The bulk of the research on the neural organization of metaphor comprehension has focused on nominal metaphors and the metaphoric relationships between word pairs. By contrast, little work has been conducted on predicate metaphors using verbs of motion such as “The man fell under her spell.” We examined predicate metaphors as compared to literal sentences of motion such as “The child fell under the slide” in an event-related, functional MRI study. Our results demonstrated greater activation in the left inferior frontal cortex and left lateral temporal lobe for predicate metaphors as compared to literal sentences, while no differences were seen in homologous areas of the right hemisphere. We suggest that the results support a neural organization principle for motion processing in which greater abstraction proceeds along a posterior-to-anterior axis within the lateral portion of the left temporal cortex.
The neural basis for syntactic processing was studied using event-related fMRI to determine the locations of BOLD signal increases in the contrast of syntactically complex sentences with center-embedded, object-extracted relative clauses and syntactically simple sentences with right-branching, subject-extracted relative clauses in a group of 15 participants in three tasks. In a sentence verification task, participants saw a target sentence in one of these two syntactic forms, followed by a probe in a simple active form, and determined whether the probe expressed a proposition in the target. In a plausibility judgment task, participants determined whether a sentence in one of these two syntactic forms was plausible or implausible. Finally, in a non-word detection task, participants determined whether a sentence in one of these two syntactic forms contained only real words or a non-word. BOLD signal associated with the syntactic contrast increased in the left posterior inferior frontal gyrus in non-word detection and in a widespread set of areas in the other two tasks. We conclude that the BOLD activity in the left posterior inferior frontal gyrus reflects syntactic processing independent of concurrent cognitive operations and the more widespread areas of activation reflect the use of strategies and the use of the products of syntactic processing to accomplish tasks.
Event-related functional magnetic resonance imaging (fMRI) was used to investigate the determinants of blood oxygenation level-dependent (BOLD) signal correlates of processing relative clauses. Matched pairs of sentences that differed in their processing demands were compared. One member of the pair consisted of a syntactically simpler object-subject (OS) sentence, containing a subject-relativized clause attached to the object noun phrase. The second member of the pair consisted of a syntactically more complex subject-object (SO) sentence, containing an object-relativized clause attached to the subject noun phrase. Participants made plausibility judgments about the sentences in whole sentence visual presentation. Voxel-wise statistical activation maps showed increased BOLD signal in multiple cortical regions for complex compared to simple syntactic structures. This pattern was found for plausible sentences only and, within the set of plausible sentences, for SO sentences in which the head noun of the relative clause was animate and the subject noun of the relative clause was inanimate. These results require a re-interpretation of previous results with the same materials using positron emission tomography.
This paper presents three self-paced, word-by-word reading experiments that test for the existence of on-line syntactic storage/expectation costs in English. To investigate this issue, we compared reading times for sentence regions in which syntactic expectation costs varied, keeping other factors constant. Experiment 1 manipulated the number of verbs needed to form a grammatical sentence. It was observed that in the critical region, people read the condition in which zero verbs were predicted fastest, followed by the conditions in which one verb was predicted, with the condition in which two verbs were predicted slowest. Experiments 2 and 3 investigated whether incomplete filler-gap dependencies also incur storage costs. It was observed that people read the critical region in which a wh-filler is pending slower than if no such wh-filler is pending. The results of all three experiments demonstrate the role of online syntactic storage costs in sentence comprehension.