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Christova M, Sylwester V, Gallasch E, Fresnoza S. Reduced Cerebellar Brain Inhibition and Vibrotactile Perception in Response to Mechanical Hand Stimulation at Flutter Frequency. Cerebellum 2024; 23:67-81. [PMID: 36502502 PMCID: PMC10864223 DOI: 10.1007/s12311-022-01502-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/30/2022] [Indexed: 12/14/2022]
Abstract
The cerebellum is traditionally considered a movement control structure because of its established afferent and efferent anatomical and functional connections with the motor cortex. In the last decade, studies also proposed its involvement in perception, particularly somatosensory acquisition and prediction of the sensory consequences of movement. However, compared to its role in motor control, the cerebellum's specific role or modulatory influence on other brain areas involved in sensory perception, specifically the primary sensorimotor cortex, is less clear. In the present study, we explored whether peripherally applied vibrotactile stimuli at flutter frequency affect functional cerebello-cortical connections. In 17 healthy volunteers, changes in cerebellar brain inhibition (CBI) and vibration perception threshold (VPT) were measured before and after a 20-min right hand mechanical stimulation at 25 Hz. 5 Hz mechanical stimulation of the right foot served as an active control condition. Performance in a Grooved Pegboard test (GPT) was also measured to assess stimulation's impact on motor performance. Hand stimulation caused a reduction in CBI (13.16%) and increased VPT but had no specific effect on GPT performance, while foot stimulation had no significant effect on all measures. The result added evidence to the functional connections between the cerebellum and primary motor cortex, as shown by CBI reduction. Meanwhile, the parallel increase in VPT indirectly suggests that the cerebellum influences the processing of vibrotactile stimulus through motor-sensory interactions.
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Affiliation(s)
- Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Neue Stiftingtalstraße 6/D05, 8010, Graz, Austria.
- Institute of Physiotherapy, University of Applied Sciences FH-Joanneum, Graz, Austria.
| | | | - Eugen Gallasch
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Neue Stiftingtalstraße 6/D05, 8010, Graz, Austria
| | - Shane Fresnoza
- Institute of Psychology, University of Graz, Graz, Austria
- BioTechMed, Graz, Austria
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2
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Budini F, Christova M. Enhanced corticospinal excitability in the tibialis anterior during static stretching of the soleus in young healthy individuals. PLoS One 2023; 18:e0284289. [PMID: 37040389 PMCID: PMC10089312 DOI: 10.1371/journal.pone.0284289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 03/28/2023] [Indexed: 04/12/2023] Open
Abstract
Corticospinal excitability is known to be affected by afferent inflow arising from the proprioceptors during active or passive muscle movements. Also during static stretching (SS) afferent activity is enhanced, but its effect on corticospinal excitability received limited attention and has only been investigated as a single average value spread over the entire stretching period. Using transcranial magnetic stimulation (TMS) the present study was conducted to explore the time course of corticospinal excitability during 30 seconds SS. Motor evoked potentials (MEPs) after TMS were recorded from soleus (SOL) and tibialis anterior (TA) muscles in 14 participants during: a passive dynamic ankle dorsiflexion (DF), at six different time points during maximal individual SS (3, 6, 9, 18, 21 and 25 seconds into stretching), during a passive dynamic ankle plantar flexion (PF) and following SS. To explore the time course of corticospinal excitability during the static lengthened phase of a muscle stretch, the stretching protocol was repeated several times so that it was possible to collect a sufficient number of stimulations at each specific time point into SS, as well as during DF and PF. During passive DF, MEPs amplitude was greater than baseline in both TA and SOL (p = .001 and p = .005 respectively). During SS, MEPs amplitude was greater than baseline in TA (p = .006), but not in SOL. No differences between the investigated time points were found and no trend was detected throughout the stretching time. No effect in either muscle was observed during passive PF and after SS. These results could suggest that an increased activity of secondary afferents from SOL muscle spindles exert a corticomotor facilitation on TA. The muscle-nonspecific response observed during passive DF could instead be attributed to an increased activation within the sensorimotor cortical areas as a result of the awareness of the foot passive displacements.
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Affiliation(s)
- Francesco Budini
- Institute of Human Movement Science, Sport and Health, Graz University, Graz, Austria
| | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria
- Institute of Physiotherapy, Institute of Applied Sciences FH-Joanneum, Graz, Austria
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3
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Simi H, Guggenberger B, Holler P, Christova M, Pilz R, Staubmann W. Dual task test: Screening procedure for early detection of cognitive impairment among healthy adults. Eur J Public Health 2022. [DOI: 10.1093/eurpub/ckac130.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Early detection of cognitive impairment can slow progression to dementia when using appropriate therapy. For early detection of dementia dual task combining cognitive tasks and walking might be suitable, since individuals with cognitive impairment have shown greater changes in gait specific parameters on dual task test (DT) compared to single task test (ST). This study investigates whether these changes correlate with poorer cognitive function in healthy older adults.
Methods
In a cross-sectional study 174 healthy adults (66,48±4,26years; 40%female) completed the Cognitive Functions Dementia Test (CFD), with a lower CFD index indicating lower cognitive function. Participants performed ST (walking 20m) and DT (walking 20m & counting backwards), in which step frequency, stride length and gait speed were monitored by Pablo sensors. Cognitive cost (CC) was determined for each gait variable. CC represents a change score between SD & DT and quantifies cognitive demands, with higher CC indicating poorer cognitive function. Pearson correlations and stepwise linear regression adjusted for age and gender were applied to analyze the association between CFD Index (dependent variable) and CC gate variables (predictors) (α = 5%).
Results
Significant correlations were observed between CFD Index and CC step frequency (p=.014, r=-.187), CC stride length (p=.037, r=-.160) and CC gait speed (p=.002, r=-.232). Since gait variables were intercorrelated (multicollinearity), only gait speed was significant predictor for CFD Index (ß = -.243, p<.001, R2 = .053) in a stepwise adjusted regression model.
Conclusions
Changes in gait speed might be sensitive enough to indicate differences of cognitive performance among older individuals. Therefore, DT could be included in screening procedures as alert for potential cognitive decline.
Key messages
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Affiliation(s)
- H Simi
- Sport Science Laboratory, FH JOANNEUM, University of Applied Sciences, Bad Gleichenberg, Austria
| | - B Guggenberger
- Institute of Physiotherapy, FH JOANNEUM, University of Applied Sciences , Graz, Austria
- Department of Orthopaedics & Trauma, Medical University of Graz , Graz, Austria
| | - P Holler
- Sport Science Laboratory, FH JOANNEUM, University of Applied Sciences, Bad Gleichenberg, Austria
| | - M Christova
- Institute of Physiotherapy, FH JOANNEUM, University of Applied Sciences , Graz, Austria
- Section of Physiology, Otto Loewi Resarch Centre, Medical University of Graz , Graz, Austria
| | - R Pilz
- Institute of Dietetics & Nutrition, FH JOANNEUM, University of Applied Sciences , Graz, Austria
| | - W Staubmann
- Institute of Dietetics & Nutrition, FH JOANNEUM, University of Applied Sciences , Graz, Austria
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Christova M, Strohmaier R, Fuchs-Neuhold B, Guggenberger B, Loder-Fink B, Draxler T, Palli C, Simi H, Schadenbauer S, Nischelwitzer A, Sprung G, Pilz R, Darkow R, Staubmann W. Mixed Reality Prototype of Multimodal Screening for Early Detection of Cognitive Impairments in Elderly Individuals: Protocol Development and Usability Study (Preprint). JMIR Res Protoc 2022; 11:e39513. [PMID: 36239994 PMCID: PMC9617182 DOI: 10.2196/39513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/28/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022] Open
Abstract
Background The early diagnosis of cognitive impairments is an important step in the adequate management of dementia. The project “Smart Cognition & Behaviour Screening powered by Augmented Reality” (SCOBES-AR) aims to develop a multimodal screening tool (MST) for the early detection of cognitive impairments using augmented and virtual reality. The first project phase selected validated assessments for combination with the MST and tested it in 300 healthy older adults. Objective This study established a protocol for the implementation and usability of a mixed reality (MR)–enhanced multidisciplinary screening tool for the early detection of cognitive impairments in older adults. The developed MST will be partially enhanced by MR, which is a combination of augmented reality (AR) and virtual reality (VR). This MR-enhanced prototype of the screening tool (MR-MST) will be tested and compared to the previously developed MST. The usability of the prototype will also be examined. Methods This single-center observational crossover design study screens 100 healthy participants (aged 60-75 years) for cognitive decline using a specially developed MST (assessment of cognitive functions, olfactory sensitivity, nutritional preferences, gait parameters, reaction times, and activities of daily living) and an MR-enhanced MST in which the assessments of cognitive functions, reaction time, activities of daily living, and gait will be performed using tailor-made software and AR and VR hardware. The results of the MR-enhanced MST will be compared to those without MR. The usability of the developed MR-enhanced MST will be tested on 10 investigators and 10 test participants using observed summative evaluation and the codiscovery method, and on 2 usability experts using the codiscovery and cognitive walkthrough methods. Results This study was funded by the Austrian Research Promotion Agency (grant 866873) and received approval from the ethics committee of the Medical University of Graz. The MR-MST and the experimental protocol for this study were developed. All participants gave written informed consent. As of July 15, 2022, a total of 70 participants have been screened. Data analysis and dissemination are scheduled for completion by September 2023. Conclusions The development and testing of the MR-MST is an important step toward the establishment of the best practice procedure for the implementation of AR and VR in the screening of cognitive declines in older adults. It will help improve our knowledge of the usability and applicability of the developed prototype and promote further advancement in AR and VR technologies to be used in therapeutic settings. International Registered Report Identifier (IRRID) DERR1-10.2196/39513
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Affiliation(s)
- Monica Christova
- Institute of Physiotherapy, University of Applied Sciences FH JOANNEUM, Graz, Austria
- Section of Physiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Robert Strohmaier
- Institute of Business Informatics and Data Science, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Bianca Fuchs-Neuhold
- Institute of Dietetics and Nutrition, University of Applied Sciences FH JOANNEUM, Graz, Austria
- Institute of Health and Tourism Management, University of Applied Sciences FH JOANNEUM, Bad Gleichenberg, Austria
| | - Bernhard Guggenberger
- Institute of Physiotherapy, University of Applied Sciences FH JOANNEUM, Graz, Austria
- Department of Orthopaedics and Trauma, Medical University of Graz, Graz, Austria
| | - Brigitte Loder-Fink
- Institute of Occupational Therapy, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Theresa Draxler
- Institute of Dietetics and Nutrition, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Christoph Palli
- Institute of Health Care and Nursing, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Helmut Simi
- Institute of Health and Tourism Management, University of Applied Sciences FH JOANNEUM, Bad Gleichenberg, Austria
| | - Sandra Schadenbauer
- Institute of Business Informatics and Data Science, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Alexander Nischelwitzer
- Institute of Business Informatics and Data Science, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Gerhard Sprung
- Institute of Business Informatics and Data Science, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - René Pilz
- Department of Psychiatry and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Robert Darkow
- Institute of Logopedics, University of Applied Sciences FH JOANNEUM, Graz, Austria
| | - Wolfgang Staubmann
- Institute of Dietetics and Nutrition, University of Applied Sciences FH JOANNEUM, Graz, Austria
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Fresnoza S, Mayer RM, Schneider KS, Christova M, Gallasch E, Ischebeck A. Modulation of proper name recall by transcranial direct current stimulation of the anterior temporal lobes. Sci Rep 2022; 12:5735. [PMID: 35388106 PMCID: PMC8987057 DOI: 10.1038/s41598-022-09781-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 03/08/2022] [Indexed: 01/11/2023] Open
Abstract
We often fail to recall another person's name. Proper names might be more difficult to memorize and retrieve than other pieces of knowledge, such as one's profession because they are processed differently in the brain. Neuroimaging and neuropsychological studies associate the bilateral anterior temporal lobes (ATL) in the retrieval of proper names and other person-related knowledge. Specifically, recalling a person's name is thought to be supported by the left ATL, whereas recalling specific information such as a person's occupation is suggested to be subserved by the right ATL. To clarify and further explore the causal relationship between both ATLs and proper name retrieval, we stimulated these regions with anodal, cathodal and sham transcranial direct current stimulation (tDCS) while the participants memorized surnames (e.g., Mr. Baker) and professions (e.g., baker) presented with a person’s face. The participants were then later asked to recall the surname and the profession. Left ATL anodal stimulation resulted in higher intrusion errors for surnames than sham, whereas right ATL anodal stimulation resulted in higher overall intrusion errors, both, surnames and professions, compared to cathodal stimulation. Cathodal stimulation of the left and right ATL had no significant effect on surname and profession recall. The results indicate that the left ATL plays a role in recalling proper names. On the other hand, the specific role of the right ATL remaines to be explored.
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Affiliation(s)
- Shane Fresnoza
- Institute of Psychology, University of Graz, Universitätsplatz 2/DG, 8010, Graz, Austria. .,BioTechMed, Graz, Austria.
| | - Rosa-Maria Mayer
- Institute of Psychology, University of Graz, Universitätsplatz 2/DG, 8010, Graz, Austria
| | | | - Monica Christova
- Section of Physiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria.,Institute for Physiotherapy, University of Applied Sciences, FH-Joanneum, Graz, Austria
| | - Eugen Gallasch
- Section of Physiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Anja Ischebeck
- Institute of Psychology, University of Graz, Universitätsplatz 2/DG, 8010, Graz, Austria.,BioTechMed, Graz, Austria
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Fresnoza S, Christova M, Purgstaller S, Jehna M, Zaar K, Hoffermann M, Mahdy Ali K, Körner C, Gallasch E, von Campe G, Ischebeck A. Dissociating Arithmetic Operations in the Parietal Cortex Using 1 Hz Repetitive Transcranial Magnetic Stimulation: The Importance of Strategy Use. Front Hum Neurosci 2020; 14:271. [PMID: 32765240 PMCID: PMC7378795 DOI: 10.3389/fnhum.2020.00271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 06/16/2020] [Indexed: 11/13/2022] Open
Abstract
The triple-code model (TCM) of number processing suggests the involvement of distinct parietal cortex areas in arithmetic operations: the bilateral horizontal segment of the intraparietal sulcus (hIPS) for arithmetic operations that require the manipulation of numerical quantities (e.g., subtraction) and the left angular gyrus (AG) for arithmetic operations that require the retrieval of answers from long-term memory (e.g., multiplication). Although neuropsychological, neuroimaging, and brain stimulation studies suggest the dissociation of these operations into distinct parietal cortex areas, the role of strategy (online calculation vs. retrieval) is not yet fully established. In the present study, we further explored the causal involvement of the left AG for multiplication and left hIPS for subtraction using a neuronavigated repetitive transcranial magnetic stimulation (rTMS) paradigm. Stimulation sites were determined based on an fMRI experiment using the same tasks. To account for the effect of strategy, participants were asked whether they used retrieval or calculation for each individual problem. We predicted that the stimulation of the left AG would selectively disrupt the retrieval of the solution to multiplication problems. On the other hand, stimulation of the left hIPS should selectively disrupt subtraction. Our results revealed that left AG stimulation was detrimental to the retrieval and online calculation of solutions for multiplication problems, as well as, the retrieval (but not online calculation) of the solutions to subtraction problems. In contrast, left hIPS stimulation had no detrimental effect on both operations regardless of strategy.
