|
|
||||||||
1 From the Dipartimento di Informatica e Sistemistica, University of Pavia, Italy and the Departments of 2 Neurology, 3 Biomedical Engineering, and 4 Neuroscience, Department of Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, Ohio.
PURPOSE. To characterize dynamic properties of combined saccadevergence eye movements that occur as the point of visual fixation is shifted between objects lying in different directions and at different depths.
METHODS. Using the scleral search-coil technique, eye movements were measured in 10 normal subjects as they made voluntary, disjunctive gaze shifts comprising a range of saccades and vergence movements.
RESULTS. By analyzing eye acceleration records, the authors identified small-amplitude (0.20.7°), high-frequency (2333 Hz), conjugate horizontal oscillations of the eyes during the vergence movement that followed the initial saccade. When the shift of the fixation point required a large vergence component (17°), every subject showed these oscillations; they were present in approximately a third of responses. Approximately 5% of responses showed oscillations that had horizontal and vertical components. Oscillations were less prominent with shifts that had smaller vergence components and were absent after saccades made between targets located at optical infinity.
CONCLUSIONS. These findings suggest that a common mechanism gates both the saccadic and vergence components of disjunctive gaze shifts, a likely candidate being the pontine omnipause neurons. When a saccade is immediately followed by a prolonged vergence movement, the omnipause neurons remain silent, leading to small-amplitude saccadic oscillations. Shifts in the point of visual fixation that require a large vergence movement may be a useful experimental strategy to induce saccadic oscillations.
This article has been cited by other articles:
![]() |
A. Serra, K. Liao, M. Matta, and R. J. Leigh Diagnosing disconjugate eye movements: Phase-plane analysis of horizontal saccades Neurology, October 7, 2008; 71(15): 1167 - 1175. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. R. Van Horn and K. E. Cullen Dynamic Coding of Vertical Facilitated Vergence by Premotor Saccadic Burst Neurons J Neurophysiol, October 1, 2008; 100(4): 1967 - 1982. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. R. Van Horn, P. A. Sylvestre, and K. E. Cullen The Brain Stem Saccadic Burst Generator Encodes Gaze in Three-Dimensional Space J Neurophysiol, May 1, 2008; 99(5): 2602 - 2616. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Vernet, Q. Yang, G. Daunys, C. Orssaud, T. Eggert, and Z. Kapoula How the Brain Obeys Hering's Law: A TMS Study of the Posterior Parietal Cortex Invest. Ophthalmol. Vis. Sci., January 1, 2008; 49(1): 230 - 237. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. N. Kumar, Y. Han, L. F. Dell'osso, D. M. Durand, and R. J. Leigh Directional Asymmetry During Combined Saccade-Vergence Movements J Neurophysiol, May 1, 2005; 93(5): 2797 - 2808. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. C. Rucker, B. E. Shapiro, Y. H. Han, A. N. Kumar, S. Garbutt, E. L. Keller, and R. J. Leigh Neuro-ophthalmology of late-onset Tay-Sachs disease (LOTS) Neurology, November 23, 2004; 63(10): 1918 - 1926. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Busettini and L. E. Mays Pontine Omnipause Activity During Conjugate and Disconjugate Eye Movements in Macaques J Neurophysiol, December 1, 2003; 90(6): 3838 - 3853. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Garbutt, Y. Han, A. N. Kumar, M. Harwood, C. M. Harris, and R. J. Leigh Vertical Optokinetic Nystagmus and Saccades in Normal Human Subjects Invest. Ophthalmol. Vis. Sci., September 1, 2003; 44(9): 3833 - 3841. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. N. Kumar, Y. Han, S. Garbutt, and R. J. Leigh Properties of Anticipatory Vergence Responses Invest. Ophthalmol. Vis. Sci., August 1, 2002; 43(8): 2626 - 2632. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Bhidayasiri, D.E. Riley, J.T. Somers, A.J. Lerner, J.A. Buttner-Ennever, and R.J. Leigh Pathophysiology of slow vertical saccades in progressive supranuclear palsy Neurology, December 11, 2001; 57(11): 2070 - 2077. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |