Browsing by Subject "Transcranial direct current stimulation"

Now showing 1 - 7 of 7
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    Cerebellar tDCS consistency and metabolite changes: A recommendation to decrease barriers to replicability
    (Elsevier, 2020-11) Moussa-Tooks, Alexandra B.; Burroughs, Leah P.; Rejimon, Abinand C.; Cheng, Hu; Hetrick, William P.; Psychiatry, School of Medicine
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    The Influence of Transcranial Direct Current Stimulation on Shooting Performance in Elite Deaflympic Athletes: A Case Series
    (MDPI, 2022-05-25) Pantovic, Milan; Macak, Drazenka; Cokorilo, Nebojsa; Moonie, Sheniz; Riley, Zachary A.; Madic, Dejan M.; Poston, Brach; Kinesiology, School of Health and Human Sciences
    Transcranial direct current stimulation (tDCS) has been shown to improve motor learning in numerous studies. However, only a few of these studies have been conducted on elite-level performers or in complex motor tasks that have been practiced extensively. The purpose was to determine the influence of tDCS applied to the dorsolateral prefrontal cortex (DLPFC) on motor learning over multiple days on 10-m air rifle shooting performance in elite Deaflympic athletes. Two male and two female elite Deaflympic athletes (World, European, and National medalists) participated in this case series. The study utilized a randomized, double-blind, SHAM-controlled, cross-over design. Anodal tDCS or SHAM stimulation was applied to the left DLPFC for 25 min with a current strength of 2 mA concurrent with three days of standard shooting practice sessions. Shooting performance was quantified as the points and the endpoint error. Separate 2 Condition (DLPFC-tDCS, SHAM) × 3 Day (1,2,3) within-subjects ANOVAs revealed no significant main effects or interactions for either points or endpoint error. These results indicate that DLPFC-tDCS applied over multiple days does not improve shooting performance in elite athletes. Different stimulation parameters or very long-term (weeks/months) application of tDCS may be needed to improve motor learning in elite athletes.
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    Motor Learning in a Complex Motor Task Is Unaffected by Three Consecutive Days of Transcranial Alternating Current Stimulation
    (MDPI, 2024-07-23) Wilkins, Erik W.; Pantovic, Milan; Noorda, Kevin J.; Premyanov, Mario I.; Boss, Rhett; Davidson, Ryder; Hagans, Taylor A.; Riley, Zachary A.; Poston, Brach; Exercise & Kinesiology, School of Health and Human Sciences
    Transcranial alternating current stimulation (tACS) delivered to the primary motor cortex (M1) can increase cortical excitability, entrain neuronal firing patterns, and increase motor skill acquisition in simple motor tasks. The primary aim of this study was to assess the impact of tACS applied to M1 over three consecutive days of practice on the motor learning of a challenging overhand throwing task in young adults. The secondary aim was to examine the influence of tACS on M1 excitability. This study implemented a double-blind, randomized, SHAM-controlled, between-subjects experimental design. A total of 24 healthy young adults were divided into tACS and SHAM groups and performed three identical experimental sessions that comprised blocks of overhand throwing trials of the right dominant arm concurrent with application of tACS to the left M1. Performance in the overhand throwing task was quantified as the endpoint error. Motor evoked potentials (MEPs) were assessed in the right first dorsal interosseus (FDI) muscle with transcranial magnetic stimulation (TMS) to quantify changes in M1 excitability. Endpoint error was significantly decreased in the post-tests compared with the pre-tests when averaged over the three days of practice (p = 0.046), but this decrease was not statistically significant between the tACS and SHAM groups (p = 0.474). MEP amplitudes increased from the pre-tests to the post-tests (p = 0.003), but these increases were also not different between groups (p = 0.409). Overall, the main findings indicated that tACS applied to M1 over multiple days does not enhance motor learning in a complex task to a greater degree than practice alone (SHAM).
