Brain ; physiopathology ; Humans ; Schizophrenia ; physiopathology

Humans ; Nervous System ; physiopathology ; Schizophrenia ; physiopathology

AIMVarious forms of social adversity have been implicated in the development and emergence of psychosis. However, how and when these events exert their influences are not clear. In this paper, we attempt to examine these putative psychosocial factors and place them in a temporal context and propose a neurobiological mechanism linking these factors.

METHODSMedline databases were searched between 1966 and 2007 followed by the cross-checking of references using the following keywords: psychosocial, stress, stressors, life events, psychological, combined with psychosis and schizophrenia.

RESULTSWhile some findings are conflicting, there are a number of positive studies which suggest that factors like prenatal stress, urban birth and childhood trauma accentuate the vulnerability for schizophrenia and other psychoses while other factors like life events, migration particularly being a minority group, and high expressed emotions, which occur later in the vulnerable individual may move the individual towards the tipping point for psychosis.

CONCLUSIONOverall, there is evidence to implicate psychosocial factors in the pathophysiology of schizophrenia. These factors may act via a common pathway, which involves stress-induced dysregulation of the HPA axis and the dopaminergic systems. To establish the causal relationship of the various factors would require prospective studies that are adequately powered.

Humans ; Nervous System ; physiopathology ; Psychology ; Schizophrenia ; physiopathology

Humans ; Nervous System ; physiopathology ; Schizophrenia ; physiopathology

BACKGROUNDAuditory verbal hallucinations (AVHs) of schizophrenia have been associated with structural and functional alterations of some brain regions. However, the brain regional homogeneity (ReHo) alterations specific to AVHs of schizophrenia remain unclear. In the current study, we aimed to investigate ReHo alterations specific to schizophrenic AVHs.

METHODSThirty-five schizophrenic patients with AVH, 41 schizophrenic patients without AVHs, and fifty healthy subjects underwent resting-state functional magnetic resonance imaging. ReHo differences across the three groups were tested using a voxel-wise analysis.

RESULTSCompared with the healthy control group, the two schizophrenia groups showed significantly increased ReHo in the right caudate and inferior temporal gyrus and decreased ReHo in the bilateral postcentral gyrus and thalamus and the right inferior occipital gyrus (false discovery rate corrected, P < 0.05). More importantly, the AVH group exhibited significantly increased ReHo in the left precuneus compared with the non-AVH group. However, using correlation analysis, we did not find any correlation between the auditory hallucination rating scale score and the ReHo of brain regions.

CONCLUSIONSOur results suggest that increased ReHo in the left precuneus may be a pathological feature exclusive to schizophrenic AVHs.

Adult ; Female ; Hallucinations ; pathology ; physiopathology ; Humans ; Magnetic Resonance Imaging ; Male ; Parietal Lobe ; physiopathology ; Schizophrenia ; pathology ; physiopathology

Animal models of schizophrenia are important for research aimed at developing improved pharmacotherapies. In particular, the cognitive deficits of schizophrenia remain largely refractory to current medications and there is a need for improved medications. We discuss the pathophysiology of schizophrenia and in particular the possible mechanisms underlying the cognitive deficits. We review the current animal models of schizophrenia and discuss the extent to which they meet the need for models reflecting the various domains of the symptomatology of schizophrenia, including positive symptoms, negative symptoms and cognitive symptoms.
Animals ; Drug Therapy ; Humans ; Models, Animal ; Schizophrenia ; drug therapy ; physiopathology

Power noise is constantly found in EEG signals; thus the acquisition and analysis of EEG signals can be strongly influenced. Comparison of the efficiencies of four ICA algorithms (Fastica, Extended Infomax, EGLD, Pearson-ICA) and SVD methods in extracting power noise in the EEG signals showed that ICA algorithms appear insensitive to the noise disturbance, whereas the commonly used SVD method does not. By applying the Extended-Infomax ICA with better convergence in this paper, it was demonstrated that the power noise contained in the 16-channel EEG signals of one Alzheimer-disease patient were removed successfully(the lowest signal-noise-ratio for power noise is 0 dB). ICA has a possible important value and prospect in biomedical signal processing, especially in clinical medical engineering.
Algorithms ; Artifacts ; Electroencephalography ; Humans ; Schizophrenia ; physiopathology ; Signal Processing, Computer-Assisted

