The effect of lexical priming on sentence comprehension: An fMRI study (original) (raw)
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Brain and Language, 2006
The current experiment investigated how sentential form-class expectancies influenced lexical-semantic priming within each hemisphere. Sentences were presented that led readers to expect a noun or a verb and the sentence-final target word was presented to one visual field/hemisphere for a lexical decision response. Noun and verb targets in the semantically related condition were compared to an unrelated prime condition, which also predicted part of speech but did not contain any lexical-semantic associates of the target word. The semantic priming effect was strongly modulated by form-class expectancy for RVF/LH targets, for both nouns and verbs. In the LVF/RH, semantic priming was obtained in all conditions, regardless of whether the form-class expectancy was violated. However, the nouns that were preceded by a noun-predicting sentence showed an extremely high priming value in the LVF/RH, suggesting that the RH may have some sensitivity to grammatical predictions for nouns. Comparisons of LVF/RH priming to calculations derived from the LSA model of language representation, which does not utilize word order, suggested that the RH might derive message-level meaning primarily from lexical-semantic relatedness.
The anatomy and time course of semantic priming investigated by fMRI and ERPs
Neuropsychologia, 2003
We combined complementary non-invasive brain imaging techniques with behavioural measures to investigate the anatomy and time course of brain activity associated with semantic priming in a lexical-decision task. Participants viewed pairs of stimuli, and decided whether the second item was a real word or not. There were two variables, the semantic relationship between the prime and the target (related or unrelated) and the interval between the onset of prime and target (200 or 1000 ms), to vary the degree of semantic expectancy that was possible during task performance. Behavioural results replicated the well-established finding that identification of the target is facilitated by a preceding semantically related prime. Event-related functional magnetic resonance imaging (efMRI) identified two brain areas involved in the semantic-priming effect. Activity in the anterior medial temporal cortex was diminished when target words were primed by semantically related words, suggesting involv...
Brain research, 2008
Event-related potential (ERP) studies of semantic processing have generally focused on the N400, a component that peaks at about 400 ms in response to words and which is larger when words are incongruent with the preceding sentence context. An earlier left-lateralized posterior N2 p3 has also been found to be correlated with an "unexpectedness" rating for incongruent sentence endings , Parametric analysis of eventrelated potentials in semantic comprehension: evidence for parallel brain mechanisms, Cognitive Brain Research, 15: 137-153]. Because the incongruent endings were too odd to be explicitly predicted, we here hypothesize that this rating, and hence the N2 p3 , reflects the degree of automatic spreading activation (ASA) in the visual lexical network rather than semantic expectancy, an interpretation also consistent with the early latency of this ERP (208 ms). In order to identify the brain systems involved in these linguistic processes, functional magnetic resonance imaging (fMRI) was utilized in a replication of the ERP study , Parametric analysis of event-related potentials in semantic comprehension: evidence for parallel brain mechanisms, Cognitive Brain Research, 15: 137-153]. We found that activation in the fusiform semantic area (FSA), an area that converges with the source solution for the N2 p3 , responded to the "unexpectedness" parameter in the same manner as the N2 p3 component. These findings suggest that the FSA helps mediate ASA processes and that the N2 p3 can serve as an index of ASA. Furthermore, cloze effects were found in the superior frontal gyrus and the inferior frontal gyrus that could reflect subvocalization and semantic selection processes respectively.
Neuroimage, 2003
Semantic priming occurs when a subject is faster in recognising a target word when it is preceded by a related word compared to an unrelated word. The effect is attributed to automatic or controlled processing mechanisms elicited by short or long interstimulus intervals (ISIs) between primes and targets. We employed event-related functional magnetic resonance imaging (fMRI) to investigate blood oxygen level dependent (BOLD) responses associated with automatic semantic priming using an experimental design identical to that used in standard behavioural priming tasks. Prime-target semantic strength was manipulated by using lexical ambiguity primes (e.g., bank) and target words related to dominant or subordinate meaning of the ambiguity. Subjects made speeded lexical decisions (word/nonword) on dominant related, subordinate related, and unrelated word pairs presented randomly with a short ISI. The major finding was a pattern of reduced activity in middle temporal and inferior prefrontal regions for dominant versus unrelated and subordinate versus unrelated comparisons, respectively. These findings are consistent with both a dual process model of semantic priming and recent repetition priming data that suggest that reductions in BOLD responses represent neural priming associated with automatic semantic activation and implicate the left middle temporal cortex and inferior prefrontal cortex in more automatic aspects of semantic processing.
Neuropsychologia, 2006
The priming of a stimulus by another has become an important tool for exploring the neural underpinnings of conceptual representations. However, priming effects can derive from many different types of relationships and it is important to distinguish between them in order to be able to develop theoretical accounts of the representation of conceptual knowledge. While it is well known that repetition priming (the repeated presentation of the same stimulus) is associated with a reduced neural response, called repetition suppression (RS), the neural correlates of semantic priming (when two stimuli are related in meaning but not identical) are not so well established. We compared the neural correlates of repetition and semantic priming using written words, independently manipulating form and meaning. In an fMRI study, subjects saw single words and made a concrete-abstract decision. Two consecutive words were identical (town-town) or varied along a continuum of semantic relatedness, from highly related (cord-string) to unrelated (face-sail). We found distinct patterns of activation for repetition and semantic priming. Repetition priming was associated with RS in LIFG, bilateral parahippocampal gyrus and R fusiform gyrus. We also observed increased activation for word repetition in the RMFG and RMTG/STG, which may reflect recognition of item's earlier presentation. There was no evidence of suppression for semantic relatedness. Semantic priming was associated with enhanced activation in multiple bilateral fronto-temporal areas, i.e. semantic enhancement. The results suggest that repetition and semantic priming in visual word recognition depend on distinct cognitive processes and neural substrates.
An Event-Related fMRI Investigation of Implicit Semantic Priming
Journal of Cognitive Neuroscience, 2003
& The neural basis underlying implicit semantic priming was investigated using event-related fMRI. Prime-target pairs were presented auditorily for lexical decision (LD) on the target stimulus, which was either semantically related or unrelated to the prime, or was a nonword. A tone task was also administered as a control. Behaviorally, all participants demonstrated semantic priming in the LD task. fMRI results showed that for all three conditions of the LD task, activation was seen in the superior temporal gyrus (STG), the middle temporal gyrus (MTG), and the inferior parietal lobe, with greater activation in the unrelated and nonword conditions than in the related condition. Direct comparisons of the related and unrelated conditions revealed foci in the left STG, left precentral gyrus, left and right MTGs, and right caudate, exhibiting significantly lower activation levels in the related condition. The reduced activity in the temporal lobe suggests that the perception of the prime word activates a lexicalsemantic network that shares common elements with the target word, and, thus, the target can be recognized with enhanced neural efficiency. The frontal lobe reductions most likely reflect the increased efficiency in monitoring the activation of lexical representations in the temporal lobe, making a decision, and planning the appropriate motor response. & D
Neuropsychologia, 2001
Semantic relations may be studied using the experimental technique known as semantic priming, in which a word 'primes' the processing of a related target (e.g. lion-tiger), following a short delay. Priming may be automatic or, with longer delays, under more controlled processing. This study used functional magnetic resonance imaging (fMRI) to examine the cerebral activation during two lexical-decision semantic priming experiments, with a short and long delay, representing automatic and controlled processing, respectively. A further two un-primed lexical-decision tasks were performed to distinguish cerebral activation specific to semantic priming itself from those utilised during lexical-decision processes. Distinct regions of anterior cingulate cortex (ACC) were critical to automatic and controlled semantic priming, whilst the putamen and hippocampal complex responded differently to unrelated and semantically related prime-target pairs. Lexical-decision alone revealed activation in posterior temporal cortex especially on the left, in agreement with previous neuroimaging studies. The results provide a plausible neural substrate for common semantic relations independent of task demands and further emphasise the regional functional specialisation of the ACC.
Lexically-mediated syntactic priming effects in comprehension: Sources of facilitation
Quarterly Journal of Experimental Psychology
The nature of the facilitation occurring when sentences share a verb and syntactic structure (i.e., lexically-mediated syntactic priming) has not been adequately addressed in comprehension. In four eye-tracking experiments, we investigated the degree to which lexical, syntactic, thematic, and verb form repetition contribute to facilitated target sentence processing. Lexically-mediated syntactic priming was observed when primes and targets shared a verb and abstract syntactic structure, regardless of the ambiguity of the prime. In addition, repeated thematic role assignment resulted in syntactic priming (to a lesser degree), and verb form repetition facilitated lexical rather than structural processing. We conclude that priming in comprehension involves lexically associated abstract syntactic representations, and facilitation of verb and thematic role processes. The results also indicate that syntactic computation errors during prime processing are not necessary for lexically-mediate...
Neuroreport, 2002
Evidence from multiple paradigms has converged on the ¢nding that stimulus repetition most often results in decreases in neural activity.The mechanisms of these decreases, however, are not yet well understood. The current study attempted to determine, through the use of masked word repetition priming, whether decreases in activity levels occur in response to pre-or post-prime identi¢cation processes. fMRI was performed while participants engaged in a lexical decision task where words were primed with a brie£y presented and masked word. Masked word priming resulted in increased fMRI signal in regions of cortex associated with the perceptual identi¢cation of the target words. This ¢nding provides evidence suggesting that the impact of repetition priming on the fMRI signal may depend upon whether or not the prime is identi¢ed. NeuroReport13:281^284
Separate Brain Circuits Support Integrative and Semantic Priming in the Human Language System
Cerebral Cortex, 2015
Semantic priming is a crucial phenomenon to study the organization of semantic memory. A novel type of priming effect, integrative priming, has been identified behaviorally, whereby a prime word facilitates recognition of a target word when the two concepts can be combined to form a unitary representation. Here, we used both functional and anatomical imaging approaches to investigate the neural substrates supporting such integrative priming, and compare them with those in semantic priming. Similar behavioral priming effects for both semantic (Bread -Cake) and integrative conditions (Cherry -Cake) were observed when compared to an unrelated condition. However, a clearly dissociated brain response was observed between these two types of priming. The semantic priming effect was localized to the posterior superior temporal and middle temporal gyrus. In contrast, the integrative priming effect localized to the left anterior inferior frontal gyrus and left anterior temporal cortices. Furthermore, fiber tractography showed that the integrative-priming regions were connected via uncinate fasciculus fiber bundle forming an integrative circuit, whereas the semantic-priming regions connected to the posterior frontal cortex via separated pathways. The results point to dissociable neural pathways underlying the two distinct types of priming, illuminating the neural circuitry organization of semantic representation and integration.