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Affiliation(s)
- Shane Fresnoza
- Institute of Psychology, University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria.,Department of Physiotherapy, University of Applied Sciences FH-Joanneum Graz, Graz, Austria
| | | | - Margit Jehna
- Department of Radiology, Medical University of Graz, Graz, Austria
| | - Karla Zaar
- Department of Neurosurgery, Medical University of Graz, Graz, Austria
| | - Markus Hoffermann
- Department of Neurosurgery, Medical University of Graz, Graz, Austria
| | - Kariem Mahdy Ali
- Department of Neurosurgery, Medical University of Graz, Graz, Austria
| | - Christof Körner
- Institute of Psychology, University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Eugen Gallasch
- BioTechMed, Graz, Austria.,Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria
| | - Gord von Campe
- Department of Neurosurgery, Medical University of Graz, Graz, Austria
| | - Anja Ischebeck
- Institute of Psychology, University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
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Budini F, Rafolt D, Christova M, Gallasch E, Tilp M. The Recovery of Muscle Spindle Sensitivity Following Stretching Is Promoted by Isometric but Not by Dynamic Muscle Contractions. Front Physiol 2020; 11:905. [PMID: 32848855 PMCID: PMC7418680 DOI: 10.3389/fphys.2020.00905] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 07/06/2020] [Indexed: 11/13/2022] Open
Abstract
It is often suggested that stretching-related changes in performance can be partially attributed to stretching-induced neural alterations. Recent evidence though shows that neither spinal nor cortico-spinal excitability are susceptible of a long-lasting effect and only the amplitude of stretch or tap reflex (TR) is reduced up to several minutes. Since afferents from muscle spindles contribute to voluntary muscle contractions, muscle stretching could be detrimental to muscle performance. However, the inhibition of muscle spindle sensitivity should be reversed as soon as the stretched muscle contracts again, due to α-γ co-activation. The present work evaluated which type of muscle contraction (static or dynamic) promotes the best recovery from the inhibition in spindle sensitivity following static stretching. Fifteen students were tested for TR at baseline and after 30 s maximal individual static stretching of the ankle plantar flexors followed by one of three randomized interventions (isometric plantar flexor MVC, three counter movement jumps, and no contraction/control). Ten TRs before and 20 after the procedures were induced with intervals of 30 s up to 10 min after static stretching. The size of the evoked TRs (peak to peak amplitude of the EMG signal) following stretching without a subsequent contraction (control) was on average reduced by 20% throughout the 10 min following the intervention and did not show a recovery trend. Significant decrease in relation to baseline were observed at 9 of the 20 time points measured. After MVC of plantar flexors, TR recovered immediately showing no differences with baseline at none of the investigated time points. Following three counter movement jumps it was observed a significant 34.4% group average inhibition (p < 0.0001) at the first time point. This effect persisted for most of the participants for the next measurement (60 s after intervention) with an average reduction of 23.4% (p = 0.008). At the third measurement, 90 s after the procedure, the reflexes were on average still 21.4% smaller than baseline, although significant level was not reached (p = 0.053). From 120 s following the intervention, the reflex was fully recovered. This study suggests that not every type of muscle contraction promotes a prompt recovery of a stretch-induced inhibition of muscle spindle sensitivity.
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Affiliation(s)
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria.,Institute of Physiotherapy, Institute of Applied Sciences FH-Joanneum, Graz, Austria
| | - Eugen Gallasch
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria
| | - Markus Tilp
- Institute for Sport Science, Graz University, Graz, Austria
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Christova M, Gallisch E, Rafolt D. P286 Alternating magnetic fields generated by a rotating permanent magnet decreases the motor cortex excitability. Clin Neurophysiol 2020. [DOI: 10.1016/j.clinph.2019.12.396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fresnoza S, Christova M, Bieler L, Körner C, Zimmer U, Gallasch E, Ischebeck A. Age-Dependent Effect of Transcranial Alternating Current Stimulation on Motor Skill Consolidation. Front Aging Neurosci 2020; 12:25. [PMID: 32116653 PMCID: PMC7016219 DOI: 10.3389/fnagi.2020.00025] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 01/22/2020] [Indexed: 12/30/2022] Open
Abstract
Transcranial alternating current stimulation (tACS) is the application of subthreshold, sinusoidal current to modulate ongoing brain rhythms related to sensory, motor and cognitive processes. Electrophysiological studies suggested that the effect of tACS applied at an alpha frequency (8–12 Hz) was state-dependent. The effects of tACS, that is, an increase in parieto-occipital electroencephalography (EEG) alpha power and magnetoencephalography (MEG) phase coherence, was only observed when the eyes were open (low alpha power) and not when the eyes were closed (high alpha power). This state-dependency of the effects of alpha tACS might extend to the aging brain characterized by general slowing and decrease in spectral power of the alpha rhythm. We additionally hypothesized that tACS will influence the motor cortex, which is involved in motor skill learning and consolidation. A group of young and old healthy adults performed a serial reaction time task (SRTT) with their right hand before and after the tACS stimulation. Each participant underwent three sessions of stimulation: sham, stimulation applied at the individual participant’s alpha peak frequency or individual alpha peak frequency (iAPF; α-tACS) and stimulation with iAPF plus 2 Hz (α2-tACS) to the left motor cortex for 10 min (1.5 mA). We measured the effect of stimulation on general motor skill (GMS) and sequence-specific skill (SS) consolidation. We found that α-tACS and α2-tACS improved GMS and SS consolidation in the old group. In contrast, α-tACS minimally improved GMS consolidation but impaired SS consolidation in the young group. On the other hand, α2-tACS was detrimental to the consolidation of both skills in the young group. Our results suggest that individuals with aberrant alpha rhythm such as the elderly could benefit more from tACS stimulation, whereas for young healthy individuals with intact alpha rhythm the stimulation could be detrimental.
