Language pathway abnormalities in schizophrenia: a review of fMRI and other imaging studies

Hypoactivation of the language network during auditory imagery contributes to hallucinations in Schizophrenia

Auditory verbal hallucinations (AVHs) involve perceptions, often voices, in the absence of external stimuli, and rank among the most common symptoms of schizophrenia. Metrical stress evaluation requires determination of the stronger syllable in words, and therefore requires auditory imagery, of interest for investigation of hallucinations in schizophrenia. The current functional magnetic resonance imaging study provides an updated whole-brain network analysis of a previously published study on metrical stress, which showed reduced directed connections between Broca's and Wernicke's regions of interest (ROIs) for hallucinations. Three functional brain networks were extracted, with the language network (LN) showing an earlier and shallower blood-oxygen-level dependent (BOLD) response for hallucinating patients, in the auditory imagery condition only (the reduced activation for hallucinations observed in the original ROI-based results were not specific to the imagery condition). This suggests that hypoactivation of the LN during internal auditory imagery may contribute to the propensity to hallucinate. This accords with cognitive accounts holding that an impaired balance between internal and external linguistic processes (underactivity in networks involved in internal auditory imagery and overactivity in networks involved in speech perception) contributes to our understanding of the biological underpinnings of hallucinations.

Polygenic risk for schizophrenia and the language network: Putative compensatory reorganization in unaffected siblings

Language-related symptoms, such as disorganized, impoverished speech and communicative behaviors, are one of the core features of schizophrenia. These features most strongly correlate with cognitive deficits and polygenic risk among various symptom dimensions of schizophrenia. Nevertheless, unaffected siblings with genetic high-risk fail to show consistent deficits in language network (LN), indicating that either (1) polygenic risk has no notable effect on LN and/or (2) siblings show compensatory changes in opposing direction to patients. To answer this question, we related polygenic risk scores (PRS) to the region-level, tract-level, and systems-level structure (cortical thickness and fiber connectivity) of LN in 182 patients, 48 unaffected siblings and 135 healthy controls. We also studied the relationships between symptoms, language-related cognition, social functioning and LN structure. We observed a significantly lower thickness in LN (especially the Broca's, Wernicke's area and their right homologues) in patients. Siblings had a distinctly higher thickness in parts of the LN and a more pronounced small-world-like structural integration within the LN. Patients with reduced LN thickness had higher PRS, more disorganization and impoverished speech with lower language-related cognition and social functioning. We conclude that the genetic susceptibility and putative compensatory changes for schizophrenia operate, in part, via key regions in the Language Network.

Genetic variations in DOCK4 contribute to schizophrenia susceptibility in a Chinese cohort: A genetic neuroimaging study

BACKGROUND

Emerging evidence suggests that the DOCK4 gene increases susceptibility to schizophrenia. However, no study has hitherto repeated this association in Chinese, and further investigated the relationship between DOCK4 and clinical symptoms in schizophrenic patients using clinical scales and functional magnetic resonance imaging (fMRI).

METHODS

In this study, we genotyped three single nucleotide polymorphisms (SNPs) (rs2074127, rs2217262, and rs2074130) within the DOCK4 gene using a case-control design (including 1289 healthy controls and 1351 patients with schizophrenia). 55 first-episode schizophrenia (FES) patients and 59 healthy participants were divided by the genotypes of rs2074130 into CC and CT+TT groups. We further investigated the association with clinical symptoms and neural characteristics (brain activation/connectivity and nodal network metrics).

RESULTS

Our results showed significant associations between all selected SNPs and schizophrenia (all P < 0.05). In patients, letter fluency and motor speed scores of T allele carriers were significantly higher than the CC group (all P < 0.05). Interestingly, greater brain activity, functional connectivity, and betweenness centrality (BC) in language processing and motor coordination were also observed in the corresponding brain zones in patients with the T allele based on a two-way ANCOVA model. Moreover, a potential positive correlation was found between brain activity/connectivity of these brain regions and verbal fluency and motor speed.

CONCLUSION

Our findings suggest that the DOCK4 gene may contribute to the onset of schizophrenia and lead to language processing and motor coordination dysfunction in this patient population from China.

From communication dysfunction to treatment options in serious mental illness

The Commentary covers research focused on language dysfunction in schizophrenia, and more broadly in communication dysfunction in this disorder, which I have examined with a variety of both behavioral and imaging methodologies. It briefly outlines how further progress can be achieved in pursuing the goal of a comprehensive understanding of its underlying causes. Possible therapeutic approaches are also briefly discussed.

