Short-interval interhemispheric inhibition does not originate from the motor hotspot
Loading...
Access rights
openAccess
CC BY
CC BY
publishedVersion
URL
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Other link related to publication (opens in new window)
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Other link related to publication (opens in new window)
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Date
Major/Subject
Mcode
Degree programme
Language
en
Pages
8
Series
Brain Stimulation, Volume 18, issue 4, pp. 1074-1081
Abstract
Background: Paired-coil TMS can delineate causal connections between cortical areas. Short-interval interhemispheric inhibition (SIHI) is a rapid inhibitory process, in which one primary motor cortex (M1) inhibits the other through the corpus callosum. Previous work suggests that both SIHI and motor evoked potentials (MEPs) originate in the motor hotspot. However, SIHI and MEPs are mediated by different neuronal populations. Objectives: Here we used a recently published TMS-based association-method (Weise et al., 2023, Nat Protoc 18:293–318) to test if the neuronal populations mediating SIHI and MEPs can be spatially discriminated. Method: s: We mapped the origin of SIHI and MEPs of hand muscles in each hemisphere, using the novel association-method to perform a ‘source space’ mapping on 18 healthy volunteers. Results: The origin of SIHI (the ‘coldspot’) was identifiable in the majority of subjects near the motor hotspot, at the hand-knob and around the central sulcus. It was displaced posterolaterally from the motor hotspot by about 6 mm. Post-hoc analyses revealed that precisely targeting the coldspot elicited significantly stronger SIHI compared to targeting the motor hotspot. Conclusions: Findings demonstrate that the TMS-based association-method for source-space mapping enables physiological investigation of the distinct neuronal populations that give rise to interhemispheric inhibition of the contralateral motor cortex versus motor evoked potentials in contralateral hand muscles. SIHI can be more effectively elicited by targeting the coldspot rather than the hotspot, a potentially relevant distinction when aiming to modify interhemispheric neural communication, e.g., in stroke rehabilitation.Description
| openaire: EC/H2020/810377/EU//ConnectToBrain
Other note
Citation
Vetter, D E, Jooß, A, Mutanen, T P, Kozák, G & Ziemann, U 2025, 'Short-interval interhemispheric inhibition does not originate from the motor hotspot', Brain Stimulation, vol. 18, no. 4, pp. 1074-1081. https://doi.org/10.1016/j.brs.2025.05.115