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Affiliation(s)
- Shane Fresnoza
- Institute of Psychology University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Monica Christova
- Otto Loewi Research Center, Division of Physiology, Medical University of Graz, Graz, Austria.,Institute of Physiotherapy, University of Applied Sciences FH-JOANNEUM, Graz, Austria
| | - Lara Bieler
- Institute of Psychology University of Graz, Graz, Austria.,Otto Loewi Research Center, Division of Physiology, Medical University of Graz, Graz, Austria
| | - Christof Körner
- Institute of Psychology University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Ulrike Zimmer
- Institute of Psychology University of Graz, Graz, Austria.,Faculty of Human Sciences, Medical School Hamburg (MSH), Hamburg, Germany
| | - Eugen Gallasch
- BioTechMed, Graz, Austria.,Otto Loewi Research Center, Division of Physiology, Medical University of Graz, Graz, Austria
| | - Anja Ischebeck
- Institute of Psychology University of Graz, Graz, Austria.,Otto Loewi Research Center, Division of Physiology, Medical University of Graz, Graz, Austria
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Nardone R, Versace V, Sebastianelli L, Brigo F, Christova M, Scarano GI, Saltuari L, Trinka E, Hauer L, Sellner J. Transcranial magnetic stimulation in subjects with phantom pain and non-painful phantom sensations: A systematic review. Brain Res Bull 2019; 148:1-9. [DOI: 10.1016/j.brainresbull.2019.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 03/03/2019] [Accepted: 03/05/2019] [Indexed: 12/18/2022]
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Budini F, Kemper D, Christova M, Gallasch E, Rafolt D, Tilp M. Five minutes static stretching influences neural responses at spinal level in the background of unchanged corticospinal excitability. J Musculoskelet Neuronal Interact 2019; 19:30-37. [PMID: 30839301 PMCID: PMC6454261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES Corticospinal tract excitability and spinal reflex pathways are transiently affected by short applications of static stretching. However, it remains unclear whether the duration and magnitude of these neurophysiological responses can be increased with a longer duration of the applied stretch. The purpose of this study was to investigate alterations in cortical and spinal excitability following five minutes static stretching. METHODS Seventeen participants (22.8±2.3 years old) were tested for the tendon tap reflex (T-reflex), Hoffman reflex (H-reflex) and motor-evoked potentials (MEPs) after transcranial magnetic stimulation (TMS) of the ankle flexor muscles in two separate occasions: before and after 5 minute static stretching or 5 minute control period, in a randomized order. RESULTS No changes were observed following the control condition. H/M ratio increased by 16.2% after stretching (P=.036). Furthermore, immediately after stretching it was observed a strong inhibition of the T-reflex (57.6% inhibition, P=.003) that persisted up to five minutes after stretching (16.2% inhibition, P=.013) but returned to baseline following 10 minutes. MEPs were not affected by stretching. CONCLUSIONS This study suggests that the neuromuscular responses that follow five minute of static stretching do not influence the excitability of the corticospinal tract and follow a different time course within spinal reflex pathways.
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Affiliation(s)
- Francesco Budini
- Institute for Sport Science, Graz University, Austria,Corresponding author: Francesco Budini, Institut für Sportwissenschaft, Karl-Franzens-Universität, Mozartgasse 14/I 8010 Graz, Austria E-mail:
| | - Daniela Kemper
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria
| | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria,Institute of Physiotherapy, Institute of Applied Sciences FH-Joanneum, Graz, Austria
| | - Eugen Gallasch
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Markus Tilp
- Institute for Sport Science, Graz University, Austria
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Budini F, Christova M, Gallasch E, Rafolt D, Tilp M. Soleus H-Reflex Inhibition Decreases During 30 s Static Stretching of Plantar Flexors, Showing Two Recovery Steps. Front Physiol 2018; 9:935. [PMID: 30061844 PMCID: PMC6054967 DOI: 10.3389/fphys.2018.00935] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/25/2018] [Indexed: 11/22/2022] Open
Abstract
During the period when the ankle joint is kept in a dorsiflexed position, the soleus (SOL) H-reflex is inhibited. The nature of this inhibition is not fully understood. One hypothesis is that the decrease in spinal excitability could be attributed to post-activation depression of muscle spindle afferents due to their higher firing rate during the stretch-and-hold procedure. As the static stretching position is maintained though, a partial restoration of the neurotransmitter is expected and should mirror a decrease in H-reflex inhibition. In the present study, we explored the time course of spinal excitability during a period of stretching. SOL H-reflex was elicited during a passive dorsiflexion movement, at 3, 6, 9, 12, 18, 21, and 25 s during maximal ankle dorsiflexion, during plantar flexion (PF) and after stretching, in 12 healthy young individuals. Measurements during passive dorsiflexion, PF and after stretching were all performed with the ankle at 100° angle; measurements during static stretching were performed at individual maximal dorsiflexion. H-reflex was strongly inhibited during the dorsiflexion movement and at maximal dorsiflexion (p < 0.0001) but recovered during PF and after stretching. During stretching H-reflex showed a recovery pattern (r = 0.836, P = 0.019) with two distinct recovery steps at 6 and 21 s into stretching. It is hypothesized that the H-reflex inhibition observed until 18 s into stretching is the result of post-activation depression of Ia afferent caused by the passive dorsiflexion movement needed to move the ankle into testing position. From 21 s into stretching, the lower inhibition could be caused by a weaker post-activation depression, inhibition from secondary afferents or post-synaptic inhibitions.
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Affiliation(s)
- Francesco Budini
- Institute of Sport Sciences, University of Graz, Graz, Austria.,Institute of Physiotherapy, FH Joanneum - University of Applied Sciences, Graz, Austria
| | - Monica Christova
- Institute of Physiotherapy, FH Joanneum - University of Applied Sciences, Graz, Austria.,Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria
| | - Eugen Gallasch
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Markus Tilp
- Institute of Sport Sciences, University of Graz, Graz, Austria
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13
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Fresnoza S, Christova M, Feil T, Gallasch E, Körner C, Zimmer U, Ischebeck A. The effects of transcranial alternating current stimulation (tACS) at individual alpha peak frequency (iAPF) on motor cortex excitability in young and elderly adults. Exp Brain Res 2018; 236:2573-2588. [PMID: 29943239 PMCID: PMC6153871 DOI: 10.1007/s00221-018-5314-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/14/2018] [Indexed: 11/28/2022]
Abstract
Transcranial alternating current stimulation (tACS) can modulate brain oscillations, cortical excitability and behaviour. In aging, the decrease in EEG alpha activity (8–12 Hz) in the parieto-occipital and mu rhythm in the motor cortex are correlated with the decline in cognitive and motor functions, respectively. Increasing alpha activity using tACS might therefore improve cognitive and motor function in the elderly. The present study explored the influence of tACS on cortical excitability in young and old healthy adults. We applied tACS at individual alpha peak frequency for 10 min (1.5 mA) to the left motor cortex. Transcranial magnetic stimulation was used to assess the changes in cortical excitability as measured by motor-evoked potentials at rest, before and after stimulation. TACS increased cortical excitability in both groups. However, our results also suggest that the mechanism behind the effects was different, as we observed an increase and decrease in intracortical inhibition in the old group and young group, respectively. Our results indicate that both groups profited similarly from the stimulation. There was no indication that tACS was more effective in conditions of low alpha power, that is, in the elderly.