Disembodiment and Language in Schizophrenia: An Integrated Psychopathological and Evolutionary Perspective

Different hypotheses have flourished to explain the evolutionary paradox of schizophrenia. In this contribution, we sought to illustrate how, in the schizophrenia spectrum, the concept of embodiment may underpin the phylogenetic and developmental pathways linking sensorimotor processes, the origin of human language, and the construction of a basic sense of the self. In particular, according to an embodied model of language, we suggest that the reuse of basic sensorimotor loops for language, while enabling the development of fully symbolic thought, has pushed the human brain close to the threshold of a severe disruption of self-embodiment processes, which are at the core of schizophrenia psychopathology. We adopted an inter-disciplinary approach (psychopathology, neuroscience, developmental biology) within an evolutionary framework, to gain an integrated, multi-perspectival model on the origin of schizophrenia vulnerability. A maladaptive over-expression of evolutionary-developmental trajectories toward language at the expense of embodiment processes would have led to the evolutionary "trade-off" of a hyper-symbolic activity to the detriment of a disembodied self. Therefore, schizophrenia psychopathology might be the cost of long-term co-evolutive interactions between brain and language.

Hemispheric lateralization of semantic processing before and after aripiprazole treatment in first-episode psychosis or ultra-high risk state

Whether aberrant language-related lateralization can be improved after antipsychotic treatment in drug-free patients with first-episode psychosis or ultra-high risk state is little known. We aimed to investigate the improvement in lateralization of semantic processing after antipsychotic treatment and associated clinical and cognitive changes. Twenty-one drug-free patients with first-episode psychosis or ultra-high risk state underwent functional magnetic resonance imaging with a semantic task, neuropsychological testing, and clinical assessments with the Positive and Negative Syndrome Scale before and after 6 weeks of aripiprazole treatment. A lateralization index of the region of interest, i.e., inferior frontal gyrus, was calculated and correlated with the behavioral indices of the semantic task, Positive and Negative Syndrome Scale scores, and language-related neuropsychological test scores. After treatment, the lateralization index of the inferior frontal gyrus was significantly increased, which was related to reduced activation of the right inferior frontal gyrus. The increase in the lateralization index was significantly associated with the increase in verbal fluency score. A higher baseline accuracy of the semantic task was associated with a higher post-treatment lateralization index of the inferior frontal gyrus and greater improvement of the total score and positive subscore of the Positive and Negative Syndrome Scale. Our findings indicated aripiprazole treatment significantly increased semantic processing-related lateralization in the inferior frontal gyrus in drug-free patients with first-episode psychosis or ultra-high risk state. A higher baseline accuracy might predict a higher post-treatment lateralization index and greater symptom improvement.

Language abnormalities in schizophrenia: binding core symptoms through contemporary empirical evidence

Both the ability to speak and to infer complex linguistic messages from sounds have been claimed as uniquely human phenomena. In schizophrenia, formal thought disorder (FTD) and auditory verbal hallucinations (AVHs) are manifestations respectively relating to concrete disruptions of those abilities. From an evolutionary perspective, Crow (1997) proposed that "schizophrenia is the price that Homo sapiens pays for the faculty of language". Epidemiological and experimental evidence points to an overlap between FTD and AVHs, yet a thorough investigation examining their shared neural mechanism in schizophrenia is lacking. In this review, we synthesize observations from three key domains. First, neuroanatomical evidence indicates substantial shared abnormalities in language-processing regions between FTD and AVHs, even in the early phases of schizophrenia. Second, neurochemical studies point to a glutamate-related dysfunction in these language-processing brain regions, contributing to verbal production deficits. Third, genetic findings further show how genes that overlap between schizophrenia and language disorders influence neurodevelopment and neurotransmission. We argue that these observations converge into the possibility that a glutamatergic dysfunction in language-processing brain regions might be a shared neural basis of both FTD and AVHs. Investigations of language pathology in schizophrenia could facilitate the development of diagnostic tools and treatments, so we call for multilevel confirmatory analyses focused on modulations of the language network as a therapeutic goal in schizophrenia.

