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Frontal increase of beta modulation during the practice of a motor task is enhanced by visuomotor learning. Sci Rep 2021; 11:17441. [PMID: 34465846 PMCID: PMC8408223 DOI: 10.1038/s41598-021-97004-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
Movement is accompanied by beta power changes over frontal and sensorimotor regions: a decrease during movement (event-related desynchronization, ERD), followed by an increase (event-related synchronization, ERS) after the movement end. We previously found that enhancements of beta modulation (from ERD to ERS) during a reaching test (mov) occur over frontal and left sensorimotor regions after practice in a visuo-motor adaptation task (ROT) but not after visual learning practice. Thus, these enhancements may reflect local cumulative effects of motor learning. Here we verified whether they are triggered by the learning component inherent in ROT or simply by motor practice in a reaching task without such learning (MOT). We found that beta modulation during mov increased over frontal and left areas after three-hour practice of either ROT or MOT. However, the frontal increase was greater after ROT, while the increase over the left area was similar after the two tasks. These findings confirm that motor practice leaves local traces in beta power during a subsequent motor test. As they occur after motor tasks with and without learning, these traces likely express the cost of processes necessary for both usage and engagement of long-term potentiation mechanisms necessary for the learning required by ROT.
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Covid-19 and Parkinson's disease: an overview. J Neurol 2021; 268:4415-4421. [PMID: 34313818 PMCID: PMC8313415 DOI: 10.1007/s00415-021-10721-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 06/26/2021] [Accepted: 07/20/2021] [Indexed: 12/17/2022]
Abstract
In March 2020, WHO declared Covid-19 outbreak pandemic. There has been increasing evidence that frail, old, multi-pathological patients are at greater risk of developing severe Covid-19 infection than younger, healthy ones. Covid-19's impact on Parkinson's Disease (PD) patients could be analysed through both the influence on PD patients' health and their risk of developing severe Covid-19, and the consequences of lockdown and restrictive measures on mental and cognitive health on both patients and caregivers. Moreover, there are critical issues to be considered about patients' care and management through an unprecedented time like this. One important issue to consider is physiotherapy, as most patients cannot keep exercising because of restrictive measures which has profoundly impacted on their health. Lastly, the relationship between PD and Sars-Cov2 may be even more complicated than it seems as some studies have hypothesized a possible Covid-19-induced parkinsonism. Hereby, we review the state of the art about the relationship between Covid-19 and Parkinson's Disease, focusing on each of these five points.
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Low-intensity repetitive paired associative stimulation targeting the motor hand area at theta frequency causes a lasting reduction in corticospinal excitability. Clin Neurophysiol 2020; 131:2402-2409. [PMID: 32828043 DOI: 10.1016/j.clinph.2020.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 06/08/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Sub-motor threshold 5 Hz repetitive paired associative stimulation (5 Hz-rPAS25ms) produces a long-lasting increase in corticospinal excitability. Assuming a spike-timing dependent plasticity-like (STDP-like) mechanism, we hypothesized that 5 Hz-rPAS at a shorter inter-stimulus interval (ISI) of 15 ms (5 Hz-rPAS15ms) would exert a lasting inhibitory effect on corticospinal excitability. METHODS 20 healthy volunteers received two minutes of 5 Hz-rPAS15ms. Transcranial magnetic stimulation (TMS) was applied over the motor hotspot of the right abductor pollicis brevis muscle at 90% active motor threshold. Sub-motor threshold peripheral electrical stimulation was given to the left median nerve 15 ms before each TMS pulse. We assessed changes in mean amplitude of the unconditioned motor evoked potential (MEP), short-latency intracortical inhibition (SICI), intracortical facilitation (ICF), short-latency afferent inhibition (SAI), long-latency afferent inhibition (LAI), and cortical silent period (CSP) before and for 60 minutes after 5-Hz rPAS15ms. RESULTS Subthreshold 5-Hz rPAS15ms produced a 20-40% decrease in mean MEP amplitude along with an attenuation in SAI, lasting at least 60 minutes. A follow-up experiment revealed that MEP facilitation was spatially restricted to the target muscle. CONCLUSIONS Subthreshold 5-Hz rPAS15ms effectively suppresses corticospinal excitability. Together with the facilitatory effects of subthreshold 5-Hz rPAS25ms (Quartarone et al., J Physiol 2006;575:657-670), the results show that sub-motor threshold 5-Hz rPAS induces STDP-like bidirectional plasticity in the motor cortex. SIGNIFICANCE The results of the present study provide a new short-time paradigm of long term depression (LTD) induction in human sensory-motor cortex.
