Differential patterns of initial and sustained responses in amygdala and cortical regions to emotional stimuli in schizophrenia patients and healthy participants

Background

We sought to investigate the altered brain responses to emotional stimuli in patients with schizophrenia.

Methods

We analyzed data from 14 patients with schizophrenia and 14 healthy controls who performed an emotional face matching task. We evaluated brain activity and connectivity in the amygdala and cortical regions during the initial (first 21 seconds of each stimulation block) and sustained (last 21 seconds) stages of an emotional processing task, and we determined changes in amygdala activity across the emotional processing task.

Results

The patients with schizophrenia showed similar amygdala activation to the controls during the initial stage of processing, but their activation decreased during the sustained stage. The controls showed increasing amygdala activity across the emotional blocks, whereas activity progressively decreased in the schizophrenia group. The patients with schizophrenia showed increased cortical activity and interconnectivity in the medial frontal and inferior parietal cortex in the initial stage of emotional processing. There was increased activity in the superior temporal cortex and greater connectivity with the inferior parietal cortex in the sustained stage. Performance accuracy was lower in the schizophrenia group in the first part of the block, while their reaction time was longer in the latter part of the block.

Limitations

It was not possible to specify the moment at which the switch in amygdala response occurred.

Conclusion

Our findings suggest that patients with schizophrenia have an initial automatic emotional response but that they need to switch to a compensatory cognitive strategy to solve the task.     

Schizophrenic Patients and Their Unaffected Siblings Share Increased Resting-State Connectivity in the Task-Negative Network but Not Its Anticorrelated Task-Positive Network

Background:

Abnormal connectivity of the anticorrelated intrinsic networks, the task-negative network (TNN), and the task-positive network (TPN) is implicated in schizophrenia. Comparisons between schizophrenic patients and their unaffected siblings enable further understanding of illness susceptibility and pathophysiology. We examined the resting-state connectivity differences in the intrinsic networks between schizophrenic patients, their unaffected siblings, and healthy controls.

Methods:

Resting-state functional magnetic resonance images were obtained from 25 individuals in each subject group. The posterior cingulate cortex/precuneus and right dorsolateral prefrontal cortex were used as seed regions to identify the TNN and TPN through functional connectivity analysis. Interregional connectivity strengths were analyzed using overlapped intrinsic networks composed of regions common to all subject groups.

Results:

Schizophrenic patients and their unaffected siblings showed increased connectivity in the TNN between the bilateral inferior temporal gyri. By contrast, schizophrenic patients alone demonstrated increased connectivity between the posterior cingulate cortex/precuneus and left inferior temporal gyrus and between the ventral medial prefrontal cortex and right lateral parietal cortex in the TNN. Schizophrenic patients exhibited increased connectivity between the left dorsolateral prefrontal cortex and right inferior frontal gyrus in the TPN relative to their unaffected siblings, though this trend only approached statistical significance in comparison to healthy controls.

Conclusion:

Resting-state hyperconnectivity of the intrinsic networks may disrupt network coordination and thereby contribute to the pathophysiology of schizophrenia. Similar, though milder, hyperconnectivity of the TNN in unaffected siblings of schizophrenic patients may contribute to the identification of schizophrenia endophenotypes and ultimately to the determination of schizophrenia risk genes.     

Dysconnectivity of multiple resting-state networks in patients with schizophrenia who have persistent auditory verbal hallucinations

Background

Functional neuroimaging studies on schizophrenia have suggested abnormal task-related functional connectivity in patients with schizophrenia who have auditory verbal hallucinations (AVHs). However, little is known about intrinsic functional connectivity in these patients.

Methods

Between January 2009 and February 2010, we studied patients with schizophrenia who had persistent and treatment-refractory AVHs in comparison with healthy controls. Using functional magnetic resonance imaging, we studied the functional connectivity of multiple resting state networks (RSNs) and their relation to symptom severity. We analyzed the data using a spatial group independent component analysis, and we used random-effects t tests to compare spatial components between groups.

