare no conflicts of interest.Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versionsof this article on the journal’s Web site (www.jnpt.org).
Correspondence:
 Mary Ellen Stoykov, PhD, OTR/L, Department of Occupational Therapy, Rush University Medical Center,600SPaulinaSt,Chicago,IL 60612 (mary_stoykov@rush.edu).Copyright
 C

2015 Neurology Section, APTA.ISSN: 1557-0576/15/3901-0033DOI: 10.1097/NPT.0000000000000065
different from other types of implicit learning because skill-learning requires repetition.
5
Studies of priming originated in psychology, but have since been investigated in neuroscience,neurorehabilitation, and cognitive neuroscience using behav-ioral and brain mapping techniques. These studies, both translational and clinical, have been examining motor priming asa tool for inducing neuroplasticity and enhancing the effects of rehabilitation. Priming can be categorized as a restorative intervention that reduces impairment by targeting underlying neural mechanisms in neurological disorders.
6
Priming stimuli can be from the same modality as the accompanying task(modal-specific) or from a different modality(cross-modal). An example of modal-specific priming is bilat-eralmirrorsymmetricalmovement(aformofmovement-based  priming) that is performed prior to a motor task practice and has been found to increase the rate of motor learning in neuro-logically healthy subjects.
7
Cross-modal priming can also beused to enhance motor learning. For example, semantic priming, reading relevant words describing an action, can produce more efficient movements in young, neurologically healthy adults compared with a control condition.
8
Although there are examples of cross-modal priming producing positive results,results from studies in the psychology literature have reported that the effects of priming are smaller with cross-modal prim-ing as compared with priming using the same modality.
9
Initial interest in priming was fueled by popular psychology research completed several decades ago that included the isolation of memory subtypes and examination of individuals with amnesia.
10
Priming is an action that generates a type of implicit memory; therefore, researchers were surprised when individuals with amnesia had intact priming as this indicates that priming, unlike explicit memory, is not controlled by the medial temporal lobe. In contrast to explicit memory, priming is believed to arise from facilitated neural processing in a variety of cortical regions that are specific to the stimulus and the accompanying task. For example, the posterior cortex (extratriatal area) is implicated in perceptual priming, whereas the prefrontal cortex is implicated in conceptually based semantic priming.
9
The general theory underlying priming is that the brain,that has been primed by prior activation is generally more responsive to the accompanying or subsequent training. Priming presupposes that enhanced neural activity before or during training can facilitate the activation of long-term potentiation-(LTP) or long-term depression-(LTD) like mechanisms.
11
Two proposed neural mechanisms for priming include
 gating
 and
homeostatic plasticity
.
12
Gating occurs by disinhibition of intracortical inhibitory circuits as a result of an increase in
Copyright © 2015 Neurology Section, APTA. Unauthorized reproduction of this article is prohibited.
 JNPT
 
 Volume 39, January 2015
 33

Stoykov and Madhavan
 JNPT
 
 Volume 39, January 2015
calcium in the targeted cortical neurons. Gating occurs instan-taneously and is achieved
 concurrently with
 motor training.
11
Homeostatic plasticity is the ability of neurons to increaseexcitability after a period of low synaptic activity (and con-versely, to decrease excitability after a period of high synapticactivity) and is related to changes in postsynaptic glutamatereceptors.
11,12
The time scale of homeostatic metaplasticity,in comparison to gating, is protracted, and hence the resting state of neurons is modulated
 prior to
 motor training to induce synaptic plasticity. Neural mechanisms mediating motor priming varyaccording to priming method. However, they may produce similar effects that may include increased excitability or normalization of inhibition, which coincide with improvements in motor behavior.
13
Methodsofprimingthemotorcortexthataremost relevant to rehabilitation include (1) stimulation-based  priming
14
−
22
; (2) motor imagery and action observation
23
−
28
;(3) manipulation of sensory input
29
−
31
; (4) movement-based  priming
7,32
−
36
; and (5) pharmacology-based priming.
37
Studies examining priming for the primary motor cortex (M1) are increasing in number. Hence, it is important for neurorehabilitation professionals to be aware of the basic principles of  priming and how they influence motor training (Table 1).A search of the literature through December 2013 was performed using the search engines: PubMed, Web of Science, and Ovid. Key words used were “priming” combined with one of the following terms: “brain plasticity,” “motor recovery,” “TMS,” “rTMS,” “tDCS,” “PAS,” “PNS,” “motor imagery,” “action observation,” “movement based,” “bilateral movements,” unilateral movements, “aerobic exercise,”“pharmacology based,” “sensory priming,” “peripheral nerve stimulation,” “temporary functional deafferentation,” and “vibration.” Peer-reviewed articles were selected if they met the following criteria: (1) written in English, (2) involved more than 1 human participant, and (3) included at least 1 motor performance-based outcome measure, and (4) fit the defini-tion of “priming” as described in the “Introduction” section.Papers that were cited in the selected articles, such as mechanistic or studies using animal models, were also included for  background information. We also included studies that cited the selected articles. The 5 priming paradigms are described later.