Author:

Keywords:

11F6921N|11F6923N#55783277, I005018N#54777490, C16/15/070#53326576, 11L9322N, BOF21INCENT15, EOS 30446199, MEMODYN, G039821N, Hercules fund AUHL/11/01 (R-3987), Science & Technology, Life Sciences & Biomedicine, Clinical Neurology, Neurosciences, Neurosciences & Neurology, Transcranial magnetic stimulation (TMS), Dual -site TMS (dsTMS), Intrahemispheric interaction, Dorsal premotor cortex (PMd), Effective functional connectivity, TRANSCRANIAL MAGNETIC STIMULATION, PRIMARY MOTOR CORTEX, DORSAL PREMOTOR CORTEX, INTRACORTICAL INHIBITION, INTERHEMISPHERIC INTERACTIONS, FUNCTIONAL CONNECTIVITY, CORTICAL EXCITABILITY, BIMANUAL MOVEMENTS, BRAIN-STIMULATION, COIL, Dual-site TMS (dsTMS), Humans, Evoked Potentials, Motor, Transcranial Magnetic Stimulation, Motor Cortex, Head, 09 Engineering, 11 Medical and Health Sciences, 17 Psychology and Cognitive Sciences, Neurology & Neurosurgery, 3209 Neurosciences

Abstract:

Highlights: - We developed a novel dual-site TMS setup to stimulate two adjacent brain regions. - It is subject to fewer technical and spatial limitations than previous attempts. - This enables more accurate and repeatable targeting of brain regions. Abstract: Objective: Using dual-site transcranial magnetic stimulation (dsTMS), the effective connectivity between the primary motor cortex (M1) and adjacent brain areas such as the dorsal premotor cortex (PMd) can be investigated. However, stimulating two brain regions in close proximity (e.g., ±2.3 cm for intrahemispheric PMd–M1) is subject to considerable spatial restrictions that potentially can be overcome by combining two standard figure-of-eight coils in a novel dsTMS setup. Methods: After a technical evaluation of its induced electric fields, the dsTMS setup was tested in vivo (n = 23) by applying a short-interval intracortical inhibition (SICI) protocol. Additionally, the intrahemispheric PMd–M1 interaction was probed. E-field modelling was performed using SimNIBS. Results: The technical evaluation yielded no major alterations of the induced electric fields due to coil overlap. In vivo, the setup reliably elicited SICI. Investigating intrahemispheric PMd–M1 interactions was feasible (inter-stimulus interval 6 ms), resulting in modulation of M1 output. Conclusions: The presented dsTMS setup provides a novel way to stimulate two adjacent brain regions with fewer technical and spatial limitations than previous attempts. Significance: This dsTMS setup enables more accurate and repeatable targeting of brain regions in close proximity and can facilitate innovation in the field of effective connectivity.