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Affiliation(s)
- Shane Fresnoza
- Institute of Psychology, University of Graz, Graz, Austria. .,Institute of Physiology, Medical University of Graz, Graz, Austria.
| | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria.,Department of Physiotherapy, University of Applied Sciences FH-Joanneum Graz, Graz, Austria
| | - Theresa Feil
- Institute of Psychology, University of Graz, Graz, Austria
| | - Eugen Gallasch
- Institute of Physiology, Medical University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Christof Körner
- Institute of Psychology, University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
| | - Ulrike Zimmer
- Institute of Psychology, University of Graz, Graz, Austria.,Faculty of Human Sciences, Medical School Hamburg (MSH), Hamburg, Germany
| | - Anja Ischebeck
- Institute of Psychology, University of Graz, Graz, Austria.,BioTechMed, Graz, Austria
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14
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Budini F, Christova M, Gallasch E, Kressnik P, Rafolt D, Tilp M. Transient Increase in Cortical Excitability Following Static Stretching of Plantar Flexor Muscles. Front Physiol 2018; 9:530. [PMID: 29942261 PMCID: PMC6004398 DOI: 10.3389/fphys.2018.00530] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/24/2018] [Indexed: 11/13/2022] Open
Abstract
Spinal excitability in humans is inhibited by both passively holding a static position with the muscle lengthened (static stretching) and by a single non-active lengthening movement. However, whilst immediately after a passive lengthening movement the inhibition persists for several seconds, there seem to be an immediate recovery following static stretching. This result is counter intuitive and could be attributed to methodological procedures. Indeed, differently to what has been done until now, in order to study whether static stretching has a transient effect on the neuromuscular pathway, the procedure should be repeated many times and measurements collected at different time points after stretching. In the present study we repeated 60 times 30 s static stretching of ankle plantar flexors and measured tap reflex (T-reflex), Hoffman reflex (H-reflex), and motor evoked potentials (MEPs) from the Soleus muscle at several time points, starting from immediately after until 30 s following the procedure. T-reflex was strongly inhibited (range 31–91%, p = 0.005) and the inhibition persisted for 30 s showing a slow recovery (r = 0.541, p = 0.037). H-reflex was not affected by the procedure. Stretching increased the size of the MEPs (p < 0.0001), differences at times 0 and 2 s after stretching (p = 0.015 and p = 0.047, respectively). These results confirm that static stretching reduces muscle spindle sensitivity. Moreover it is suggested that post-activation depression of Ia afferents, which is commonly considered the cause of H-reflex depression during both dorsiflexion and static stretching, vanished immediately following stretching or is counteracted by an increased corticospinal excitability.
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Affiliation(s)
| | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria.,Institute of Physiotherapy, Institute of Applied Sciences FH-Joanneum, Graz, Austria
| | - Eugen Gallasch
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Graz, Austria
| | - Paul Kressnik
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Markus Tilp
- Institute for Sport Science, Graz University, Graz, Austria
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15
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Fresnoza SM, Christova M, Gallasch E, Feil T, Körner C, Zimmer U, Ischebeck A. T117. The effects of Transcranial Alternating Current Stimulation (tACS) at Individual Alpha Peak Frequency (iAPF) on motor cortex excitability of young and elderly adults. Clin Neurophysiol 2018. [DOI: 10.1016/j.clinph.2018.04.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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16
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Gallasch E, Rafolt D, Postruznik M, Fresnoza S, Christova M. Decrease of motor cortex excitability following exposure to a 20 Hz magnetic field as generated by a rotating permanent magnet. Clin Neurophysiol 2018; 129:1397-1402. [PMID: 29729595 DOI: 10.1016/j.clinph.2018.03.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/14/2018] [Accepted: 03/30/2018] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Rotation of a static magnet over the motor cortex (MC) generates a transcranial alternating magnetic field (tAMF), and a linked alternating electrical field. The aim of this transcranial magnetic stimulation (TMS) study is to investigate whether such fields are able to influence MC excitability, and whether there are parallels to tACS induced effects. METHODS Fourteen healthy volunteers received 20 Hz tAMF stimulation over the MC, over the vertex, and 20 Hz tACS over the MC, each with a duration of 15 min. TMS assessments were performed before and after the interventions. Changes in motor evoked potentials (MEP), short interval intra-cortical inhibition (SICI) and intra-cortical facilitation (ICF) were evaluated. RESULTS The tACS and the tAMF stimulation over the MC affected cortical excitability in a different way. After tAMF stimulation MEP amplitudes and ICF decreased and the effect of SICI increased. After tACS MEP amplitudes increased and there were no effects on SICI and ICF. CONCLUSIONS The recorded single and paired pulse MEPs indicate a general decrease of MC excitability following 15 min of tAMF stimulation. SIGNIFICANCE The effects demonstrate that devices based on rotating magnets are potentially suited to become a novel brain stimulation tool in clinical neurophysiology.
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Affiliation(s)
- Eugen Gallasch
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria.
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Magdalena Postruznik
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria
| | | | - Monica Christova
- Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria; Institute of Physiotherapy, University of Applied Sciences FH-Joanneum, Graz, Austria
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17
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Fresnoza S, Christova M, Bieler L, Körner C, Zimmer U, Gallasch E, Ischebeck A. State-dependent effect of transcranial alternating current stimulation (TACS) on motor skill consolidation. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.3215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Budini F, Gallasch E, Christova M, Rafolt D, Rauscher AB, Tilp M. One minute static stretch of plantar flexors transiently increases H reflex excitability and exerts no effect on corticospinal pathways. Exp Physiol 2017; 102:901-910. [PMID: 28585766 DOI: 10.1113/ep086374] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/24/2017] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What mediates neural responses following static stretching, and how long do these influences last? What is the main finding and its importance? This study shows that 1 min of static stretching inhibits the tendon tap reflex and facilitates the H reflex without influencing motor-evoked potentials. The results indicate that at least two different mechanisms mediate neural responses after static stretching. The purpose of this study was to determine whether the neural responses observed after static stretching are mediated by sensitivity of muscle spindles, spinal excitability or cortical excitability and how long these influences last. Nineteen volunteers (25.7 ± 5.6 years old) were tested for the tendon tap reflex (T-reflex), H reflex and motor-evoked potentials on ankle flexors and extensors immediately, 5 and 10 min after 1 min static stretching applied at individual maximal ankle dorsiflexion, as well as immediately, 5 and 10 min after a control period of the same duration. Comparison of measurements collected immediately after stretching or control conditions revealed that the T-reflex was weaker after stretching than after control (-59.2% P = 0.000). The T-reflex showed a slow recovery rate within the first 150 s after stretching, but 5 min after the inhibition had disappeared. The H reflex increased immediately after stretching (+18.3%, P = 0.036), showed a quick tendency to recover and returned to control values within 5 min from stretching. Motor-evoked potentials were not affected by the procedure. These results suggest that 1 min of static stretching primarily decreases muscle spindle sensitivity and facilitates the H reflex, whereas effects on the motor cortex can be excluded.
