What determines the direction of microsaccades

During visual fixation, our eyes are not entirely still. Instead, small eye movements, such as microsaccades, can be observed. We here investigate what determines the direction and frequency of these microsaccades, as this information might help to clarify what purpose they serve. The relative contribution of three possible factors was examined: (1) the orienting of covert attention, (2) the spatial distribution of possible target locations, and (3) whether monocular or binocular microsaccades are considered. The orienting of covert attention and the distribution of possible target locations had a relatively weak effect on microsaccade rates and directions. In contrast, the classification of micro-saccades as binocular (occurring in both eyes simultaneously) or monocular (observed in one eye only) strongly affected both the rate and the direction of microsaccades. The results are discussed in the context of existing findings.

[1]  J NACHMIAS,et al.  Two-dimensional motion of the retinal image during monocular fixation. , 1959, Journal of the Optical Society of America.

[2]  L. R. Gottlob,et al.  Location cuing and response time distributions in visual attention , 2004, Perception & psychophysics.

[3]  Ralf Engbert,et al.  Microsaccade dynamics during covert attention , 2005, Vision Research.

[4]  Brian J. Murphy,et al.  Simple forms and fluctuations of the line of sight: Implications for motor theories of form processing , 1974 .

[5]  M. Turatto,et al.  Inhibition of return in microsaccades , 2004, Experimental Brain Research.

[6]  Martina Poletti,et al.  Eye movements under various conditions of image fading. , 2010, Journal of vision.

[7]  D. Hubel,et al.  Microsaccadic eye movements and firing of single cells in the striate cortex of macaque monkeys , 2000, Nature Neuroscience.

[8]  David L. Sheinberg,et al.  Fixational eye movements are not affected by abrupt onsets that capture attention , 2002, Vision Research.

[9]  J M Findlay,et al.  A Simple Apparatus for Recording Microsaccades during Visual Fixation , 1974, The Quarterly journal of experimental psychology.

[10]  Ralf Engbert,et al.  When do microsaccades follow spatial attention? , 2010, Attention, perception & psychophysics.

[11]  A. A. Skavenski,et al.  Miniature eye movement. , 1973, Science.

[12]  Martina Poletti,et al.  Miniature eye movements enhance fine spatial detail , 2007, Nature.

[13]  Robin Walker,et al.  Gaze and Arrow Distractors Influence Saccade Trajectories Similarly , 2010, Quarterly journal of experimental psychology.

[14]  KRAUSKOPFt.  Analysis of Eye Movements during Monocular and Binocular Fixation * , 2004 .

[15]  M. Turatto,et al.  Microsaccadic response during inhibition of return in a target–target paradigm , 2007, Vision Research.

[16]  Ralf Engbert,et al.  Microsaccades are triggered by low retinal image slip. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[17]  M. Posner,et al.  Orienting of Attention* , 1980, The Quarterly journal of experimental psychology.

[18]  Xoana G. Troncoso,et al.  Saccades and microsaccades during visual fixation, exploration, and search: foundations for a common saccadic generator. , 2008, Journal of vision.

[19]  S. Martinez-Conde.  Fixational eye movements in normal and pathological vision. , 2006, Progress in brain research.

[20]  J. Braun,et al.  Rare but precious: Microsaccades are highly informative about attentional allocation , 2010, Vision Research.

[21]  R. Kliegl,et al.  Shortening and prolongation of saccade latencies following microsaccades , 2006, Experimental Brain Research.

[22]  R. Steinman,et al.  Small saccades serve no useful purpose: Reply to a letter by R. W. Ditchburn , 1980, Vision Research.

[23]  M. Turatto,et al.  Are you ready? I can tell by looking at your microsaccades , 2006, Neuroreport.

[24]  J M Findlay,et al.  Direction perception and human fixation eye movements. , 1974, Vision research.

[25]  L. Riggs,et al.  Eye Movements Recorded During Convergence and Divergence , 1960 .

[26]  Edward A Essock,et al.  A horizontal bias in human visual processing of orientation and its correspondence to the structural components of natural scenes. , 2004, Journal of vision.

[27]  Ralf Engbert,et al.  Toward a model of microsaccade generation: the case of microsaccadic inhibition. , 2008, Journal of vision.

[28]  M. Turatto,et al.  Visual oddballs induce prolonged microsaccadic inhibition , 2007, Experimental Brain Research.

[29]  John M. Findlay,et al.  Commentary on Section 1 – Eye Movements and Visual Information Processing , 2003 .

[30]  Eileen Kowler.  Eye Movements and Visual Information Processing. , 1981 .

[31]  Robin Walker,et al.  Microsaccades and preparatory set: a comparison between delayed and immediate, exogenous and endogenous pro- and anti-saccades , 2010, Experimental Brain Research.

[32]  Reinhold Kliegl,et al.  Binocular coordination in microsaccades , 2003 .

[33]  James J. Clark,et al.  Microsaccades as an overt measure of covert attention shifts , 2002, Vision Research.

[34]  J. Nachmias.  Determiners of the drift of the eye during monocular fixation. , 1961, Journal of the Optical Society of America.

[35]  Luigi Tamè,et al.  Microsaccades distinguish between global and local visual processing , 2007, Neuroreport.

[36]  Stephanie Jainta,et al.  Microsaccades under monocular viewing conditions , 2009 .

[37]  Eileen Kowler.  The role of visual and cognitive processes in the control of eye movement. , 1990, Reviews of oculomotor research.

[38]  B. L. Zuber,et al.  Microsaccades and the Velocity-Amplitude Relationship for Saccadic Eye Movements , 1965, Science.

[39]  Ralf Engbert.  Microsaccades: A microcosm for research on oculomotor control, attention, and visual perception. , 2006, Progress in brain research.

[40]  Gustav Kuhn,et al.  The influence of eye-gaze and arrow pointing distractor cues on voluntary eye movements , 2007, Perception & psychophysics.

[41]  M. Platt,et al.  Reflexive Social Attention in Monkeys and Humans , 2003, Current Biology.

[42]  Xoana G. Troncoso,et al.  Microsaccades Counteract Visual Fading during Fixation , 2005, Neuron.

[43]  Xoana G. Troncoso,et al.  Microsaccades: a neurophysiological analysis , 2009, Trends in Neurosciences.

[44]  Reinhold Kliegl,et al.  Microsaccade orientation supports attentional enhancement opposite to a peripheral cue , 2004 .

[45]  Ziad M. Hafed,et al.  A Neural Mechanism for Microsaccade Generation in the Primate Superior Colliculus , 2009, Science.

[46]  Gregory D Horwitz,et al.  Short-latency fixational saccades induced by luminance increments. , 2003, Journal of neurophysiology.

[47]  Richard V Abadi,et al.  Characteristics of saccadic intrusions , 2004, Vision Research.

[48]  H. Collewijn,et al.  The significance of microsaccades for vision and oculomotor control. , 2008, Journal of vision.

[49]  M. Rolfs.  Microsaccades: Small steps on a long way , 2009, Vision Research.

[50]  Nikos K. Logothetis,et al.  The Distribution of Microsaccade Directions Need Not Reveal the Location of Attention: Reply to Rolfs, Engbert, and Kliegl , 2004 .

[51]  Ralf Engbert,et al.  Microsaccade Orientation Supports Attentional Enhancement Opposite a Peripheral Cue: Commentary on Tse, Sheinberg, and Logothetis (2003) , 2004, Psychological science.

[52]  Ralf Engbert,et al.  Crossmodal coupling of oculomotor control and spatial attention in vision and audition , 2005, Experimental Brain Research.

[53]  J. Zanker,et al.  A new look at Op art: towards a simple explanation of illusory motion , 2004, Naturwissenschaften.

[54]  J. Wolfe,et al.  Fixational Eye Movements Are Not an Index of Covert Attention , 2007, Psychological science.

[55]  Ralf Engbert,et al.  Microsaccades uncover the orientation of covert attention , 2003, Vision Research.

[56]  R. Miall,et al.  Modulation of saccadic intrusions by exogenous and endogenous attention , 2007, Brain Research.

[57]  H. J. Muller,et al.  Reflexive and voluntary orienting of visual attention: time course of activation and resistance to interruption. , 1989, Journal of experimental psychology. Human perception and performance.

[58]  Ralf Engbert,et al.  Microsaccades Are an Index of Covert Attention , 2007, Psychological science.