The insula-claustrum region and delusions in schizophrenia
ABSTRACT We examined the relationship between cerebral gray matter (GM) volume and severity of delusions and hallucinations in adults with schizophrenia.
MRI scans in 43 patients with schizophrenia were acquired. Correlations were computed between GM volume and clinician ratings of hallucinations and delusions.
The analysis revealed significant inverse correlations between ratings of the severity of delusions and volumes of the left claustrum and right insula. Significant correlations were not observed between cerebral GM volume and ratings of hallucinations.
The insula/claustrum region may be critical to the experience of delusions and more careful scrutiny of the claustrum in relation to schizophrenia appears warranted.
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ABSTRACT: Although individuals vulnerable to psychosis show brain volumetric abnormalities, structural alterations underlying different probabilities for later transition are unknown. The present study addresses this issue by means of voxel-based morphometry (VBM). We investigated grey matter volume (GMV) abnormalities by comparing four neuroleptic-free groups: individuals with first episode of psychosis (FEP) and with at-risk mental state (ARMS), with either long-term (ARMS-LT) or short-term ARMS (ARMS-ST), compared to the healthy control (HC) group. Using three-dimensional (3D) magnetic resonance imaging (MRI), we examined 16 FEP, 31 ARMS, clinically followed up for on average 3 months (ARMS-ST, n=18) and 4.5 years (ARMS-LT, n=13), and 19 HC. The ARMS-ST group showed less GMV in the right and left insula compared to the ARMS-LT (Cohen's d 1.67) and FEP groups (Cohen's d 1.81) respectively. These GMV differences were correlated positively with global functioning in the whole ARMS group. Insular alterations were associated with negative symptomatology in the whole ARMS group, and also with hallucinations in the ARMS-ST and ARMS-LT subgroups. We found a significant effect of previous antipsychotic medication use on GMV abnormalities in the FEP group. GMV abnormalities in subjects at high clinical risk for psychosis are associated with negative and positive psychotic symptoms, and global functioning. Alterations in the right insula are associated with a higher risk for transition to psychosis, and thus may be related to different transition probabilities.Psychological Medicine 11/2011; 42(8):1613-25. DOI:10.1017/S0033291711002716 · 5.43 Impact Factor
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ABSTRACT: The claustrum is a small structure of poorly understood function situated subcortically in the basal forebrain. The fact that it is extensively and reciprocally connected with the cerebral cortex has led to suggestions that it is involved in coordination of cortical activity. In this study, we created excitotoxic lesions to the anterior claustrum of rats and tested performance on three tasks that involve neural processing in one or more frontal and limbic cortical structures. We tested reversal learning and spatial working memory in a water maze and tested latent inhibition using conditioned taste aversion. Lesioned rats were not impaired at acquiring the initial location of the platform in a water maze, but were impaired at acquiring a switched location in the reversal phase. The lesioned rats also exhibited an increased rate of perseverance errors compared to control rats during reversal. Lesioned rats were not impaired in the working memory task or latent inhibition. These results indicate that cell loss in the claustrum may lead to deficits in behavioral flexibility, and are consistent with theories of claustral function that suggest it may help coordinate information necessary for at least some cortical-dependent tasks.Brain research 01/2013; 1499. DOI:10.1016/j.brainres.2013.01.014 · 2.83 Impact Factor
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ABSTRACT: This study proposes a transdiagnostic framework for delusion development, analysing psychiatric (schizophrenia, bipolar disorder, major depressive disorder) and neurological disorders (stroke, and neurodegenerative diseases) in which delusions are predominant. Our aim is to identify a transdiagnostic core of neural and cognitive alterations associated with delusions across distinct clinical disorders. Reviewed empirical evidence suggests delusions are associated: on the neural level with changes in the ventromedial prefrontal cortex (vmPFC) networks, and on the neuropsychological level with dysfunction in the processes (generation of affective value, the construction of internal models of the world, and the reflection about Self and/or Other's mental states) that these network mediate. The concurrent aberration of all these processes could be critical for the clinical transition to a psychotic delusional state. In particular, delusions could become clinically manifest when (1) stimuli are attributed an aberrant affective salience, that (2) is explained by the patient within distorted explanatory internal models that (3) are poorly inhibited by cognitive control systems. This framework extends the two-factor account of delusion model and suggests that common neural mechanisms for the delusions in psychiatric and in neurological disorders.08/2013; 210(3). DOI:10.1016/j.psychres.2013.07.032