Results

There were 10 patients and 14 controls enrolled in this study. In total, 16 RSNs were identified, from which we selected 4 networks of interest for further analyses. Within a speech-related network, patients showed increased connectivity in bilateral temporal regions and decreased connectivity in the cingulate cortex. Within 2 additional RSNs associated with attention and executive control, respectively, patients exhibited abnormal connectivity in the precuneus and right lateral prefrontal areas. We found correlations between measures of AVH severity and functional connectivity of the left anterior cingulate, left superior temporal gyrus and right lateral prefrontal cortex.

Limitations

The relatively small sample size, the patients’ use of antipsychotic medication and the lack of a clinical control group have to be considered as potential limitations.

Conclusion

Our findings indicate that disrupted intrinsic connectivity of a speech-related network could underlie persistent AVHs in patients with schizophrenia. In addition, the occurrence of hallucinatory symptoms seems to modulate RSNs associated with attention and executive control.     

Left-Dominant Temporal-Frontal Hypercoupling in Schizophrenia Patients With Hallucinations During Speech Perception

Background:

Task-based functional neuroimaging studies of schizophrenia have not yet replicated the increased coordinated hyperactivity in speech-related brain regions that is reported with symptom-capture and resting-state studies of hallucinations. This may be due to suboptimal selection of cognitive tasks.

Methods:

In the current study, we used a task that allowed experimental manipulation of control over verbal material and compared brain activity between 23 schizophrenia patients (10 hallucinators, 13 nonhallucinators), 22 psychiatric (bipolar), and 27 healthy controls. Two conditions were presented, one involving inner verbal thought (in which control over verbal material was required) and another involving speech perception (SP; in which control verbal material was not required).

Results:

A functional connectivity analysis resulted in a left-dominant temporal-frontal network that included speech-related auditory and motor regions and showed hypercoupling in past-week hallucinating schizophrenia patients (relative to nonhallucinating patients) during SP only.

Conclusions:

These findings replicate our previous work showing generalized speech-related functional network hypercoupling in schizophrenia during inner verbal thought and SP, but extend them by suggesting that hypercoupling is related to past-week hallucination severity scores during SP only, when control over verbal material is not required. This result opens the possibility that practicing control over inner verbal thought processes may decrease the likelihood or severity of hallucinations.Key words: schizophrenia, inner speech, speech perception, functional magnetic resonance imaging, functional connectivity     

Prefrontal Brain Network Connectivity Indicates Degree of Both Schizophrenia Risk and Cognitive Dysfunction

Objective:

Cognitive dysfunction is a core feature of schizophrenia, and persons at risk for schizophrenia may show subtle deficits in attention and working memory. In this study, we investigated the relationship between integrity of functional brain networks and performance in attention and working memory tasks as well as schizophrenia risk.

Methods:

A total of 235 adults representing 3 levels of risk (102 outpatients with schizophrenia, 70 unaffected first-degree relatives of persons with schizophrenia, and 63 unrelated healthy controls [HCs]) completed resting-state functional magnetic resonance imaging and a battery of attention and working memory tasks (Brief Test of Attention, Hopkins Verbal Learning Test, and Brief Visuospatial Memory Test) on the same day. Functional networks were defined based on coupling with seeds in the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and primary visual cortex. Networks were then dissected into regional clusters of connectivity that were used to generate individual interaction matrices representing functional connectivity within each network.

Results:

Both patients with schizophrenia and their first-degree relatives showed cognitive dysfunction compared with HCs. First canonicals indicated an inverse relationship between cognitive performance and connectivity within the DLPFC and MPFC networks. Multivariate analysis of variance revealed multivariate main effects of higher schizophrenia risk status on increased connectivity within the DLPFC and MPFC networks.

Conclusions:

These data suggest that excessive connectivity within brain networks coupled to the DLPFC and MPFC, respectively, accompany cognitive deficits in persons at risk for schizophrenia. This might reflect compensatory reactions in neural systems required for cognitive processing of attention and working memory tasks to brain changes associated with schizophrenia.Key words: resting state, fMRI, default-mode network, attention, working memory     

Altered resting-state amygdala functional connectivity in men with posttraumatic stress disorder

Background

Converging neuroimaging research suggests altered emotion neurocircuitry in individuals with posttraumatic stress disorder (PTSD). Emotion activation studies in these individuals have shown hyperactivation in emotion-related regions, including the amygdala and insula, and hypoactivation in emotion-regulation regions, including the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC). However, few studies have examined patterns of connectivity at rest in individuals with PTSD, a potentially powerful method for illuminating brain network structure.

