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Editorial

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4 pages, 191 KiB

Open AccessEditorial

Modern Developments in Transcranial Magnetic Stimulation: The Editorial

by Nico Sollmann and Petro Julkunen

Brain Sci. 2022, 12(5), 628; https://doi.org/10.3390/brainsci12050628 - 11 May 2022

Cited by 1 | Viewed by 2150

Abstract

Transcranial magnetic stimulation (TMS) is being increasingly applied in neuroscience and the clinical setup [...] Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

Research

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17 pages, 8146 KiB

Open AccessArticle

Functional Connectivity States of Alpha Rhythm Sources in the Human Cortex at Rest: Implications for Real-Time Brain State Dependent EEG-TMS

by Davide Tabarelli, Arianna Brancaccio, Christoph Zrenner and Paolo Belardinelli

Brain Sci. 2022, 12(3), 348; https://doi.org/10.3390/brainsci12030348 - 3 Mar 2022

Cited by 7 | Viewed by 3856

Abstract

Alpha is the predominant rhythm of the human electroencephalogram, but its function, multiple generators and functional coupling patterns are still relatively unknown. In this regard, alpha connectivity patterns can change between different cortical generators depending on the status of the brain. Therefore, in [...] Read more.

Alpha is the predominant rhythm of the human electroencephalogram, but its function, multiple generators and functional coupling patterns are still relatively unknown. In this regard, alpha connectivity patterns can change between different cortical generators depending on the status of the brain. Therefore, in the light of the communication through coherence framework, an alpha functional network depends on the functional coupling patterns in a determined state. This notion has a relevance for brain-state dependent EEG-TMS because, beyond the local state, a network connectivity overview at rest could provide further and more comprehensive information for the definition of ‘instantaneous state’ at the stimulation moment, rather than just the local state around the stimulation site. For this reason, we studied functional coupling at rest in 203 healthy subjects with MEG data. Sensor signals were source localized and connectivity was studied at the Individual Alpha Frequency (IAF) between three different cortical areas (occipital, parietal and prefrontal). Two different and complementary phase-coherence metrices were used. Our results show a consistent connectivity between parietal and prefrontal regions whereas occipito-prefrontal connectivity is less marked and occipito-parietal connectivity is extremely low, despite physical closeness. We consider our results a relevant add-on for informed, individualized real-time brain state dependent stimulation, with possible contributions to novel, personalized non-invasive therapeutic approaches. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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14 pages, 1689 KiB

Open AccessArticle

Capturing Neuroplastic Changes after iTBS in Patients with Post-Stroke Aphasia: A Pilot fMRI Study

by Shuo Xu, Qing Yang, Mengye Chen, Panmo Deng, Ren Zhuang, Zengchun Sun, Chong Li, Zhijie Yan, Yongli Zhang and Jie Jia

Brain Sci. 2021, 11(11), 1451; https://doi.org/10.3390/brainsci11111451 - 31 Oct 2021

Cited by 15 | Viewed by 3450

Abstract

Intermittent theta-burst stimulation (iTBS) is a high-efficiency transcranial magnetic stimulation (TMS) paradigm that has been applied to post-stroke aphasia (PSA). However, its efficacy mechanisms have not been clarified. This study aimed to explore the immediate effects of iTBS of the primary motor cortex [...] Read more.

Intermittent theta-burst stimulation (iTBS) is a high-efficiency transcranial magnetic stimulation (TMS) paradigm that has been applied to post-stroke aphasia (PSA). However, its efficacy mechanisms have not been clarified. This study aimed to explore the immediate effects of iTBS of the primary motor cortex (M1) of the affected hemisphere, on the functional activities and connectivity of the brains of PSA patients. A total of 16 patients with aphasia after stroke received iTBS with 800 pulses for 300 s. All patients underwent motor, language, and cognitive assessments and resting-state functional MRI scans immediately before and after the iTBS intervention. Regional, seed-based connectivity, and graph-based measures were used to test the immediate functional effects of the iTBS intervention, including the fractional amplitude of low-frequency fluctuation (fALFF), degree centrality (DC), and functional connectivity (FC) of the left M1 area throughout the whole brain. The results showed that after one session of iTBS intervention, the fALFF, DC, and FC values changed significantly in the patients’ brains. Specifically, the DC values were significantly higher in the right middle frontal gyrus and parts of the left parietal lobe (p < 0.05), while fALFF values were significantly lower in the right medial frontal lobe and parts of the left intracalcarine cortex (p < 0.05), and the strength of the functional connectivity between the left M1 area and the left superior frontal gyrus was reduced (p < 0.05). Our findings provided preliminary evidences that the iTBS on the ipsilesional M1 could induce neural activity and functional connectivity changes in the motor, language, and other brain regions in patients with PSA, which may promote neuroplasticity and functional recovery. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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30 pages, 1996 KiB

