Brain potentials and the availability of semantic and phonological codes over time.
ERPs were recorded from subjects performing semantic and rhyme matching tasks using either spoken words, printed words or pictures as stimuli. Mismatches enhanced N400 (in the semantic task) and N450 (in the rhyme task). Onset and peak latencies were shorter for N450 than for N400 with spoken words; this relationship was inverted for pictures. Thus these latencies could index availability of semantic and phonological codes. For printed words, the latencies were shorter for N400 than N450, a result that supports direct-access modes of reading with late phonological code activation. The longer latencies found for N400 and N450 to pictures could suggest longer initial decoding for pictures with respect to words.
Perez-Abalo
M C
MC
Cognitive Neuroscience Department, Cuban Center for Neurosciences, La Habana.
Rodriguez
R
R
Bobes
M A
MA
Gutierrez
J
J
Valdes-Sosa
M
M
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006801:Humans; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D013997:Time Factors