Blink-Perturbed Saccades in Monkey. I. Behavioral Analysis

• Published in: Journal of neurophysiology 2000-06, Vol.83 (6), p.3411-3429
• Main Authors: Goossens, H.H.L.M, Van Opstal, A. J
• Format: Article
• Language: English
• Subjects: Algorithms; Animals; Behavior, Animal - physiology; Biomechanical Phenomena; blink reflex; Blinking - physiology; Calibration; Electromyography; Eyelids - innervation; Eyelids - physiology; Functional Laterality - physiology; Macaca mulatta; Male; Oculomotor Muscles - innervation; Oculomotor Muscles - physiology; Photic Stimulation; Physical Stimulation; Saccades - physiology; Space life sciences
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.2000.83.6.3411

  1 Department of Medical Physics and Biophysics, University of Nijmegen, NL-6525 EZ Nijmegen; and   2 Departments of Physiology and Anatomy, Erasmus University Rotterdam, NL-3000 DR Rotterdam, The Netherlands Goossens, H.H.L.M. and A. J. Van Opstal. Blink-Perturbed Saccades in Monkey. I. Behavioral Analysis. J. Neurophysiol. 83: 3411-3429, 2000. Saccadic eye movements are thought to be influenced by blinking through premotor interactions, but it is still unclear how. The present paper describes the properties of blink-associated eye movements and quantifies the effect of reflex blinks on the latencies, metrics, and kinematics of saccades in the monkey. In particular, it is examined to what extent the saccadic system accounts for blink-related perturbations of the saccade trajectory. Trigeminal reflex blinks were elicited near the onset of visually evoked saccades by means of air puffs directed on the eye. Reflex blinks were also evoked during a straight-ahead fixation task. Eye and eyelid movements were measured with the magnetic-induction technique. The data show that saccade latencies were reduced substantially when reflex blinks were evoked prior to the impending visual saccades as if these saccades were triggered by the blink. The evoked blinks also caused profound spatial-temporal perturbations of the saccades. Deflections of the saccade trajectory, usually upward, extended up to ~15°. Saccade peak velocities were reduced, and a two- to threefold increase in saccade duration was typically observed. In general, these perturbations were largely compensated in saccade mid-flight, despite the absence of visual feedback, yielding near-normal endpoint accuracies. Further analysis revealed that blink-perturbed saccades could not be described as a linear superposition of a pure blink-associated eye movement and an unperturbed saccade. When evoked during straight-ahead fixation, blinks were accompanied by initially upward and slightly abducting eye rotations of ~2-15°. Back and forth wiggles of the eye were frequently seen; but in many cases the return movement was incomplete. Rather than drifting back to its starting position, the eye then maintained its eccentric orbital position until a downward corrective saccade toward the fixation spot followed. Blink-associated eye movements were quite rapid, albeit slower than saccades, and the velocity-amplitude-duration characteristics of the initial excursions as well as the return movements were approximately line