Methods

Using the amygdala as a seed region, we measured resting-state brain connectivity using 3 T functional magnetic resonance imaging in returning male veterans with PTSD and combat controls without PTSD.

Results

Fifteen veterans with PTSD and 14 combat controls enrolled in our study. Compared with controls, veterans with PTSD showed greater positive connectivity between the amygdala and insula, reduced positive connectivity between the amygdala and hippocampus, and reduced anticorrelation between the amygdala and dorsal ACC and rostral ACC.

Limitations

Only male veterans with combat exposure were tested, thus our findings cannot be generalized to women or to individuals with non–combat related PTSD.

Conclusion

These results demonstrate that studies of functional connectivity during resting state can discern aberrant patterns of coupling within emotion circuits and suggest a possible brain basis for emotion-processing and emotion-regulation deficits in individuals with PTSD.     

Functional connectivity between the amygdala and prefrontal cortex in medication-naive individuals with major depressive disorder

Background

Convergent evidence suggests dysfunction within the prefrontal cortex (PFC) and amygdala, important components of a neural system that subserves emotional processing, in individuals with major depressive disorder (MDD). Abnormalities in this system in the left hemisphere and during processing of negative emotional stimuli are especially implicated. In this study, we used functional magnetic resonance imaging (fMRI) to investigate amygdala–PFC functional connectivity during emotional face processing in medication-naive individuals with MDD.

Methods

Individuals with MDD and healthy controls underwent fMRI scanning while processing 3 types of emotional face stimuli. We compared the strength of functional connectivity from the amygdala between the MDD and control groups.

Results

Our study included 28 individuals with MDD and 30 controls. Decreased amygdala–left rostral PFC (rPFC) functional connectivity was observed in the MDD group compared with controls for the fear condition (p < 0.05, corrected). No significant differences were found in amygdala connectivity to any cerebral regions between the MDD and control groups for the happy or neutral conditions.

Limitations

All participants with MDD were experiencing acute episodes, therefore the findings could not be generalized to the entire MDD population.

Conclusion

Medication-naive individuals with MDD showed decreased amygdala–left rPFC functional connectivity in response to negative emotional stimuli, suggesting that abnormalities in amygdala–left rPFC neural circuitry responses to negative emotional stimuli might play an important role in the pathophysiology of MDD.     

Aberrant cortical gyrification in schizophrenia: a surface-based morphometry study

Background

Schizophrenia is considered to be a disorder of cerebral connectivity associated with disturbances of cortical development. Disturbances in connectivity at an early period of cortical maturation can result in widespread defects in gyrification. Investigating the anatomic distribution of gyrification defects can provide important information about neurodevelopment in patients with schizophrenia.

Methods

We undertook an automated surface-based morphometric assessment of gyrification on 3-dimensionally reconstructed cortical surfaces across multiple vertices that cover the entire cortex. We used a sample from our previous research of 57 patients (50 men) with schizophrenia and 41 controls (39 men) in whom we had tested a specific hypothesis regarding presence of both hypo-and hypergyria in the prefrontal cortex using a frontal region-of-interest approach.

Results

Regions with significant reductions in gyrification (hypogyria) were seen predominantly in the left hemisphere, involving the insula and several regions of the multimodal association cortex. Although the prefrontal hypergyria documented earlier did not survive the statistical correction required for a whole brain search (cluster inclusion at p = 0.0001), significant hypergyric frontal clusters emerged when the threshold was lowered (cluster inclusion at p = 0.05). In the insula, a reduction in gyrification was related to reduced cortical thickness in patients with schizophrenia.

Limitations

We studied a sample of patients taking antipsychotic medications, which could have confounded the results. Our sample was predominantly male, limiting the generalizability of our findings.

Conclusion

Our observations suggest that the disturbances in cortical gyrification seen in patients with schizophrenia might be related to a disrupted interaction between the paralimbic and the multimodal association cortex and thus might contribute to the pathogenesis of the illness.     

Static and Dynamic Characteristics of Cerebral Blood Flow During the Resting State in Schizophrenia

Background:

The cerebral network that is active during rest and is deactivated during goal-oriented activity is called the default mode network (DMN). It appears to be involved in self-referential mental activity. Atypical functional connectivity in the DMN has been observed in schizophrenia. One hypothesis suggests that pathologically increased DMN connectivity in schizophrenia is linked with a main symptom of psychosis, namely, misattribution of thoughts.