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    Multifocal Transcranial Direct Current Stimulation to Modulate Motor Learning
    (2025-03) Greenwell, Davin Ross; Riley, Zachary; Kaleth, Anthony; Naugle, Kelly; Streepey, Jake; Metzler-Wilson, Kristen
    Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that modulates neural excitability in targeted brain regions, influencing processes such as motor learning. While tDCS has been previously shown to benefit motor skill acquisition, much of this research has focused on relatively simple, unimanual tasks. Conversely, the effects of tDCS on more complex, bimanual motor tasks remain understudied, with existing findings often yielding mixed results. This inconsistency poses challenges for translating laboratory findings to functional, real-world motor skills, which frequently involve coordinated, two-handed movements and heightened cognitive demands. Emerging evidence suggests that multifocal tDCS paradigms, which simultaneously target multiple brain regions, may provide enhanced learning effects, particularly for complex motor tasks. Unlike traditional monofocal stimulation protocols that focus on the primary motor cortex (M1) or cerebellum individually, multifocal approaches may better address the neural dynamics underlying bimanual coordination and interhemispheric interactions. The purpose of this dissertation was to investigate the potential of multifocal tDCS to enhance motor learning in complex tasks, examining both unimanual and bimanual skill acquisition. This research involved a series of studies beginning with monofocal tDCS applied to M1 and the cerebellum during a non-dominant unimanual rhythm-timing task and culminating in a multifocal “tri-focal” stimulation protocol during a bimanual motor learning task. In Study One, we compared the effects of excitatory M1 stimulation against excitatory and inhibitory cerebellar and sham stimulation. While none of the monofocal tDCS conditions significantly enhanced learning compared to sham, small, non-significant trends were observed which informed the design of Study Two. Here, we observed that combining excitatory M1 stimulation with inhibitory cerebellar stimulation resulted in significant and robust improvements in motor learning. In Study Three, we found that bilateral M1 stimulation significantly enhanced the early stages of bimanual skill learning at lower intensities. However, Study Four revealed that increasing stimulation intensity or adding inhibitory cerebellar stimulation impaired bimanual learning. Together, these findings contribute to a growing understanding of how multifocal stimulation paradigms can be tailored to enhance motor learning in real-world tasks while underscoring the importance of carefully optimizing stimulation parameters to task-specific demands.
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    Non-Dominant Hemisphere Excitability Is Unaffected during and after Transcranial Direct Current Stimulation of the Dominant Hemisphere
    (MDPI, 2024-07-12) Wilkins, Erik W.; Young, Richard J.; Houston, Daniel; Kawana, Eric; Lopez Mora, Edgar; Sunkara, Meghana S.; Riley, Zachary A.; Poston, Brach; Exercise & Kinesiology, School of Health and Human Sciences
    Transcranial direct current stimulation (tDCS) increases primary motor cortex (M1) excitability and improves motor performance when applied unilaterally to the dominant hemisphere. However, the influence of tDCS on contralateral M1 excitability both during and after application has not been quantified. The purpose was to determine the influence of tDCS applied to the dominant M1 on the excitability of the contralateral non-dominant M1. This study employed a double-blind, randomized, SHAM-controlled, within-subject crossover experimental design. Eighteen young adults performed two experimental sessions (tDCS, SHAM) in counterbalanced order separated by a one-week washout. Transcranial magnetic stimulation (TMS) was used to quantify the excitability of the contralateral M1 to which anodal tDCS was applied for 20 min with a current strength of 1 mA. Motor evoked potential (MEP) amplitudes were assessed in 5 TMS test blocks (Pre, D5, D10, D15, and Post). The Pre and Post TMS test blocks were performed immediately before and after tDCS application, whereas the TMS test blocks performed during tDCS were completed at the 5, 10, and 15 min stimulation timepoints. MEPs were analyzed with a 2 condition (tDCS, SHAM) × 5 test (Pre, D5, D10, D15, Post) within-subject ANOVA. The main effect for condition (p = 0.213), the main effect for test (p = 0.502), and the condition × test interaction (p = 0.860) were all not statistically significant. These results indicate that tDCS does not modulate contralateral M1 excitability during or immediately after application, at least under the current set of common tDCS parameters of stimulation.