Sexual dimorphism in the relationship between Forkhead-Box P2 and BMI with cognitive deficits in schizophrenia

FOXP2, cognitive deficits, and schizophrenia are associated with neurodegenerative pathophyisiology. Mounting evidence suggests that body mass index (BMI) and FOXP2 may contribute to cognitive deficits in schizophrenia. However, the sex difference in the contribution of FOXP2 and BMI, as well as their potential interaction with cognitive deficits in schizophrenia, have not been investigated. A total of 867 schizophrenia patients and 402 controls were recruited. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The polymorphism rs10447760 of the FOXP2 gene was genotyped. Male schizophrenia patients had superior language performance compared to female patients (F = 17.83; pBonferroni &lt; 0.0001). BMI was positively associated with language scores in male patients with schizophrenia (ß = 0.60, t = 3.30, p = 0.001), as well as in patients with schizophrenia who carried the FOXP2 rs10447760 CC genotype (ß = 0.53, t = 3.16, p = 0.002). Interestingly, this association was only found in male patients with schizophrenia who also carried the FOXP2 rs10447760 CC genotype (ß = 0.63, t = 3.44, p = 0.001). Our study reveals a sex difference in the language deficits of schizophrenia patients and shows sexual dimorphism in the contribution of FOXP2, BMI, and their interaction to cognitive deficits in patients with schizophrenia.

Differential aberrant connectivity of precuneus and anterior insula may underpin the diagnosis of schizophrenia and mood disorders

BACKGROUND

Over the past decade, resting-state functional magnetic resonance imaging (rs-fMRI) has concentrated on brain networks such as the default mode network (DMN), the salience network (SN), and the central executive network (CEN), allowing for a better understanding of cognitive deficits observed in mental disorders, as well as other characteristic psychopathological phenomena such as thought and behavior disorganization.

AIM

To investigate differential patterns of effective connectivity across distributed brain networks involved in schizophrenia (SCH) and mood disorders.

METHODS

The sample comprised 58 patients with either paranoid syndrome in the context of SCH (n = 26) or depressive syndrome (Ds) (n = 32), in the context of major depressive disorder or bipolar disorder. The methods used include rs-fMRI and subsequent dynamic causal modeling to determine the direction and strength of connections to and from various nodes in the DMN, SN and CEN.

RESULTS

A significant excitatory connection from the dorsal anterior cingulate cortex to the anterior insula (aI) was observed in the SCH patient group, whereas inhibitory connections from the precuneus to the ventrolateral prefrontal cortex and from the aI to the precuneus were observed in the Ds group.

CONCLUSION

The results delineate specific patterns associated with SCH and Ds and offer a better explanation of the underlying mechanisms of these disorders, and inform differential diagnosis and precise treatment targeting.

Lateralization of Color Discrimination Performance and Lexical Effects in Patients With Chronic Schizophrenia

Introduction: Patients with schizophrenia experience various visual disturbances. However, information regarding color perception in these patients is rare. In this study, we used a lateralized color search task to investigate whether difference in color name affects color recognition in patients with schizophrenia.

Methods: In a color search task, we controlled the position of the target that emerged from the left visual field (LVF) or right visual field (RVF) as well as the color category. In this task, both the target and the distractors had the same or different color name (e.g., blue or green).

Results: Patients with schizophrenia showed faster performance in the color search task with different color names for target-distractors when the target emerged from the LVF than when it emerged from the RVF. However, the same laterality was not observed in healthy controls. This finding indicates that semantic processing for color name differences influenced visual discrimination performance in patients with schizophrenia more profoundly in the LVF than in the RVF.

Conclusion: This lateralized performance could imply the failure of the left hemisphere language processing dominance in schizophrenia. A search paradigm combining target position and category may indicate that automatic language processing depends on imbalanced hemispheric function in schizophrenia.

rTMS Induces Brain Functional and Structural Alternations in Schizophrenia Patient With Auditory Verbal Hallucination

BACKGROUND

Low-frequency transcranial magnetic stimulation (rTMS) over the left temporoparietal cortex reduces the auditory verbal hallucination (AVH) in schizophrenia. However, the underlying neural basis of the rTMS treatment effect for schizophrenia remains not well understood. This study investigates the rTMS induced brain functional and structural alternations and their associations with clinical as well as neurocognitive profiles in schizophrenia patients with AVH.

METHODS

Thirty schizophrenia patients with AVH and thirty-three matched healthy controls were enrolled. The patients were administered by 15 days of 1 Hz rTMS delivering to the left temporoparietal junction (TPJ) area. Clinical symptoms and neurocognitive measurements were assessed at pre- and post-rTMS treatment. The functional (amplitude of low-frequency fluctuation, ALFF) and structural (gray matter volume, GMV) alternations were compared, and they were then used to related to the clinical and neurocognitive measurements after rTMS treatment.

RESULTS

The results showed that the positive symptoms, including AVH, were relieved, and certain neurocognitive measurements, including visual learning (VisLearn) and verbal learning (VerbLearn), were improved after the rTMS treatment in the patient group. Furthermore, the rTMS treatment induced brain functional and structural alternations in patients, such as enhanced ALFF in the left superior frontal gyrus and larger GMV in the right inferior temporal cortex. The baseline ALFF and GMV values in certain brain areas (e.g., the inferior parietal lobule and superior temporal gyrus) could be associated with the clinical symptoms (e.g., positive symptoms) and neurocognitive performances (e.g., VerbLearn and VisLearn) after rTMS treatment in patients.

