Publications by authors named "Joel S Burma"

13 Publications

  • Page 1 of 1

Concurrent Validity of a Stationary Cycling Test and Buffalo Concussion Treadmill Test in Adults with Concussion.

J Athl Train 2021 Apr 22. Epub 2021 Apr 22.

1Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.

Context: Following concussion, a multi-faceted assessment is recommended, including tests of physical exertion. The current gold standard for exercise testing following concussion is the Buffalo Concussion Treadmill Test (BCTT); however, there is a lack of validated tests that utilize alternative exercise modalities.

Objective: To assess the feasibility and concurrent validity of a novel cycling test of exertion compared to the BCTT.

Design: Crossover Study Setting: University Sport-Medicine Clinic Patients: Twenty adults (aged 18-60 years) diagnosed with a Sport-Related Concussion Intervention: Participants completed the BCTT and a cycling test of exertion in a random order, approximately 48 hours apart.

Main Outcome Measures: The primary outcome of interest was maximum heart rate [HRmax; beats per minute (bpm)]. Secondary outcomes of interest included whether the participant reached volitional fatigue (yes/no), symptom responsible for test cessation (Post Concussion Symptom Scale), and Symptom Severity on a Visual Scale (/10).

Results: Of the 20 participants, 19 (10 male, 9 female) completed both tests. One participant did not return for the second test and was excluded from the analysis. No adverse events were reported. The median HRmax for the BCTT [171 bpm; (IQR: 139-184bpm)] was not significantly different than the median HRmax for the Cycle [173 bpm; (IQR: 160-182)] (z=-0.63, p=0.53). For both tests, the three most frequently reported symptoms responsible for test cessation were Headache, Dizziness, and Pressure in the head. Of interest, the majority of participants (64%) reported a different symptom responsible for test cessation on each test.

Conclusion: The novel cycling test of exertion achieved similar HRmax and test duration and may be a suitable alternative to the BCTT. Future research to understand the physiological reason for the heterogeneity in symptoms responsible for test cessation is warranted.
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http://dx.doi.org/10.4085/1062-6050-0003.21DOI Listing
April 2021

The validity and reliability of ultra-short-term heart rate variability parameters and the influence of physiological covariates.

J Appl Physiol (1985) 2021 Apr 15. Epub 2021 Apr 15.

Faculty of Kinesiology, University of Calgary, Canada.

Background: Ultra-short-term (UST) heart rate variability (HRV) metrics have increasingly been proposed as surrogates for short-term HRV metrics. However, the concurrent validity, within-day reliability, and between-day reliability of UST HRV have yet to be comprehensively documented.

Methods: Thirty-six adults (18 males, age: 26 ± 5 years, BMI: 24 ± 3 kg/m)were recruited. Measures of HRV were quantified in a quiet-stance upright orthostatic position via three-lead electrocardiogram (ADInstruments, FE232 BioAmp). All short-term data recordings were 300-seconds in length and five UST time points (i.e., 30-seconds, 60-seconds, 120-seconds, 180-seconds, and 240-seconds) were extracted from the original 300-second recording. Bland-Altman plots with 95% limits of agreement, repeated measures ANOVA, and two-tailed paired t-tests demarcated differences between UST and short-term recordings. Linear regressions, coefficient of variation, intraclass correlation coefficients, and other tests examined the validity and reliability in both time- and frequency-domains.

Results: No group differences were noted between all short-term and UST measures, for either time- (all p>0.202) or frequency-domain metrics (all p>0.086). A longer recording duration was associated with augmented validity and reliability, that was less impacted by confounding influences from physiological variables (e.g., respiration rate, carbon dioxide end-tidals, and blood pressure). Conclusively, heart rate, time-domain, and relative frequency-domain HRV metrics were acceptable with recordings greater or equal to 60s, 240s, and 300s, respectively.

Conclusions: Future studies employing UST HRV metrics, should thoroughly understand the methodological requirements to obtain accurate results. Moreover, a conservative approach should be utilized regarding the minimum acceptable recording duration, which ensures valid/reliable HRV estimates are obtained.
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http://dx.doi.org/10.1152/japplphysiol.00955.2020DOI Listing
April 2021

Temporal evolution of neurovascular coupling recovery following moderate- and high-intensity exercise.

