Table of Contents

Eye Movements Modulate the Spatiotemporal Dynamics of Word Processing

  1. Emery N. Brown4,5
  1. 1MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, Massachusetts 02129,
  2. 2Department of Psychology, Tufts University, Medford, Massachusetts 02155,
  3. 3Department of Radiology, University of California, San Diego, California 92093,
  4. 4Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, and
  5. 5Department of Brain and Cognitive Sciences, Harvard/Massachusetts Institute of Technology Division of Health Sciences and Technology, Cambridge, Massachusetts 02139
  1. Author contributions: S.T. and E.H. designed research; S.T. performed research; S.T., M.S.H., S.M.S., E.H., and E.N.B. analyzed data; S.T., M.S.H., G.K., S.M.S., and E.N.B. wrote the paper.

Abstract

Active reading requires coordination between frequent eye movements (saccades) and short fixations in text. Yet, the impact of saccades on word processing remains unknown, as neuroimaging studies typically employ constant eye fixation. Here we investigate eye-movement effects on word recognition processes in healthy human subjects using anatomically constrained magnetoencephalography, psychophysical measurements, and saccade detection in real time. Word recognition was slower and brain responses were reduced to words presented early versus late after saccades, suggesting an overall transient impairment of word processing after eye movements. Response reductions occurred early in visual cortices and later in language regions, where they colocalized with repetition priming effects. Qualitatively similar effects occurred when words appeared early versus late after background movement that mimicked saccades, suggesting that retinal motion contributes to postsaccadic inhibition. Further, differences in postsaccadic and background-movement effects suggest that central mechanisms also contribute to postsaccadic modulation. Together, these results suggest a complex interplay between visual and central saccadic mechanisms during reading.

  • Received November 4, 2011.
  • Revision received February 3, 2012.
  • Accepted February 8, 2012.