@misc{RolfsEngbertKliegl2005,
  author    = {Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold},
  title     = {Crossmodal coupling of oculomotor controland spatial attention in vision and audition},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56804},
  year      = {2005},
  abstract  = {Fixational eye movements occur involuntarily during visual fixation of stationary scenes. The fastest components of these miniature eye movements are microsaccades, which can be observed about once per second. Recent studies demonstrated that microsaccades are linked to covert shifts of visual attention [e.g., Engbert \& Kliegl (2003), Vision Res 43:1035-1045]. Here,we generalized this finding in two ways. First, we used peripheral cues, rather than the centrally presented cues of earlier studies. Second, we spatially cued attention in vision and audition to visual and auditory targets. An analysis of microsaccade responses revealed an equivalent impact of visual and auditory cues on microsaccade-rate signature (i.e., an initial inhibition followed by an overshoot and a final return to the pre-cue baseline rate). With visual cues or visual targets,microsaccades were briefly aligned with cue direction and then opposite to cue direction during the overshoot epoch, probably as a result of an inhibition of an automatic saccade to the peripheral cue. With left auditory cues and auditory targets microsaccades oriented in cue direction. Thus, microsaccades can be used to study crossmodal integration of sensory information and to map the time course of saccade preparation during covert shifts of visual and auditory attention.},
  language  = {en}
}
@article{SinnEngbert2016,
  author    = {Sinn, Petra and Engbert, Ralf},
  title     = {Small saccades versus microsaccades: Experimental distinction and model-based unification},
  series = {Vision research : an international journal for functional aspects of vision.},
  volume    = {118},
  journal   = {Vision research : an international journal for functional aspects of vision.},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0042-6989},
  doi       = {10.1016/j.visres.2015.05.012},
  pages     = {132 -- 143},
  year      = {2016},
  abstract  = {Natural vision is characterized by alternating sequences of rapid gaze shifts (saccades) and fixations. During fixations, microsaccades and slower drift movements occur spontaneously, so that the eye is never motionless. Theoretical models of fixational eye movements predict that microsaccades are dynamically coupled to slower drift movements generated immediately before microsaccades, which might be used as a criterion to distinguish microsaccades from small voluntary saccades. Here we investigate a sequential scanning task, where participants generate goal-directed saccades and microsaccades with overlapping amplitude distributions. We show that properties of microsaccades are correlated with precursory drift motion, while amplitudes of goal-directed saccades do not dependent on previous drift epochs. We develop and test a mathematical model that integrates goal-directed and fixational eye movements, including microsaccades. Using model simulations, we reproduce the experimental finding of correlations within fixational eye movement components (i.e., between physiological drift and microsaccades) but not between goal-directed saccades and fixational drift motion. These results lend support to a functional difference between microsaccades and goal-directed saccades, while, at the same time, both types of behavior may be part of an oculomotor continuum that is quantitatively described by our mathematical model. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}