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The aim of this study is to analyze the differences in low frequency fluctuation (LFF) values between schizophrenia patients with and without auditory verbal hallucinations (AVH). Nineteen schizophrenia patients with persistent AVH (HP), fourteen non-hallucinating schizophrenia patients (nHP) and twenty healthy controls (HC) underwent R-fMRI. LFF values were calculated in the slow frequency band (0.01-0.08Hz). By means of group level contrasts, we performed direct voxel-wise group comparisons. Both groups of patients showed decreased amplitude LFF (ALFF) values in the occipital pole and lingual gyrus compared to HC, whereas increased ALFF values were found in the temporal pole and fusifom gyrus. Schizophrenia patients exhibited decreased fractional ALFF (fALFF) values in the precuneus, occipital pole and bilateral occipital cortex, and increased fALFF in the insula compared to HC. There were also differences between patients with and without AVH. (Ok to start with lower case?) fALFF values were higher in the putamen and insular cortex and lower in the frontal pole in HP compared to nHP and HC. ALFF increased in HP patients in the bilateral thalamus and bilateral parahippocampal gyrus, compared to nHP patients and HC. Our results suggest that altered dynamics in low-frequency fluctuations may play a key role in the neurophysiology of auditory hallucinations., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The biological basis of the association between cannabis-induced dopamine dysregulation and psychosis remains poorly understood. This (123)I-IBZM SPECT study assessed striatal dopamine D2 receptor (D2R) binding in 37 untreated first-episode psychosis (FEP) subjects, and 18 healthy controls. The aim was to examine if there were differences between FEP subjects with (n=14) and without (n=23) cannabis use in uptake ratios in the D2R. Striatal/Frontal cortex (S/F) uptake ratios were obtained. Healthy controls showed the lowest D2R binding ratios. No differences were found in S/F ratios between users and non-users, suggesting similar dopaminergic mechanisms underlying psychotic symptoms in both groups., (Copyright © 2011 Elsevier B.V. All rights reserved.)