CONCLUSION

The low-frequency rTMS over the left TPJ area is an efficacious treatment for schizophrenia patients with AVH and could selectively modulate the neural basis underlying psychiatric symptoms and neurocognitive domains in schizophrenia.

FOXP2 expression and gray matter density in the male brains of patients with schizophrenia

Common genetic variants of FOXP2 may contribute to schizophrenia vulnerability, but controversial results have been reported for this proposal. Here we evaluated the potential impact of the common FOXP2 rs2396753 polymorphism in schizophrenia. It was previously reported to be part of a risk haplotype for this disease and to have significant effects on gray matter concentration in the patients. We undertook the first examination into whether rs2396753 affects the brain expression of FOXP2 and a replication study of earlier neuroimaging findings of the influence of this genetic variant on brain structure. FOXP2 expression levels were measured in postmortem prefrontal cortex samples of 84 male subjects (48 patients and 36 controls) from the CIBERSAM Brain and the Stanley Foundation Array Collections. High-resolution anatomical magnetic resonance imaging was performed on 79 male subjects (61 patients, 18 controls) using optimized voxel-based morphometry. We found differences in FOXP2 expression and brain morphometry depending on the rs2396753, relating low FOXP2 mRNA levels with reduction of gray matter density. We detected an interaction between rs2396753 and the clinical groups, showing that heterozygous patients for this polymorphism have gray matter density decrease and low FOXP2 expression comparing with the heterozygous controls. This study shows the importance of independent replication of neuroimaging genetic studies of FOXP2 as a candidate gene in schizophrenia. Furthermore, our results suggest that the FOXP2 rs2396753 affects mRNA levels, thus providing new knowledge about its significance as a potential susceptibility polymorphism in schizophrenia.

Abnormalities in hemispheric lateralization of intra- and inter-hemispheric white matter connections in schizophrenia

Hemispheric lateralization is a prominent feature of the human brain and is grounded into intra- and inter-hemispheric white matter (WM) connections. However, disruptions in hemispheric lateralization involving both intra- and inter-hemispheric WM connections in schizophrenia is still unclear. Hence, a quantitative measure of the hemispheric lateralization of intra- and inter-hemispheric WM connections could provide new insights into schizophrenia. This work performed diffusion tensor imaging on 50 patients and 58 matched healthy controls. Using graph theory, the global and nodal efficiencies were computed for both intra- and inter-hemispheric networks. We found that patients with schizophrenia showed significantly decrease in both global and nodal efficiency of hemispheric networks relative to healthy controls. Specially, deficits in intra-hemispheric integration and inter-hemispheric communication were revealed in frontal and temporal regions for schizophrenia. We also found disrupted hemispheric asymmetries in brain regions associated with emotion, memory, and visual processes for schizophrenia. Moreover, abnormal hemispheric asymmetry of nodal efficiency was significantly correlated with the symptom of the patients. Our finding indicated that the hemispheric WM lateralization of intra- and inter-hemispheric connections could serve as a potential imaging biomarker for schizophrenia.

Language Dysfunction in Schizophrenia: Assessing Neural Tracking to Characterize the Underlying Disorder(s)?

Deficits in language production and comprehension are characteristic of schizophrenia. To date, it remains unclear whether these deficits arise from dysfunctional linguistic knowledge, or dysfunctional predictions derived from the linguistic context. Alternatively, the deficits could be a result of dysfunctional neural tracking of auditory information resulting in decreased auditory information fidelity and even distorted information. Here, we discuss possible ways for clinical neuroscientists to employ neural tracking methodology to independently characterize deficiencies on the auditory-sensory and abstract linguistic levels. This might lead to a mechanistic understanding of the deficits underlying language related disorder(s) in schizophrenia. We propose to combine naturalistic stimulation, measures of speech-brain synchronization, and computational modeling of abstract linguistic knowledge and predictions. These independent but likely interacting assessments may be exploited for an objective and differential diagnosis of schizophrenia, as well as a better understanding of the disorder on the functional level-illustrating the potential of neural tracking methodology as translational tool in a range of psychotic populations.