Physiol Rep 2021 Jan;9(2):e14695

Concussion Research Laboratory, Faculty of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada.

Purpose: Studies examining neurovascular coupling (NVC) require participants to refrain from exercise for 12-24 hours. However, there is a paucity of empirical evidence for this restriction. The objectives for this study were to delineate the time-course recovery of NVC metrics following exercise and establish the NVC within- and between-day reliability.

Methods: Nine participants completed a complex visual search paradigm to assess NVC via transcranial Doppler ultrasound of the posterior cerebral artery blood velocity (PCA). Measurements were performed prior to and throughout the 8-hour recovery period following three randomized conditions: 45 minutes of moderate-intensity exercise (at 50% heart-rate reserve), 30 minutes high-intensity intervals (10, 1-minute intervals at 85% heart-rate reserve), and control (30 minutes quiet rest). In each condition, baseline measures were collected at 8:00am with serial follow-ups at hours zero, one, two, four, six, and eight.

Results: Area-under-the-curve and time-to-peak PCA velocity during the visual search were attenuated at hour zero following high-intensity intervals (all p < 0.05); however, these NVC metrics recovered at hour one (all p > 0.13). Conversely, baseline PCA velocity, peak PCA velocity, and the relative percent increase were not different following high-intensity intervals compared to baseline (all p > 0.26). No NVC metrics differed from baseline following both moderate exercise and control conditions (all p > 0.24). The majority of the NVC parameters demonstrated high levels of reliability (intraclass correlation coefficient: >0.90).

Conclusion: Future NVC assessments can take place a minimum of one hour following exercise. Moreover, all metrics did not change across the control condition, therefore future studies using this methodology can reliably quantify NVC between 8:00am and 7:00 pm.
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http://dx.doi.org/10.14814/phy2.14695DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7814491PMC
January 2021

The impact of high- and moderate-intensity exercise on near-point of convergence metrics.

Brain Inj 2021 Jan 16;35(2):248-254. Epub 2021 Jan 16.

Concussion Research Laboratory, Faculty of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada.

: Near point of convergence (NPC) assesses the vergence ability of the visuo-oculomotor system; however, little is known regarding: the extent and duration exercise impacts NPC and the between- and within-day reliability of NPC metrics.: An accommodative ruler with a miniature Snellen chart was placed upon the philtrum (upper lip). Participants (n=9) focused upon a 'V' sized 20/20, while the chart was moved at ~1-2 cm/s toward and away from the eyes (twice in each direction). Testing commenced at 8:00am with NPC measures being collected at baseline before three randomized conditions with serial follow-ups occurring at six post-condition timepoints (0-8 hours following). The conditions consisted of 25-minutes high-intensity intervals (10, one-minute intervals at ~85-90% heart-rate reserve), 45-minutes of moderate-intensity exercise (at ~50-60% heart-rate reserve), and a control condition (30-minutes quiet rest).: NPC was not impacted across any of the three conditions (all ). Additionally, NPC measures between baseline conditions and across the control condition displayed very high levels of within-day and between-day reliability (coefficient of variation <3.8%).: Future NPC measures using an accommodative ruler can be taken immediately following exercise and may be pertinent as a complementary tool in the future sideline screening of concussion.
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http://dx.doi.org/10.1080/02699052.2021.1871953DOI Listing
January 2021

An Acute Bout of Soccer Heading Subtly Alters Neurovascular Coupling Metrics.

Front Neurol 2020 24;11:738. Epub 2020 Jul 24.

Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada.