Methods:

A resting-state pseudocontinuous arterial spin labeling (ASL) study was conducted to measure absolute cerebral blood flow (CBF) in 34 schizophrenia patients and 27 healthy controls. Using independent component analysis (ICA), the DMN was extracted from ASL data. Mean CBF and DMN connectivity were compared between groups using a 2-sample t test.

Results:

Schizophrenia patients showed decreased mean CBF in the frontal and temporal regions (P < .001). ICA demonstrated significantly increased DMN connectivity in the precuneus (x/y/z = −16/−64/38) in patients than in controls (P < .001). CBF was not elevated in the respective regions. DMN connectivity in the precuneus was significantly correlated with the Positive and Negative Syndrome Scale scores (P < .01).

Conclusions:

In schizophrenia patients, the posterior hub—which is considered the strongest part of the DMN—showed increased DMN connectivity. We hypothesize that this increase hinders the deactivation of the DMN and, thus, the translation of cognitive processes from an internal to an external focus. This might explain symptoms related to defective self-monitoring, such as auditory verbal hallucinations or ego disturbances.Key words: psychosis, default mode network, arterial spin labeling, functional connectivity, precuneus     

Nonlinear Analysis of Electroencephalogram in Schizophrenia Patients with Persistent Auditory Hallucination

Objective

The recent nonlinear analyses of electroencephalogram (EEG) data have shown that the correlation dimension (D2) reflects the degree of integration of information processing in the brain. There is now considerable evidence that auditory hallucination (AH) reflects dysfunctional gamma and beta frequency oscillations. Gamma oscillations are thought to reflect internally driven representations of objects, and the occurrence of subsequent beta oscillations can reflect the modification of the neuronal circuitry used to encode the sensory perception. The purpose of this study was to test whether AH in schizophrenia patients is reflected in abnormalities in D2 in their EEG, especially in the gamma and beta frequency bands.

Methods

Twenty-five schizophrenia patients with a history of treatment-refractory AH over at least the past 2 years, and 23 schizophrenia patients with no AH (N-AH) within the past 2 years were recruited for the study. Artifact-free 30-s EEG epochs during rest were examined for D2.

Results

The AH patients showed significantly increased gamma frequency D2 in Fp2 and decreased beta frequency D2 in the P3 region compared with the N-AH patients. These results imply that gamma frequency D2 in the right prefrontal cortex is more chaotic and that beta frequency D2 in the left parietal cortex is more coherent (less chaotic) in AH patients than in N-AH patients.

Conclusion

Our study supports the previous evidence indicating that gamma and beta oscillations are pivotal to AH, and also shows the distinctive dimensional complexity between the right prefrontal and left parietal cortexes as the underlying biological correlates of AH in schizophrenia patients.     

Comparison of the Heritability of Schizophrenia and Endophenotypes in the COGS-1 Family Study

Background:

Twin and multiplex family studies have established significant heritability for schizophrenia (SZ), often summarized as 81%. The Consortium on the Genetics of Schizophrenia (COGS-1) family study was designed to deconstruct the genetic architecture of SZ using neurocognitive and neurophysiological endophenotypes, for which heritability estimates ranged from 18% to 50% (mean = 30%). This study assessed the heritability of SZ in these families to determine whether there is a “heritability gap” between the diagnosis and related endophenotypes.

Methods:

Nuclear families (N = 296) with a SZ proband, an unaffected sibling, and both parents (n = 1366 subjects; mean family size = 4.6) underwent comprehensive endophenotype and clinical characterization. The Family Interview for Genetic Studies was administered to all participants and used to obtain convergent psychiatric symptom information for additional first-degree relatives of interviewed subjects (N = 3304 subjects; mean family size = 11.2). Heritability estimates of psychotic disorders were computed for both nuclear and extended families.

Results:

The heritability of SZ was 31% and 44% for nuclear and extended families. The inclusion of bipolar disorder increased the heritability to 37% for the nuclear families. When major depression was added, heritability estimates dropped to 34% and 20% for nuclear and extended families, respectively.