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Affiliation(s)
| | - Eugen Gallasch
- Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Monica Christova
- Institute of Physiology, Medical University of Graz, Graz, Austria.,Institute of Physiotherapy, Institute of Applied Sciences FH-Joanneum, Graz, Austria
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | - Markus Tilp
- Institute for Sport Science, Graz University, Graz, Austria
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19
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Nardone R, Golaszewski S, Christova M, Gallasch E, Brigo F, Trinka E. Effects of focal muscle vibration on corticospinal excitability. J Neurol Sci 2017; 375:486-487. [PMID: 28202199 DOI: 10.1016/j.jns.2017.02.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/08/2017] [Indexed: 10/20/2022]
Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Merano, Italy; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria.
| | - Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria
| | | | - Eugen Gallasch
- Department of Physiology, Medical University of Graz, Austria
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Merano, Italy; Department of Neurological and Movement Sciences, University of Verona, Italy
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
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20
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Golaszewski S, Langthaler PB, Schwenker K, Florea C, Christova M, Brigo F, Trinka E, Nardone R. Abnormal cortical synaptic plasticity in minimal hepatic encephalopathy. Brain Res Bull 2016; 125:200-4. [DOI: 10.1016/j.brainresbull.2016.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/23/2016] [Accepted: 07/25/2016] [Indexed: 12/13/2022]
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21
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Nardone R, Langthaler PB, Bathke AC, Höller Y, Brigo F, Lochner P, Christova M, Trinka E. Effects of passive pedaling exercise on the intracortical inhibition in subjects with spinal cord injury. Brain Res Bull 2016; 124:144-9. [DOI: 10.1016/j.brainresbull.2016.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/16/2016] [Accepted: 04/20/2016] [Indexed: 01/13/2023]
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22
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Fresnoza S, Ischebeck A, Christova M, Gallasch E. ID 314 – Dissociating arithmetic processes in the parietal cortex using repetitive transcranial magnetic stimulation. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2015.11.415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Golaszewski S, Schwenker K, Bergmann J, Brigo F, Christova M, Trinka E, Nardone R. Abnormal short-latency synaptic plasticity in the motor cortex of subjects with Becker muscular dystrophy: a rTMS study. Neurosci Lett 2016; 610:218-22. [PMID: 26562314 DOI: 10.1016/j.neulet.2015.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 11/03/2015] [Accepted: 11/05/2015] [Indexed: 11/28/2022]
Abstract
We used repetitive transcranial magnetic stimulation (rTMS) to further investigate motor cortex excitability in 13 patients with Becker muscular dystrophy (BMD), six of them with slight mental retardation. RTMS delivered at 5Hz frequency and suprathreshold intensity progressively increases the size of motor evoked potentials (MEPs) in healthy subjects; the rTMS-induced facilitation of MEPs was significantly reduced in the BMD patients mentally retarded or classified as borderline when compared with age-matched control subjects and the BMD patients with normal intelligence. The increase in the duration of the cortical silent period was similar in both patient groups and controls. These findings suggest an altered cortical short-term synaptic plasticity in glutamate-dependent excitatory circuits within the motor cortex in BMD patients with intellectual disabilities. RTMS studies may shed new light on the physiological mechanisms of cortical involvement in dystrophinopathies.
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Affiliation(s)
- Stefan Golaszewski
- Department of Neurology and Neuroscience Institute, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria; TMS & fMRI Lab, Department of Neurology, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria.
| | - Kerstin Schwenker
- Department of Neurology and Neuroscience Institute, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria; TMS & fMRI Lab, Department of Neurology, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria
| | - Jürgen Bergmann
- Department of Neurology and Neuroscience Institute, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Merano, Italy; Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Italy
| | - Monica Christova
- Department of Physiology, Medical University of Graz, Graz, Austria
| | - Eugen Trinka
- Department of Neurology and Neuroscience Institute, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria
| | - Raffaele Nardone
- Department of Neurology and Neuroscience Institute, Christian Doppler Clinic, Paracelsus Medical University, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Merano, Italy
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24
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Gallasch E, Christova M, Kunz A, Rafolt D, Golaszewski S. Modulation of sensorimotor cortex by repetitive peripheral magnetic stimulation. Front Hum Neurosci 2015; 9:407. [PMID: 26236220 PMCID: PMC4500907 DOI: 10.3389/fnhum.2015.00407] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 07/01/2015] [Indexed: 11/13/2022] Open
Abstract
This study examines with transcranial magnetic stimulation (TMS) and with functional magnetic resonance imaging (fMRI) whether 20 min of repetitive peripheral magnetic stimulation (rPMS) has a facilitating effect on associated motor controlling regions. Trains of rPMS with a stimulus intensity of 150% of the motor threshold (MT) were applied over right hand flexor muscles of healthy volunteers. First, with TMS, 10 vs. 25 Hz rPMS was examined and compared to a control group. Single and paired pulse motor evoked potentials (MEPs) from flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles were recorded at baseline (T0), post rPMS (T1), 30 min post (T2), 1 h post (T3) and 2 h post rPMS (T4). Then, with fMRI, 25 Hz rPMS was compared to sham stimulation by utilizing a finger tapping activation paradigm. Changes in bloodoxygen level dependent (BOLD) contrast were examined at baseline (PRE), post rPMS (POST1) and 1 h post rPMS (POST2). With TMS facilitation was observed in the target muscle (FCR) following 25 Hz rPMS: MEP recruitment curves (RCs) were increased at T1, T2 and T3, and intracortical facilitation (ICF) was increased at T1 and T2. No effects were observed following 10 Hz rPMS. With fMRI the BOLD contrast at the left sensorimotor area was increased at POST1. Compared to inductions protocols based on transcutaneous electrical stimulation and mechanical stimulation, the rPMS induced effects appeared shorter lasting.
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Affiliation(s)
- Eugen Gallasch
- Department of Physiology, Medical University of Graz Graz, Austria
| | - Monica Christova
- Department of Physiology, Medical University of Graz Graz, Austria ; Institute of Physiotherapy, University of Applied Sciences FH-Joanneum Graz, Austria
| | - Alexander Kunz
- Department of Neurology, Paracelsus Medical University of Salzburg Salzburg, Austria
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna Vienna, Austria
| | - Stefan Golaszewski
- Department of Neurology, Paracelsus Medical University of Salzburg Salzburg, Austria
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25
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Nardone R, Höller Y, Orioli A, Brigo F, Christova M, Tezzon F, Golaszewski S, Trinka E. Trigemino-cervical-spinal reflexes after traumatic spinal cord injury. Clin Neurophysiol 2015; 126:983-6. [PMID: 25270243 DOI: 10.1016/j.clinph.2014.08.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 08/20/2014] [Accepted: 08/29/2014] [Indexed: 10/24/2022]
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26
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Christova M, Rafolt D, Gallasch E. Transcranial direct current stimulation improves pegboard test performance and has a positive effect on motor memory. Brain Stimul 2015. [DOI: 10.1016/j.brs.2015.01.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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27
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Nardone R, Höller Y, Tezzon F, Christova M, Schwenker K, Golaszewski S, Trinka E, Brigo F. Neurostimulation in Alzheimer's disease: from basic research to clinical applications. Neurol Sci 2015; 36:689-700. [PMID: 25721941 DOI: 10.1007/s10072-015-2120-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/20/2015] [Indexed: 02/02/2023]
Abstract
The development of different methods of brain stimulation provides a promising therapeutic tool with potentially beneficial effects on subjects with impaired cognitive functions. We performed a systematic review of the studies published in the field of neurostimulation in Alzheimer's disease (AD), from basic research to clinical applications. The main methods of non-invasive brain stimulation are repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Preliminary findings have suggested that both techniques can enhance performances on several cognitive functions impaired in AD. Another non-invasive emerging neuromodulatory approach, the transcranial electromagnetic treatment, was found to reverse cognitive impairment in AD transgenic mice and even improves cognitive performance in normal mice. Experimental studies suggest that high-frequency electromagnetic fields may be critically important in AD prevention and treatment through their action at mitochondrial level. Finally, the application of a widely known invasive technique, the deep brain stimulation (DBS), has increasingly been considered as a therapeutic option also for patients with AD; it has been demonstrated that DBS of fornix/hypothalamus and nucleus basalis of Meynert might improve or at least stabilize cognitive functioning in AD. Initial encouraging results provide support for continuing to investigate non-invasive and invasive brain stimulation approaches as an adjuvant treatment for AD patients.