The efficacy of real-time functional magnetic resonance imaging neurofeedback for psychiatric illness: A meta-analysis of brain and behavioral outcomes

Real-time functional magnetic resonance imaging neurofeedback (rtfMRI-NF) has gained popularity as an experimental treatment for a variety of psychiatric illnesses. However, there has yet to be a quantitative review regarding its efficacy. Here, we present the first meta-analysis of rtfMRI-NF for psychiatric disorders, evaluating its impact on brain and behavioral outcomes. Our literature review identified 17 studies and 105 effect sizes across brain and behavioral outcomes. We find that rtfMRI-NF produces a medium-sized effect on neural activity during training (g = .59, 95 % CI [.44, .75], p < .0001), a large-sized effect after training when no neurofeedback is provided (g = .84, 95 % CI [.37, 1.31], p = .005), and small-sized effects for behavioral outcomes (symptoms g = .37, 95 % CI [.16, .58], p = .002; cognition g = .23, 95 % CI [-.33, .78], p = .288). Mixed-effects analyses revealed few moderators. Together, these data suggest a positive impact of rtfMRI-NF on brain and behavioral outcomes, although more research is needed to determine how rtfMRI-NF works, for whom, and under what circumstances.

What a Clinician Should Know About the Neurobiology of Schizophrenia: A Historical Perspective to Current Understanding

The brain is no doubt the "organ" of psychiatry; yet, over the years, few evidence-based classifications of psychiatric disorders have been based on brain mechanisms. The National Institute of Mental Health notably proposed one such system, known as Research Domain Criteria, although it has not yet influenced any changes in the DSM. Of all the major psychiatric disorders, the brain has been studied most extensively in schizophrenia, with its speculative pathology first documented by Emil Kraepelin as early as the beginning of the 20th century. Subsequently, the revolution in technology over the past 50 years has changed how investigators are able to view the brain before death without performing biopsies. Schizophrenia is thus found to have both structural and functional widespread brain anomalies that likely lead to its clinical deterioration. At the onset of illness, acquiring an MRI scan could be part of the routine evaluation to determine how progressive the disease has so far been. However, this practice is not yet recognized by the American Psychiatric Association in any of its guidelines on the treatment of schizophrenia.

Assessment of Psychiatric Symptomatology in Bilingual Psychotic Patients: A Systematic Review and Meta-Analysis

Language plays an important role in psychiatric conditions. Language disturbances are core symptoms of psychiatric ailments, and language is the main diagnostic tool to assess psychopathological severity. Although the importance of language in psychiatry, the effect of bilingualism, and more specifically of using the mother language or a later acquired language at the time of assessing psychotic symptoms, has been scarcely studied and, thus, remains unclear. We conducted a systematic review and meta-analysis to ascertain whether differences exist in the severity of psychopathology in psychotic patients when assessed either in the mother language or in an acquired language. Of 3121 retrieved references from three databases (PsycINFO, MEDLINE, Embase) and complementary searches, four studies—including 283 psychotic patients—were included in the review. The meta-analytical combined effect suggested that more overall symptomatology is detected when clinical assessment is conducted in the mother language rather than in the acquired language (very low quality evidence, random effects model standardized mean difference (SMD) 0.44, 95% CI = 0.19 to 0.69, p value = 0.0006, I² = 90%). Considering the growing migration flows and the increasing number of bilingual people in the world population, the effect of the chosen language at the time of conducting psychopathological assessments of psychotic patients is a clinically relevant issue. Based on our findings, we recommend that clinical interviews with bilingual psychotic patients should be conducted, when feasible, in the patient’s mother language.

Anomalies in language as a biomarker for schizophrenia

PURPOSE OF REVIEW

After more than a century of neuroscience research, reproducible, clinically relevant biomarkers for schizophrenia have not yet been established. This article reviews current advances in evaluating the use of language as a diagnostic or prognostic tool in schizophrenia.

RECENT FINDINGS

The development of computational linguistic tools to quantify language disturbances is rapidly gaining ground in the field of schizophrenia research. Current applications are the use of semantic space models and acoustic analyses focused on phonetic markers. These features are used in machine learning models to distinguish patients with schizophrenia from healthy controls or to predict conversion to psychosis in high-risk groups, reaching accuracy scores (generally ranging from 80 to 90%) that exceed clinical raters. Other potential applications for a language biomarker in schizophrenia are monitoring of side effects, differential diagnostics and relapse prevention.

SUMMARY

Language disturbances are a key feature of schizophrenia. Although in its early stages, the emerging field of research focused on computational linguistics suggests an important role for language analyses in the diagnosis and prognosis of schizophrenia. Spoken language as a biomarker for schizophrenia has important advantages because it can be objectively and reproducibly quantified. Furthermore, language analyses are low-cost, time efficient and noninvasive in nature.