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    Polarity- and Intensity-Independent Modulation of Timing During Delay Eyeblink Conditioning Using Cerebellar Transcranial Direct Current Stimulation
    (SpringerLink, 2020-06) Mitroi, Jessica; Burroughs, Leah; Moussa-Tooks, Alexandra B.; Bolbecker, Amanda R.; Lundin, Nancy B.; O’Donnell, Brian F.; Hetrick, William P.; Psychiatry, School of Medicine
    Delay eyeblink conditioning (dEBC) is widely used to assess cerebellar-dependent associative motor learning, including precise timing processes. Transcranial direct current stimulation (tDCS), noninvasive brain stimulation used to indirectly excite and inhibit select brain regions, may be a promising tool for understanding how functional integrity of the cerebellum influences dEBC behavior. The aim of this study was to assess whether tDCS-induced inhibition (cathodal) and excitation (anodal) of the cerebellum differentially impact timing of dEBC. A standard 10-block dEBC paradigm was administered to 102 healthy participants. Participants were randomized to stimulation conditions in a double-blind, between-subjects sham-controlled design. Participants received 20-min active (anodal or cathodal) stimulation at 1.5 mA (n = 20 anodal, n = 22 cathodal) or 2 mA (n = 19 anodal, n = 21 cathodal) or sham stimulation (n = 20) concurrently with dEBC training. Stimulation intensity and polarity effects on percent conditioned responses (CRs) and CR peak and onset latency were examined using repeated-measures analyses of variance. Acquisition of CRs increased over time at a similar rate across sham and all active stimulation groups. CR peak and onset latencies were later, i.e., closer to air puff onset, in all active stimulation groups compared to the sham group. Thus, tDCS facilitated cerebellar-dependent timing of dEBC, irrespective of stimulation intensity and polarity. These findings highlight the feasibility of using tDCS to modify cerebellar-dependent functions and provide further support for cerebellar contributions to human eyeblink conditioning and for exploring therapeutic tDCS interventions for cerebellar dysfunction.
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    Transcranial Direct Current Stimulation of Primary Motor Cortex over Multiple Days Improves Motor Learning of a Complex Overhand Throwing Task
    (MDPI, 2023-10-10) Pantovic, Milan; Lima de Albuquerque, Lidio; Mastrantonio, Sierra; Pomerantz, Austin S.; Wilkins, Erik W.; Riley, Zachary A.; Guadagnoli, Mark A.; Poston, Brach; Exercise & Kinesiology, School of Health and Human Sciences
    Transcranial direct current stimulation (tDCS) applied to the primary motor cortex (M1) improves motor learning in relatively simple motor tasks performed with the hand and arm. However, it is unknown if tDCS can improve motor learning in complex motor tasks involving whole-body coordination with significant endpoint accuracy requirements. The primary purpose was to determine the influence of tDCS on motor learning over multiple days in a complex over-hand throwing task. This study utilized a double-blind, randomized, SHAM-controlled, between-subjects experimental design. Forty-six young adults were allocated to either a tDCS group or a SHAM group and completed three experimental sessions on three consecutive days at the same time of day. Each experimental session was identical and consisted of overhand throwing trials to a target in a pre-test block, five practice blocks performed simultaneously with 20 min of tDCS, and a post-test block. Overhand throwing performance was quantified as the endpoint error. Transcranial magnetic stimulation was used to obtain motor-evoked potentials (MEPs) from the first dorsal interosseus muscle to quantify changes in M1 excitability due to tDCS. Endpoint error significantly decreased over the three days of practice in the tDCS group but not in the SHAM group. MEP amplitude significantly increased in the tDCS group, but the MEP increases were not associated with increases in motor learning. These findings indicate that tDCS applied over multiple days can improve motor learning in a complex motor tasks in healthy young adults.