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Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria,
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28
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Nardone R, Höller Y, Brigo F, Orioli A, Tezzon F, Schwenker K, Christova M, Golaszewski S, Trinka E. Descending motor pathways and cortical physiology after spinal cord injury assessed by transcranial magnetic stimulation: a systematic review. Brain Res 2014; 1619:139-54. [PMID: 25251591 DOI: 10.1016/j.brainres.2014.09.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 08/06/2014] [Accepted: 09/15/2014] [Indexed: 02/02/2023]
Abstract
We performed here a systematic review of the studies using transcranial magnetic stimulation (TMS) as a research and clinical tool in patients with spinal cord injury (SCI). Motor evoked potentials (MEPs) elicited by TMS represent a highly accurate diagnostic test that can supplement clinical examination and neuroimaging findings in the assessment of SCI functional level. MEPs allows to monitor the changes in motor function and evaluate the effects of the different therapeutic approaches. Moreover, TMS represents a useful non-invasive approach for studying cortical physiology, and may be helpful in elucidating the pathophysiological mechanisms of brain reorganization after SCI. Measures of motor cortex reactivity, e.g., the short interval intracortical inhibition and the cortical silent period, seem to point to an increased cortical excitability. However, the results of TMS studies are sometimes contradictory or divergent, and should be replicated in a larger sample of subjects. Understanding the functional changes at brain level and defining their effects on clinical outcome is of crucial importance for development of evidence-based rehabilitation therapy. TMS techniques may help in identifying neurophysiological biomarkers that can reliably assess the extent of neural damage, elucidate the mechanisms of neural repair, predict clinical outcome, and identify therapeutic targets. Some researchers have begun to therapeutically use repetitive TMS (rTMS) in patients with SCI. Initial studies revealed that rTMS can induce acute and short duration beneficial effects especially on spasticity and neuropathic pain, but the evidence is to date still very preliminary and well-designed clinical trials are warranted. This article is part of a Special Issue entitled SI: Spinal cord injury.
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Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria.
| | - Yvonne Höller
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy; Department of Neurological, Neuropsychological, Morphological and Movement Sciences, Section of Clinical Neurology, University of Verona, Italy
| | - Andrea Orioli
- Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy
| | - Frediano Tezzon
- Department of Neurology, Franz Tappeiner Hospital, Merano, Via Rossini 5, 39012 Meran/o (BZ), Italy
| | - Kerstin Schwenker
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
| | - Monica Christova
- Department of Physiology, Medical University of Graz, Graz, Austria
| | - Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University and Center for Cognitive Neuroscience, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Salzburg, Austria
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Christova M, Rafolt D, Golaszewski S, Nardone R, Gallasch E. Electrical stimulation during skill training with a therapeutic glove enhances the induction of cortical plasticity and has a positive effect on motor memory. Behav Brain Res 2014; 270:171-8. [DOI: 10.1016/j.bbr.2014.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/05/2014] [Accepted: 05/12/2014] [Indexed: 11/16/2022]
Affiliation(s)
- Monica Christova
- Department of Physiology, Medical University of Graz, Harrachgasse 21/5, 8010 Graz, Austria; Department of Physiotherapy, University of Applied Sciences FH JOANNEUM, Graz, Austria.
| | - Dietmar Rafolt
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria
| | - Stefan Golaszewski
- Department of Neurology, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Raffaele Nardone
- Department of Neurology, Paracelsus Medical University of Salzburg, Salzburg, Austria; Department of Neurology, F. Tappeiner Hospital, Merano, Italy
| | - Eugen Gallasch
- Department of Physiology, Medical University of Graz, Harrachgasse 21/5, 8010 Graz, Austria
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Christova M, Rafolt D, Golaszewski S, Gallasch E. P666: Lowering neuronal activity with cathodal tDCS shows no effect on anodal tDCS-enhanced online learning but improves the offline leaning. Clin Neurophysiol 2014. [DOI: 10.1016/s1388-2457(14)50759-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Koenig LS, Christova M, Schwenker K, Bartsch H, Luthringshausen G, Gallasch E, Kunz A, Seidl M, Trinka E, Golaszewski S. Modulation of cortical plasticity by whole-hand electrical stimulation in attempt to improve hand motor functions after stroke. J Neurol Sci 2013. [DOI: 10.1016/j.jns.2013.07.1921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Christova M, Rafolt D, Golaszewski S, Gallasch E. P 157. Anodal tDCS during skill learning preconditioned by cathodal tDCS improves motor memory – A TMS study. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.04.234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Nardone R, Golaszewski S, Höller Y, Christova M, Trinka E, Brigo F. Neurophysiological insights into the pathophysiology of REM sleep behavior disorders: A review. Neurosci Res 2013; 76:106-12. [DOI: 10.1016/j.neures.2013.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 03/08/2013] [Accepted: 03/20/2013] [Indexed: 11/24/2022]
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Nardone R, Höller Y, Brigo F, Seidl M, Christova M, Bergmann J, Golaszewski S, Trinka E. Functional brain reorganization after spinal cord injury: Systematic review of animal and human studies. Brain Res 2013; 1504:58-73. [DOI: 10.1016/j.brainres.2012.12.034] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 11/26/2012] [Accepted: 12/24/2012] [Indexed: 12/18/2022]
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Nardone R, Bergmann J, Brigo F, Christova M, Kunz A, Seidl M, Tezzon F, Trinka E, Golaszewski S. Functional evaluation of central cholinergic circuits in patients with Parkinson’s disease and REM sleep behavior disorder: a TMS study. J Neural Transm (Vienna) 2012; 120:413-22. [DOI: 10.1007/s00702-012-0888-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/03/2012] [Indexed: 01/04/2023]
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Nardone R, Bergmann J, Kunz A, Christova M, Brigo F, Tezzon F, Trinka E, Golaszewski S. Cortical afferent inhibition is reduced in patients with idiopathic REM sleep behavior disorder and cognitive impairment: A TMS study. Sleep Med 2012; 13:919-25. [DOI: 10.1016/j.sleep.2012.03.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 03/04/2012] [Accepted: 03/06/2012] [Indexed: 11/30/2022]
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Christova M, Golaszewski S, Ischebeck A, Kunz A, Rafolt D, Nardone R, Gallasch E. Mechanical flutter stimulation induces a lasting response in the sensorimotor cortex as revealed with BOLD fMRI. Hum Brain Mapp 2012; 34:2767-74. [PMID: 22611041 DOI: 10.1002/hbm.22102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 02/02/2012] [Accepted: 03/19/2012] [Indexed: 11/08/2022] Open
Abstract
It has been recently shown that 20 min of mechanical flutter stimulation induces lasting motor cortical excitability changes, as assessed by transcranial magnetic stimulation in relaxed hand muscles. The present functional magnetic resonance imaging (fMRI) study aims to examine if such neuromodulatory changes are reflected in the BOLD signal during a motor test. Therefore, two groups were recruited: one group receiving whole-hand flutter stimulation with a frequency of 25 Hz (FSTIM group, n = 22) and a second group receiving no stimulation (NOSTIM group, n = 22). As motor test finger-to-thumb tapping was performed to activate a wide sensorimotor network during the fMRI measurements. Three fMRI measurements were obtained with this test: before stimulation (PRE), after stimulation (POST1), and 1 h after stimulation (POST2). Three regions of interest (ROIs) were defined: primary motor area (M1), primary somatosensory area (S1), and supplementary motor area. In the absence of baseline differences between both groups, the FSTIM group showed increased movement-related brain activations compared with the NOSTIM group, both at POST1 and POST2. ROI analysis revealed increased blood-oxygenation-level-dependent (BOLD) responses within contralateral S1 (+20%) and M1 (+25%) at POST1, which lasted until POST2. These poststimulatory effects within S1 and M1 obviously reflect neuroplastic changes associated with augmented cortical excitability. These findings are of high clinical relevance, for example, to improve the treatment of stroke patients.
