Semantic priming in thought disordered schizophrenic patients.
ABSTRACT Groups of thought disordered (TD) and non-thought disordered (NTD) schizophrenic patients, unipolar affective patients and normal controls performed a lexical decision task involving the recognition of words immediately preceded (primed) by either an associated or an unrelated word. Significant increments in recognition speed in the associated prime condition were found in all groups, with significantly greater gain by TD schizophrenics than by others. These findings are consistent with network models of associational activation and lend support to an attentional deficit hypothesis for schizophrenic language functioning.
- SourceAvailable from: Karen DavrancheCognition 01/2015; · 3.63 Impact Factor
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ABSTRACT: Abnormalities in language and language neural circuitry are observed in schizophrenia (SZ). Similar, but less pronounced language deficits are also seen in young first-degree relatives of people with SZ, who are at higher familial risk (FHR) for the disorder than the general population. The neural underpinnings of these deficits in people with FHR are unclear. Participants were 43 people with FHR and 32 comparable controls. fMRI scans were collected while participants viewed associated and unrelated word pairs, and performed a lexical decision task. fMRI analyses conducted in SPM8 examined group differences in the modulation of hemodynamic activity by semantic association. There were no group differences in demographics, IQ or behavioral semantic priming, but FHR participants had more schizotypal traits than controls. Controls exhibited the expected suppression of hemodynamic activity to associated versus unrelated word pairs. Compared to controls, FHR participants showed an opposite pattern of hemodynamic modulation to associated versus unrelated word pairs, in the left inferior frontal gyrus (IFG), right superior and middle temporal gyrus (STG) and the left cerebellum. Group differences in activation were significant, FWE-corrected for multiple comparisons (p<0.05). Activity within the IFG during the unrelated condition predicted schizotypal symptoms in FHR participants. FHR for SZ is associated with abnormally increased neural activity to semantic associates within an inferior frontal/temporal network. This might increase the risk of developing unusual ideas, perceptions and disorganized language that characterize schizotypal traits, potentially predicting which individuals are at greater risk to develop a psychotic disorder.Schizophrenia Research 10/2013; 151(1-3). DOI:10.1016/j.schres.2013.09.023 · 4.43 Impact Factor
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ABSTRACT: Analysis of the pattern of altered cognition observed in schizophrenia provides better insight into neurocognitive deficits. It reveals a potential novel target for schizophrenia research. To understand this target we reviewed the findings of neuroimaging studies on implicit [nonconscious] memory. These studies have consistently reported attenuated activity in the area V3A of the extrastriate cortex during retrieval of studied items. It was suggested that the attenuation limits the pool of information available for further cognitive processing. Therefore, if V3A is functionally damaged, individuals will have access to a larger pool of information for cognitive processing. Since cognitive tasks that are not dependent on attention [attention independent] process a larger pool of information more efficiently, performance in these tasks is likely to improve after V3A is damaged. Conversely, tasks that are dependent on attentional resources are more efficient in processing smaller pool of information. Performance in these tasks therefore is expected to deteriorate if a large pool of information is made available following V3A damage. A review of cognitive performance in schizophrenia suggests that patients perform at above normal level in attention independent priming tasks and perform at subnormal level in attention dependent episodic and working memory tasks. These findings indicate possible impairment of V3A activity. It could therefore be a potentially important unstudied target for schizophrenia research, particularly because a number of investigators have reported that the activity in this area is altered in schizophrenia.Open Journal of Psychiatry 11/2012; 2(4A). DOI:10.4236/ojpsych.2012.224047