Open AccessArticle

Bihemispheric Navigated Transcranial Magnetic Stimulation Mapping for Action Naming Compared to Object Naming in Sentence Context

by Ann-Katrin Ohlerth, Roelien Bastiaanse, Chiara Negwer, Nico Sollmann, Severin Schramm, Axel Schröder and Sandro M. Krieg

Brain Sci. 2021, 11(9), 1190; https://doi.org/10.3390/brainsci11091190 - 10 Sep 2021

Cited by 12 | Viewed by 2951

Abstract

Preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) is currently based on the disruption of performance during object naming. The resulting cortical language maps, however, lack accuracy when compared to intraoperative mapping. The question arises whether nTMS results can be improved, when [...] Read more.

Preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) is currently based on the disruption of performance during object naming. The resulting cortical language maps, however, lack accuracy when compared to intraoperative mapping. The question arises whether nTMS results can be improved, when another language task is considered, involving verb retrieval in sentence context. Twenty healthy German speakers were tested with object naming and a novel action naming task during nTMS language mapping. Error rates and categories in both hemispheres were compared. Action naming showed a significantly higher error rate than object naming in both hemispheres. Error category comparison revealed that this discrepancy stems from more lexico-semantic errors during action naming, indicating lexico-semantic retrieval of the verb being more affected than noun retrieval. In an area-wise comparison, higher error rates surfaced in multiple right-hemisphere areas, but only trends in the left ventral postcentral gyrus and middle superior temporal gyrus. Hesitation errors contributed significantly to the error count, but did not dull the mapping results. Inclusion of action naming coupled with a detailed error analysis may be favorable for nTMS mapping and ultimately improve accuracy in preoperative planning. Moreover, the results stress the recruitment of both left- and right-hemispheric areas during naming. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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18 pages, 2916 KiB

Open AccessArticle

Comparing the Impact of Multi-Session Left Dorsolateral Prefrontal and Primary Motor Cortex Neuronavigated Repetitive Transcranial Magnetic Stimulation (nrTMS) on Chronic Pain Patients

by Sascha Freigang, Christian Lehner, Shane M. Fresnoza, Kariem Mahdy Ali, Elisabeth Hlavka, Annika Eitler, Istvan Szilagyi, Helmar Bornemann-Cimenti, Hannes Deutschmann, Gernot Reishofer, Anže Berlec, Senta Kurschel-Lackner, Antonio Valentin, Bernhard Sutter, Karla Zaar and Michael Mokry

Brain Sci. 2021, 11(8), 961; https://doi.org/10.3390/brainsci11080961 - 22 Jul 2021

Cited by 11 | Viewed by 3151

Abstract

Repetitive transcranial stimulation (rTMS) has been shown to produce an analgesic effect and therefore has a potential for treating chronic refractory pain. However, previous studies used various stimulation parameters (including cortical targets), and the best stimulation protocol is not yet identified. The present [...] Read more.

