Neuroimaging in schizophrenia: A review article

Abstract

In this review article we have consolidated the imaging literature of patients with schizophrenia across the full spectrum of modalities in radiology including computed tomography (CT), morphologic magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), positron emission tomography (PET), and magnetoencephalography (MEG). We look at the impact of various subtypes of schizophrenia on imaging findings and the changes that occur with medical and transcranial magnetic stimulation (TMS) therapy. Our goal was a comprehensive multimodality summary of the findings of state-of-the-art imaging in untreated and treated patients with schizophrenia. Clinical imaging in schizophrenia is used to exclude structural lesions which may produce symptoms that may mimic those of patients with schizophrenia. Nonetheless one finds global volume loss in the brains of patients with schizophrenia with associated increased cerebrospinal fluid (CSF) volume and decreased gray matter volume. These features may be influenced by the duration of disease and or medication use. For functional studies, be they fluorodeoxyglucose positron emission tomography (FDG PET), rs-fMRI, task-based fMRI, diffusion tensor imaging (DTI) or MEG there generally is hypoactivation and disconnection between brain regions. However, these findings may vary depending upon the negative or positive symptomatology manifested in the patients. MR spectroscopy generally shows low N-acetylaspartate from neuronal loss and low glutamine (a neuroexcitatory marker) but glutathione may be elevated, particularly in non-treatment responders. The literature in schizophrenia is difficult to evaluate because age, gender, symptomatology, comorbidities, therapy use, disease duration, substance abuse, and coexisting other psychiatric disorders have not been adequately controlled for, even in large studies and meta-analyses.

Convergent and divergent genes expression profiles associated with brain-wide functional connectome dysfunction in deficit and non-deficit schizophrenia

“…Previous studies have reported inconsistent changes of FC in these brain regions, but most of them have shown relationships with clinical symptoms and cognitive changes [ 51 – 53 ]. The extensive FC abnormalities also support that SCZ is one of the disconnection disorders [ 54 – 56 ]. Additionally, our previous neuroimaging studies have shown altered neural activity and FC in the calcarine fissure, lingual gyrus and insula in patients with DS [ 20 , 21 ], and the present study further validates these findings.…”

Aetiology and Risk Factors of Schizophrenia

“…Ventriculomegaly and cortical atrophy are also more common in patients with schizophrenia than controls. Ventriculomegaly is associated with age, impaired cognitive function, decreased response to treatment, and negative symptoms [108,109].…”

Associations among plasma markers for N-methyl-d-aspartate receptor hypofunction, redox dysregulation, and insufficient myelination in patients with schizophrenia

“…Thus, abnormalities in homocysteine may disturb normal methylation reactions, including DNA methylation, detoxification of xenobiotics via GSH conjugation, and redox regulation by GSH antioxidant activity [ 13 ]. In addition to the dysregulation of these signaling factors, cerebral volume is consistently reported to be lower in patients with schizophrenia [ 14 , 15 ], partly due to a reduction in myelin volume [ 16 ]. Nardilysin (N-arginine dibasic convertase, NRDC) is a metalloendopeptidase that positively regulates myelin formation.…”