The current investigation examined how a bout of soccer heading may impact brain function. Semi-randomized crossover cohort. Controlled soccer heading. Seven male soccer players (24.1 ± 1.5 years). 40 successful soccer headers were performed in 20 min (25 m, launch velocity ~80 km/h). X2 xPatch recorded linear and rotational head accelerations during each impact. A contact control " condition - ball made body contact, but not by the head; and a no activity time " condition were also completed. Posterior and middle cerebral artery (PCA and MCA, respectively), cerebral blood velocity (CBV) was recorded during a visual task (neurovascular coupling: NVC) alongside SCAT3 symptoms scores pre/post a controlled bout of soccer heading. Cumulative linear and rotational accelerations were 1,574 ± 97.9 g and 313,761 ± 23,966 rads/s, respectively, during heading and changes in SCAT3 symptom number (pre: 2.6 ± 3.0; post: 6.7 ± 6.2, = ) and severity (pre: 3.7 ± 3.6, post: 9.4 ± 7.6, = ) were unchanged. In the PCA, no NVC differences were observed, including: relative CBV increase (28.0 ± 7.6% = ) and total activation (188.7 ± 68.1 cm, = ). However, MCA-derived NVC metrics were blunted following heading, demonstrating decreased relative CBV increase (7.8 ± 3.1%, = ) and decreased total activation (26.7 ± 45.3 cm, = ). Although an acute bout of soccer heading did not result in an increase of concussion-like symptoms, there were alterations in NVC responses within the MCA during a visual task. This suggests an acute bout of repetitive soccer heading can alter CBV regulation within the region of the brain associated with the header impacts.
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http://dx.doi.org/10.3389/fneur.2020.00738DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7396491PMC
July 2020

Alterations in resting cerebrovascular regulation do not affect reactivity to hypoxia, hyperoxia or neurovascular coupling following a SCUBA dive.

Exp Physiol 2020 09 19;105(9):1540-1549. Epub 2020 Jul 19.

Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada.

New Findings: What is the central question of this study? What are the characteristics of cerebral blood flow (CBF) regulation following a single SCUBA dive to a depth of 18 m sea water with a 47 min bottom time. What is the main finding and its importance? Acute alterations in CBF regulation at rest, including extra-cranial vasodilatation, reductions in shear patterns and elevations in intra-cranial blood velocity were observed at rest following a single SCUBA dive. These subtle changes in CBF regulation did not translate into any functional changes in cerebrovascular reactivity to hypoxia or hyperoxia, or neurovascular coupling following a single SCUBA dive.

Abstract: Reductions in vascular function during a SCUBA dive - due to hyperoxia-induced oxidative stress, arterial and venous gas emboli and altered endothelial integrity - may also extend to the cerebrovasculature following return to the surface. This study aimed to characterize cerebral blood flow (CBF) regulation following a single SCUBA dive to a depth of 18 m sea water with a 47 min bottom time. Prior to and following the dive, participants (n = 11) completed (1) resting CBF in the internal carotid (ICA) and vertebral (VA) arteries (duplex ultrasound) and intra-cranial blood velocity (v) of the middle and posterior cerebral arteries (MCAv and PCAv, respectively) (transcranial Doppler ultrasound); (2) cerebrovascular reactivity to acute poikilocapnic hypoxia (i.e. , 0.10) and hyperoxia (i.e. , 1.0); and (3) neurovascular coupling (NVC; regional CBF response to local increases in cerebral metabolism). Global CBF, cerebrovascular reactivity to hypoxia and hyperoxia, and NVC were unaltered following a SCUBA dive (all P > 0.05); however, there were subtle changes in other cerebrovascular metrics post-dive, including reductions in ICA (-13 ± 8%, P = 0.003) and VA (-11 ± 14%, P = 0.021) shear rate, lower ICAv (-10 ± 9%, P = 0.008) and VAv (-9 ± 14%, P = 0.028), increases in ICA diameter (+4 ± 5%, P = 0.017) and elevations in PCAv (+10 ± 19%, P = 0.047). Although we observed subtle alterations in CBF regulation at rest, these changes did not translate into any functional changes in cerebrovascular reactivity to hypoxia or hyperoxia, or NVC. Whether prolonged exposure to hyperoxia and hyperbaria during longer, deeper, colder and/or repetitive SCUBA dives would provoke changes to the cerebrovasculature requires further investigation.
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http://dx.doi.org/10.1113/EP088746DOI Listing
September 2020

Comparison of diurnal variation, anatomical location, and biological sex within spontaneous and driven dynamic cerebral autoregulation measures.

Physiol Rep 2020 06;8(11):e14458

Concussion Research Laboratory, Faculty of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada.