Repetitive transcranial stimulation (rTMS) has been shown to produce an analgesic effect and therefore has a potential for treating chronic refractory pain. However, previous studies used various stimulation parameters (including cortical targets), and the best stimulation protocol is not yet identified. The present study investigated the effects of multi-session 20 Hz (2000 pulses) and 5 Hz (1800 pulses) rTMS stimulation of left motor cortex (M1-group) and left dorsolateral prefrontal cortex (DLPFC-group), respectively. The M1-group (n = 9) and DLPFC-group (n = 7) completed 13 sessions of neuronavigated stimulation, while a Sham-group (n = 8) completed seven sessions of placebo stimulation. The outcome was measured using the German Pain Questionnaire (GPQ), Depression, Anxiety and Stress Scale (DASS), and SF-12 questionnaire. Pain perception significantly decreased in the DLPFC-group (38.17%) compared to the M1-group (56.11%) (p ≤ 0.001) on the later sessions. Health-related quality of life also improved in the DLPFC-group (40.47) compared to the Sham-group (35.06) (p = 0.016), and mental composite summary (p = 0.001) in the DLPFC-group (49.12) compared to M1-group (39.46). Stimulation of the left DLPFC resulted in pain relief, while M1 stimulation was not effective. Nonetheless, further studies are needed to identify optimal cortical target sites and stimulation parameters. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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19 pages, 73530 KiB

Open AccessArticle

Downregulation of CD73/A_2AR-Mediated Adenosine Signaling as a Potential Mechanism of Neuroprotective Effects of Theta-Burst Transcranial Magnetic Stimulation in Acute Experimental Autoimmune Encephalomyelitis

by Milorad Dragić, Milica Zeljković, Ivana Stevanović, Marija Adžić, Andjela Stekić, Katarina Mihajlović, Ivana Grković, Nela Ilić, Tihomir V. Ilić, Nadežda Nedeljković and Milica Ninković

Brain Sci. 2021, 11(6), 736; https://doi.org/10.3390/brainsci11060736 - 1 Jun 2021

Cited by 13 | Viewed by 4060

Abstract

Multiple sclerosis (MS) is a chronic neurodegenerative disease caused by autoimmune-mediated inflammation in the central nervous system. Purinergic signaling is critically involved in MS-associated neuroinflammation and its most widely applied animal model—experimental autoimmune encephalomyelitis (EAE). A promising but poorly understood approach in the [...] Read more.

Multiple sclerosis (MS) is a chronic neurodegenerative disease caused by autoimmune-mediated inflammation in the central nervous system. Purinergic signaling is critically involved in MS-associated neuroinflammation and its most widely applied animal model—experimental autoimmune encephalomyelitis (EAE). A promising but poorly understood approach in the treatment of MS is repetitive transcranial magnetic stimulation. In the present study, we aimed to investigate the effect of continuous theta-burst stimulation (CTBS), applied over frontal cranial bone, on the adenosine-mediated signaling system in EAE, particularly on CD73/A_2AR/A₁R in the context of neuroinflammatory activation of glial cells. EAE was induced in two-month-old female DA rats and in the disease peak treated with CTBS protocol for ten consecutive days. Lumbosacral spinal cord was analyzed immunohistochemically for adenosine-mediated signaling components and pro- and anti-inflammatory factors. We found downregulated IL-1β and NF- κB-ir and upregulated IL-10 pointing towards a reduction in the neuroinflammatory process in EAE animals after CTBS treatment. Furthermore, CTBS attenuated EAE-induced glial eN/CD73 expression and activity, while inducing a shift in A_2AR expression from glia to neurons, contrary to EAE, where tight coupling of eN/CD73 and A_2AR on glial cells is observed. Finally, increased glial A₁R expression following CTBS supports anti-inflammatory adenosine actions and potentially contributes to the overall neuroprotective effect observed in EAE animals after CTBS treatment. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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18 pages, 3107 KiB

Open AccessArticle

Navigated TMS in the ICU: Introducing Motor Mapping to the Critical Care Setting

by Severin Schramm, Alexander F. Haddad, Lawrence Chyall, Sandro M. Krieg, Nico Sollmann and Phiroz E. Tarapore

Brain Sci. 2020, 10(12), 1005; https://doi.org/10.3390/brainsci10121005 - 18 Dec 2020

Cited by 3 | Viewed by 3582

Abstract

Navigated transcranial magnetic stimulation (nTMS) is a modality for noninvasive cortical mapping. Specifically, nTMS motor mapping is an objective measure of motor function, offering quantitative diagnostic information regardless of subject cooperation or consciousness. Thus far, it has mostly been restricted to the outpatient [...] Read more.

