title: The same oculomotor vermal Purkinje cells encode the different kinematics of saccades and of smooth pursuit eye movements.
abstract: Saccades and smooth pursuit eye movements (SPEM) are two types of goal-directed eye movements whose kinematics differ profoundly, a fact that may have contributed to the notion that the underlying cerebellar substrates are separated. However, it is suggested that some Purkinje cells (PCs) in the oculomotor vermis (OMV) of monkey cerebellum may be involved in both saccades and SPEM, a puzzling finding in view of the different kinematic demands of the two types of eye movements. Such 'dual' OMV PCs might be oddities with little if any functional relevance. On the other hand, they might be representatives of a generic mechanism serving as common ground for saccades and SPEM. In our present study, we found that both saccade- and SPEM-related responses of individual PCs could be predicted well by linear combinations of eye acceleration, velocity and position. The relative weights of the contributions that these three kinematic parameters made depended on the type of eye movement. Whereas in the case of saccades eye position was the most important independent variable, it was velocity in the case of SPEM. This dissociation is in accordance with standard models of saccades and SPEM control which emphasize eye position and velocity respectively as the relevant controlled state variables.
authors.affiliation: Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.|Graduate School of Neural and Behavioural Sciences, International Max Planck Research School for Cognitive and Systems Neuroscience, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Zongpeng
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.|Graduate School of Neural and Behavioural Sciences, International Max Planck Research School for Cognitive and Systems Neuroscience, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Smilgin
authors.affiliation: Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.|Graduate School of Neural and Behavioural Sciences, International Max Planck Research School for Cognitive and Systems Neuroscience, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Junker
authors.affiliation: Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Dicke
authors.affiliation: Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Thier
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001696:Biomechanical Phenomena; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000502:physiology; D009801:Oculomotor Muscles / Q000166:cytology* / Q000502:physiology*; D011689:Purkinje Cells / Q000502:physiology*; D011698:Pursuit, Smooth; D012438:Saccades / Q000502:physiology*