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Neural correlates of fatigue in multiple sclerosis: a combined neurophysiological and neuroimaging approach (R1). Arch Ital Biol 2018; 155:142-151. [PMID: 29220866 DOI: 10.12871/00039829201735] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The present study is aimed at further exploring structural and functional correlates of fatigue in Relapsing- Remitting Multiple Sclerosis (RRMS) patients by using a combined approach by means of transcranial magnetic stimulation (TMS) and a Diffusion Tensor Imaging (DTI). The physiopathology of fatigue in MS is still poorly understood, although a variety of pathogenic mechanisms has been proposed. Our working hypothesis is that diffuse microstructural white matter damage may subtend the cortico-subcortical functional disconnection described in patients with MS and fatigue. We enrolled 30 RRMS patients (mean age 39±13; age range 24-63 years) with mild neurological impairment Expanded Disability Status Scale <3.5, divided into two groups on the basis of their fatigue severity scale (FSS) scoring (cutoff ≥ 4). All the patients underwent a neurological evaluation, a brain MRI acquisition (including DTI study) and a neurophysiological assessment by means of TMS in a pre-movement facilitation paradigm. Our data showed a significant mean diffusivity (MD) increase (p=0.036) in left thalamo-frontal reconstructions in the MS patients with fatigue compared to those classified as non-fatigued. Moreover, significant correlations were observed between FSS scale and MD as well as planar coefficient (CP) values extracted from frontal-thalamic connections bilaterally. Instead, the pre-movement facilitation showed a significant difference between the groups with particular regard to the Reaction Time- MEP50ms amplitude (p=0.03). Our work confirms that fatigue is associated with a disruption of brain networks involved in motor preparation processes, depending on several frontal-thalamic pathways. Such findings can have an important role when dealing with fatigue management in MS patients and could be eventually used as prognostic marker of MS course.
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43. Intraoperative neurophysiological monitoring in spine surgery: A significant tool for neuronal protection and functional restoration. Clin Neurophysiol 2017. [DOI: 10.1016/j.clinph.2017.09.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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68. Painful laser evoked potential inhibition during high-frequency non-noxious somatosensory stimulation. Clin Neurophysiol 2017. [DOI: 10.1016/j.clinph.2017.09.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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The associative brain at work: Evidence from paired associative stimulation studies in humans. Clin Neurophysiol 2017; 128:2140-2164. [DOI: 10.1016/j.clinph.2017.08.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/20/2017] [Accepted: 08/03/2017] [Indexed: 12/25/2022]
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8
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67. Neural response to transcranial magnetic stimulation in adult thyroid hormone resistance. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2015.09.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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58. Repetitive transcranial magnetic stimulation induces neuroprotection via activating CaMKII α -CREB-Bcl-2 pathway in rat brain. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2015.09.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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10
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Cortical excitability in patients with resistance to thyroid hormone compared to patients with hypothyroidism and euthyroid controls: a transcranial magnetic stimulation study. Arch Ital Biol 2016; 154:68-77. [PMID: 27918064 DOI: 10.12871/00039829201624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Resistance to thyroid hormone (RTH) describes a rare syndrome in which serum levels of thyroid hormones are elevated but serum levels of thyroid stimulating hormone (TSH) are unsuppressed. The importance of thyroid hormones for the normal function of the adult brain is corroborated by the frequent association of thyroid dysfunctions with neurological and psychiatric symptoms. In this study we investigated whether adult thyroid hormone resistance affects cortical excitability and modulates inhibitory and excitatory intracortical circuitries by using transcranial magnetic stimulation. Cortical excitability was probed with transcranial magnetic stimulation in 4 patients with thyroid hormone resistance, 10 patients affected by overt hypothyroidism (OH) and 10 age-matched healthy controls. We tested motor thresholds, motor evoked potential recruitment curve, cortical silent period (CSP), short interval intracortical inhibition (SICI) and intracortical facilitation. In both OH and RTH patients, the inhibitory cortical circuits were affected compared with euthyroid controls, but in opposite ways. In OH patients, CSP was prolonged and SICI was decreased. On the contrary, in RTH patients CSP was shortened and SICI was increased. Thyroid hormones may influence cortical excitability and cortical inhibitory circuits.
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11
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118. High frequency paired associative stimulation modulates the corticospinal excitability in human subjects: An EEG study. Clin Neurophysiol 2015. [DOI: 10.1016/j.clinph.2014.10.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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119. Cortical excitability in patients affected by brain tumors. Clin Neurophysiol 2015. [DOI: 10.1016/j.clinph.2014.10.138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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P16.11 * A NEW TECHNIQUE OF "FUNCTIONAL" DTI TRACTOGRAPHY OF THE CORTICO-SPINAL TRACT BASED ON NAVIGATED BRAIN STIMULATION FOR SURGERY OF BRAIN TUMORS LOCATED NEAR THE MOTOR PATHWAY. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou174.307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P07.02 * THE ROLE OF INTRAOPERATIVE NEUROPHYSIOLOGICAL MONITORING IN SURGERY OF INTRADURAL EXTRAMEDULLARY SPINAL CORD TUMORS. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou174.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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15
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P702: Chronic rTMS increases the expression of down-stream long-term effects regulatory molecules in rat brain and lymphocytes. Clin Neurophysiol 2014. [DOI: 10.1016/s1388-2457(14)50795-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Obsessive-compulsive disorder: A “sensory-motor” problem? Int J Psychophysiol 2014; 92:74-8. [DOI: 10.1016/j.ijpsycho.2014.02.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/25/2014] [Accepted: 02/28/2014] [Indexed: 01/26/2023]
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17
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135. Chronic rTMS increases the expression of down-stream long-term effects regulatory molecules in rat brain and lymphocytes. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.06.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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143. High frequency paired associative stimulation modulates the corticospinal excitability in human subjects: A TMS/EEG study. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.06.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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81. Preoperative functional mapping for rolandic brain tumor surgery: A one year experience. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.06.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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IS 37. Repetitive transcranial magnetic stimulation enhances BDNF–TrkB signaling in both brain and lymphocyte. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.04.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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P 183. Long term depression: A study with rapid-rate PAS. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.04.260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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P 182. Normal lateral inhibition mechanism during sensory-motor plasticity in dystonia. Clin Neurophysiol 2013. [DOI: 10.1016/j.clinph.2013.04.259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Experimental pathology. Nephrol Dial Transplant 2012. [DOI: 10.1093/ndt/gfs241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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24
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A practical guide to diagnostic transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol 2012; 123:858-82. [PMID: 22349304 DOI: 10.1016/j.clinph.2012.01.010] [Citation(s) in RCA: 775] [Impact Index Per Article: 64.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 01/16/2012] [Accepted: 01/22/2012] [Indexed: 11/29/2022]
Abstract
Transcranial magnetic stimulation (TMS) is an established neurophysiological tool to examine the integrity of the fast-conducting corticomotor pathways in a wide range of diseases associated with motor dysfunction. This includes but is not limited to patients with multiple sclerosis, amyotrophic lateral sclerosis, stroke, movement disorders, disorders affecting the spinal cord, facial and other cranial nerves. These guidelines cover practical aspects of TMS in a clinical setting. We first discuss the technical and physiological aspects of TMS that are relevant for the diagnostic use of TMS. We then lay out the general principles that apply to a standardized clinical examination of the fast-conducting corticomotor pathways with single-pulse TMS. This is followed by a detailed description of how to examine corticomotor conduction to the hand, leg, trunk and facial muscles in patients. Additional sections cover safety issues, the triple stimulation technique, and neuropediatric aspects of TMS.
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W13.2 Brain plasticity and mechanisms of neural encoding of skills. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60142-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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P10.19 Neural response to transcranial magnetic stimulation in adult thyroid hormone resistance. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60386-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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28
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PTMS9 No evidence for a modifying effect of the BDNF val66met polymorphism on TBS-induced plasticity in human motor cortex. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60662-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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29
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P22.24 Central fatigue in multiple sclerosis: from motor preparation to motor execution. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60585-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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P6.2 Normal motor cortex plasticity in patients with complex regional pain syndrome type I and fixed posture of the hand. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60291-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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W2.3 Somatosensory dysfunction in psychogenic dystonia. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60025-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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32
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P6.16 Impairment of paced digital movements in task specific focal hand dystonia. Clin Neurophysiol 2011. [DOI: 10.1016/s1388-2457(11)60305-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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33
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Associative cortico-cortical plasticity may affect ipsilateral finger opposition movements. Behav Brain Res 2011; 216:433-9. [DOI: 10.1016/j.bbr.2010.08.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/06/2010] [Accepted: 08/24/2010] [Indexed: 11/29/2022]
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34
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Impairment of sensory-motor integration in patients affected by RLS. J Neurol 2010; 257:1979-85. [DOI: 10.1007/s00415-010-5644-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/31/2010] [Accepted: 06/28/2010] [Indexed: 11/28/2022]
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35
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Reply: Plasticity and intracortical inhibition in dystonia--methodological reconsiderations. Brain 2010. [DOI: 10.1093/brain/awq025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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36
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Abstract
Dystonia is characterized by two main pathophysiological abnormalities: 'reduced' excitability of inhibitory systems at many levels of the sensorimotor system, and 'increased' plasticity of neural connections in sensorimotor circuits at a brainstem and spinal level. A surprising finding in two recent papers has been the fact that abnormalities of inhibition similar to those in organic dystonia are also seen in patients who have psychogenic dystonia. To try to determine the critical feature that might separate organic and psychogenic conditions, we investigated cortical plasticity in a group of 10 patients with psychogenic dystonia and compared the results with those obtained in a matched group of 10 patients with organic dystonia and 10 healthy individuals. We confirmed the presence of abnormal motor cortical inhibition (short-interval intracortical inhibition) in both organic and psychogenic groups. However, we found that plasticity (paired associative stimulation) was abnormally high only in the organic group, while there was no difference between the plasticity measured in psychogenic patients and healthy controls. We conclude that abnormal plasticity is a hallmark of organic dystonia; furthermore it is not a consequence of reduced inhibition since the latter is seen in psychogenic patients who have normal plasticity.
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37
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Paired Associative Stimulation of Left and Right Human Motor Cortex Shapes Interhemispheric Motor Inhibition based on a Hebbian Mechanism. Cereb Cortex 2008; 19:907-15. [DOI: 10.1093/cercor/bhn144] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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38
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Abnormal plasticity of sensorimotor circuits extends beyond the affected body part in focal dystonia. J Neurol Neurosurg Psychiatry 2008; 79:985-90. [PMID: 17634214 DOI: 10.1136/jnnp.2007.121632] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To test whether abnormal sensorimotor plasticity in focal hand dystonia is a primary abnormality or is merely a consequence of the dystonic posture. METHODS This study used the paired associative stimulation (PAS) paradigm, an experimental intervention, capable of producing long term potentiation (LTP) like changes in the sensorimotor system in humans. PAS involves transcranial magnetic stimulation combined with median nerve stimulation. 10 patients with cranial and cervical dystonia, who showed no dystonic symptoms in the hand, and nine patients with hemifacial spasm (HFS), a non-dystonic condition, were compared with 10 healthy age matched controls. Motor evoked potential amplitudes and cortical silent period (CSP) duration were measured at baseline before PAS and for up to 60 min (T0, T30 and T60) after PAS in the abductor pollicis brevis and the first dorsal interosseus muscles. RESULTS Patients with dystonia showed a stronger increase in corticospinal excitability than healthy controls and patients with HFS. In addition, patients with dystonia showed a loss of topographical specificity of PAS induced effects, with a facilitation in both the median and ulnar innervated muscles. While PAS conditioning led to a prolonged CSP in healthy controls and patients with HFS, it had no effect on the duration of the CSP in patients with cranial and cervical dystonia. CONCLUSION The data suggests that excessive motor cortex plasticity is not restricted to the circuits clinically affected by dystonia but generalises across the entire sensorimotor system, possibly representing an endophenotypic trait of the disease.
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Bi-directional enduring changes of cortical plasticity induced by a novel paired stimulation protocol. Brain Stimul 2008. [DOI: 10.1016/j.brs.2008.06.242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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40
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Fatiguing exercises based on repetitive finger opposition movements can influence corticospinal excitability and motor behavior: a time course study. Brain Stimul 2008. [DOI: 10.1016/j.brs.2008.06.127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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41
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P19.3 Bi-directional changes of cortical plasticity induced by transcranial anodal and cathodal direct current combined with peripheral nerve stimulation. Clin Neurophysiol 2006. [DOI: 10.1016/j.clinph.2006.06.401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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FC14.3 Paired low-frequency transcranial magnetic stimulation (TMS) delivered over homologous primary motor areas induces changes in cortical excitability. Clin Neurophysiol 2006. [DOI: 10.1016/j.clinph.2006.06.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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43
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The basal ganglia are hyperactive during the discrimination of tactile stimuli in writer's cramp. Brain 2006; 129:2697-708. [PMID: 16854945 DOI: 10.1093/brain/awl181] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Writer's cramp is a focal hand dystonia that specifically affects handwriting. Though writer's cramp has been attributed to a dysfunction of the basal ganglia, the role of the basal ganglia in the pathogenesis of writer's cramp remains to be determined. Seventeen patients with writer's cramp (nine females; age range: 24-71 years) and 17 healthy individuals (six females; age range: 27-68 years) underwent functional MRI (fMRI) while they discriminated the orientation of gratings delivered to the tip of the right index finger. Statistical parametric mapping was used to analyse the fMRI data. The significance level was set at a corrected P-value of 0.05. Relative to healthy controls, patients with writer's cramp showed a widespread bilateral increase in task-related activity in the putamen, caudate nucleus, internal globus pallidus and lateral thalamus. In these areas, hyperactivity was more pronounced in patients who had recently developed writer's cramp. The enhanced response of the basal ganglia to tactile input from the affected hand is compatible with the concept of impaired centre-surround inhibition within the basal ganglia-thalamic circuit and may lead to an excessive activation of sensorimotor cortical areas during skilled movements affected by dystonia. Outside the basal ganglia, dystonic patients showed task-related overactivity in visual cortical areas, left anterior insula and right intraparietal sulcus, but not in the primary or secondary sensory cortex. In addition, task-related activity in the cerebellar nuclei, posterior vermis, right paramedian cerebellar hemisphere and dorsal pons was inversely related with the severity of hand dystonia. Regional activity in these areas may reflect secondary adaptive reorganization at the systems level to compensate for the dysfunction in the basal ganglia-thalamic loop.
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Transcranial magnetic stimulation as trigger of dystonic attacks in a patient affected by paroxysmal kinesigenic dyskinesia. Neurol Sci 2006; 26:362-6. [PMID: 16388375 DOI: 10.1007/s10072-005-0497-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2005] [Accepted: 09/02/2005] [Indexed: 11/28/2022]
Abstract
A 22-year-old patient presented with attacks of paroxysmal dystonia characterised by involuntary and uncontrollable movements affecting lower and upper limbs with sustained turning or twisting of the trunk. These motor paroxysms were induced by voluntary movements and lasted between 10 and 15 s with a frequency of 1-5 attacks per day. Transcranial magnetic stimulation of the motor cortex was found to induce motor paroxysms very similar to the spontaneous attacks. To evaluate motor cortex and brainstem excitability immediately after and between the attacks, a neurophysiological study was performed.
