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1.
Pedro Caldana Gordon Christoph Zrenner Debora Desideri Paolo Belardinelli Brigitte Zrenner André Russowsky Brunoni Ulf Ziemann 《Brain stimulation》2018,11(5):1024-1032
Background
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Objectives
To investigate effects of tDCS with different parameter settings applied to the left DLPFC on cortical responses, measured by resting-state electroencephalography (rs-EEG) and transcranial magnetic stimulation (TMS)-evoked/induced EEG responses.Methods
22 healthy subjects underwent 5 tDCS sessions with different tDCS parameter settings in a double-blinded randomized crossover design (1: 1.5?mA, anode left-DLPFC, cathode right-DLPFC; 2: 1.5?mA, cathode left-DLPFC, anode right-DLPFC; 3: 0.5?mA, anode left-DLPFC, cathode right-DLPFC; 4: 1.5?mA, anode left-DLPFC, cathode left deltoid muscle; 5: sham stimulation). Rs-EEG and TMS-EEG were recorded before and after tDCS.Results
Rs-EEG power spectrum analysis showed no difference comparing baseline with post stimulation in any of the tDCS conditions. TMS-EEG evoked potential amplitude decreased in parietal cortex after 1.5?mA left-DLPFC anodal tDCS, and TMS-induced gamma and theta oscillations decreased after all conditions using left-DLPFC anodal tDCS. Left-DLPFC cathodal tDCS did not lead to significant change. None of the post-intervention changes was different when comparing the effects across conditions, including sham.Conclusions
Our study does not provide evidence that a single tDCS session results in significant changes in rs-EEG, using the current stimulation parameters. Significant changes in EEG responses to TMS pulses were observed following the anodal 1.5?mA tDCS interventions, although these changes were not statistically significant in a group comparison. 相似文献2.
Yeowool Huh Dahee Jung Taeyoon Seo Sukkyu Sun Su Hyun Kim Hyewhon Rhim Sooyoung Chung Chong-Hyun Kim Youngwoo Kwon Marom Bikson Yong-an Chung Jeansok J. Kim Jeiwon Cho 《Brain stimulation》2018,11(5):1151-1160
Background
The bursting pattern of thalamocortical (TC) pathway dampens nociception. Whether brain stimulation mimicking endogenous patterns can engage similar sensory gating processes in the cortex and reduce nociceptive behaviors remains uninvestigated.Objective
We investigated the role of cortical parvalbumin expressing (PV) interneurons within the TC circuit in gating nociception and their selective response to TC burst patterns. We then tested if transcranial magnetic stimulation (TMS) patterned on endogenous nociceptive TC bursting modulate nociceptive behaviors.Methods
The switching of TC neurons between tonic (single spike) and burst (high frequency spikes) firing modes may be a critical component in modulating nociceptive signals. Deep brain electrical stimulation of TC neurons and immunohistochemistry were used to examine the differential influence of each firing mode on cortical PV interneuron activity. Optogenetic stimulation of cortical PV interneurons assessed a direct role in nociceptive modulation. A new TMS protocol mimicking thalamic burst firing patterns, contrasted with conventional continuous and intermittent theta burst protocols, tested if TMS patterned on endogenous TC activity reduces nociceptive behaviors in mice.Results
Immunohistochemical evidence confirmed that burst, but not tonic, deep brain stimulation of TC neurons increased the activity of PV interneurons in the cortex. Both optogenetic activation of PV interneurons and TMS protocol mimicking thalamic burst reduced nociceptive behaviors.Conclusions
Our findings suggest that burst firing of TC neurons recruits PV interneurons in the cortex to reduce nociceptive behaviors and that neuromodulation mimicking thalamic burst firing may be useful for modulating nociception. 相似文献3.
Pedro Caldana Gordon Debora Desideri Paolo Belardinelli Christoph Zrenner Ulf Ziemann 《Brain stimulation》2018,11(6):1322-1330
Background
The analysis of cortical responses to transcranial magnetic stimulation (TMS) recorded by electroencephalography (EEG) has been successfully applied to study human cortical physiology. However, in addition to the (desired) activation of cortical neurons and fibers, TMS also causes (undesired) indirect brain responses through auditory and somatosensory stimulation, which may contribute significantly to the overall EEG signal and mask the effects of intervention on direct cortical responses.Objectives
To test differences in EEG responses to real TMS at intensities above and below resting motor threshold (RMT) and a realistic sham stimulation.Methods
12 healthy subjects participated in one session in which single-pulse TMS was applied to the left motor cortex in 3 different blocks, 150 pulses per block: 110%RMT, 90%RMT and realistic sham stimulation. Cortical responses were collected by a 64 electrode EEG system. TMS evoked potentials (TEPs) and TMS induced oscillations were analyzed.Methods
12 healthy subjects participated in one session in which single-pulse TMS was applied to the left motor cortex in 3 different blocks, 150 pulses per block: 110%RMT, 90%RMT and realistic sham stimulation. Cortical responses were collected by a 64-channel EEG system. TMS evoked potentials (TEPs) and TMS induced oscillations were analyzed.Results
TEPs from all conditions differed significantly, with TEPs from 110%RMT showing overall highest amplitudes and realistic sham lowest amplitudes. Sham stimulation had only minor effects on induced cortical oscillations compared to pre-stimulus baseline, TMS at 90%RMT resulted in a significant increase (50–200?m?s) followed by a decrease (200–500?m?s) in power of alpha and beta oscillations; TMS at 110% RMT led to an additional increase in beta power at late latencies (650–800?m?s).Conclusions
Real TMS of motor cortex results in cortical responses significantly different from realistic sham. These differences very likely reflect to a significant extent direct activation of neurons, rather than sensory evoked activity. 相似文献4.
Zhen Ni Robin F.H. Cash Carolyn Gunraj Eduard Bercovici Mark Hallett Robert Chen 《Brain stimulation》2019,12(1):84-86
Background
Paired associative stimulation (PAS), with stimulus interval of 21.5 or 25?ms, using transcranial magnetic stimulation in the posterior-anterior (PA) current direction, produces a long-term-potentiation-like effect. Stimulation with PA directed current generates both early and late indirect (I)-waves while that in anterior-posterior (AP) current predominantly elicits late I-waves. Short interval intracortical inhibition (SICI) inhibits late I-waves but not early I-waves.Objective
To investigate how cortical inhibition modulates the effects of PAS.Methods
PAS at stimulus interval of 21.5?ms conditioned by SICI (SICI-PAS) was compared to PAS alone with both PA and AP directed currents.Results
PAS with both current directions increased cortical excitability. SICI-PAS increased cortical excitability in the PA but not the AP current direction.Conclusions
Both early and late I-waves circuits can mediate cortical PAS plasticity under different conditions. Plasticity induction with the late but not the early I-wave circuits is blocked by SICI. 相似文献5.
George M. Opie Simranjit K. Sidhu Nigel C. Rogasch Michael C. Ridding John G. Semmler 《Brain stimulation》2018,11(3):545-557
Background
Alterations in inhibitory processes mediated by gamma-aminobutyric acid type B (GABAB) receptors may contribute to age-related functional impairments. However, investigation of these circuits using conventional paired-pulse transcranial magnetic stimulation (TMS) at long interstimulus intervals (～100-200ms) have produced conflicting results in older adults, possibly due to the indirect nature of the TMS motor evoked potential (MEP).Objective
To utilise electroencephalography and TMS coregistration (TMS-EEG) to more directly assess age-related changes in GABAB-mediated long-interval intracortical inhibition (LICI).Methods
In 17 young (24.2?±?1.1 years) and 17 older (71.4?±?1.4 years) subjects, the TMS-evoked potential (TEP) was used to assess the global scalp response to single-pulse TMS and LICI applied at two interstimulus intervals of 100 ms (LICI100) and 150 ms (LICI150).Results
For single-pulse stimulation, P30 amplitude was unaffected by age. Despite this, N45 amplitude was increased in older adults and both N100 and P180 showed altered spatial distributions. Furthermore, the latency of P30 was shorter, while the latency of P180 was longer, in the elderly. In addition, inhibition of the N100 and P180 was increased in older adults following both LICI100 and LICI150.Conclusions
These findings with TMS-EEG suggest that the ageing process is associated with a potentiation of GABAergic inhibition, particularly for the GABAB-receptor subtype. 相似文献6.