Navigated transcranial magnetic stimulation (nTMS) is a modality for noninvasive cortical mapping. Specifically, nTMS motor mapping is an objective measure of motor function, offering quantitative diagnostic information regardless of subject cooperation or consciousness. Thus far, it has mostly been restricted to the outpatient setting. This study evaluates the feasibility of nTMS motor mapping in the intensive care unit (ICU) setting and solves the challenges encountered in this special environment. We compared neuronavigation based on computed tomography (CT) and magnetic resonance imaging (MRI). We performed motor mappings in neurocritical patients under varying conditions (e.g., sedation or hemicraniectomy). Furthermore, we identified ways of minimizing electromyography (EMG) noise in the interference-rich ICU environment. Motor mapping was performed in 21 patients (six females, median age: 69 years). In 18 patients, motor evoked potentials (MEPs) were obtained. In three patients, MEPs could not be evoked. No adverse reactions occurred. We found CT to offer a comparable neuronavigation to MRI (CT maximum e-field 52 ± 14 V/m vs. MRI maximum e-field 52 ± 11 V/m; p = 0.6574). We detailed EMG noise reduction methods and found that propofol sedation of up to 80 mcg/kg/h did not inhibit MEPs. Yet, nTMS equipment interfered with exposed pulse oximetry. nTMS motor mapping application and use was illustrated in three clinical cases. In conclusion, we present an approach for the safe and reliable use of nTMS motor mapping in the ICU setting and outline possible benefits. Our findings support further studies regarding the clinical value of nTMS in critical care settings. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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11 pages, 2176 KiB

Open AccessFeature PaperArticle

Brain Response Induced with Paired Associative Stimulation Is Related to Repetition Suppression of Motor Evoked Potential

by Shohreh Kariminezhad, Jari Karhu, Laura Säisänen, Jusa Reijonen, Mervi Könönen and Petro Julkunen

Brain Sci. 2020, 10(10), 674; https://doi.org/10.3390/brainsci10100674 - 26 Sep 2020

Cited by 5 | Viewed by 2912

Abstract

Repetition suppression (RS), i.e., the reduction of neuronal activity upon repetition of an external stimulus, can be demonstrated in the motor system using transcranial magnetic stimulation (TMS). We evaluated the RS in relation to the neuroplastic changes induced by paired associative stimulation (PAS). [...] Read more.

Repetition suppression (RS), i.e., the reduction of neuronal activity upon repetition of an external stimulus, can be demonstrated in the motor system using transcranial magnetic stimulation (TMS). We evaluated the RS in relation to the neuroplastic changes induced by paired associative stimulation (PAS). An RS paradigm, consisting of 20 trains of four identical suprathreshold TMS pulses 1 s apart, was assessed for motor-evoked potentials (MEPs) in 16 healthy subjects, before and following (at 0, 10, and 20 min) a common PAS protocol. For analysis, we divided RS into two components: (1) the ratio of the second MEP amplitude to the first one in RS trains, i.e., the “dynamic” component, and (2) the mean of the second to fourth MEP amplitudes, i.e., the “stable” component. Following PAS, five subjects showed change in the dynamic RS component. However, nearly all the individuals (n = 14) exhibited change in the stable component (p < 0.05). The stable component was similar between subjects showing increased MEPs and those showing decreased MEPs at this level (p = 0.254). The results suggest the tendency of the brain towards a stable state, probably free from the ongoing dynamics, following PAS. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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19 pages, 2490 KiB

Open AccessArticle

Effects of Transcranial Magnetic Stimulation Therapy on Evoked and Induced Gamma Oscillations in Children with Autism Spectrum Disorder

by Manuel F. Casanova, Mohamed Shaban, Mohammed Ghazal, Ayman S. El-Baz, Emily L. Casanova, Ioan Opris and Estate M. Sokhadze

Brain Sci. 2020, 10(7), 423; https://doi.org/10.3390/brainsci10070423 - 3 Jul 2020

Cited by 27 | Viewed by 5363

Abstract

Autism spectrum disorder (ASD) is a behaviorally diagnosed neurodevelopmental condition of unknown pathology. Research suggests that abnormalities of elecltroencephalogram (EEG) gamma oscillations may provide a biomarker of the condition. In this study, envelope analysis of demodulated waveforms for evoked and induced gamma oscillations [...] Read more.

