Functional analysis of the deficit in semantic context processes in schizophrenic patients: an event-related potentials study

Kostova, Milena; Passerieux, Christine; Laurent, Jean‐Paul; Saint-Georges, Catherine; Hardy-Baylé, Marie-Christine

doi:10.1016/s0987-7053(03)00006-6

Cited by 35 publications

(38 citation statements)

References 35 publications

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“…The absence of significant between-group N400 effect differences in the present study contrasts with other studies where such differences were found to be associated with schizophrenia (Condray et al, 2003;Condray et al, 1999;Kostova et al, 2005;Kostova et al, 2003;Mathalon et al, 2002;Mitchell et al, 1991;Ohta et al, 1999;Strandburg et al, 1997), or with schizotypal personality (Kiang and Kutas, 2005;Kimble et al, 2000;Niznikiewicz et al, 2002), which is thought to share genetic and neurophysiological substrates with schizophrenia (Siever and Davis, 2004). Our results, however, are not an isolated instance, as there are other published reports in which no such differences were detected between schizophrenia patients and controls (Andrews et al, 1993;Koyama et al, 1994;Olichney et al, 1997).…”

Section: Discussioncontrasting

confidence: 96%

“…In addition, studies that found N400 effect differences between patients and controls may have examined more severely ill patients than studies that did not find such differences. In support of this hypothesis, some studies that found patient-control differences included a mixture of inpatients and outpatients (Kostova et al, 2005;Kostova et al, 2003;Mathalon et al, 2002;Ohta et al, 1999), whereas studies that found no such differences examined either outpatients only (our study and that of Olichney et al (1997)), patients with "no acute illness" (Koyama et al, 1994), or patients of unspecified admission status (Andrews et al, 1993). Nevertheless, comparing illness severity among these studies directly is difficult, as they used a variety of symptom rating scales.…”

Section: Discussionmentioning

confidence: 58%

“…In a picture-word matching task (SOA=250 ms) (Mathalon et al, 2002), target words referring to an item from the same category as the picture elicited a smaller N400 in patients than in controls, consistent with increased activation of related items. Studies with sentence-final word paradigms (Kostova et al, 2003;Ohta et al, 1999) showed larger N400 amplitudes to congruent words in patients than controls, consistent with impairment in using context to activate semantically congruent items.…”

Section: Introductionmentioning

confidence: 71%

“…Prime-target word pairs with SOA=450 (Kostova et al, 2005;Kostova et al, 2003) and 600 ms (Strandburg et al, 1997)) were associated with larger N400 amplitudes to related targets in schizophrenia patients than in normal controls, while amplitudes to unrelated targets did not differ between patients and controls. These results suggest decreased activation of related targets in schizophrenia, consistent with the impaired context use hypothesis.…”

Section: Introductionmentioning

confidence: 80%

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Electrophysiological insights into conceptual disorganization in schizophrenia

Kiang

Kutas

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et al. 2007

Schizophrenia Research

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Disorganized speech, or thought disorder, in schizophrenia may reflect abnormal processing of meaningful concepts. To examine whether schizophrenia involves abnormalities in how a meaningful context influences processing of concepts strongly, weakly, or not related to it, we used the N400, an event-related brain potential (ERP) index of semantic relatedness. ERPs were recorded from schizophrenia patients (n=18) and normal controls (n=18) while they viewed category definitions (e.g., a type of fruit), each followed by a target word that was either a hightypicality category exemplar (apple), low-typicality exemplar (cherry), or non-exemplar (clamp). Participants' task was to indicate via button-press whether or not the target belonged to the category. In both patients and controls, N400 amplitude was largest (most negative) for nonexemplars, intermediate for low-typicality exemplars, and smallest (least negative) for hightypicality exemplars. Compared to controls, patients showed a trend toward reduced N400 amplitude differences between non-exemplars and low-typicality exemplars. Most importantly, within patients, reduced N400 amplitude differences between high-and low-typicality exemplars were correlated with psychotic symptoms. In schizophrenia patients, an N400 index of semantic processing was associated with psychotic symptoms. Psychosis may be associated with greater similarity in how concepts strongly and weakly meaningfully related to their context are processed.

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Section: Discussioncontrasting

confidence: 96%

Section: Discussionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 80%

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Electrophysiological insights into conceptual disorganization in schizophrenia

Kiang

Kutas

Light

et al. 2007

Schizophrenia Research

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“…Numerous studies have found evidence for larger (more negative) than normal N400 amplitudes in response to contextually related items, and smaller than normal N400 semantic priming effects, in schizophrenia (Condray et al 2003;Condray et al 2010;Ditman and Kuperberg 2007;Kiang et al 2011;Kiang et al 2008;Kostova et al 2005;Kostova et al 2003;Laurent et al 2010;Mathalon et al 2010;Ohta et al 1999;Salisbury 2010;Salisbury 2008;Strandburg et al 1997). In contrast, a few other schizophrenia studies have found smaller than normal N400 amplitudes to contextually related targets and increased N400 relatedness priming effects (Kreher et al 2009;Kreher et al 2008;Mathalon et al 2002;Salisbury 2008).…”

Section: Introductionmentioning

confidence: 99%

Association of abnormal semantic processing with delusion-like ideation in frequent cannabis users: an electrophysiological study

et al. 2012

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Rationale-Frequent cannabis use is a risk marker for schizophrenia and delusions, but the neurocognitive mechanisms of this relationship remain unclear.Objectives-We sought evidence that cannabis users have deficits in processing relationships between meaningful stimuli, similar to abnormalities reported in schizophrenia, and that these deficits are associated with delusion-like ideation. We used the N400 event-related brain potential (ERP) waveform as a neurophysiological probe of activation of concepts in semantic memory. We hypothesized that cannabis users would exhibit larger (more negative) than normal N400 amplitudes in response to stimuli meaningfully related to a preceding prime-reflecting deficient activation of concepts related to the prime. We further hypothesized that the magnitude of this abnormality would correlate with severity of delusion-like ideation.Methods-We recorded ERPs in 24 frequent cannabis users and 24 non-using comparison participants who viewed prime words followed by targets which were either words related or unrelated to the prime or pronounceable non-words. The participants' task was to indicate whether the target was a word. Delusion-like ideation was measured via the Schizotypal Personality Questionnaire.Results-Contrary to our hypothesis, cannabis users exhibited smaller than normal N400s to both related and unrelated targets. These abnormalities correlated with delusion-like ideation in cannabis users only. Conclusions-The results are consistent with a generalized abnormality of activation within semantic memory neural networks in cannabis users. Further research is needed to investigate whether such an abnormality plays a role in the development of delusion-like ideation in cannabis users.

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