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Affiliation(s)
- Monica Christova
- Department of Physiology, Medical University of Graz, Graz, Austria
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Golaszewski SM, Bergmann J, Christova M, Kunz AB, Kronbichler M, Rafolt D, Gallasch E, Staffen W, Trinka E, Nardone R. Modulation of motor cortex excitability by different levels of whole-hand afferent electrical stimulation. Clin Neurophysiol 2012; 123:193-9. [DOI: 10.1016/j.clinph.2011.06.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 06/06/2011] [Accepted: 06/14/2011] [Indexed: 11/16/2022]
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Nardone R, Christova M, Bratti A, Lochner P, Covi M, Trinka E, Tezzon F, Golaszewski S. Corticospinal tract dysfunction in a patient with acute motor axonal neuropathy (AMAN). Clin Neurol Neurosurg 2011; 113:779-81. [DOI: 10.1016/j.clineuro.2011.07.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Revised: 07/23/2011] [Accepted: 07/26/2011] [Indexed: 11/25/2022]
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Christova M, Rafolt D, Golaszewski S, Gallasch E. P22.7 Outlasting cortical plasticity changes induced by 25 Hz whole-hand mechanical stimulation. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60568-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Gallasch E, Christova M, Rafolt D, Kunz A, Golaszewski S. PTMS24 Modulation of sensorimotor cortex by repetitive peripheral magnetic stimulation. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60677-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Christova M, Rafolt D, Golaszewski S, Gallasch E. Outlasting corticomotor excitability changes induced by 25 Hz whole-hand mechanical stimulation. Eur J Appl Physiol 2011; 111:3051-9. [PMID: 21455615 DOI: 10.1007/s00421-011-1933-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 03/17/2011] [Indexed: 12/19/2022]
Affiliation(s)
- Monica Christova
- Department of Physiology, Medical University of Graz, Harrachgasse 21/5, 8010 Graz, Austria.
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Christova M, Rafolt D, Mayr W, Wilfling B, Gallasch E. Vibration stimulation during non-fatiguing tonic contraction induces outlasting neuroplastic effects. J Electromyogr Kinesiol 2010; 20:627-35. [PMID: 20363152 DOI: 10.1016/j.jelekin.2010.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 03/02/2010] [Accepted: 03/02/2010] [Indexed: 10/19/2022] Open
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Golaszewski SM, Bergmann J, Christova M, Nardone R, Kronbichler M, Rafolt D, Gallasch E, Staffen W, Ladurner G, Beisteiner R. Increased motor cortical excitability after whole-hand electrical stimulation: a TMS study. Clin Neurophysiol 2009; 121:248-54. [PMID: 20036618 DOI: 10.1016/j.clinph.2009.09.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 09/18/2009] [Accepted: 09/26/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To examine the neuromodulatory effect of whole-hand mesh-glove (MG) stimulation on motor cortical pathways, we explored motor cortical excitability before and after suprathreshold whole-hand MG stimulation using transcranial magnetic stimulation (TMS). METHODS Twenty-eight healthy volunteers (14 controls) were studied at baseline, immediately post and 1h post-MG stimulation for 30 min. Motor thresholds (MTs), motor evoked potentials (MEPs) recruitment curve, short intracortical inhibition (SICI) and intracortical facilitation (ICF) after paired magnetic stimuli were evaluated. RESULTS After MG stimulation the MTs were significantly reduced and slope of MEP recruitment curve significantly increased; furthermore, the stimulation led to a sustained decrease of SICI and increase of ICF in the contralateral motor cortex. These effects lasted for at least 60 min and were stronger 1h post-stimulation compared with testing immediately after stimulation. A sham group did not show any differences before and after MG stimulation. CONCLUSIONS We provide a first demonstration that MG whole-hand stimulation induces increases in motor cortical excitability lasting at least 1h. Both the strength of the corticospinal projections and the inhibitory and facilitatory intracortical mechanisms are involved. Synaptic modifications such as long-term potentiation mechanisms may underlie this stimulation-induced cortical plasticity changes. SIGNIFICANCE Present results prove the MG stimulation to be a promising tool in neurorehabilitation.
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Affiliation(s)
- Stefan M Golaszewski
- Department of Neurology and Neuroscience Institute, Christian Doppler Clinic, Paracelsus Medical University Salzburg, Salzburg, Austria.
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Christova M, Castaños-Martinez E, Calzada MD, Kabouzi Y, Luque JM, Moisan M. Electron density and gas temperature from line broadening in an argon surface-wave-sustained discharge at atmospheric pressure. Appl Spectrosc 2004; 58:1032-1037. [PMID: 15479518 DOI: 10.1366/0003702041959415] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have used the collisional broadening of neutral argon lines to determine the electron density and gas temperature of a microwave discharge at atmospheric pressure. The gas temperature can be obtained from the Van der Waals broadening, provided that the Stark broadening is negligible. This can be achieved by using lines from low-lying levels (close to the ground state). On the other hand, lines corresponding to transitions from high-lying levels, which are more sensitive to Stark (quadratic) broadening, can be utilized to determine electron density. The electron density values obtained from the quadratic Stark broadening of argon atoms are in reasonable agreement with those derived from the linear Stark broadening of the H(beta) line. The proposed method ensures perturbation-free access to plasma parameters, which is not the case when adding hydrogen to the discharge, even in a small amount, to observe the Balmer series lines.
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Affiliation(s)
- M Christova
- Institute of Applied Physics, Technical University of Sofia, BG-1797 Sofia, Bulgaria
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Krezhov K, Christova M, Genov D, Genchev N, Sechkariov V. NIGU-5 self-contained research irradiator. Radiat Phys Chem Oxf Engl 1993 1995. [DOI: 10.1016/0969-806x(95)00206-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
A histochemical method for demonstration of 2',3'-cyclic nucleotide 3'-phosphohydrolase activity is proposed. Cryostat sections, fixed in chlorophorm-methanol mixture, are incubated in a solution containing cyclic adenosine 2',3'-monophosphate, acid phosphatase, lead nitrate in acetate buffer, pH = 6,4 or 6.5. This method is based on conversion by the 2',3'-cyclic nucleotide 3'-phosphohydrolase of cyclic adenosine 2',3'-monophosphate to nucleotide-2'-monophosphate. Under the action of exogenous acid phosphatase, inorganic phosphate is released. It precipitates as lead phosphate if lead ions are present. By adding yellow ammonium sulphide, the lead phosphate is converted to lead sulphide which is the visible reaction product.
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