Mitochondrial dysfunction and oxidative stress are increasingly implicated in the pathophysiology of schizophrenia. The brain is the body's highest energy consumer, and the glutathione system is the brain's dominant free radical scavenger. In the current paper, we review the evidence of central and peripheral nervous system anomalies in the oxidative defences of individuals with schizophrenia, principally involving the glutathione system. This is reflected by evidence of the manifold consequences of oxidative stress that include lipid peroxidation, protein carboxylation, DNA damage and apoptosis - all potentially part of the process of neuroprogression in the disorder. Importantly, oxidative stress is amenable to intervention. We consider the clinical potential of some possible interventions that help reduce oxidative stress, via augmentation of the glutathione system, particularly N-acetyl cysteine. We argue that a better understanding of the mechanisms and pathways underlying oxidative stress will assist in developing the therapeutic potential of this area.
Acetylcysteine ; Glutathione ; Humans ; Magnetic Resonance Imaging ; Mitochondrial Diseases ; Nervous System ; physiopathology ; Oxidative Stress ; Schizophrenia ; physiopathology

Social isolation influences the development of the brain, causing dysfunctions at behavioral, cellular and molecular levels. The present paper summarizes the abnormalities induced by social isolation in behaviors, neurotransmitters and cell apoptosis. At the behavioral level, social isolation induces hyperlocomotion, abnormalities in startle reflex and prepulse inhibition (PPI), and dysfunctions in conditioned learning, reversal learning and memory. Moreover, social isolation causes changes of neurotransmitters, such as the increase of dopamine in the nucleus accumbens, the amygdala and other brain regions in the limbic system, the decrease of dopamine in medial prefrontal cortex, the decrease of 5-HT in the nucleus accumbens and the hippocampus, and changes of glutamine in the prefrontal cortex. Finally, social isolation affects cell apoptosis in different brain areas, such as the medial prefrontal cortex, amygdala, nucleus accumbens, and hippocampus. Both the changes in neurotransmitters and cell apoptosis may contribute to the behavioral dysfunctions in social isolated rats. Since schizophrenic patients have similar abnormalities in behaviors and neurotransmitters, isolation rearing can be used as a useful animal model of schizophrenia.
Animals ; Brain ; physiopathology ; Disease Models, Animal ; Neurotransmitter Agents ; metabolism ; Rats ; Schizophrenia ; physiopathology ; Social Isolation

BACKGROUNDDysconnectivity hypothesis of schizophrenia has been increasingly emphasized. Recent researches showed that this dysconnectivity might be related to occurrence of auditory hallucination (AH). However, there is still no consistent conclusion. This study aimed to explore intrinsic dysconnectivity pattern of whole-brain functional networks at voxel level in schizophrenic with AH.

METHODSAuditory hallucinated patients group (n = 42 APG), no hallucinated patients group (n = 42 NPG) and normal controls (n = 84 NCs) were analyzed by resting-state functional magnetic resonance imaging. The functional connectivity metrics index (degree centrality [DC]) across the entire brain networks was calculated and evaluated among three groups.

RESULTSDC decreased in the bilateral putamen and increased in the left superior frontal gyrus in all the patients. However, in APG, the changes of DC were more obvious compared with NPG. Symptomology scores were negatively correlated with the DC of bilateral putamen in all patients. AH score of APG positively correlated with the DC in left superior frontal gyrus but negatively correlated with the DC in bilateral putamen.

CONCLUSIONOur findings corroborated that schizophrenia was characterized by functional dysconnectivity, and the abnormal DC in bilateral putamen and left superior frontal gyrus might be crucial in the occurrence of AH.

Adult ; Brain Mapping ; Female ; Gyrus Cinguli ; pathology ; physiopathology ; Hallucinations ; pathology ; physiopathology ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Putamen ; pathology ; physiopathology ; Schizophrenia ; pathology ; physiopathology ; Young Adult