To make sense of a sentence, we must compute morphosyntactic and semantic-thematic relationships between its verbs and arguments and evaluate the resulting propositional meaning against any preceding context and our real-world knowledge. Recent electrophysiological studies suggest that, in comparison with non-violated verbs (e.g. "...at breakfast the boys would eat..."), animacy semantic-thematically violated verbs (e.g. "...at breakfast the eggs would eat...") and morphosyntactically violated verbs (e.g. "...at breakfast the boys would eats...") evoke a similar neural response. This response is distinct from that evoked by verbs that only violate real-world knowledge (e.g. "...at breakfast the boys would plant..."). Here we used fMRI to examine the neuroanatomical regions engaged in response to these three violations. Real-world violations, relative to other sentence types, led to increased activity within the left anterior inferior frontal cortex, reflecting participants’ increased and prolonged efforts to retrieve semantic knowledge about the likelihood of events occurring in the real world. In contrast, animacy semantic-thematic violations of the actions depicted by the central verbs engaged a frontal/inferior parietal/basal ganglia network known to mediate the execution and comprehension of goal-directed action. We suggest that the recruitment of this network reflected a semantic-thematic combinatorial process that involved an attempt to determine whether the actions described by the verbs could be executed by their NP Agents. Intriguingly, this network was also activated to morphosyntactic violations between the verbs and their subject NP arguments. Our findings support the pattern of electrophysiological findings in suggesting (a) that a clear division within the semantic system plays out during sentence comprehension, and (b) that semantic-thematic and syntactic violations of verbs within simple active sentences are treated similarly by the brain.

Traditionally, event-related brain potential (ERP) studies of language processing have presented words at a fixed rate using rapid serial visual presentation. Recent studies suggest, however, that the processes engaged during sentence comprehension are contingent on word presentation rate. These findings underscore the importance of allowing participants to read at a natural pace. The present study employed simultaneous self-paced reading and ERP methodologies to examine behavioral and neural responses while participants read sentences containing pragmatic or morphosyntactic violations or no violations. ERP and self-paced reading results replicated previous findings. This novel combination of behavioral and ERP methodologies combines the high temporal resolution and direct neural measures offered by ERPs with the more natural reading environment and information about processing load provided by self-paced reading.

Recent event-related potential studies report a P600 effect to incongruous verbs preceded by semantically associated inanimate noun-phrase (NP) arguments, e.g., "eat" in "At breakfast the eggs would eat...". This P600 effect may reflect the processing cost incurred when semantic-thematic relationships between critical verbs and their preceding NP argument(s) bias towards different interpretations to those dictated by their sentences’ syntactic structures. We have termed such violations of alternative thematic roles, ’thematic role violations.’ Semantic-thematic relationships are influenced both by semantic associations and by more basic semantic features, such as a noun’s animacy. This study determined whether a P600 effect can be evoked by verbs whose thematic structures are violated by their preceding inanimate NP arguments, even in the absence of close semantic-associative relationships with these arguments or their preceding contexts. ERPs were measured to verbs under four conditions: (1) non-violated ("At breakfast the boys would eat..."); (2) preceded by introductory clauses and animate NPs that violated their pragmatic expectations but not their thematic structures ("At breakfast the boys would plant..."); (3) preceded by semantically related contexts but inanimate NPs that violated their thematic structures ("At breakfast the eggs would eat..."); (4) preceded by semantically unrelated contexts and inanimate NPs that also violated their thematic structures ("At breakfast the eggs would plant..."). Pragmatically non-thematic role violated verbs preceded by unrelated contexts and animate NPs evoked robust N400 effects and small P600 effects. Thematically violated verbs preceded by inanimate argument NPs evoked robust P600 effects but no N400 effects, regardless of whether these inanimate arguments or their preceding contexts were semantically related or unrelated to these verbs. These findings suggest that semantic-thematic relations, related to animacy constraints on verbs’ arguments, are computed online and can immediately impact verb processing within active, English sentences.

Event-related potentials to critical verbs were measured as patients with schizophrenia and healthy controls read sentences word by word. Relative to their preceding context, critical verbs were (a) congruous, (b) incongruous and semantically unrelated to individual preceding words (pragmatic-semantic violations), (c) incongruous but semantically related to individual preceding words (animacy-semantic violations), or (d) syntactically anomalous. The N400 was modulated normally in patients, suggesting that semantic integration between individual words within sentences was normal in schizophrenia. The amplitude of the P600 to both syntactic and animacy-semantic violations was reduced in patients relative to controls. The authors suggest that, in schizophrenia, an abnormality in combining semantic and syntactic information online to build up propositional meaning leaves sentence processing to be primarily driven by semantic relationships between individual words.

