Differentiating transcranial magnetic stimulation cortical and auditory responses via single pulse and paired pulse protocols: A TMS-EEG study

Poorganji, Mohsen; Zomorrodi, Reza; Hawco, Colin; Hill, Aron T.; Hadas, Itay; Rajji, Tarek K.; Chen, Robert; Voineskos, Daphne; Daskalakis, Anastasios A.; Blumberger, Daniel M.; Daskalakis, Zafiris J.

doi:10.1016/j.clinph.2021.05.009

Cited by 17 publications

(15 citation statements)

References 31 publications

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“…The signi cant LICI over the DLPFC has been demonstrated in previous reports across both healthy and diseased states 16,17,20,30 . This nding is also in accordance with our previous results where the active paired-pulse protocol resulted in signi cant LICI, whereas auditory stimulation alone did not 10 .…”

Section: Licisupporting

confidence: 93%

“…However, in these two studies, the same concern with regards to the similarity of sensory co-stimulation between active and sham blocks seems to be valid. A lower level of activation with sham stimulation is also consistent with our previous ndings10 where auditory stimulation resulted in signi cantly lower TEP amplitudes compared to active stimulation in both single-pulse and LICI protocols over the DLPFC. On the other hand, our results are not in accordance with those ofConde et al (2019) andGordon et al (2021) who demonstrated that somatosensory and auditory co-activation from sham stimulation resembled the typical TEP response, speci cally in late responses.…”

supporting

confidence: 91%

“…The question remains whether auditory masking and foam spacing (to minimize the sensory artifacts) would cause different excitatory and inhibitory responses at suprathreshold stimulation intensity and over the prefrontal cortex in comparison with older methods of delivering TMS-EEG. In a recent publication 10 , our group has quanti ed the contribution of auditory coactivation on the TMS-EEG response over left dorsolateral prefrontal cortex (DLPFC) at suprathreshold level of stimulation. However, we neither investigated the distinct somatosensory artifact of stimulation, nor the effect of applying advanced artifact reduction methods (i.e., playing white noise and applying a layer of foam) on TMS-EEG recordings over this region.…”

Section: Introductionmentioning

confidence: 99%

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Isolating sensory artifacts in the suprathreshold TMS-EEG signal over DLPFC

Poorganji

Zomorrodi

Hawco

et al. 2022

Preprint

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Objective Combined transcranial magnetic stimulation and electroencephalography (TMS-EEG) is an effective way to evaluate neurophysiological processes at the level of the cortex. To further characterize the TMS-evoked potential (TEP) generated with TMS-EEG, beyond the motor cortex, we aimed to distinguish between cortical reactivity to TMS versus non-specific somatosensory and auditory co-activations using both single-pulse and paired-pulse protocols at suprathreshold stimulation intensities over the left dorsolateral prefrontal cortex (DLPFC). Method Fifteen right-handed healthy participants received six blocks of stimulation including single and paired TMS delivered as active-masked (i.e., TMS-EEG with auditory masking and foam spacing), active-unmasked (TMS-EEG without auditory masking and foam spacing) and sham (sham TMS coil). We evaluated cortical excitability following single-pulse TMS, and cortical inhibition following a paired-pulse paradigm (long-interval cortical inhibition (LICI)). Results Repeated measure ANOVAs revealed significant differences in mean cortical evoked activity (CEA) of active-masked, active-unmasked, and sham conditions for both the single-pulse (F(1.76, 24.63)=21.88 , p<0.001, η2=0.61) and LICI (F(1.68, 23.49)=10.09 , p<0.001, η2=0.42) protocols. Furthermore, global mean field amplitude (GMFA) differed significantly across the three conditions for both single-pulse (F(1.85, 25.89)=24.68 , p<0.001, η2=0.64) and LICI (F(1.8, 25.16)=14.29 , p<0.001, η2=0.5). Finally, only active LICI protocols but not sham stimulation ([active-masked (0.78±0.16, P<0.0001)], [active-unmasked (0.83±0.25, P<0.01)]) resulted in significant signal inhibition. Conclusion While previous findings of a significant somatosensory and auditory contribution to the evoked EEG signal is replicated by our study, an artifact attenuated cortical reactivity can reliably be measured in TMS-EEG signal with suprathreshold stimulation of DLPFC. Artifact attenuation can be accomplished using standard procedures and even when masked, the level of cortical reactivity is still far above what is produced by sham stimulation. Significance Our study illustrates that TMS-EEG of DLPFC remains a valid investigational tool.