Conclusions:

Endophenotypes and psychotic disorders exhibit comparable levels of heritability in the COGS-1 family sample. The ascertainment of families with discordant sibpairs to increase endophenotypic contrast may underestimate diagnostic heritability relative to other studies. However, population-based studies also report significantly lower heritability estimates for SZ. Collectively, these findings support the importance of endophenotype-based strategies and the dimensional view of psychosis.Key words: schizophrenia, psychosis, endophenotypes, cognition, biomarkers, heritability     

Differential effects of serotonergic and noradrenergic antidepressants on brain activity during a cognitive control task and neurofunctional prediction of treatment outcome in patients with depression

Background

We investigated the differential effects of serotonergic and noradrenergic antidepressants on brain activation in patients with major depressive disorder during a Stroop task. We predicted that pretreatment hyperactivity in the rostral anterior cingulate cortex would predict better treatment outcomes.

Methods

In total, 20 patients underwent naturalistic open-label clinical treatment with citalopram (n = 12) or reboxetine (n = 8). We performed functional magnetic resonance imaging at baseline and after 6 weeks of treatment.

Results

There were no significant group differences in clinical characteristics, treatment outcomes or baseline fMRI activations. The group by time interaction revealed significant voxels in the right amygdala–hippocampus complex (p < 0.05, family-wise error corrected by use of the bilateral amygdala and hippocampus mask image as a small volume), indicating a posttreatment blood oxygen level–dependent signal decrease in the citalopram group. Pretreatment hyperactivity in the rostral anterior cingulate cortex was not related to symptom improvement.

Limitations

Our study was a nonrandomized clinical trial.

Conclusion

These results indicate that serotonergic and noradrenergic antidepressants have a differential effect on brain activity, especially in the amygdala and hippocampus.     

Modafinil Reverses Phencyclidine-Induced Deficits in Cognitive Flexibility,Cerebral Metabolism,and Functional Brain Connectivity

Objective:

In the present study, we employ mathematical modeling (partial least squares regression, PLSR) to elucidate the functional connectivity signatures of discrete brain regions in order to identify the functional networks subserving PCP-induced disruption of distinct cognitive functions and their restoration by the procognitive drug modafinil.

Methods:

We examine the functional connectivity signatures of discrete brain regions that show overt alterations in metabolism, as measured by semiquantitative 2-deoxyglucose autoradiography, in an animal model (subchronic phencyclidine [PCP] treatment), which shows cognitive inflexibility with relevance to the cognitive deficits seen in schizophrenia.

Results:

We identify the specific components of functional connectivity that contribute to the rescue of this cognitive inflexibility and to the restoration of overt cerebral metabolism by modafinil. We demonstrate that modafinil reversed both the PCP-induced deficit in the ability to switch attentional set and the PCP-induced hypometabolism in the prefrontal (anterior prelimbic) and retrosplenial cortices. Furthermore, modafinil selectively enhanced metabolism in the medial prelimbic cortex. The functional connectivity signatures of these regions identified a unifying functional subsystem underlying the influence of modafinil on cerebral metabolism and cognitive flexibility that included the nucleus accumbens core and locus coeruleus. In addition, these functional connectivity signatures identified coupling events specific to each brain region, which relate to known anatomical connectivity.

Conclusions:

These data support clinical evidence that modafinil may alleviate cognitive deficits in schizophrenia and also demonstrate the benefit of applying PLSR modeling to characterize functional brain networks in translational models relevant to central nervous system dysfunction.     

Neural circuitry of emotional face processing in autism spectrum disorders

Background

Autism spectrum disorders (ASD) are associated with severe impairments in social functioning. Because faces provide nonverbal cues that support social interactions, many studies of ASD have examined neural structures that process faces, including the amygdala, ventromedial prefrontal cortex and superior and middle temporal gyri. However, increases or decreases in activation are often contingent on the cognitive task. Specifically, the cognitive domain of attention influences group differences in brain activation. We investigated brain function abnormalities in participants with ASD using a task that monitored attention bias to emotional faces.

Methods

Twenty-four participants (12 with ASD, 12 controls) completed a functional magnetic resonance imaging study while performing an attention cuing task with emotional (happy, sad, angry) and neutral faces.