The aim of this study was to determine whether or not the brain distinguishes between two types of conceptual relationships between noun-phrases (NPs) and verbs during online processing of simple, unambiguous English sentences. A total of 15 participants read and made plausibility judgments on sentences that were presented word-by-word. Event-related potentials elicited by critical verbs were measured. In all cases, the critical verb assigned a thematic role of ’agent’ to its subject NP. In non-violated sentences (e.g. "For breakfast the boys would only eat em leader"), the preceding NP was animate ("boys") and was a likely agent for a given verb ("eat") given its preceding context ("For breakfast"). In both types of conceptually violated sentences, the NPs were unlikely agents for the verbs given their preceding contexts. In ’thematic role animacy violations’ (e.g. "For breakfast the eggs would only eat em leader"), the NP was inanimate ("eggs") and was therefore more likely to occupy the role of ’theme’ than ’agent’, i.e. eggs, being inanimate, cannot eat but they can be eaten. In ’non-thematic role pragmatic violations’ (e.g. "For breakfast the boys would only bury em leader"), the thematic role of agent assigned by the verb ("bury") to its preceding NP ("boys") is inherently acceptable (boys can bury), but the sentence is still pragmatically incongruous given the preceding context ("At breakfast"). As expected, the non-thematic role pragmatic violations elicited a significant N400 effect. The thematic role animacy violations elicited a smaller N400 effect that only approached significance across all participants. The thematic role animacy violations, however, elicited a significant P600 effect-an ERP component that is most commonly associated with processing syntactic information during language comprehension. We discuss the possibility that the P600 was elicited by the thematic role animacy violations (but not by the non-thematic role pragmatic violations) because, in the former but not the latter, there was an online attempt to structurally repair and make sense of the sentences by reassigning the thematic role of the NP that preceded the critical verb from ’agent’ to ’theme’. Our findings suggest a qualitative neural distinction in processing these two types of conceptual anomalies within simple, unambiguous sentences.

Deficits in language comprehension in schizophrenia were examined using event-related potentials (ERPs). Schizophrenic and healthy participants read sentences in which the first clause ended with a homograph, and the second clause started with a target word that was semantically related to the homograph’s dominant meaning (e.g., 1. Diving was forbidden from the bridge because the river had rocks in it. or 2. The guests played bridge because the river had rocks in it.). Processing of the targets (e.g., “river”) was expected to be primarily influenced by the preceding overall sentence context (congruent in 1; incongruent in 2) in healthy participants, but to be inappropriately affected by the dominant meaning of homographs (e.g., the “structure” meaning of “bridge”) in sentences like 2 in schizophrenic patients. The N400 ERP component that is known to be sensitive to contextual effects during language processing confirmed these predictions. This showed that language abnormalities in schizophrenia may be related to deficient processing of context-irrelevant semantic representations of words from the discourse.

Extracting meaning from speech requires the use of pragmatic, semantic, and syntactic information. A central question is: Does the processing of these different types of linguistic information have common or distinct neuroanatomical substrates? We addressed this issue using functional magnetic resonance imaging (fMRI) to measure neural activity when subjects listened to spoken normal sentences contrasted with sentences that had either (A) pragmatical, (B) semantic (selection restriction), or (C) syntactic (subcategorical) violations sentences. All three contrasts revealed robust activation of the left-inferior-temporal/fusiform gyrus. Activity in this area was also observed in a combined analysis of all three experiments, suggesting that it was modulated by all three types of linguistic violation. Planned statistical comparisons between the three experiments revealed (1) a greater difference between conditions in activation of the left-superior-temporal gyrus for the pragmatic experiment than the semantic/syntactic experiments; (2) a greater difference between conditions in activation of the right-superior and middle-temporal gyrus in the semantic experiment than in the syntactic experiment; and (3) no regions activated to a greater degree in the syntactic experiment than in the semantic experiment. These data show that, while left- and right-superior-temporal regions may be differentially involved in processing pragmatic and lexico-semantic information within sentences, the left-inferior-temporal/fusiform gyrus is involved in processing all three types of linguistic information. We suggest that this region may play a key role in using pragmatic, semantic (selection restriction), and subcategorical information to construct a higher representation of meaning of sentences.