scholarly journals Plasticity Induced by Intermittent Theta Burst Stimulation in Bilateral Motor Cortices Is Not Altered in Older Adults

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Daina S. E. Dickins ◽  
Martin V. Sale ◽  
Marc R. Kamke

Numerous studies have reported that plasticity induced in the motor cortex by transcranial magnetic stimulation (TMS) is attenuated in older adults. Those investigations, however, have focused solely on the stimulated hemisphere. Compared to young adults, older adults exhibit more widespread activity across bilateral motor cortices during the performance of unilateral motor tasks, suggesting that the manifestation of plasticity might also be altered. To address this question, twenty young (<35 years old) and older adults (>65 years) underwent intermittent theta burst stimulation (iTBS) whilst attending to the hand targeted by the plasticity-inducing procedure. The amplitude of motor evoked potentials (MEPs) elicited by single pulse TMS was used to quantify cortical excitability before and after iTBS. Individual responses to iTBS were highly variable, with half the participants showing an unexpected decrease in cortical excitability. Contrary to predictions, however, there were no age-related differences in the magnitude or manifestation of plasticity across bilateral motor cortices. The findings suggest that advancing age does not influence the capacity for, or manifestation of, plasticity induced by iTBS.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel M. McCalley ◽  
Daniel H. Lench ◽  
Jade D. Doolittle ◽  
Julia P. Imperatore ◽  
Michaela Hoffman ◽  
...  

AbstractTheta-burst stimulation (TBS) is a form of non-invasive neuromodulation which is delivered in an intermittent (iTBS) or continuous (cTBS) manner. Although 600 pulses is the most common dose, the goal of these experiments was to evaluate the effect of higher per-dose pulse numbers on cortical excitability. Sixty individuals were recruited for 2 experiments. In Experiment 1, participants received 600, 1200, 1800, or sham (600) iTBS (4 visits, counterbalanced, left motor cortex, 80% active threshold). In Experiment 2, participants received 600, 1200, 1800, 3600, or sham (600) cTBS (5 visits, counterbalanced). Motor evoked potentials (MEP) were measured in 10-min increments for 60 min. For iTBS, there was a significant interaction between dose and time (F = 3.8296, p = 0.01), driven by iTBS (1200) which decreased excitability for up to 50 min (t = 3.1267, p = 0.001). For cTBS, there was no overall interaction between dose and time (F = 1.1513, p = 0.33). Relative to sham, cTBS (3600) increased excitability for up to 60 min (t = 2.0880, p = 0.04). There were no other significant effects of dose relative to sham in either experiment. Secondary analyses revealed high within and between subject variability. These results suggest that iTBS (1200) and cTBS (3600) are, respectively, the most effective doses for decreasing and increasing cortical excitability.


2021 ◽  
Vol 65 ◽  
pp. 162-166
Author(s):  
B. N. Keerthy ◽  
Sai Sreevalli Sarma Sreepada ◽  
Shalini S. Naik ◽  
Anushree Bose ◽  
Raju Hanumegowda ◽  
...  

Objectives: Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been used as neuromodulators in neuropsychiatric conditions. This study is aimed to find the effects of a single session of priming cathodal tDCS with intermittent theta-burst stimulation (iTBS) over left dorsolateral prefrontal cortex on heart rate variability (HRV) and cortical excitability parameters before and after perturbation. Materials and Methods: The neuromodulatory techniques used in the study were Cathodal tDCS for 20 min followed by iTBS for 3 min on the left dorsolateral prefrontal cortex (DLPFC). HRV variables and TMS parameters were recorded before and after this intervention of combined neuromodulation in 31 healthy volunteers (20 males and 11 females; age range of 19–35 years with Mean ± SD = 24.2 ± 4.7 years). Results: The results showed an overall increase in cortical excitability and parasympathetic dominance in healthy volunteers. Other measures of cortical excitability and HRV did not change significantly following single session of combined neuromodulation. Conclusion: This study showed that there is an overall increase in cortical excitability and parasympathetic dominance in the cohort of healthy volunteers following a combination of neuromodulation involving cathodal tDCS followed by iTBS over left DLPFC. Future studies exploring the effects of other possible combinations with sham stimulation could be carried out to explore the utility of dual stimulation as add-on therapy in disorders.