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Homeostatic plasticity of the motor cortex is impaired in focal dystonia. AKTUELLE NEUROLOGIE 2005. [DOI: 10.1055/s-2005-919365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Transcranial magnetic stimulation of the motor sytem in focal dystonia. AKTUELLE NEUROLOGIE 2005. [DOI: 10.1055/s-2005-916311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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One-hertz subthreshold rTMS increases the threshold for evoking inhibition in the human motor cortex. Exp Brain Res 2004; 160:368-74. [PMID: 15480605 DOI: 10.1007/s00221-004-2020-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Accepted: 05/11/2004] [Indexed: 11/24/2022]
Abstract
Despite indisputable evidence that repetitive transcranial magnetic stimulation (rTMS) modulates motor cortical excitability, the effects of subthreshold low-frequency rTMS on intracortical inhibition (ICI) are controversial. In this paper we investigated whether increasing the level of baseline ICI increases the sensitivity of ICI for disclosing the after-effects of rTMS on cortical excitability. In experiment 1, we studied changes in ICI, tested at two different baseline levels, after a train of 900 subthreshold rTMS pulses delivered at 1 Hz. In experiment 2, we studied whether the same conditioning rTMS train changed the ICI threshold, and in experiment 3 whether it changed the facilitatory I-wave interaction. Conditioning rTMS reduced ICI tested at a baseline level of 75% but left ICI tested at a baseline level of 50% unchanged. It also increased the ICI threshold but left the facilitatory I-wave interaction unchanged. These findings suggest that conditioning rTMS selectively reduced ICI tested at a baseline level of 75% by increasing the threshold for evoking inhibition in the motor cortex. The inhibitory system mediating ICI may therefore be more efficient than other motor cortical systems in reducing high cortical excitability after external intervention. Hence studies investigating the after-effects of rTMS should standardize ICI levels at baseline.
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Impaired Motor Cortex Plasticity in Patients with ALS. KLIN NEUROPHYSIOL 2004. [DOI: 10.1055/s-2004-832068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Different patterns of I-waves summation in ALS patients according to the central conduction time. Clin Neurophysiol 2002; 113:1301-7. [PMID: 12140011 DOI: 10.1016/s1388-2457(02)00152-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES To study facilitatory I-waves interaction, using two near threshold stimuli, to test both excitability and conductivity changes related to cortico-motoneuronal involvement in amyotrophic lateral sclerosis (ALS) patients in different stages of the disease. METHODS Pairs of threshold magnetic stimuli were applied over the motor cortex at inter-stimulus intervals (ISI) ranging from 1-1.5 to 2.5-3 ms and from 4 to 4.5ms. The electromyogram responses were recorded from relaxed first dorsal interosseus (FDI). RESULTS The data of I-waves summation were distributed according to the central conduction time (CCT) and all 3 peaks of facilitation were considered for statistical analysis. Patients with normal CCT showed a normal I-waves summation for the first peak, whilst patients with abnormal CCT had a significant reduction in facilitation (P<0.02). Six out of 11 patients with normal CCT had facilitation in the first peak, which exceeded 2 SD of normal values. CONCLUSIONS In conclusion ALS patients showed two different and opposite patterns of I-waves summation which could be related to different stages of the disease.
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A patient with atypical stiff-person syndrome: an electrophysiological study. J Clin Neuromuscul Dis 2001; 3:20-22. [PMID: 19078649 DOI: 10.1097/00131402-200109000-00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We describe a patient with insulin-dependent diabetes mellitus who noticed pain and stiffness in the neck and painful spasms and rigidity of the right thigh. Continuous motor unit activity was recorded in the lower limb muscles on the right side and in the cervical paraspinal muscles. Cutaneomuscular reflexes were at an abnormally low threshold recording from the muscles of the right leg. Laboratory investigation revealed anti-GAD antibodies in serum and oligoclonal bands in the cerebrospinal fluid. We conclude that the patient has atypical stiff-person syndrome.
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