title: TMS evidence for smooth pursuit gain control by the frontal eye fields.
abstract: Smooth pursuit eye movements are used to continuously track slowly moving visual objects. A peculiar property of the smooth pursuit system is the nonlinear increase in sensitivity to changes in target motion with increasing pursuit velocities. We investigated the role of the frontal eye fields (FEFs) in this dynamic gain control mechanism by application of transcranial magnetic stimulation. Subjects were required to pursue a slowly moving visual target whose motion consisted of 2 components: a constant velocity component at 4 different velocities (0, 8, 16, and 24 deg/s) and a superimposed high-frequency sinusoidal oscillation (4 Hz, +/-8 deg/s). Magnetic stimulation of the FEFs reduced not only the overall gain of the system, but also the efficacy of the dynamic gain control. We thus provide the first direct evidence that the FEF population is significantly involved in the nonlinear computation necessary for continuously adjusting the feedforward gain of the pursuit system. We discuss this with relation to current models of smooth pursuit.
authors.affiliation: Bernstein Center for Computational Neuroscience & Department of Neurology, Ludwig-Maximilians-University Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Nuding
authors.forename: Roger
authors.initials: R
authors.lastname: Kalla
authors.forename: Neil G
authors.initials: NG
authors.lastname: Muggleton
authors.forename: Ulrich
authors.initials: U
authors.lastname: Büttner
authors.forename: Vincent
authors.initials: V
authors.lastname: Walsh
authors.forename: Stefan
authors.initials: S
authors.lastname: Glasauer
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D008297:Male; D008959:Models, Neurological; D017711:Nonlinear Dynamics; D010775:Photic Stimulation; D011698:Pursuit, Smooth / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation