Development of instrumentation for neuronavigation and transcranial magnetic stimulation

Souza, Victor Hugo de Oliveira e

doi:10.11606/t.59.2018.tde-21032018-153036

Cited by 1 publication

(2 citation statements)

References 61 publications

(112 reference statements)

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“…Data were recorded in the same experimental sessions with another study [21], with shared subject preparation, motor mapping, and motor threshold determination. Briefly, surface electromyography (EMG) electrodes were placed over the right abductor pollicis brevis (APB), abductor digiti minimi, and first dorsal interosseous muscles in a belly-tendon montage.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, we estimated the optimal conditioning- and test-pulse orientation to maximize the SICI and ICF effects and selectively probe the inhibitory and excitatory neural circuits in the primary motor cortex. To deliver consecutive pulses in different orientations within the desired ISI, we employed multi-channel TMS (mTMS) technology [21], enabling an unprecedented approach to study the effect of stimulus orientation on the intracortical mechanisms at the time scale of neuronal excitation.…”

Section: Introductionmentioning

confidence: 99%

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Probing the orientation specificity of excitatory and inhibitory circuitries in the primary motor cortex with multi-channel TMS

Souza

Nieminen

Tugin

et al. 2021

Preprint

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Background: The electric field orientation is a crucial parameter for optimizing the excitation of neuronal tissue in transcranial magnetic stimulation (TMS). Yet, the effects of stimulus orientation on the short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) paradigms are poorly known, mainly due to significant technical challenges in manipulating the TMS-induced stimulus orientation within milliseconds. Objective: Our aim is to assess the effect of the TMS-induced stimulus orientation on the SICI and ICF paradigms and search for the optimal orientations to maximize the facilitation and suppression of the motor evoked potentials (MEP). Methods: We applied paired-pulse multi-channel TMS in healthy subjects to generate SICI and ICF with conditioning and test pulses in the same, opposite, and perpendicular orientations to each other. The conditioning- and test-stimulus intensities were 80% and 110% of the resting motor threshold, respectively. Results: Both SICI and ICF were significantly affected by the conditioning- and test-stimulus orientation. MEP suppression and facilitation were strongest with both pulses delivered in the same direction. SICI with a 2.5-ms and ICF with a 6.0-ms interstimulus interval (ISI) were more sensitive to changes in stimulus orientation compared with SICI at 0.5- and ICF at 8.0-ms ISIs, respectively. Conclusion: Our findings provide evidence that SICI and ICF at specific ISIs are mediated by distinct mechanisms. Such mechanisms exhibit a preferential orientation depending on the anatomical and morphological arrangement of inhibitory and excitatory neuronal populations. We also demonstrate that the SICI and ICF can be maximized by adjusting the TMS-induced electric field orientation.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%