The influence of semantic associations on sentence production in schizophrenia: an fMRI study

One of the most prominent symptoms of schizophrenia is thought disorder, which manifests itself in language production difficulties. In patients with thought disorders the associations are loosened and sentence production is impaired. The determining behavioral and neural mechanisms of sentence production are still an important subject of recent research and have not yet been fully understood. The aim of the current study was to examine the influence of associative relations and distractor modalities on sentence production in healthy participants and participants with schizophrenia. Therefore, reaction times and neural activation of 12 healthy subjects and 13 subjects with schizophrenia were compared in an adapted picture word interference paradigm (PWI). No significant group differences were found, neither on the behavioral nor on the neural level. On the behavioral level, for the entire group incremental sentence processing was found, i.e. processing of the second noun only starts after the first noun was processed. At the neural level, activation was discovered in the bilateral caudate nuclei and the cerebellum. Those activations could be related to response enhancement and suppression as well as to the modulation of cognitive processes.

Structural and functional alterations in the brain gray matter among first-degree relatives of schizophrenia patients: A multimodal meta-analysis of fMRI and VBM studies

OBJECTIVE

We conducted a multimodal coordinate-based meta-analysis (CBMA) to investigate structural and functional brain alterations in first-degree relatives of schizophrenia patients (FRs).

METHODS

We conducted a systematic literature search from electronic databases to find studies that examined differences between FRs and healthy controls using whole-brain functional magnetic resonance imaging (fMRI) or voxel-based morphometry (VBM). A CBMA of 30 fMRI (754 FRs; 959 controls) and 11 VBM (885 FRs; 775 controls) datasets were conducted using the anisotropic effect-size version of signed differential mapping. Further, we conducted separate meta-analyses about functional alterations in different cognitive tasks: social cognition, executive functioning, working memory, and inhibitory control.

RESULTS

FRs showed higher fMRI activation in the right frontal gyrus during cognitive tasks than healthy controls. In VBM studies, there were no differences in gray matter density between FRs and healthy controls. Furthermore, multi-modal meta-analysis obtained no differences between FRs and healthy controls. By utilizing the BrainMap database, we showed that the brain region which showed functional alterations in FRs (i) overlapped only slightly with the brain regions that were affected in the meta-analysis of schizophrenia patients and (ii) correlated positively with the brain regions that exhibited increased activity during cognitive tasks in healthy individuals.

CONCLUSIONS

Based on this meta-analysis, FRs may exhibit only minor functional alterations in the brain during cognitive tasks, and the alterations are much more restricted and only slightly overlapping with the regions that are affected in schizophrenia patients. The familial risk did not relate to structural alterations in the gray matter.

FOXP2 contributes to the cognitive impairment in chronic patients with schizophrenia

The forkhead-box P2 (FOXP2), involving in language and memory function, has been identified as susceptibility to schizophrenia. However, no study examined the role of FOXP2 on cognitive impairment in schizophrenia. Total 1106 inpatients with schizophrenia and 404 controls were recruited and genotyped. Among them, 867 patients and 402 controls were assessed through the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). SHEsis software was used to investigate the association of FOXP2 rs10447760 with schizophrenia, followed by logistic regression. The model of covariance (ANCOVA) and multivariate analysis were conducted to investigate the effect of FOXP2 rs10447760 on cognitive impairment in schizophrenia. No differences in the genotypic and allelic frequencies of the FOXP2 rs10447760 were found between patients and controls (both p> 0.05). Except for the visuospatial/constructional score (p > 0.05), other five RBANS scores were lower in patients compared to controls (all p < 0.0001). Interestingly, we found immediate memory score was lower in patients carrying genotype CT compared to genotype CC (F=5.19, p=0.02), adjusting for confounding data. Our study suggested that FOXP2 rs10447760 has no effect on the susceptibility to schizophrenia, while it may be associated with its cognitive impairment, especially immediate memory in chronic schizophrenia.

Altered topological characteristics of morphological brain network relate to language impairment in high genetic risk subjects and schizophrenia patients

OBJECTIVE

Evidence suggests relationships between abnormalities in various cortical and subcortical brain structures and language dysfunction in individuals with schizophrenia, and to some extent in those with increased genetic risk for this diagnosis. The topological features of the structural brain network at the systems-level and their impact on language function in schizophrenia and in those at high genetic risk has been less well studied.

METHOD

Single-subject morphological brain network was constructed in a total of 71 subjects (20 patients with schizophrenia, 19 individuals at high genetic risk for schizophrenia, and 32 controls). Among these 71 subjects, 56 were involved in our previous neuroimaging studies. Graphic Theoretical Techniques was applied to calculate the global and nodal topological characteristics of the morphological brain network of each participant. Index scores for five language-related cognitive tests were also attained from each participant.