2021 ◽  
Vol 11 (12) ◽  
pp. 1640
Author(s):  
Katarina Hosel ◽  
François Tremblay

Theta-burst stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (rTMS) developed to induce neuroplasticity. TBS usually consists of 50 Hz bursts at 5 Hz intervals. It can facilitate motor evoked potentials (MEPs) when applied intermittently, although this effect can vary between individuals. Here, we sought to determine whether a modified version of intermittent TBS (iTBS) consisting of 30 Hz bursts repeated at 6 Hz intervals would lead to lasting MEP facilitation. We also investigated whether recruitment of early and late indirect waves (I-waves) would predict individual responses to 30 Hz iTBS. Participants (n = 19) underwent single-pulse TMS to assess MEP amplitude at baseline and variations in MEP latency in response to anterior-posterior, posterior-anterior, and latero-medial stimulation. Then, 30 Hz iTBS was administered, and MEP amplitude was reassessed at 5-, 20- and 45-min. Post iTBS, most participants (13/19) exhibited MEP facilitation, with significant effects detected at 20- and 45-min. Contrary to previous evidence, recruitment of early I-waves predicted facilitation to 30 Hz iTBS. These observations suggest that 30 Hz/6 Hz iTBS is effective in inducing lasting facilitation in corticospinal excitability and may offer an alternative to the standard 50 Hz/5 Hz protocol.


2008 ◽  
Vol 100 (4) ◽  
pp. 2070-2076 ◽  
Author(s):  
Ennio Iezzi ◽  
Antonella Conte ◽  
Antonio Suppa ◽  
Rocco Agostino ◽  
Loredana Dinapoli ◽  
...  

Theta-burst stimulation (TBS) is a technique that elicits long-lasting changes in the excitability of human primary motor cortex (M1). Tonic contraction of the target muscle modifies the aftereffects of TBS, whereas interactions between phasic muscle contraction and the aftereffects of TBS are unknown. In this paper, we investigated whether phasic voluntary movements influence TBS-induced changes in M1 excitability. We examined whether a brief sequence of phasic finger movements performed by healthy humans before both intermittent TBS (iTBS) and continuous TBS (cTBS) influences TBS-induced aftereffects. Ten healthy subjects underwent iTBS and cTBS. To evaluate the TBS-induced aftereffects on M1 excitability, single TMS pulses were given over the FDI motor area before (T0) and 5 (T1), 15 (T2), and 30 min (T3) after TBS. To find out whether finger movements influenced the TBS-induced aftereffects, we tested motor-evoked potentials (MEPs) size by single TMS pulses at T0, immediately after movements, and at T1–T3. We also measured the kinematic variables mean amplitude and mean peak velocity of the movements. When no phasic voluntary movements preceded TBS, iTBS elicited facilitatory and cTBS elicited inhibitory aftereffects on MEP size. Conversely, movements performed before TBS elicited significant changes in the direction of the TBS-induced aftereffects. iTBS produced inhibitory instead of facilitatory aftereffects and cTBS produced facilitatory instead of inhibitory aftereffects. Finger movements alone had no effects on MEPs size tested with single-pulse TMS. Peripheral electrical stimulation had no effect on iTBS-induced aftereffects. Repeated phasic finger movements interfere with TBS-induced aftereffects probably by modulating mechanisms of brain metaplasticity.


2020 ◽  
Author(s):  
Ali Jannati ◽  
Mary A Ryan ◽  
Gabrielle Block ◽  
Fae B. Kayarian ◽  
Lindsay M. Oberman ◽  
...  

Objective. To assess the utility of the modulation of motor cortex (M1) excitability by continuous theta-burst stimulation (cTBS) as a physiologic biomarker for adults with autism spectrum disorder (ASD), and to evaluate the influences of brain-derived neurotrophic factor (BDNF) and apolipoprotein E (APOE) polymorphisms on cTBS aftereffects. Methods. 44 neurotypical individuals (NT; age 21-65, 34 males) and 19 age-matched adults with high-functioning ASD (age 21-58, 17 males) underwent M1 cTBS. Cortico-motor reactivity was assessed before cTBS and thereafter every 5-10 minutes for 60 minutes (T5-T60). Results. Logistic regressions found cTBS-induced change in amplitude of motor evoked potentials (ΔMEP) at T15 was a significant predictor of ASD diagnosis (p=0.04). ΔMEP at T15 remained a significant predictor of diagnosis among BDNF Met+ subjects and APOEε4- subjects (p-values < 0.05) but not BDNF Met- subjects. ΔMEP at T30 was the best predictor of diagnosis among APOEε4+ subjects (p = 0.08). Conclusions. We confirm previous findings on the utility of cTBS measures of plasticity for adults with ASD, and we find the diagnostic utility of cTBS is modulated by BDNF and APOE SNPs. Significance. It is important to control for BDNF and APOE polymorphisms when comparing TBS aftereffects in ASD and NT individuals.


2021 ◽  
Vol 15 ◽  
Author(s):  
Denise Y. Harvey ◽  
Laura DeLoretta ◽  
Priyanka P. Shah-Basak ◽  
Rachel Wurzman ◽  
Daniela Sacchetti ◽  
...  

