title: Repetitive TMS over the human oculomotor cortex: comparison of 1-Hz and theta burst stimulation.
abstract: The aim of the study was to compare the effect duration of two different protocols of repetitive transcranial magnetic stimulation (rTMS) on saccade triggering. In four experiments, two regions (right frontal eye field (FEF) and vertex) were stimulated using a 1-Hz and a theta burst protocol (three 30Hz pulses repeated at intervals of 100ms). The same number of TMS pulses (600 pulses) was applied with stimulation strength of 80% of the resting motor threshold for hand muscles. Following stimulation the subjects repeatedly performed an oculomotor task using a modified overlap paradigm, and saccade latencies were measured over a period of 60min. The results show that both 1-Hz and theta burst stimulation had inhibitory effects on saccade triggering when applied over the FEF, but not over the vertex. One-hertz rTMS significantly increased saccade latencies over a period of about 8min. After theta burst rTMS, this effect lasted up to 30min. Furthermore, the decay of rTMS effects was protocol-specific: After 1-Hz stimulation, saccade latencies returned to a baseline level much faster than after theta burst stimulation. We speculate that these time course differences represent distinct physiological mechanisms of how TMS interacts with brain function.
authors.affiliation: Perception and Eye Movement Laboratory, Department of Neurology, University Hospital, University of Berne, Freiburgstrasse 10, 3010 Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nyffeler
authors.forename: Pascal
authors.initials: P
authors.lastname: Wurtz
authors.forename: Hans-Rudolf
authors.initials: HR
authors.lastname: Lüscher
authors.forename: Christian W
authors.initials: CW
authors.lastname: Hess
authors.forename: Walter
authors.initials: W
authors.lastname: Senn
authors.forename: Tobias
authors.initials: T
authors.lastname: Pflugshaupt
authors.forename: Roman
authors.initials: R
authors.lastname: von Wartburg
authors.forename: Mathias
authors.initials: M
authors.lastname: Lüthi
authors.forename: René M
authors.initials: RM
authors.lastname: Müri
mesh_terms: D000328:Adult; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009802:Oculomotor Nerve / Q000502:physiology*; D011930:Reaction Time / Q000528:radiation effects; D012438:Saccades / Q000502:physiology; D013826:Theta Rhythm; D050781:Transcranial Magnetic Stimulation