Aron T. Hill Nigel C. Rogasch Paul B. Fitzgerald Kate E. Hoy 《Brain stimulation》2018,11(5):1033-1043
Background
Previous research has typically focussed on the neuromodulatory effects of direct currents applied over single regions of the cortex. However, complex processes such as working memory (WM) strongly rely on activations across a wider neural network and therefore might benefit from stimulation administered over multiple cortical targets.Objective
We examined the neurobiological and cognitive effects of High-Definition transcranial direct current stimulation (HD-tDCS) montages that either targeted the dorsolateral prefrontal cortex (DLPFC) alone, or simultaneously stimulated the DLPFC and parietal cortex (DLPFC + PC).Methods
In a within-subjects design, 16 healthy participants completed three experimental sessions in which they received HD-tDCS over either the DLPFC, the DLPFC + PC or sham stimulation. Changes in cortical reactivity were examined using transcranial magnetic stimulation combined with electroencephalography (TMS-EEG), while oscillatory power was measured via EEG recorded during n-back tasks. WM performance was also examined across several separate tasks.Results
Stimulation using both the DLPFC or DLPFC + PC montages modulated cortical reactivity, as indexed by potentiation of the P60 TMS-evoked potential. However, only the dual-site DLPFC + PC stimulation produced a reduction in the amplitude of the N100 component, relative to baseline. Increases in theta and gamma power were also observed following this montage, when compared to baseline, but were not present following HD-tDCS over the DLPFC alone. Despite these neurophysiological changes, WM performance was not significantly modulated by HD-tDCS, regardless of stimulation montage.Conclusion
These results provide important initial insight into the behavioural and biological effects of stimulation over key cortical regions linked to WM and attest to the sensitivity of TMS-EEG and EEG in detecting subtle neurophysiological changes induced by HD-tDCS. 相似文献7.
Logan T. Dowdle Truman R. Brown Mark S. George Colleen A. Hanlon 《Brain stimulation》2018,11(4):789-796
Background
In the 20 years since our group established the feasibility of performing interleaved TMS/fMRI, no studies have reported direct comparisons of active prefrontal stimulation with a matched sham. Thus, for all studies there is concern about what is truly the TMS effect on cortical neurons.Objective
After developing a sham control for use within the MRI scanner, we used fMRI to test the hypothesis of greater regional BOLD responses for active versus control stimulation.Methods
We delivered 4 runs of interleaved TMS/fMRI with a limited field of view (16 slices, centered at AC-PC) to the left DLPFC (2 active, 2 control; counterbalanced) of 20 healthy individuals (F3; 20 pulses/run, interpulse interval:10–15sec, TR:1sec). In the control condition, 3?cm of foam was placed between the TMS coil and the scalp. This ensured magnetic field decay, but preserved the sensory aspects of each pulse (empirically evaluated in a subset of 10 individuals).Results
BOLD increases in the cingulate, thalamus, insulae, and middle frontal gyri (p?<?0.05, FWE corrected) were found during both active and control stimulation. However, relative to control, active stimulation caused elevated BOLD signal in the anterior cingulate, caudate and thalamus. No significant difference was found in auditory regions.Conclusion(s)
This TMS/fMRI study evaluated a control condition that preserved many of the sensory features of TMS while reducing magnetic field entry. These findings support a relationship between single pulses of TMS and activity in anatomically connected regions, but also underscore the importance of using a sham condition in future TMS/fMRI studies. 相似文献8.
