The role of the precuneus in metaphor comprehension: evidence from an fMRI study in people with schizophrenia and healthy participants (original) (raw)
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Neural correlates of metaphor processing in schizophrenia
NeuroImage, 2007
Objective: A main feature of schizophrenic thought and language disturbance is concretism, the inability to understand the figurative meaning of proverbs and metaphors. Although this is routinely tested during clinical interview, its neural basis is unknown. Method: We investigated processing of metaphoric sentences with functional magnetic resonance imaging (fMRI) in 12 patients with schizophrenia and 12 control subjects. Stimuli consisted of 60 novel short sentences with either metaphoric or literal meaning presented visually, intersparsed by a low level baseline (grey background). Subjects read these sentences silently and judged by button press whether they had a positive or negative connotation. Results: Reading metaphors in contrast to literal sentences revealed signal changes in the left inferior frontal gyrus in the control subjects (BA 45/47) and an area 3 cm dorsal to that in the patients (BA 45). Only activation in this area was negatively correlated with the severity of concretism rated with the PANSS. Comparison between groups for the contrast metaphors vs. low level baseline revealed stronger signal changes in the control group in the right superior/middle temporal gyrus (BA 39) and the left inferior frontal gyrus (BA 45) in the patients.
Language Sciences, 2014
Sixteen patients with schizophrenia are presented with 'literal', 'conventional metaphor', 'novel metaphor' and 'unrelated' expressions in minimal and sentence contexts. In both contexts, these patients have greater difficulty in processing conventional and novel metaphor expressions than in processing literal expressions. However, in the sentence context, performance improves significantly for conventional metaphors as compared with that for novel metaphors. The results are interpreted in the light of Rachel L.C. Mitchell and Tim J. Crow's theory of abnormal lateralization and right hemisphere dysfunction in schizophrenia. The difficulty in processing metaphors in general and novel metaphors in particular may be due to right hemisphere dysfunction in schizophrenic patients. Interestingly, 'task difficulty' is found to be an important parameter modulating metaphor comprehension in patients with schizophrenia and, therefore, may also be a crucial factor in deciding the hemispheric bias of metaphor processing.
Metaphor Processing Dysfunctions in Schizophrenia Patients With and Without Substance Use Disorders
Frontiers in Psychiatry
Background: Patients with schizophrenia have difficulties comprehending metaphors, which significantly impedes communication. However, this topic has not been thoroughly studied in people with a dual diagnosis. On this basis, we formulated two research aims: a) to compare the ability to comprehend metaphors in schizophrenia patients without (SZ) and with substance use disorder (SZ-SUD) and b) to determine the relationship between the processing of metaphorical content and the severity of psychopathological symptoms in both clinical groups. Methods: A total of 40 individuals with SZ and 40 individuals with SZ-SUD took part in the study. The control group was composed of 40 individuals without a psychiatric or neurological diagnosis. Four subtests from the Right Hemisphere Language Battery (Picture Metaphor Test, Written Metaphor Test, Picture Metaphor Explanation Test, Written Metaphor Explanation Test) were used to measure the ability to understand and explain metaphors. Results: Both groups of individuals with schizophrenia (SZ and SZ-SUD) scored lower than individuals from the control group on all tests of metaphor processing. However, no differences were observed between the two clinical groups. SZ-SUD patients had better results for Picture Metaphor Explanation than for Written Metaphor Explanation. Negative symptoms were found to be significant predictors of difficulties with understanding and explaining metaphors. Conclusion: Individuals with schizophrenia, regardless of their substance use disorder (SUD) status, exhibit impaired metaphorical content processing. SUD in schizophrenia is not associated with significant impairments in understanding and explaining metaphorical content. Moreover, impairments in processing metaphorical content are associated with more severe negative symptoms of schizophrenia.
Brain Topography, 2021
Figurative language processing (e.g. metaphors) is commonly impaired in schizophrenia. In the present study, we investigated the neural activity and propagation of information within neural circuits related to the figurative speech, as a neural substrate of impaired conventional metaphor processing in schizophrenia. The study included 30 schizophrenia outpatients and 30 healthy controls, all of whom were assessed with a functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) punchline-based metaphor comprehension task including literal (neutral), figurative (metaphorical) and nonsense (absurd) endings. The blood oxygenation level-dependent signal was recorded with 3T MRI scanner and direction and strength of cortical information flow in the time course of task processing was estimated with a 64-channel EEG input for directed transfer function. The presented results revealed that the behavioral manifestation of impaired figurative language in schizophrenia is re...
Schizophrenia Research: Cognition, 2019
Previous studies suggest that understanding of non-literal expressions, and in particular metaphors, can be impaired in people with schizophrenia; although it is not clear why. We explored metaphor comprehension capacity using a novel picture selection paradigm; we compared task performance between people with schizophrenia and healthy comparator subjects and we further examined the relationships between the ability to interpret figurative expressions non-literally and performance on a number of other cognitive tasks. Eye-tracking was used to examine task strategy. We showed that even when IQ, years of education, and capacities for theory of mind and associative learning are factored in as covariates, patients are significantly more likely to interpret metaphorical expressions literally, despite eye-tracking findings suggesting that patients are following the same interpretation strategy as healthy controls. Inhibitory control deficits are likely to be one of multiple factors contributing to the poorer performance of our schizophrenia group on the metaphor trials of the picture selection task.
Figurative language processing in schizophrenia
2019
When patients diagnosed with schizophrenia process figurative language, they often make literality and/or concreteness mistakes. These mistakes can be related to certain cognitive functions that are underperforming or impaired in schizophrenia. This research found that cognitive functions that often present deficits in patients with schizophrenia (PwS) are working memory, cognitive control, cognitive flexibility and ToM. The aim of this study is to provide evidence of the cognitive impairments that might be underlying poorer figurative language processing in schizophrenia, as well as to shed a light on the cognitive functions that might be at play when figurative language is processed. Disclosing the cognitive functions that can be underperforming in schizophrenia can be relevant for therapeutics and for the development of more effective forms of treatment for the disorder. The present thesis analyses figurative language processing (metaphor, logical metonymy and irony) and theory o...
ERPs of metaphoric, literal, and incongruous semantic processing in schizophrenia
The ability of schizophrenia patients to access metaphorical meaning was studied on the basis of psycholinguistic models of metaphor processing. ERPs were recorded from 20 schizophrenic and 20 control participants who were asked to read metaphorical, literal, and incongruous sentences and to judge their meaningfulness. In all participants, incongruous endings to sentences evoked the most negative N400 amplitude, whereas literal endings evoked more negative N400 amplitude than metaphorical ones, consistent with the direct model of metaphor processing. Although the patients had ERPs patterns that were similar to controls, they exhibited a more negative N400 amplitude for all sentences, LPC amplitude reduction, and latency delay in both components. The results suggest that schizophrenics have no specific anomalies in accessing the meaning of metaphors but are less efficient in integrating the semantic context of all sentencesFboth figurative and literal.
Superior Temporal Sulcus Disconnectivity During Processing of Metaphoric Gestures in Schizophrenia
2013
The left superior temporal sulcus (STS) plays an important role in integrating audiovisual information and is functionally connected to disparate regions of the brain. For the integration of gesture information in an abstract sentence context (metaphoric gestures), intact connectivity between the left STS and the inferior frontal gyrus (IFG) should be important. Patients with schizophrenia have problems with the processing of metaphors (concretism) and show aberrant structural connectivity of long fiber bundles. Thus, we tested the hypothesis that patients with schizophrenia differ in the functional connectivity of the left STS to the IFG for the processing of metaphoric gestures. During functional magnetic resonance imaging data acquisition, 16 patients with schizophrenia (P) and a healthy control group (C) were shown videos of an actor performing gestures in a concrete (iconic, IC) and abstract (metaphoric, MP) sentence context. A psychophysiological interaction analysis based on the seed region from a previous analysis in the left STS was performed. In both groups we found common positive connectivity for IC and MP of the STS seed region to the left middle temporal gyrus (MTG) and left ventral IFG. The interaction of group (C>P) and gesture condition (MP>IC) revealed effects in the connectivity to the bilateral IFG and the left MTG with patients exhibiting lower connectivity for the MP condition. In schizophrenia the left STS is misconnected to the IFG, particularly during the processing of MP gestures. Dysfunctional integration of gestures in an abstract sentence context might be the basis of certain interpersonal communication problems in the patients.
Neural correlates of semantic associations in patients with schizophrenia
European Archives of Psychiatry and Clinical Neuroscience, 2013
Patients with schizophrenia have semantic processing disturbances leading to expressive language deficits (formal thought disorder). The underlying pathology has been related to alterations in the semantic network and its neural correlates. Moreover, crossmodal processing, an important aspect of communication, is impaired in schizophrenia. Here we investigated specific processing abnormalities in patients with schizophrenia with regard to modality and semantic distance in a semantic priming paradigm. Fourteen patients with schizophrenia and fourteen demographically matched controls made visual lexical decisions on successively presented word-pairs (SOA = 350 ms) with direct or indirect relations, unrelated word-pairs, and pseudoword-target stimuli during fMRI measurement. Stimuli were presented in a unimodal (visual) or crossmodal (auditory-visual) fashion. On the neural level, the effect of semantic relation indicated differences (patients [ controls) within the right angular gyrus and precuneus. The effect of modality revealed differences (controls [ patients) within the left superior frontal, middle temporal, inferior occipital, right angular gyri, and anterior cingulate cortex. Semantic distance (direct vs. indirect) induced distinct activations within the left middle temporal, fusiform gyrus, right precuneus, and thalamus with patients showing fewer differences between direct and indirect word-pairs. The results highlight aberrant priming-related brain responses in patients with schizophrenia. Enhanced activation for patients possibly reflects deficits in semantic processes that might be caused by a delayed and enhanced spread of activation within the semantic network. Modalityspecific decreases of activation in patients might be related to impaired perceptual integration. Those deficits could induce and increase the prominent symptoms of schizophrenia like impaired speech processing. Keywords Semantic priming Á Crossmodal presentation Á Unimodal presentation Á Formal thought disorder Á Automatic semantic processing Á Indirect priming Electronic supplementary material The online version of this article (