Brain responses during sentence reading: visual input affects central processes

THE effect of visual contrast on sentence reading was investigated using ev ent-related brain potentials (ERPs). Under the low contrast condition seman tic integration as reflected in the N400 ERP component was delayed to some degree. The left anterior negativity (LAN) reflecting initial syntactic pro cesses, in contrast, seemed to change its characteristics as a function of visual input. In the high contrast condition the LAN preceded the P200 comp onent whereas in the low contrast condition it was present after this compo nent. These ERP-data from word-by-word sentence reading together with prior results from sentence listening suggest that the physical characteristics of the input must fall within a certain optimal range to guarantee ERP-effe cts of fast initial syntactic processes. (C) 1999 Lippincott Williams & Wil kins.