Background
the influence of pulse width, pulse waveform and current direction on transcranial magnetic stimulation (TMS) outcomes is of critical importance. However, their effects have only been investigated indirectly with motor-evoked potentials (MEP). By combining TMS and EEG it is possible to examine how these factors affect evoked activity from the cortex and compare that with the effects on MEP.Objective
we used a new controllable TMS device (cTMS) to vary systematically pulse width, pulse waveform and current direction and explore their effects on global and local TMS-evoked EEG response.Methods
In 19 healthy volunteers we measured (1) resting motor threshold (RMT) as an estimate of corticospinal excitability; (2) global mean field power (GMFP) as an estimate of global cortical excitability; and (3) local mean field power (LMFP) as an estimate of local cortical excitability.Results
RMT was lower with monophasic posterior-to-anterior (PA) pulses that have a longer pulse width (p?<?0.001). After adjusting for the individual motor threshold of each pulse type we found that (a) GMFP was higher with monophasic pulses (p?<?0.001); (b) LMFP was higher with longer pulse width (p?=?0.015); (c) early TEP polarity was modulated depending on the current direction (p?=?0.01).Conclusions
Despite normalizing stimulus intensity to RMT, we found that local and global responses to TMS vary depending on pulse parameters. Since EEG responses can vary independently of the MEP, titrating parameters of TMS in relation to MEP threshold is not a useful way of ensuring that a constant set of neurons is activated within a cortical area. 相似文献9.
Xiaoming Du Laura M. Rowland Ann Summerfelt Andrea Wijtenburg Joshua Chiappelli Krista Wisner Peter Kochunov Fow-Sen Choa L. Elliot Hong 《Brain stimulation》2018,11(5):1071-1079
Background
Animal studies suggest that synchronized electrical activities in the brain are regulated by the primary inhibitory and excitatory neurotransmitters gamma-aminobutyric acid (GABA) and glutamate, respectively. Identifying direct evidence that this same basic chemical-electrical neuroscience principle operates in the human brains is critical for translation of neuroscience to pathological research.Objective/Hypothesis
We hypothesize that the background neurochemical concentrations may affect the cortical excitability probed by transcranial magnetic stimulation (TMS).Methods
We used TMS with simultaneous evoked potential recording to probe the cortical excitability and determined how background frontal cortical GABA and glutamate levels measured using magnetic resonance spectroscopy (MRS) modulate frontal electrical activities.Results
We found that TMS-evoked N100 reflects a balance between GABA-inhibitory and glutamate-excitatory levels. About 46% of individual variances in frontal N100 can be explained by their glutamate/GABA ratio (r?=??0.68, p?=?0.001). Both glutamate (r?=??0.51, p?=?0.019) and GABA (r?=?0.55, p?=?0.01) significantly contributed to this relationship but in opposite directions.Conclusion
The current finding encourages additional mechanistic studies to develop TMS evoked N100 as a potential electrophysiological biomarker for translating the known inhibitory GABAergic vs. excitatory glutamatergic chemical-electrical principle from animal brain studies to human brain studies. 相似文献10.
Background
Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation method: a magnetic field pulse from a TMS coil can excite neurons in a desired location of the cortex. Conventional TMS coils cause focal stimulation underneath the coil centre; to change the location of the stimulated spot, the coil must be moved over the new target. This physical movement is inherently slow, which limits, for example, feedback-controlled stimulation.Objective
To overcome the limitations of physical TMS-coil movement by introducing electronic targeting.Methods
We propose electronic stimulation targeting using a set of large overlapping coils and introduce a matrix-factorisation-based method to design such sets of coils. We built one such device and demonstrated the electronic stimulation targeting in vivo.Results
The demonstrated two-coil transducer allows translating the stimulated spot along a 30-mm-long line segment in the cortex; with five coils, a target can be selected from within a region of the cortex and stimulated in any direction. Thus, far fewer coils are required by our approach than by previously suggested ones, none of which have resulted in practical devices.Conclusion
Already with two coils, we can adjust the location of the induced electric field maximum along one dimension, which is sufficient to study, for example, the primary motor cortex. 相似文献11.
Jose Gomez-Tames Atsushi Hamasaka Ilkka Laakso Akimasa Hirata Yoshikazu Ugawa 《Brain stimulation》2018,11(4):839-848
Background
Transcranial magnetic stimulation (TMS) activates target brain structures in a non-invasive manner. The optimal orientation of the TMS coil for the motor cortex is well known and can be estimated using motor evoked potentials. However, there are no easily measurable responses for activation of other cortical areas and the optimal orientation for these areas is currently unknown.Objective
This study investigated the electric field strength, optimal coil orientation, and relative locations to optimally stimulate the target cortex based on computed electric field distributions.Methods
A total of 518,616 stimulation scenarios were studied using realistic head models (2401 coil locations?×?12 coil angles?×?18 head models). Inter-subject registration methods were used to generate an atlas of optimized TMS coil orientations on locations on the standard brain.Results
We found that the maximum electric field strength is greater in primary somatosensory cortex and primary motor cortex than in other cortical areas. Additionally, a universal optimal coil orientation applicable to most subjects is more feasible at the primary somatosensory cortex and primary motor cortex. We confirmed that optimal coil angle follows the anatomical shape of the hand motor area to realize personalized optimization of TMS. Finally, on average, the optimal coil positions for TMS on the scalp deviated 5.5?mm from the scalp points with minimum cortex-scalp distance. This deviation was minimal at the premotor cortex and primary motor cortex.Conclusion
Personalized optimal coil orientation is preferable for obtaining the most effective stimulation. 相似文献12.
Elisa Kallioniemi Petri Savolainen Gustaf Järnefelt Päivi Koskenkorva Jari Karhu Petro Julkunen 《Brain stimulation》2018,11(2):322-326
Background
Transcranial magnetic stimulation (TMS) induced I-wave behavior can be demonstrated at neuronal population level using paired-pulses and by observing short-interval cortical facilitation (SICF). Advancements in stimulator technology have made it possible to apply biphasic paired-pulses to induce SICF.Objective
Our aim was to characterize the SICF I-wave interaction by biphasic paired-pulses with the ultimate objective to enhance TMS effects via SICF in various TMS-applications.Methods
We used biphasic paired-pulses in 15 volunteers to characterize corticospinal SICF using various 1.2–8.0ms inter-stimulus intervals, and measuring SICF input-output response.Results
SICF interaction with the first I-wave (I1) was observed in the output responses (motor evoked potentials; MEPs) in all subjects. Most subjects (≥80%) also exhibited later SICF I-wave interaction. SICF at I1 was present at all applied intensities below 140% of resting motor threshold. At I2, we observed SICF only with intensities just above motor threshold.Conclusions
Biphasic paired-pulses can reliably induce SICF shown by the facilitatory I-wave interaction, and could therefore be applied with repetitive bursts to enhance responsiveness to TMS. 相似文献13.
Sung Wook Chung Nigel C. Rogasch Kate E. Hoy Paul B. Fitzgerald 《Brain stimulation》2018,11(3):566-574
Background
With an increasing interest in the use of theta burst stimulation (TBS) as a cognitive enhancer and a potential therapeutic tool for psychiatric disorders, there is a need to identify optimal parameters of TBS in the prefrontal cortex.Objective/Hypothesis
This study examined the effect of two blocks of prefrontal intermittent TBS (iTBS) on cortical reactivity and working memory performance, compared to one block of iTBS and sham stimulation. We hypothesized that greater cortical effects would be obtained with two blocks of iTBS.Methods
Eighteen healthy participants attended three experimental sessions and received either sham, one block or two blocks of iTBS with a 15-min interval. Concurrent transcranial magnetic stimulation with electroencephalography (TMS-EEG) was used to assess the change in cortical reactivity via TMS-evoked potentials. Working memory performance was assessed using the N-back task. Cluster-based permutation statistics and two-way ANOVAs were used for neurophysiological and behavioural data, respectively.Results
Both single and two blocks of iTBS resulted in a significant increase in the amplitude of TMS-evoked N100 and P200. No significant differences were observed between active conditions in either neurophysiological changes or working memory performance, and both failed to improve working memory performance relative to sham.Conclusions
Two blocks of iTBS did not result in stronger measured effects as compared to one block of iTBS. Future studies are needed to identify the optimal stimulation pattern in order to achieve a desired effect. It is also important to establish the best approach in quantifying neuromodulatory effects targeting the prefrontal cortex. 相似文献14.
Dalia Khammash Molly Simmonite Thad A. Polk Stephan F. Taylor Sean K. Meehan 《Brain stimulation》2019,12(3):702-704
Background
Transcranial magnetic stimulation (TMS) is a non-invasive method to stimulate localized brain regions. Despite widespread use in motor cortex, TMS is seldom performed in sensory areas due to variable, qualitative metrics.Objective
Assess the reliability and validity of tracing phosphenes, and to investigate the stimulation parameters necessary to elicit decreased visual cortex excitability with paired-pulse TMS at short inter-stimulus intervals.Methods
Across two sessions, single and paired-pulse recruitment curves were derived by having participants outline elicited phosphenes and calculating resulting average phosphene sizes.Results
Phosphene size scaled with stimulus intensity, similar to motor cortex. Paired-pulse recruitment curves demonstrated inhibition at lower conditioning stimulus intensities than observed in motor cortex. Reliability was high across sessions.Conclusions
TMS-induced phosphenes are a valid and reliable tool for measuring cortical excitability and inhibition in early visual areas. Our results also provide appropriate stimulation parameters for measuring short-latency intracortical inhibition in visual cortex. 相似文献15.
Samuel S. Shin Vijai Krishnan William Stokes Courtney Robertson Pablo Celnik Yanrong Chen Xiaolei Song Hanzhang Lu Peiying Liu Galit Pelled 《Brain stimulation》2018,11(6):1306-1313
Background
Therapeutic strategies for traumatic brain injury (TBI) in the last three decades have failed to show significant benefit in large scale studies. Given the multitude of pathological mechanisms involved in TBI, strategies focusing on multimodality regimen have gained interest as promising future interventions.Hypothesis
We hypothesized that combining noninvasive transcranial magnetic stimulation (TMS) with rehabilitative training in an environmental enrichment (EE) can facilitate post-TBI recovery in rats via cortical excitability and reorganization.Methods
We subjected rats to controlled cortical impact, and then assigned them to one of four groups: 1. No treatments (TBI), 2. EE after injury (TBI + EE), 3. TMS for one week (TBI + TMS), and 4. TMS for one week combined with EE (TBI + TMS/EE). For TMS, a 10 Hz repetitive TMS protocol was used.Results
At 7 days, TBI + TMS and TBI + TMS/EE groups had significantly increased primary somatosensory cortex local field potential (LFP) compared to TBI and TBI + EE groups (P < 0.05). Also, TBI + TMS/EE group had significantly improved performance on beam walk test compared to TBI group (P < 0.005). At 6 weeks, there was significantly higher response in TBI + TMS/EE group compared to TBI + TMS for somatosensory cortex LFP (P < 0.05), bicep motor evoked potentials (MEP) (P < 0.05), challenge ladder test performance (P < 0.01), and fMRI responses to tactile forepaw stimulation.Conclusions
We demonstrate here for the first time the mechanism by which combined therapy using TMS and EE after TBI leads to functional improvement, possibly via cortical excitability and reorganization. 相似文献16.
Ross W. Anderson AmirAli Farokhniaee Kabilar Gunalan Bryan Howell Cameron C. McIntyre 《Brain stimulation》2018,11(5):1140-1150
Background
High frequency (～130?Hz) deep brain stimulation (DBS) of the subthalamic region is an established clinical therapy for the treatment of late stage Parkinson's disease (PD). Direct modulation of the hyperdirect pathway, defined as cortical layer V pyramidal neurons that send an axon collateral to the subthalamic nucleus (STN), has emerged as a possible component of the therapeutic mechanisms. However, numerous questions remain to be addressed on the basic biophysics of hyperdirect pathway stimulation.Objective
Quantify action potential (AP) initiation, propagation, and cortical invasion in hyperdirect neurons during subthalamic stimulation.Methods
We developed an anatomically and electrically detailed computational model of hyperdirect neuron stimulation with explicit representation of the stimulating electric field, axonal response, AP propagation, and synaptic transmission.Results
We found robust AP propagation throughout the complex axonal arbor of the hyperdirect neuron. Even at therapeutic DBS frequencies, stimulation induced APs could reach all of the intracortical axon terminals with ～100% fidelity. The functional result of this high frequency axonal driving of the thousands of synaptic connections made by each directly stimulated hyperdirect neuron is a profound synaptic suppression that would effectively disconnect the neuron from the cortical circuitry.Conclusions
The synaptic suppression hypothesis integrates the fundamental biophysics of electrical stimulation, axonal transmission, and synaptic physiology to explain a generic mechanism of DBS. 相似文献17.
Background
Alpha (8–14?Hz) oscillatory power is linked to cortical excitability and corresponding modulations of sensory evoked potentials and perceptual detection performance. In somatosensory cortex (S1), negative linear and inverted U-shape relationships exist, whereas its effect on the primary motor cortex (M1) is hardly known.Objective
We used real-time EEG-triggered transcranial magnetic stimulation (TMS) of M1 to characterize the relationship between spontaneous sensorimotor mu-alpha power fluctuations at rest and corticospinal excitability.Methods
In 16 subjects, mu-alpha power was continuously monitored over the left sensorimotor cortex, and each 10%-percentile bin of the individual mu-alpha power distribution was repeatedly targeted in pseudorandomized order by single-pulse TMS of left M1, measuring motor evoked potentials (MEP) in the contralateral hand.Results
We found a weak positive relationship between mu-alpha power and MEP amplitude.Conclusion
Sensorimotor mu-alpha power may reflect a net facilitation or disinhibition of M1, possibly resulting from mu-alpha based suppression of excitatory and inhibitory input from S1. 相似文献18.
Background
A prime objective driving the recent development of human neural prosthetics is to stimulate neural circuits in a manner time-locked to ongoing brain activity. The human supplementary motor area (SMA) is a particularly useful target for this objective because it displays characteristic neural activity just prior to voluntary movement.Objective
Here, we tested a method that detected activity in the human SMA related to impending movement and then delivered cortical stimulation with intracranial electrodes to influence the timing of movement.Methods
We conducted experiments in nine patients with electrodes implanted for epilepsy localization: five patients with SMA electrodes and four control patients with electrodes outside the SMA. In the first experiment, electrocorticographic (ECoG) recordings were used to localize the electrode of interest during a task involving bimanual finger movements. In the second experiment, a real-time sense-and-stimulate (SAS) system was implemented that delivered an electrical stimulus when pre-movement gamma power exceeded a threshold.Results
Stimulation based on real-time detection of this supra-threshold activity resulted in significant slowing of motor behavior in all of the cases where stimulation was carried out in the SMA patients but in none of the patients where stimulation was performed at the control site.Conclusions
The neurophysiological correlates of impending movement can be used to trigger a closed loop stimulation device and influence ongoing motor behavior in a manner imperceptible to the subject. This is the first report of a human closed loop system designed to alter movement using direct cortical recordings and direct stimulation. 相似文献19.
Background
TMS is safe and effective in the treatment of MDD, but as with other treatments, relapse may occur on cessation of treatment.Objective
To prevent relapse in MDD, following successful acute TMS treatment.Method
5 TMS treatments over 3 days, repeated at about monthly intervals.Results
14 patients received this care for more than 12 months. At the commencement of each series the mood scores were close to relapse, but at completion they were in the remitted range.Conclusion
Such treatment is useful. It is better conceptualized as relapse prevention rather than remittance maintenance. 相似文献20.
Carina França Daniel Ciampi de Andrade Manoel Jacobsen Teixeira Ricardo Galhardoni Valquiria Silva Egberto Reis Barbosa Rubens Gisbert Cury 《Brain stimulation》2018,11(2):249-260