Visual crowding is anisotropic along the horizontal meridian during smooth pursuit.

Humans make smooth pursuit eye movements to foveate moving objects of interest. It is known that smooth pursuit alters visual processing, but there is currently no consensus on whether changes in vision are contingent on the direction the eyes are moving. We recently showed that visual crowding can be used as a sensitive measure of changes in visual processing, resulting from involvement of the saccadic eye movement system. The present paper extends these results by examining the effect of smooth pursuit eye movements on the spatial extent of visual crowding-the area over which visual stimuli are integrated. We found systematic changes in crowding that depended on the direction of pursuit and the distance of stimuli from the pursuit target. Relative to when no eye movement was made, the spatial extent of crowding increased for objects located contraversive to the direction of pursuit at an eccentricity of approximately 3°. By contrast, crowding for objects located ipsiversive to the direction of pursuit remained unchanged. There was no change in crowding during smooth pursuit for objects located approximately 7° from the fovea. The increased size of the crowding zone for the contraversive direction may be related to the distance that the fovea lags behind the pursuit target during smooth eye movements. Overall, our results reveal that visual perception is altered dynamically according to the intended destination of oculomotor commands.

[1]  Harold E Bedell,et al.  Suppression of motion-produced smear during smooth pursuit eye movements , 1996, Current Biology.

[2]  S. Klein,et al.  Suppressive and facilitatory spatial interactions in peripheral vision: peripheral crowding is neither size invariant nor simple contrast masking. , 2002, Journal of vision.

[3]  M. Carrasco,et al.  Rapid Simultaneous Enhancement of Visual Sensitivity and Perceived Contrast during Saccade Preparation , 2012, The Journal of Neuroscience.

[4]  E. L. Keller,et al.  Generation of smooth-pursuit eye movements: neuronal mechanisms and pathways , 1991, Neuroscience Research.

[5]  Thomas S A Wallis,et al.  Image correlates of crowding in natural scenes. , 2011, Journal of vision.

[6]  F A Wichmann,et al.  Ning for Helpful Comments and Suggestions. This Paper Benefited Con- Siderably from Conscientious Peer Review, and We Thank Our Reviewers the Psychometric Function: I. Fitting, Sampling, and Goodness of Fit , 2001 .

[7]  田中真樹 Latency of Saccades during Smooth Pursuit Eye Movement in Man: Directional asymmetries(ヒト滑動性眼球運動の最中の視覚誘導性サッカードの潜時変化) , 1998 .

[8]  D. Pelli,et al.  Crowding is unlike ordinary masking: distinguishing feature integration from detection. , 2004, Journal of vision.

[9]  Stephen G. Lisberger,et al.  Regulation of the gain of visually guided smooth-pursuit eye movements by frontal cortex , 2001, Nature.

[10]  M. Posner,et al.  Attention and the detection of signals. , 1980, Journal of experimental psychology.

[11]  D. Robinson,et al.  The upper limit of human smooth pursuit velocity , 1985, Vision Research.

[12]  Harold E. Bedell,et al.  A target in real motion appears blurred in the absence of other proximal moving targets , 1995, Vision Research.

[13]  Anirvan S. Nandy,et al.  Saccade-confounded image statistics explain visual crowding , 2012, Nature Neuroscience.

[14]  P. van Donkelaar,et al.  Spatiotemporal modulation of attention during smooth pursuit eye movements. , 1999, Neuroreport.

[15]  R. Leigh,et al.  Comparison of Horizontal, Vertical and Diagonal Smooth Pursuit Eye Movements in Normal Human Subjects , 1996, Vision Research.

[16]  D. Pelli Crowding: a cortical constraint on object recognition , 2008, Current Opinion in Neurobiology.

[17]  R. Kanai,et al.  Inhibition of saccade initiation by preceding smooth pursuit , 2003, Experimental Brain Research.

[18]  Thomas A Carlson,et al.  Crowding is tuned for perceived (not physical) location. , 2011, Journal of vision.

[19]  Jason B. Mattingley,et al.  Visual Crowding at a Distance during Predictive Remapping , 2013, Current Biology.

[20]  S. Dakin,et al.  The shape and size of crowding for moving targets , 2003, Vision Research.

[21]  Y. Zhang,et al.  Dorsal Y group in the squirrel monkey. I. Neuronal responses during rapid and long-term modifications of the vertical VOR. , 1995, Journal of neurophysiology.

[22]  D. Kerzel,et al.  Attentional constraints on target selection for smooth pursuit eye movements , 2011, Vision Research.

[23]  P. van Donkelaar,et al.  The allocation of attention during smooth pursuit eye movements. , 2002, Progress in brain research.

[24]  E. J. Tehovnik,et al.  Eye Movements Modulate Visual Receptive Fields of V4 Neurons , 2001, Neuron.

[25]  D. Levi,et al.  The two-dimensional shape of spatial interaction zones in the parafovea , 1992, Vision Research.

[26]  Alexander C. Schütz,et al.  Eye movements and perception: a selective review. , 2011, Journal of vision.

[27]  Joan López-Moliner,et al.  Seeing the last part of a hitting movement is enough to adapt to a temporal delay. , 2012, Journal of vision.

[28]  D. Kerzel,et al.  Visual short-term memory during smooth pursuit eye movements. , 2005, Journal of experimental psychology. Human perception and performance.

[29]  Harold E. Bedell,et al.  Asymmetry of perceived motion smear during head and eye movements: Evidence for a dichotomous neural categorization of retinal image motion , 2005, Vision Research.

[30]  Robert Tibshirani,et al.  An Introduction to the Bootstrap , 1994 .

[31]  David Whitney,et al.  Perceived Positions Determine Crowding , 2011, PloS one.

[32]  Eli Brenner,et al.  Mislocalization of flashes during smooth pursuit hardly depends on the lighting conditions , 2006, Vision Research.

[33]  D H Brainard,et al.  The Psychophysics Toolbox. , 1997, Spatial vision.

[34]  Eli Brenner,et al.  Speed judgments of three-dimensional motion incorporate extraretinal information. , 2011, Journal of vision.

[35]  L O Harvey,et al.  Identification confusions among letters of the alphabet. , 1984, Journal of experimental psychology. Human perception and performance.

[36]  A. Fuchs,et al.  Contribution of y group of vestibular nuclei and dentate nucleus of cerebellum to generation of vertical smooth eye movements. , 1982, Journal of neurophysiology.

[37]  Harold E. Bedell,et al.  Direction and extent of perceived motion smear during pursuit eye movement , 2007, Vision Research.

[38]  D G Pelli,et al.  The VideoToolbox software for visual psychophysics: transforming numbers into movies. , 1997, Spatial vision.

[39]  Eileen Kowler Cognitive expectations, not habits, control anticipatory smooth oculomotor pursuit , 1989, Vision Research.

[40]  L. Mitrani,et al.  Retinal location and visual localization during pursuit eye movement , 1982, Vision Research.

[41]  P. Cavanagh,et al.  Attentional resolution and the locus of visual awareness , 1996, Nature.

[42]  D. Levi Crowding—An essential bottleneck for object recognition: A mini-review , 2008, Vision Research.

[43]  H. Strasburger Unfocused spatial attention underlies the crowding effect in indirect form vision. , 2004, Journal of vision.

[44]  Katherine M. Armstrong,et al.  Visuomotor Origins of Covert Spatial Attention , 2003, Neuron.

[45]  Eli Brenner,et al.  Mislocalization of targets flashed during smooth pursuit depends on the change in gaze direction after the flash. , 2004, Journal of vision.

[46]  Eli Brenner,et al.  Smooth eye movements and spatial localisation , 2001, Vision Research.

[47]  Richard J. Krauzlis,et al.  Spatial allocation of attention during smooth pursuit eye movements , 2009, Vision Research.

[48]  D. Pelli,et al.  The uncrowded window of object recognition , 2008, Nature Neuroscience.

[49]  D M Wolpert,et al.  Sensorimotor integration compensates for visual localization errors during smooth pursuit eye movements. , 2001, Journal of neurophysiology.

[50]  S. Lisberger,et al.  Initial tracking conditions modulate the gain of visuo-motor transmission for smooth pursuit eye movements in monkeys , 1994, Visual Neuroscience.

[51]  Frans W Cornelissen,et al.  The Eyelink Toolbox: Eye tracking with MATLAB and the Psychophysics Toolbox , 2002, Behavior research methods, instruments, & computers : a journal of the Psychonomic Society, Inc.

[52]  F. Bremmer,et al.  Spatial perception during pursuit initiation , 2010, Vision Research.

[53]  Eileen Kowler,et al.  Shared attentional control of smooth eye movement and perception , 1986, Vision Research.

[54]  H. BOUMA,et al.  Interaction Effects in Parafoveal Letter Recognition , 1970, Nature.

[55]  Philippe Lefèvre,et al.  Biological motion drives perception and action. , 2010, Journal of vision.

[56]  Y. Yeshurun,et al.  Precueing attention to the target location diminishes crowding and reduces the critical distance. , 2010, Journal of vision.

[57]  Dirk Kerzel,et al.  Improved visual sensitivity during smooth pursuit eye movements , 2010 .

[58]  R. Remington,et al.  Eye Movement Targets Are Released from Visual Crowding , 2013, The Journal of Neuroscience.

[59]  Ingo Fründ,et al.  Inference for psychometric functions in the presence of nonstationary behavior. , 2011, Journal of vision.

[60]  H. Collewijn,et al.  Human smooth and saccadic eye movements during voluntary pursuit of different target motions on different backgrounds. , 1984, The Journal of physiology.

[61]  D. Levi,et al.  The effect of similarity and duration on spatial interaction in peripheral vision. , 1994, Spatial vision.

[62]  Paul van Donkelaar,et al.  Spatiotemporal modulation of attention during smooth pursuit eye movements. , 1999 .