Presently, the literature describing the influence of diurnal variation on dynamic cerebral autoregulation (dCA) metrics is sparse. Additionally, there is little data with respect to dCA comparisons between anterior/posterior circulation beds and biological sexes using squat-stand maneuvers. Eight male and eight female participants (n = 16) performed 5 min of spontaneous upright rest and squat-stand maneuvers at 0.05 and 0.10 Hz across seven time points throughout the day. All testing sessions commenced at 8:00 a.m. each day and dCA parameters were quantified across the cardiac cycle (diastole, mean, and systole) using transcranial Doppler ultrasound to insonate cerebral blood velocity within the middle and posterior cerebral arteries (MCA, PCA). No cardiac cycle alternations were seen spontaneous (all p > .207) while a trend was noted in some driven (all p > .051) dCA metrics. Driven dCA produced much lower coefficient of variances (all <21%) compared with spontaneous (all <58%). Moreover, no sex differences were found within driven metrics (all p > .096). Between vessels, PCA absolute gain was reduced within all spontaneous and driven measures (all p < .014) whereas coherence, phase, and normalized gain were unchanged (all p > .099). There appears to be little influence of diurnal variation on dCA measures across the day (8:00 a.m. to 6:00 p.m.). Absolute gain was blunted in the PCA relative to the MCA and consistent with previous literature, driven methods demonstrated vastly improved reproducibility metrics compared to spontaneous methods. Finally, no dCA differences were found between biological sexes, demonstrating that males and females regulate in a harmonious manner, when females are tested within the early follicular phase of the menstrual cycle.
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http://dx.doi.org/10.14814/phy2.14458DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293969PMC
June 2020

Comparison of cerebrovascular reactivity recovery following high-intensity interval training and moderate-intensity continuous training.

Physiol Rep 2020 06;8(11):e14467

Sport Concussion Research Lab, University of British Columbia, Kelowna, BC, Canada.

A common inclusion criterion when assessing cerebrovascular (CVR) metrics is for individuals to abstain from exercise for 12-24 hr prior to data collections. While several studies have examined CVR during exercise, the literature describing CVR throughout post-exercise recovery is sparse. The current investigation examined CVR measurements in nine participants (seven male) before and for 8 hr following three conditions: 45-min moderate-continuous exercise (at ~50% heart-rate reserve), 25-min high-intensity intervals (ten, one-minute intervals at ~85% heart-rate reserve), and a control day (30-min quiet rest). The hypercapnic (40-60 mmHg) and hypocapnic (25-40 mmHg) slopes were assessed via a modified rebreathing technique and controlled stepwise hyperventilation, respectively. All testing was initiated at 8:00a.m. with transcranial Doppler ultrasound measurements to index cerebral blood velocity performed prior to the condition (pre) with serial follow-ups at zero, one, two, four, six, and eight hours within the middle and posterior cerebral artery (MCA, PCA). Absolute and relative MCA and PCA hypercapnic slopes were attenuated following high-intensity intervals at hours zero and one (all p < .02). No alterations were observed in either hypocapnic or hypercapnic slopes following the control or moderate-continuous exercise (all p > .13), aside from a reduced relative hypercapnic MCA slope at hours zero and one following moderate-continuous exercise (all p < .005). The current findings indicate the common inclusion criteria of a 12-24 hr time restriction on exercise can be reduced to two hours when performing CVR measures. Furthermore, the consistent nature of the CVR indices throughout the control day indicate reproducible testing sessions can be made between 8:00a.m. and 7:00p.m.
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http://dx.doi.org/10.14814/phy2.14467DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276190PMC
June 2020

Effects of high-intensity intervals and moderate-intensity exercise on baroreceptor sensitivity and heart rate variability during recovery.

Appl Physiol Nutr Metab 2020 Oct 28;45(10):1156-1164. Epub 2020 Apr 28.

Concussion Research Laboratory, Faculty of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada.

Numerous studies have examined heart rate variability (HRV) and cardiac baroreceptor sensitivity (BRS) variables during recovery both acutely (under 3 h) and long-term (24, 48, and 72 h) postexercise. However, there is little literature examining HRV and BRS measures between these timepoints. Spontaneous short-term HRV and cardiac BRS measures were collected in 9 participants before and at zero, 1, 2, 4, 6, and 8 h after 3 separate conditions: moderate-intensity continuous exercise (MICE; 45 min at 50% heart rate reserve), high-intensity interval exercise (HIIE; 25 min including ten 1-min intervals at 85% heart rate reserve), and control (30 min quiet rest). HRV measures in the time domain were only affected immediately following HIIE and MICE at hour zero (all < 0.043), whereas frequency-domain metrics were unaltered (all > 0.102). These measures were highly consistent across the control day (all > 0.420). Cardiac BRS was assessed via low-frequency (LF) gain, and revealed reductions following HIIE at hour zero ( < 0.012). Cardiac BRS LF gain remained consistent following MICE and control interventions (all > 0.280). The common practice of waiting 12 to 24 h is overly conservative as the current findings demonstrate measures return to baseline at ∼60 min after exercise. Moreover, these metrics demonstrated high levels of within- and between-day reliability. Previously a 12-h minimum restriction from exercise was required before participation in HRV/BRS studies. Recovery from moderate-intensity exercise for HRV and BRS metrics was <60 min; whereas, high-intensity intervals led to alterations for approximately 60 min. Spontaneous HRV and cardiac BRS demonstrated high levels of within-day reproducibility.
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http://dx.doi.org/10.1139/apnm-2019-0810DOI Listing
October 2020

Dynamic cerebral autoregulation across the cardiac cycle during 8 hr of recovery from acute exercise.

Physiol Rep 2020 03;8(5):e14367

Concussion Research Laboratory, Faculty of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada.

Current protocols examining cerebral autoregulation (CA) parameters require participants to refrain from exercise for 12-24 hr, however there is sparse objective evidence examining the recovery trajectory of these measures following exercise across the cardiac cycle (diastole, mean, and systole). Therefore, this study sought to determine the duration acute exercise impacts CA and the within-day reproducibility of these measures. Nine participants performed squat-stand maneuvers at 0.05 and 0.10 Hz at baseline before three interventions: 45-min moderate-continuous exercise (at 50% heart-rate reserve), 30-min high-intensity intervals (ten, 1-min at 85% heart-rate reserve), and a control day (30-min quiet rest). Squat-stands were repeated at hours zero, one, two, four, six, and eight after each condition. Transcranial doppler ultrasound of the middle cerebral artery (MCA) and the posterior cerebral artery (PCA) was used to characterize CA parameters across the cardiac cycle. At baseline, the systolic CA parameters were different than mean and diastolic components (ps < 0.015), however following both exercise protocols in both frequencies this disappeared until hour four within the MCA (ps > 0.079). In the PCA, phase values were affected only following high-intensity intervals until hour four (ps > 0.055). Normalized gain in all cardiac cycle domains remained different following both exercise protocols (ps < 0.005) and across the control day (p < .050). All systolic differences returned by hour six across all measures (ps < 0.034). Future CA studies may use squat-stand maneuvers to assess the cerebral pressure-flow relationship 6 hr after exercise. Finally, CA measures under this paradigm appear to have negligible within-day variation, allowing for reproducible interpretations to be drawn.
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http://dx.doi.org/10.14814/phy2.14367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7066871PMC
March 2020

Modulation of vestibular-evoked responses prior to simple and complex arm movements.

Exp Brain Res 2020 Apr 11;238(4):869-881. Epub 2020 Mar 11.

School of Health and Exercise Sciences, University of British Columbia Okanagan, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada.

During destabilizing, voluntary arm movements, the vestibular system provides sensory cues related to head motion that are necessary to preserve upright balance. Although sensorimotor processing increases in accordance with task complexity during the preparation phase of reaching, it is unclear whether vestibular signals are also enhanced when maintaining postural control prior to the execution of a voluntary movement. To probe whether vestibular cues are a component of complexity-related increases in sensorimotor processing during movement preparation, vestibular-evoked responses to stochastic (0-25 Hz; root mean square = 1 mA) binaural, bipolar electrical vestibular stimulation (EVS) were examined. These responses were assessed using cumulant density function estimates in the upper and lower limbs prior to ballistic arm movements of varying complexity in both standing (experiment 1) and seated (experiment 2) conditions. In experiment 1, EVS-electromyography (EMG) cumulant density estimates surpassed 95% confidence intervals for biceps and triceps brachii, as well as the left and right medial gastrocnemius. For the latter two muscles, the responses were enhanced 10-18% with increased movement complexity. In experiment 2, the EVS-EMG cumulant density estimates also surpassed 95% confidence intervals in the upper limb, confirming the presence of vestibular-evoked responses while seated; however, the amplitude was significantly less than standing. This study demonstrates the vestibular system contributes to postural stability during the preparation phase of reaching. As such, vestibular-driven signals may be used to update an internal model for upcoming reaching tasks or to prepare for imminent postural disturbances.
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http://dx.doi.org/10.1007/s00221-020-05760-8DOI Listing
April 2020

The Time Course of Motoneuronal Excitability during the Preparation of Complex Movements.

J Cogn Neurosci 2019 06 18;31(6):781-790. Epub 2019 Mar 18.

University of British Columbia.

For a simple RT task, movement complexity increases RT and also corticospinal excitability, as measured by the motor evoked potential (MEP) elicited by TMS of the motor cortex. However, it is unknown if complexity-related increases in corticospinal excitability during the preparation of movement are mediated at the cortical or spinal level. The purposes of this study were to establish a time course of motoneuronal excitability before prime mover activation and to assess task-dependent effects of complex movements on motoneuronal and cortical excitability in a simple RT paradigm. It was hypothesized that motoneuronal and cortical excitability would increase before prime mover activation and in response to movement complexity. In a seated position, participants completed ballistic elbow extension/flexion movements with their dominant arm to one, two, or three targets. TMS and transmastoid stimulation (TS) were delivered at 0%, 70%, 80% or 90% of mean premotor RT for each complexity level. Stimulus intensities were set to elicit MEPs and cervicomedullary MEPs (CMEPs) of ∼10% of the maximal M-wave in the triceps brachii. Compared with 0% RT, motoneuronal excitability (CMEP amplitude) was already 10% greater at 70% RT. CMEP amplitude also increased with movement complexity as both the two- and three-movement conditions had greater motoneuronal excitability than the one-movement condition ( < .038). Importantly, when normalized to the CMEP, there was no increase in MEP amplitude. This suggests that complexity-related increases in corticospinal excitability are likely to be mediated more by increased excitability at a motoneuronal than cortical level.
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http://dx.doi.org/10.1162/jocn_a_01394DOI Listing
June 2019

Corticospinal excitability is enhanced while preparing for complex movements.

Exp Brain Res 2019 Mar 4;237(3):829-837. Epub 2019 Jan 4.

School of Health and Exercise Sciences, University of British Columbia -Okanagan, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada.

Movement complexity is known to increase reaction time (RT). More recently, transcranial magnetic stimulation (TMS) of the motor cortex has revealed that movement complexity can alter corticospinal excitability. However, the impact of a sequential addition of movement components on corticospinal excitability during the preparatory phase of a simple RT task is unknown. Thus, the purpose of this study was to examine how motor evoked potentials (MEPs) in the premotor period were affected by the complexity of a movement in a simple RT paradigm. Participants (n = 12) completed ballistic movements with their dominant arm, in which they directed a robotic handle to one, two or three targets (32 trials per condition). TMS was delivered prior to movement at 0, 70, 80 or 90% of each participant's mean premotor RT, at the stimulator intensity which yielded a triceps brachii MEP of ~ 10% the maximal M-wave. As expected, premotor RT slowed with increasing task complexity. Although background electromyographic activity (EMG) of the triceps brachii during the preparation phase did not differ among conditions, MEP amplitude increased with movement complexity (i.e., MEPs were greater for the 2- and 3-movement conditions, compared to the 1-movement condition at 80% of premotor RT). We propose the lengthened RTs could be due in part to less suppression of particular motor circuits, while other circuitry is responsible for the increased MEPs. This study demonstrates that, prior to movement, corticospinal excitability increases as a consequence of movement complexity.
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http://dx.doi.org/10.1007/s00221-018-05464-0DOI Listing
March 2019