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Section: Licisupporting

confidence: 93%

supporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Isolating sensory artifacts in the suprathreshold TMS-EEG signal over DLPFC

Poorganji

Zomorrodi

Hawco

et al. 2022

Preprint

Self Cite

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“…However, due to the nature of the relatively loud TMS pulses and somatosensory effects (potentially eliciting evoked potentials with auditory and somatosensory origin), caution has been warranted in attributing all TEP components to be related to the TMS pulse alone, since temporal and spatial features of a realistic sham stimulation closely matched real-TMS TEPs (Conde et al, 2019). On the other hand, as Poorganji and colleagues (Poorganji et al, 2021) recently reported in this journal, while the morphology and topography of activation appears similar, real-TEPs had considerable larger amplitudes compared to sham-TEPs.…”

Section: Editorialmentioning

confidence: 99%

Neurophysiological effects of rTMS: Revisiting the role of the N100 as a clinically useful marker in depression

Arns

Voetterl

2021

Clinical Neurophysiology

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“…In fact, since TMS stimulates not only the cerebral cortex, but also the scalp, somatosensory-evoked potentials (SSEPs), auditory-evoked potentials (AEPs) via air and bone conduction due to TMS click sounds during stimulation, and myoelectric artifacts (muscle noise) due to TMS-induced muscle contractions have been found to contaminate EEG signals, especially on the late component of TEP [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. These confounding factors could be suppressed to some extent by using noise-masking methods [ 20 , 22 , 23 , 24 ], foam layers [ 22 , 23 , 24 ], and some analysis applications [ 19 ]. However, there is evidence that, even with these methods, it is difficult to completely eliminate peripheral stimulus-derived brain activities, especially when using suprathreshold TMS [ 12 , 15 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Spatiotemporal Profiles of Single-Pulse TMS-Evoked Potentials with Active Stimulation Compared with a Novel Sham Condition

et al. 2022

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Identifying genuine cortical stimulation-elicited electroencephalography (EEG) is crucial for improving the validity and reliability of neurophysiology using transcranial magnetic stimulation (TMS) combined with EEG. In this study, we evaluated the spatiotemporal profiles of single-pulse TMS-elicited EEG response administered to the left dorsal prefrontal cortex (DLPFC) in 28 healthy participants, employing active and sham stimulation conditions. We hypothesized that the early component of TEP would be activated in active stimulation compared with sham stimulation. We specifically analyzed the (1) stimulus response, (2) frequency modulation, and (3) phase synchronization of TMS–EEG data at the sensor level and the source level. Compared with the sham condition, the active condition induced a significant increase in TMS-elicited EEG power in the 30–60 ms time interval in the stimulation area at the sensor level. Furthermore, in the source-based analysis, the active condition induced significant increases in TMS-elicited response in the 30–60 ms compared with the sham condition. Collectively, we found that the active condition could specifically activate the early component of TEP compared with the sham condition. Thus, the TMS–EEG method that was applied to the DLPFC could detect the genuine neurophysiological cortical responses by properly handling potential confounding factors such as indirect response noises.

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Differentiating transcranial magnetic stimulation cortical and auditory responses via single pulse and paired pulse protocols: A TMS-EEG study

Cited by 17 publications

References 31 publications

Isolating sensory artifacts in the suprathreshold TMS-EEG signal over DLPFC

Isolating sensory artifacts in the suprathreshold TMS-EEG signal over DLPFC

Neurophysiological effects of rTMS: Revisiting the role of the N100 as a clinically useful marker in depression

Investigation of Spatiotemporal Profiles of Single-Pulse TMS-Evoked Potentials with Active Stimulation Compared with a Novel Sham Condition

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