title: 1 Hz rTMS of the left posterior parietal cortex (PPC) modifies sensorimotor timing.
abstract: In order to investigate the relevance of the left posterior parietal cortex (PPC) for precise sensorimotor timing we applied 1 Hz repetitive transcranial magnetic stimulation (rTMS) over left PPC, right PPC and visual cortex of healthy participants for 10 min, respectively. The impact on sensorimotor timing of the right hand was assessed using a synchronization task that required subjects to synchronize their right index finger taps with respect to constant auditory, visual or auditory-visual pacing. Our results reveal reduced negative tap-to-pacer asynchronies following rTMS of the left PPC in all pacing conditions. This effect lasted for about 5 min after cessation of rTMS. Right PPC and visual cortex stimulation did not yield any significant behavioural effects. Since suppression of left PPC modified right-hand synchronization accuracy independent of the pacing signal's modality, the present data support the significance of left PPC for anticipatory motor control over a primary role in multisensory integration. The present data suggest that 1 Hz rTMS might interrupt a matching process of anticipated and real sensorimotor feedback within PPC. Alternatively, downregulation of left PPC activity may affect M1 excitability via functional connections leading to a delay in motor output and, thus, smaller tap-to-pacer asynchronies.
authors.affiliation: Heinrich-Heine-University Duesseldorf, Medical Faculty, Institute of Clinical Neuroscience and Medical Psychology, Universitaetsstr. 1, 40225 Duesseldorf, Germany. Vanessa.Krause@uni-duesseldorf.de
authors.forename: Vanessa
authors.initials: V
authors.lastname: Krause
authors.forename: Shahid
authors.initials: S
authors.lastname: Bashir
authors.forename: Bettina
authors.initials: B
authors.lastname: Pollok
authors.forename: Anuhya
authors.initials: A
authors.lastname: Caipa
authors.forename: Alfons
authors.initials: A
authors.lastname: Schnitzler
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology*; D055139:Sensory Gating / Q000502:physiology*; D013998:Time Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult