Temporal Patterns of Spike Activity underlying Smooth Pursuit Control

Gain modulation is a major computational principle of sensorimotor transformations. Changes in the sensory environment or variations of the internal state demand an adaptive reweighting of sensory inputs. Smooth pursuit eye movements exhibit a dynamic gain control, resulting in an increased sensitivity to retinal image motion for higher pursuit velocities. This project investigates the underlying neuronal mechanisms and the involved central nervous structures. Several complementary approaches have been utilized and consolidated. Behavioural experiments enabled a precise quantification of pursuit gain control which was then implemented in a control systems model of smooth pursuit. A specific anatomical property of the pursuit system is the existence of two parallel pathways from higher cortical to lower motor areas in the brainstem. We found that this dual pathway architecture can be explained by the proposed model and that it predicts that the gain control is accomplished in the frontal eye fields (FEF). To verify this hypothesis, we applied repetitive transcranial magnetic stimulation over the FEF in humans and measured the eye movement responses to the same stimulus as described above. We could show that the disruption of neuronal activity in the FEF yields not only an overall reduction of the feedforward gain, as already shown in lesion studies, but also a decrease in the efficacy of the gain control mechanism.

Related Publications

• Nuding U, Kalla R, Muggleton NG, Büttner U, Walsh V, Glasauer S. TMS evidence for smooth pursuit gain control by the frontal eye fields. Cereb Cortex, 2008, [Epub ahead of print]
• Nuding U, Ono S, Mustari MJ, Büttner U, Glasauer S. A theory of the dual pathways for smooth pursuit based on dynamic gain control. J Neurophysiol 99: 2798-2808, 2008
• Nuding U, Ono S, Mustari MJ, Büttner U, Glasauer S. Neural activity in cortical areas MST and FEF in relation to smooth pursuit gain control. Prog Brain Res 171: 261-264, 2008
• Büttner U, Ono S, Glasauer S, Mustari MJ, Nuding U. MSTd neurons during ocular following and smooth pursuit perturbation.Prog Brain Res 171:253-260, 2008
• Bayer O, Eggert T, Glasauer S, Büttner U. Human smooth pursuit gain is modulated by a signal related to gaze velocity.Neuroreport 19: 1217-1220, 2008