title: Paired-Pulse Parietal-Motor Stimulation Differentially Modulates Corticospinal Excitability across Hemispheres When Combined with Prism Adaptation.
abstract: Rightward prism adaptation ameliorates neglect symptoms while leftward prism adaptation (LPA) induces neglect-like biases in healthy individuals. Similarly, inhibitory repetitive transcranial magnetic stimulation (rTMS) on the right posterior parietal cortex (PPC) induces neglect-like behavior, whereas on the left PPC it ameliorates neglect symptoms and normalizes hyperexcitability of left hemisphere parietal-motor (PPC-M1) connectivity. Based on this analogy we hypothesized that LPA increases PPC-M1 excitability in the left hemisphere and decreases it in the right one. In an attempt to shed some light on the mechanisms underlying LPA's effects on cognition, we investigated this hypothesis in healthy individuals measuring PPC-M1 excitability with dual-site paired-pulse TMS (ppTMS). We found a left hemisphere increase and a right hemisphere decrease in the amplitude of motor evoked potentials elicited by paired as well as single pulses on M1. While this could indicate that LPA biases interhemispheric connectivity, it contradicts previous evidence that M1-only MEPs are unchanged after LPA. A control experiment showed that input-output curves were not affected by LPA per se. We conclude that LPA combined with ppTMS on PPC-M1 differentially alters the excitability of the left and right M1.
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France.
authors.forename: Selene
authors.identifier: 0000-0002-6362-3905
authors.initials: S
authors.lastname: Schintu
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Martín-Arévalo
authors.affiliation: Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, ON, Canada M5T 2S8.
authors.forename: Michael
authors.identifier: 0000-0003-3609-4902
authors.initials: M
authors.lastname: Vesia
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France; Hospices Civils de Lyon, Neuro-Immersion & Mouvement et Handicap, 69000 Lyon, France.
authors.forename: Yves
authors.identifier: 0000-0001-8867-4496
authors.initials: Y
authors.lastname: Rossetti
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France; Hospices Civils de Lyon, Neuro-Immersion & Mouvement et Handicap, 69000 Lyon, France.
authors.forename: Romeo
authors.initials: R
authors.lastname: Salemme
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Pisella
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France; Hospices Civils de Lyon, Neuro-Immersion & Mouvement et Handicap, 69000 Lyon, France.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Farnè
authors.affiliation: Integrative Multisensory Perception Action & Cognition Team (ImpAct), INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center (CRNL), 69000 Lyon, France; University of Lyon 1, 69000 Lyon, France.
authors.forename: Karen T
authors.identifier: 0000-0002-2840-1610
authors.initials: KT
authors.lastname: Reilly
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011712:Pyramidal Tracts / Q000502:physiology*; D011897:Random Allocation; D050781:Transcranial Magnetic Stimulation / Q000379:methods*