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Abstract:
Abstract: The more frequent a word occurs, the easier it is
to recognize. This basic effect can be modified by a number of
other factors such as sentence context. The goal of the positron
emission tomography study reported here was to investigate which
areas of the brain are influenced by frequency and sentential vs.
non-sentential context and how these factors interact to determine
the activation found in these areas. We show that both sentences
and word lists containing low frequency content words activate the
left occipital cortex more than those containing high frequency
words do. This occipital activation is, however, sensitive to
context, with more difference in sentences than word lists. There
was also a main effect of sentences vs. word lists in the anterior
temporal lobe, replicating previous results; we have previously
suggested that this area is involved in encoding lexical (semantic
or syntactic) information into temporary storage so that it remains
available/active for use later in the sentence or discourse (Stowe
et al, Psychophysiology 36: 786-801, 1999). As predicted by this
hypothesis, this area is more activated by sentences containing low
frequency content words, which require additional effort to encode,
than by sentences containing high frequency words.
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