Objective: To evaluate whether a common polymorphism (Val66Met) in the gene for brain-derived neurotrophic factor (BDNF)—a gene thought to influence plasticity—contributes to inter-individual variability in responses to continuous theta-burst stimulation (cTBS), and explore whether variability in stimulation-induced plasticity among Val66Met carriers relates to differences in stimulation intensity (SI) used to probe plasticity.Methods: Motor evoked potentials (MEPs) were collected from 33 healthy individuals (11 Val66Met) prior to cTBS (baseline) and in 10 min intervals immediately following cTBS for a total of 30 min post-cTBS (0 min post-cTBS, 10 min post-cTBS, 20 min post cTBS, and 30 min post-cTBS) of the left primary motor cortex. Analyses assessed changes in cortical excitability as a function of BDNF (Val66Val vs. Val66Met) and SI.Results: For both BDNF groups, MEP-suppression from baseline to post-cTBS time points decreased as a function of increasing SI. However, the effect of SI on MEPs was more pronounced for Val66Met vs. Val66Val carriers, whereby individuals probed with higher vs. lower SIs resulted in paradoxical cTBS aftereffects (MEP-facilitation), which persisted at least 30 min post-cTBS administration.Conclusions: cTBS aftereffects among BDNF Met allele carriers are more variable depending on the SI used to probe cortical excitability when compared to homozygous Val allele carriers, which could, to some extent, account for the inconsistency of previously reported cTBS effects.Significance: These data provide insight into the sources of cTBS response variability, which can inform how best to stratify and optimize its use in investigational and clinical contexts.


2017 ◽  
Vol 41 (S1) ◽  
pp. S374-S374
Author(s):  
M. Klírová ◽  
M. Hejzlar ◽  
T. Novák ◽  
R. Rokyta

IntroductionRepetitive transcranial magnetic stimulation (rTMS) has important role in treatment of neuropsychiatric disorders. Theta burst stimulation (TBS), a modification of rTMS, seems to produce greater changes in cortical excitability (CE) than those observed in conventional rTMS protocols. TBS is used in different protocols: intermittent TBS (iTBS) and continuous TBS (cTBS). While iTBS facilitates CE, cTBS leads to CE inhibition. However, a prolonged cTBS produces facilitatory effect similar to that of iTBS. Prolonged TBS (pTBS), a novel rTMS paradigm, is of great clinical interest for its short duration, but also because it may induce stronger effect.AimTo prove the effect of pTBS of motor cortex on changes of motor threshold (MT), CE and pain threshold (PT) in healthy volunteers (HV). To compare the effects of two different forms of active pTBS (pcTBS, piTBS) with placebo.MethodsA double-blind, placebo-controlled, cross-over study compared the effects of different pTBS of contralateral M1 area on MT, CE and PT. We enrolled 24 HV to the study, who underwent all types of pTBS in randomized order and were assessed before and after each pTBS application. We used MagPro R30 (with coil focused to contralateral M1 area, 1200 pulses/session, 90% MT).ResultsA significant changes in CE and MT were found after application of continuous pTBS. Intermittent and placebo pTBS did not confirm the effect. There were no significant changes on PT after pTBS. Continuous pTBS was better tolerated than intermittent pTBS.ConclusionpTBS should be considered as an effective and safe treatment option for neuropsychiatric disorders.Disclosure of interestSupported by AZV 16-31380A.


2021 ◽  
Author(s):  
Angela Sanna ◽  
Paolo Follesa ◽  
Paolo Tacconi ◽  
Mariangela Serra ◽  
Maria Giuseppina Pisu ◽  
...  

AbstractSpinocerebellar ataxia 38 (SCA 38) is an autosomal dominant disorder caused by conventional mutations in the ELOVL5 gene which encodes an enzyme involved in the synthesis of very long fatty acids, with a specific expression in cerebellar Purkinje cells. Three Italian families carrying the mutation, one of which is of Sardinian descent, have been identified and characterized. One session of cerebellar intermittent theta burst stimulation (iTBS) was applied to 6 affected members of the Sardinian family to probe motor cortex excitability measured by motor-evoked potentials (MEPs). Afterwards, patients were exposed to ten sessions of cerebellar real and sham iTBS in a cross-over study and clinical symptoms were evaluated before and after treatment by Modified International Cooperative Ataxia Rating Scale (MICARS). Moreover, serum BDNF levels were evaluated before and after real and sham cerebellar iTBS and the role of BDNF Val66Met polymorphism in influencing iTBS effect was explored. Present data show that one session of cerebellar iTBS was able to increase MEPs in all tested patients, suggesting an enhancement of the cerebello-thalamo-cortical pathway in SCA 38. MICARS scores were reduced after ten sessions of real cerebellar iTBS showing an improvement in clinical symptoms. Finally, although serum BDNF levels were not affected by cerebellar iTBS when considering all samples, segregating for genotype a difference was found between Val66Val and Val66Met carriers. These preliminary data suggest a potential therapeutic use of cerebellar iTBS in improving motor symptoms of SCA38.


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