Results

In response to emotional faces, those in the ASD group showed greater right amygdala activation than those in the control group. A preliminary psychophysiological connectivity analysis showed that ASD participants had stronger positive right amygdala and ventromedial prefrontal cortex coupling and weaker positive right amygdala and temporal lobe coupling than controls. There were no group differences in the behavioural measure of attention bias to the emotional faces.

Limitations

The small sample size may have affected our ability to detect additional group differences.

Conclusion

When attention bias to emotional faces was equivalent between ASD and control groups, ASD was associated with greater amygdala activation. Preliminary analyses showed that ASD participants had stronger connectivity between the amygdala ventromedial prefrontal cortex (a network implicated in emotional modulation) and weaker connectivity between the amygdala and temporal lobe (a pathway involved in the identification of facial expressions, although areas of group differences were generally in a more anterior region of the temporal lobe than what is typically reported for emotional face processing). These alterations in connectivity are consistent with emotion and face processing disturbances in ASD.     

Role of Visual Integration in Gaze Perception and Emotional Intelligence in Schizophrenia

Background:

Individuals with schizophrenia demonstrate a wide range of social cognitive deficits that significantly compromise functioning. Early visual processing is frequently disrupted in schizophrenia, and growing evidence suggests a role of perceptual dysfunctions in socioemotional functioning in the disorder. This study examined visual integration (the ability to effectively integrate individual, local visual features into a holistic representation), a target construct of basic perception identified by the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia initiative, and its relationship with eye- contact perception and emotional intelligence in schizophrenia.

Methods:

Twenty-nine participants with schizophrenia (SCZ) and 23 healthy controls (HC) completed tasks measuring visual integration (Coherent Motion Task, Contour Integration Task), an eye-contact perception task, and a measure of emotional intelligence.

Results:

SCZ participants showed compromised visual integration as suggested by poorer performance on the Contour Integration Task relative to HC. Visual integration was a significant predictor of eye-contact perception and emotional intelligence among SCZ. The amounts of variances in these 2 social cognitive areas accounted for by visual integration were comparable to and overlapped with those accounted for by the diagnosis of schizophrenia.

Conclusions:

Individuals with schizophrenia showed compromised visual integration, and this may play a significant role in the observed deficits in higher level processing of social information in the disorder.Key words: psychosis, visual perception, perceptual organization, social cognition, sensory processing     

Visual sensory processing deficits in patients with bipolar disorder revealed through high-density electrical mapping

Background

Etiological commonalities are apparent between bipolar disorder and schizophrenia. For example, it is becoming clear that both populations show similar electrophysiological deficits in the auditory domain. Recent studies have also shown robust visual sensory processing deficits in patients with schizophrenia using the event-related potential technique, but this has not been formally tested in those with bipolar disorder. Our goal here was to assess whether early visual sensory processing in patients with bipolar disorder, as indexed by decreased amplitude of the P1 component of the visual evoked potential (VEP), would show a similar deficit to that seen in those with schizophrenia. Since the P1 deficit has already been established as an endophenotype in schizophrenia, a finding of commonality between disorders would raise the possibility that it represents a measure of common genetic liability.

Methods

We visually presented isolated-check stimuli to euthymic patients with a diagnosis of bipolar disorder and age-matched healthy controls within a simple go/no-go task and recorded VEPs using high-density (72-channel) electroencephalography.

Results

The P1 VEP amplitude was substantially reduced in patients with bipolar disorder, with an effect size of f = 0.56 (large according to Cohen’s criteria).

Limitations

Our sample size was relatively small and as such, did not allow for an examination of potential relations between the physiologic measures and clinical measures.

Conclusion

This reduction in P1 amplitude among patients with bipolar disorder represents a dysfunction in early visual processing that is highly similar to that found repeatedly in patients with schizophrenia and their healthy first-degree relatives. Since the P1 deficit has been related to susceptibility genes for schizophrenia, our results raise the possibility that the deficit may in fact be more broadly related to the development of psychosis and that it merits further investigation as a candidate endophenotype for bipolar disorder.     

The Associations between Visual Attention and Facial Expression Identification in Patients with Schizophrenia

Objective

Visual search is an important attention process that precedes the information processing. Visual search also mediates the relationship between cognition function (attention) and social cognition (such as facial expression identification). However, the association between visual attention and social cognition in patients with schizophrenia remains unknown. The purposes of this study were to examine the differences in visual search performance and facial expression identification between patients with schizophrenia and normal controls, and to explore the relationship between visual search performance and facial expression identification in patients with schizophrenia.

Methods

Fourteen patients with schizophrenia (mean age=46.36±6.74) and 15 normal controls (mean age=40.87±9.33) participated this study. The visual search task, including feature search and conjunction search, and Japanese and Caucasian Facial Expression of Emotion were administered.

Results

Patients with schizophrenia had worse visual search performance both in feature search and conjunction search than normal controls, as well as had worse facial expression identification, especially in surprised and sadness. In addition, there were negative associations between visual search performance and facial expression identification in patients with schizophrenia, especially in surprised and sadness. However, this phenomenon was not showed in normal controls.

Conclusion

Patients with schizophrenia who had visual search deficits had the impairment on facial expression identification. Increasing ability of visual search and facial expression identification may improve their social function and interpersonal relationship.     

Is the Prevalence of Metabolic Syndrome and Metabolic Abnormalities Increased in Early Schizophrenia? A Comparative Meta-Analysis of First Episode,Untreated and Treated Patients

We aimed to discover whether metabolic complications of schizophrenia (SZ) are present in first episode (FE) and unmedicated (UM) patients, in comparison with patients established on antipsychotic medication (AP).

Method:

A systematic search, critical appraisal, and meta-analysis were conducted of studies to December 2011 using Medline, PsycINFO, Embase and experts. Twenty-six studies examined FE SZ patients (n = 2548) and 19 included UM SZ patients (n = 1325). For comparison we identified 78 publications involving 24 892 medicated patients who had chronic SZ already established on AP.

Results:

In UM, the overall rate of metabolic syndrome (MetS) was 9.8% using any standardized criteria. Diabetes was found in only 2.1% and hyperglycaemia (>100mg/dl) in 6.4%. In FE, the overall MetS rate was 9.9%, diabetes was found in only 1.2%, and hyperglycaemia in 8.7%. In UM and FE, the rates of overweight were 26.6%, 22%; hypertriglyceridemia 16.9%, 19.6%; low HDL 20.4%, 21.9%; high blood pressure 24.3%, 30.4%; smoking 40.2%, 46.8%, respectively. In both groups all metabolic components and risk factors were significantly less common in early SZ than in those already established on AP. Waist size, blood pressure and smoking were significantly lower in UM compared with FE.

Conclusion:

There is a significantly lower cardiovascular risk in early SZ than in chronic SZ. Both diabetes and pre-diabetes appear uncommon in the early stages, especially in UM. However, smoking does appear to be elevated early after diagnosis. Clinicians should focus on preventing initial cardiometabolic risk because subsequent reduction in this risk is more difficult to achieve, either through behavioral or pharmacologic interventions.Key words: cardiovascular risk, diabetes, lipids, glucose, waist, obesity     

Structural covariance in the hallucinating brain: a voxel-based morphometry study

Background

Neuroimaging studies have indicated that a number of cortical regions express altered patterns of structural covariance in schizophrenia. The relation between these alterations and specific psychotic symptoms is yet to be investigated. We used voxel-based morphometry to examine regional grey matter volumes and structural covariance associated with severity of auditory verbal hallucinations.

Methods

We applied optimized voxel-based morphometry to volumetric magnetic resonance imaging data from 26 patients with medication-resistant auditory verbal hallucinations (AVHs); statistical inferences were made at p < 0.05 after correction for multiple comparisons.

Results

Grey matter volume in the left inferior frontal gyrus was positively correlated with severity of AVHs. Hallucination severity influenced the pattern of structural covariance between this region and the left superior/middle temporal gyri, the right inferior frontal gyrus and hippocampus, and the insula bilaterally.

Limitations

The results are based on self-reported severity of auditory hallucinations. Complementing with a clinician-based instrument could have made the findings more compelling. Future studies would benefit from including a measure to control for other symptoms that may covary with AVHs and for the effects of antipsychotic medication.

Conclusion

The results revealed that overall severity of AVHs modulated cortical intercorrelations between frontotemporal regions involved in language production and verbal monitoring, supporting the critical role of this network in the pathophysiology of hallucinations.