title: Differentiating between reflex and spontaneous blinks using simultaneous recording of the orbicularis oculi electromyogram and the electro-oculogram in startle research.
abstract: The present study documents the differences between reflex and spontaneous blinks by recording the vertical electro-oculogram (EOG) along with the orbicularis oculi electromyogram (OO-EMG). EOG and OO-EMG were applied without fixation of the head in 15 freely moving children during an auditory startle experiment. Results revealed that the easily-recorded EOG shows the same relationships between orbicularis oculi contraction and velocity of lid movement in startle blinks as the head-constraining methods, e.g. the magnetic search coil, used in previous studies. The OO-EMG onset occurred before the EOG onset in most reflex blinks while no such pattern occurred for spontaneous blinks. In comparison with spontaneous blinks, reflex blinks showed a shorter duration between onset and peak and between onset and offset in OO-EMG and EOG. In addition, reflex blinks showed greater OO-EMG activity and smaller EOG-recorded lid movements compared with spontaneous blinks. Simultaneous recording of OO-EMG and EOG can distinguish reflex from spontaneous blinks and lid saccades in populations, e.g. children, that cannot tolerate head restraint and in experiments permitting or requiring movement.
authors.affiliation: Department of Psychology and Social Behavior, University of California, Irvine, 3340 Social Ecology II, Irvine, CA 92697, USA. jgehrick@uci.edu
authors.forename: Jean-Guido
authors.initials: JG
authors.lastname: Gehricke
authors.forename: Edward M
authors.initials: EM
authors.lastname: Ornitz
authors.forename: Prabha
authors.initials: P
authors.lastname: Siddarth
mesh_terms: D001767:Blinking / Q000502:physiology*; D004576:Electromyography; D004585:Electrooculography; D005143:Eyelids / Q000502:physiology; D006801:Humans; D009068:Movement / Q000502:physiology; D009801:Oculomotor Muscles / Q000502:physiology*; D011930:Reaction Time; D013216:Reflex, Startle / Q000502:physiology*; D012438:Saccades