Autism spectrum disorder (ASD) is a behaviorally diagnosed neurodevelopmental condition of unknown pathology. Research suggests that abnormalities of elecltroencephalogram (EEG) gamma oscillations may provide a biomarker of the condition. In this study, envelope analysis of demodulated waveforms for evoked and induced gamma oscillations in response to Kanizsa figures in an oddball task were analyzed and compared in 19 ASD and 19 age/gender-matched neurotypical children. The ASD group was treated with low frequency transcranial magnetic stimulation (TMS), (1.0 Hz, 90% motor threshold, 18 weekly sessions) targeting the dorsolateral prefrontal cortex. In ASD subjects, as compared to neurotypicals, significant differences in evoked and induced gamma oscillations were evident in higher magnitude of gamma oscillations pre-TMS, especially in response to non-target cues. Recordings post-TMS treatment in ASD revealed a significant reduction of gamma responses to task-irrelevant stimuli. Participants committed fewer errors post-TMS. Behavioral questionnaires showed a decrease in irritability, hyperactivity, and repetitive behavior scores. The use of a novel metric for gamma oscillations. i.e., envelope analysis using wavelet transformation allowed for characterization of the impedance of the originating neuronal circuit. The results suggest that gamma oscillations may provide a biomarker reflective of the excitatory/inhibitory balance of the cortex and a putative outcome measure for interventions in autism. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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18 pages, 2551 KiB

Open AccessArticle

Function-Based Tractography of the Language Network Correlates with Aphasia in Patients with Language-Eloquent Glioblastoma

by Haosu Zhang, Severin Schramm, Axel Schröder, Claus Zimmer, Bernhard Meyer, Sandro M. Krieg and Nico Sollmann

Brain Sci. 2020, 10(7), 412; https://doi.org/10.3390/brainsci10070412 - 1 Jul 2020

Cited by 5 | Viewed by 3573

Abstract

To date, the structural characteristics that distinguish language-involved from non-involved cortical areas are largely unclear. Particularly in patients suffering from language-eloquent brain tumors, reliable mapping of the cortico-subcortical language network is of high clinical importance to prepare and guide safe tumor resection. To [...] Read more.

To date, the structural characteristics that distinguish language-involved from non-involved cortical areas are largely unclear. Particularly in patients suffering from language-eloquent brain tumors, reliable mapping of the cortico-subcortical language network is of high clinical importance to prepare and guide safe tumor resection. To investigate differences in structural characteristics between language-positive and language-negative areas, 20 patients (mean age: 63.2 ± 12.9 years, 16 males) diagnosed with language-eloquent left-hemispheric glioblastoma multiforme (GBM) underwent preoperative language mapping by navigated transcranial magnetic stimulation (nTMS) and nTMS-based diffusion tensor imaging fiber tracking (DTI FT). The number of language-positive and language-negative points as well as the gray matter intensity (GMI), normalized volumes of U-fibers, interhemispheric fibers, and fibers projecting to the cerebellum were assessed and compared between language-positive and language-negative nTMS mappings and set in correlation with aphasia grades. We found significantly lower GMI for language-positive nTMS points (5.7 ± 1.7 versus 7.1 ± 1.6, p = 0.0121). Furthermore, language-positive nTMS points were characterized by an enhanced connectivity profile, i.e., these points showed a significantly higher ratio in volumes for U-fibers (p ≤ 0.0056), interhemispheric fibers (p = 0.0494), and fibers projecting to the cerebellum (p = 0.0094). The number of language-positive nTMS points (R ≥ 0.4854, p ≤ 0.0300) as well as the ratio in volumes for U-fibers (R ≤ −0.4899, p ≤ 0.0283) were significantly associated with aphasia grades, as assessed pre- or postoperatively and during follow-up examinations. In conclusion, this study provides evidence for structural differences on cortical and subcortical levels between language-positive and language-negative areas, as detected by nTMS language mapping. The results may further increase confidence in the technique of nTMS language mapping and nTMS-based tractography in the direct clinical setting. Future studies may confirm our results in larger cohorts and may expand the findings to patients with other tumor entities than GBM. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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Review

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24 pages, 389 KiB

Open AccessReview

Stimulating Memory: Reviewing Interventions Using Repetitive Transcranial Magnetic Stimulation to Enhance or Restore Memory Abilities

by Connor J. Phipps, Daniel L. Murman and David E. Warren

Brain Sci. 2021, 11(10), 1283; https://doi.org/10.3390/brainsci11101283 - 28 Sep 2021

Cited by 18 | Viewed by 4232

Abstract

Human memory systems are imperfect recording devices that are affected by age and disease, but recent findings suggest that the functionality of these systems may be modifiable through interventions using non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). The translational potential [...] Read more.

Human memory systems are imperfect recording devices that are affected by age and disease, but recent findings suggest that the functionality of these systems may be modifiable through interventions using non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). The translational potential of these rTMS interventions is clear: memory problems are the most common cognitive complaint associated with healthy aging, while pathological conditions such as Alzheimer’s disease are often associated with severe deficits in memory. Therapies to improve memory or treat memory loss could enhance independence while reducing costs for public health systems. Despite this promise, several important factors limit the generalizability and translational potential of rTMS interventions for memory. Heterogeneity of protocol design, rTMS parameters, and outcome measures present significant challenges to interpretation and reproducibility. However, recent advances in cognitive neuroscience, including rTMS approaches and recent insights regarding functional brain networks, may offer methodological tools necessary to design new interventional studies with enhanced experimental rigor, improved reproducibility, and greater likelihood of successful translation to clinical settings. In this review, we first discuss the current state of the literature on memory modulation with rTMS, then offer a commentary on developments in cognitive neuroscience that are relevant to rTMS interventions, and finally close by offering several recommendations for the design of future investigations using rTMS to modulate human memory performance. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

52 pages, 6404 KiB

Open AccessReview

Mapping of Motor Function with Neuronavigated Transcranial Magnetic Stimulation: A Review on Clinical Application in Brain Tumors and Methods for Ensuring Feasible Accuracy

by Nico Sollmann, Sandro M. Krieg, Laura Säisänen and Petro Julkunen

Brain Sci. 2021, 11(7), 897; https://doi.org/10.3390/brainsci11070897 - 7 Jul 2021

Cited by 35 | Viewed by 6397

Abstract

Navigated transcranial magnetic stimulation (nTMS) has developed into a reliable non-invasive clinical and scientific tool over the past decade. Specifically, it has undergone several validating clinical trials that demonstrated high agreement with intraoperative direct electrical stimulation (DES), which paved the way for increasing [...] Read more.

Navigated transcranial magnetic stimulation (nTMS) has developed into a reliable non-invasive clinical and scientific tool over the past decade. Specifically, it has undergone several validating clinical trials that demonstrated high agreement with intraoperative direct electrical stimulation (DES), which paved the way for increasing application for the purpose of motor mapping in patients harboring motor-eloquent intracranial neoplasms. Based on this clinical use case of the technique, in this article we review the evidence for the feasibility of motor mapping and derived models (risk stratification and prediction, nTMS-based fiber tracking, improvement of clinical outcome, and assessment of functional plasticity), and provide collected sets of evidence for the applicability of quantitative mapping with nTMS. In addition, we provide evidence-based demonstrations on factors that ensure methodological feasibility and accuracy of the motor mapping procedure. We demonstrate that selection of the stimulation intensity (SI) for nTMS and spatial density of stimuli are crucial factors for applying motor mapping accurately, while also demonstrating the effect on the motor maps. We conclude that while the application of nTMS motor mapping has been impressively spread over the past decade, there are still variations in the applied protocols and parameters, which could be optimized for the purpose of reliable quantitative mapping. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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18 pages, 6966 KiB

Open AccessReview

Contribution of TMS and TMS-EEG to the Understanding of Mechanisms Underlying Physiological Brain Aging

by Andrea Guerra, Lorenzo Rocchi, Alberto Grego, Francesca Berardi, Concetta Luisi and Florinda Ferreri

Brain Sci. 2021, 11(3), 405; https://doi.org/10.3390/brainsci11030405 - 22 Mar 2021

Cited by 17 | Viewed by 3962

Abstract

In the human brain, aging is characterized by progressive neuronal loss, leading to disruption of synapses and to a degree of failure in neurotransmission. However, there is increasing evidence to support the notion that the aged brain has a remarkable ability to reorganize [...] Read more.

In the human brain, aging is characterized by progressive neuronal loss, leading to disruption of synapses and to a degree of failure in neurotransmission. However, there is increasing evidence to support the notion that the aged brain has a remarkable ability to reorganize itself, with the aim of preserving its physiological activity. It is important to develop objective markers able to characterize the biological processes underlying brain aging in the intact human, and to distinguish them from brain degeneration associated with many neurological diseases. Transcranial magnetic stimulation (TMS), coupled with electromyography or electroencephalography (EEG), is particularly suited to this aim, due to the functional nature of the information provided, and thanks to the ease with which it can be integrated with behavioral manipulation. In this review, we aimed to provide up to date information about the role of TMS and TMS-EEG in the investigation of brain aging. In particular, we focused on data about cortical excitability, connectivity and plasticity, obtained by using readouts such as motor evoked potentials and transcranial evoked potentials. Overall, findings in the literature support an important potential contribution of TMS to the understanding of the mechanisms underlying normal brain aging. Further studies are needed to expand the current body of information and to assess the applicability of TMS findings in the clinical setting. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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Other

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12 pages, 3684 KiB

Open AccessCase Report

Preoperative Repetitive Navigated TMS and Functional White Matter Tractography in a Bilingual Patient with a Brain Tumor in Wernike Area

by Valentina Baro, Samuel Caliri, Luca Sartori, Silvia Facchini, Brando Guarrera, Pietro Zangrossi, Mariagiulia Anglani, Luca Denaro, Domenico d’Avella, Florinda Ferreri and Andrea Landi

Brain Sci. 2021, 11(5), 557; https://doi.org/10.3390/brainsci11050557 - 28 Apr 2021

Cited by 6 | Viewed by 2503

Abstract

Awake surgery and intraoperative neuromonitoring represent the gold standard for surgery of lesion located in language-eloquent areas of the dominant hemisphere, enabling the maximal safe resection while preserving language function. Nevertheless, this functional mapping is invasive; it can be executed only during surgery [...] Read more.

Awake surgery and intraoperative neuromonitoring represent the gold standard for surgery of lesion located in language-eloquent areas of the dominant hemisphere, enabling the maximal safe resection while preserving language function. Nevertheless, this functional mapping is invasive; it can be executed only during surgery and in selected patients. Moreover, the number of neuro-oncological bilingual patients is constantly growing, and performing awake surgery in this group of patients can be difficult. In this scenario, the application of accurate, repeatable and non-invasive preoperative mapping procedures is needed, in order to define the anatomical distribution of both languages. Repetitive navigated transcranial magnetic stimulation (rnTMS) associated with functional subcortical fiber tracking (nTMS-based DTI-FT) represents a promising and comprehensive mapping tool to display language pathway and function reorganization in neurosurgical patients. Herein we report a case of a bilingual patient affected by brain tumor in the left temporal lobe, who underwent rnTMS mapping for both languages (Romanian and Italian), disclosing the true eloquence of the anterior part of the lesion in both tests. After surgery, language abilities were intact at follow-up in both languages. This case represents a preliminary application of nTMS-based DTI-FT in neurosurgery for brain tumor in eloquent areas in a bilingual patient. Full article

(This article belongs to the Special Issue Modern Developments in Transcranial Magnetic Stimulation (TMS) –Applications and Perspectives in Clinical Neuroscience)

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