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Presents a study on brain structure abnormalities before the onset of psychosis. Prevalence of grey matter in the cortex of individuals with psychosis; Application of magnetic resonance imaging in the study; Significance of the study.

BackgroundGrey matter volume and cortical thickness represent two complementary aspects of brain structure. Several studies have described reductions in grey matter volume in people at ultra-high risk (UHR) of psychosis; however, little is known about cortical thickness in this group. The aim of the present study was to investigate cortical thickness alterations in UHR subjects and compare individuals who subsequently did and did not develop psychosis.MethodWe examined magnetic resonance imaging data collected at four different scanning sites. The UHR subjects were followed up for at least 2 years. Subsequent to scanning, 50 UHR subjects developed psychosis and 117 did not. Cortical thickness was examined in regions previously identified as sites of neuroanatomical alterations in UHR subjects, using voxel-based cortical thickness.ResultsAt baseline UHR subjects, compared with controls, showed reduced cortical thickness in the right parahippocampal gyrus (p < 0.05, familywise error corrected). There were no significant differences in cortical thickness between the UHR subjects who later developed psychosis and those who did not.ConclusionsThese data suggest that UHR symptomatology is characterized by alterations in the thickness of the medial temporal cortex. We did not find evidence that the later progression to psychosis was linked to additional alterations in cortical thickness, although we cannot exclude the possibility that the study lacked sufficient power to detect such differences. [ABSTRACT FROM AUTHOR]

Schizophrenia is associated with structural brain abnormalities, but the timing of onset and course of these changes remains unclear. Longitudinal magnetic resonance imaging (MRI) studies have demonstrated progressive brain volume decreases in patients around and after the onset of illness, although considerable discrepancies exist regarding which brain regions are affected. The anatomical pattern of these progressive changes in schizophrenia is largely unknown. In this study, MRI scans were acquired repeatedly from 16 schizophrenia patients approximately 2 years apart following their first episode of illness, and also from 14 age-matched healthy subjects. Cortical Pattern Matching, in combination with Structural Image Evaluation, using Normalisation, of Atrophy, was applied to compare the rates of cortical surface contraction between patients and controls. Surface contraction in the dorsal surfaces of the frontal lobe was significantly greater in patients with first-episode schizophrenia (FESZ) compared with healthy controls. Overall, brain surface contraction in patients and healthy controls showed similar anatomical patterns, with that of the former group exaggerated in magnitude across the entire brain surface. That the pattern of structural change in the early course of schizophrenia corresponds so closely to that associated with normal development is consistent with the hypothesis that a schizophrenia-related factor interacts with normal adolescent brain developmental processes in the pathophysiology of schizophrenia. The exaggerated progressive changes seen in patients with schizophrenia may reflect an increased rate of synaptic pruning, resulting in excessive loss of neuronal connectivity, as predicted by the late neurodevelopmental hypothesis of the illness. [ABSTRACT FROM AUTHOR]

Objective: Anterior cingulate cortex (ACC) abnormalities are commonly reported in studies of patients with bipolar disorder (BD), but it is unclear whether these precede or follow illness onset. We investigated the evidence for early neurodevelopmental anomalies in the ACC and adjacent paracingulate cortex (PaC) of BD patients by studying cortical folding patterns of the region. Method: Magnetic resonance images were acquired from 54 BD patients and 116 healthy controls. Cortical folding patterns were assessed by classifying the incidence of the paracingulate sulcus (PCS) and interruptions in the course of the cingulate sulcus (CS). Results: Patients were significantly less likely to show a PCS bilaterally. There were no differences in the frequency of CS interruptions. Conclusion: The bilateral reduction observed in our patient sample implicates aberrant pre- or peri-natal developmental processes. To our knowledge, this is the first in vivo evidence for early neurodevelopmental anomaly of the ACC/PaC region in BD. [ABSTRACT FROM AUTHOR]