Pa. Carpenter et al., Time course of fMRI-activation in language and spatial networks during sentence comprehension, NEUROIMAGE, 10(2), 1999, pp. 216-224
Functional neuroimaging previously has been considered to provide inadequat
e temporal resolution to study changes of brain states as a function of cog
nitive computations; however, we have obtained evidence of differential amo
unts of brain activity related to high-level cognition (sentence processing
) within 1.5 s of stimulus onset. The study used an event-related paradigm
with high-speed echoplanar functional magnetic resonance imaging (fMRI) to
trace the time course of the brain activation in the temporal and parietal
regions as participants comprehended single sentences describing a spatial
configuration. Within the first set of images, on average 1 s from when the
participant begins to read a sentence, there was significant activation in
a key cortical area involved in language comprehension (the left posterior
temporal gyrus) and visuospatial processing (the left and right parietal r
egions). In all three areas, the amount of activation during sentence compr
ehension was higher for negative sentences than for their affirmative count
erparts, which are linguistically less complex. The effect of negation indi
cates that the activation in these areas is modulated by the difficulty of
the Linguistic processing. These results suggest a relatively rapid coactiv
ation in both linguistic and spatial cortical regions to support the integr
ation of information from multiple processing streams.