RESULTS

Significantly smaller nodal degree in bilateral superior occipital gyri (SOG) were observed in individuals with schizophrenia, as compared to the controls and those at high risk; while significantly reduced nodal betweenness centrality (quantifying the level of a node in connecting other nodes in the network) in right middle frontal gyrus (MFG) was found in the high-risk group, relative to controls. The right MFG nodal efficiency and hub capacity (represented by both nodal degree and betweenness centrality) of the morphological brain network were negatively associated with the wide range achievement test (WRAT) standard performance score; while the right SOG nodal degree was positively associated with the WRAT standard performance score, in the entire study sample.

CONCLUSIONS

These findings enhance the understanding of structural brain abnormalities at the systems-level in individuals with schizophrenia and those at high genetic risk, which may serve as critical neural substrates for the origin of the language-related impairments and symptom manifestations of schizophrenia.

No association between FOXP2 rs10447760 and schizophrenia in a replication study of the Chinese Han population

BACKGROUND

Schizophrenia (SCZ) is a severe and heritable psychiatric disorder, and previous studies have shown that regulation of the forkhead-box P2 gene (FOXP2) may play a role in schizophrenia. Moreover, just a few studies have identified a single nucleotide polymorphism (SNP) rs10447760 within the gene that was a risk variant for SCZ in the Chinese Han population.

METHODS

To examine whether the variant in the FOXP2 gene contributes toward SCZ susceptibility, we carried out an association analysis of the SNP rs10447760 of the FOXP2 gene in a case-control study (1405 cases, 1137 controls) from China.

RESULTS

We identified no association of rs10447760 in the FOXP2 gene with SCZ (all P>0.05). In addition, a meta-analysis indicated that the SNP rs10447760 was not associated with susceptibility to SCZ in Han Chinese populations (pooled odds ratio=1.44, 95% confidence interval: 0.63-3.31, P=0.39).

CONCLUSION

Thus, our results did not support the association between FOXP2 rs10447760 and schizophrenia in a Chinese Han population, and large-scale genetic replication studies with different racial and geographic origins are required in the future.

Reading deficits in schizophrenia and their relationship to developmental dyslexia: A review

Although schizophrenia and developmental dyslexia are considered distinct disorders in terms of clinical presentation and functional outcome, they both involve disruption in the processes that support skilled reading, including language, auditory perception, visual perception, oculomotor control, and executive function. Further, recent work has proposed a common neurodevelopmental basis for the two disorders, as suggested by genetic and pathophysiological overlap. Thus, these lines of research suggest that reading may be similarly impacted in schizophrenia and dyslexia. In this review, we survey research on reading abilities in individuals with schizophrenia, and review the potential mechanisms underlying reading deficits in schizophrenia that may be shared with those implicated in dyslexia. Elucidating the relationship between reading impairment in schizophrenia and dyslexia could allow for a better understanding of the pathophysiological underpinnings of schizophrenia, and could facilitate remediation of cognitive deficits that impact day-to-day functioning.

Investigation of superior longitudinal fasciculus fiber complexity in recent onset psychosis

BACKGROUND

Standard diffusion tensor imaging measures (e.g., fractional anisotropy; FA) are difficult to interpret in brain regions with crossing white-matter (WM) fibers. Diffusion spectrum imaging (DSI) can be used to resolve fiber crossing, but has been difficult to implement in studies of patients with psychosis given long scan times.

METHODS

We used four fold accelerated compressed sensing to accelerate DSI acquisition to investigate the superior longitudinal fasciculus (SLF) in 27 (20M/7F) patients with recent onset psychosis and 23 (11M/12F) healthy volunteers. Dependent measures included the number of crossing fiber directions, multi directional anisotropy (MDA), which is a measure sensitive to the anisotropy of the underlying water diffusion in regions of crossing fibers, generalized FA (GFA) computed from the orientation distribution function, FA and tract volume.

RESULTS

Patients demonstrated a greater number of crossing WM fibers, lower MDA, GFA and FA in the left SLF compared to healthy volunteers. Patients also demonstrated a reversal in the normal (R>L) asymmetry of crossing fiber directions in the SLF and a lack of normal (L>R) asymmetry in MDA, GFA and FA compared to healthy volunteers. Lower GFA correlated significantly (p<0.05) with worse overall neuropsychological functioning; posthoc tests revealed significant effects with verbal functioning and processing speed.

CONCLUSIONS

Our findings provide the first in vivo evidence for abnormal crossing fibers within the SLF among individuals with psychosis and their functional correlates. A reversal in the normal pattern of WM asymmetry of crossing fibers in patients may be consistent with an aberrant neurodevelopmental process.

The Comprehension of Familiar and Novel Metaphoric Meanings in Schizophrenia: A Pilot Study

Miscomprehension of nonliteral (“figurative”) language like metaphors, proverbs, idioms, and ironic expressions by patients with schizophrenia is a phenomenon mentioned already in historical psychiatric descriptions. However, it was only recently that studies did differentiate between novel and conventional metaphors, a factor that is known to influence the difficulty of comprehension in healthy subjects. Further, familiarity with stimuli is an important factor for comprehension, which was not recommended in utmost previous studies. In this study, 23 patients with DSM IV schizophrenia and 19 healthy control subjects performed a newly-developed German metaphor comprehension test with three types of stimuli: novel metaphors, conventional German metaphors, and meaningless statements. During the test procedure, participants indicated familiarity with the stimulus and then matched the meaning with one out of four given alternatives. Familiarity rankings did not significantly differ between patients and control subjects. However, on descriptive level, there was a tendency for healthy controls to be more familiar with conventional metaphors than schizophrenic patients. Further, comprehension of conventional and novel metaphors differed significantly between the groups, with higher performance in healthy controls. Considering only those metaphors that had been ranked as familiar, patients only revealed significant lower performance opposed to controls regarding novel metaphors, while they did not differ in conventional metaphors. Taken together, the results indicate that patients with schizophrenia might show an altered way of comprehension in novel metaphors, leading to more misunderstandings. However, their previously reported impairments in conventional metaphors might rather be due to a lack of familiarity with the stimuli—making conventional metaphors to novel metaphors in the individual case.

Reduced language lateralization in first episode schizophrenia: A near infrared spectroscopy study

BACKGROUND

Diminished functional lateralization in language-related areas is found in chronic schizophrenia (SZ). However, whether this reduced lateralization exists at the early stage of SZ remains unclear. The present study aimed to investigate language lateralization in first episode schizophrenia (FES) using near infrared spectroscopy (NIRS) during a letter version of verbal fluency test (VFT).

METHODS

A total of 28 FES patients and 33 healthy controls (HCs) underwent NIRS while performing a VFT. Six regions of interests (ROIs) were defined: the bilateral frontal-, inferior frontal gyrus (IFG), and temporal regions. Laterality index (LI) was calculated and compared between the two groups in ROIs. In addition, we investigated whether language lateralization was correlated with severity of clinical symptoms.

RESULTS

Across all ROIs, LI was significantly reduced in FES patients (p=0.037) compared to controls in the IFG region. In addition, LI was not found to be correlated with VFT performance, the PANSS positive, negative or general psychopathology subscales.

CONCLUSIONS

Our study demonstrated a diminution of leftward functional lateralization in the IFG during a VFT in FES patients. This is the first NIRS study to report reduced functional lateralization in patients at the early stage of schizophrenia.

Brain anatomy of symptom stratification in schizophrenia: a voxel-based morphometry study

BACKGROUND

Although some Magnetic Resonance Imaging (MRI) studies have investigated the relationship between clinical severity and neuroanatomical alterations in patients with schizophrenia (SCZ), the biological signature associated with illness severity in schizophrenia is still uncertain. Therefore, this study aims to investigate structural brain abnormalities in SCZ, with particular regards to the identification of potential deficits associated with the severity of illness.

METHODS

In total, 1.5T MRI data were acquired for 61 subjects with SCZ and 59 matched healthy controls (HC). The patient group was divided in two sub-groups based on clinical severity, one composed of 34 mild-to-moderately ill patients, and the other of 27 severely ill patients, and compared with matched HC.

RESULTS

The whole group of patients with SCZ had significantly reduced grey matter (GM) volumes in the left inferior and middle temporal gyrus compared to HC (p < 0.05, pFWE corrected). Furthermore, compared to HC, patients with mild-to-moderate illness showed decreased GM volumes in the inferior and middle temporal gyrus, whereas those with severe illness had reduced GM volumes in the middle temporal gyrus and cerebellum bilaterally (all p < 0.001 uncorrected). No differences were observed between the two sub-groups of patients.

CONCLUSION

The results showed significant GM volume reductions in temporal regions in patients with SCZ compared to matched HC, confirming the role of these regions in the pathophysiology of SCZ. Furthermore, specific cerebellar grey matter volume reductions were identified in patients with severe illness, which may contribute to stratifying patients with SCZ according to their clinical phenotype expression, ultimately helping in guiding targeted therapeutic/rehabilitation interventions.

Can RDoC Help Find Order in Thought Disorder?

Thought disorder is a pernicious and nonspecific aspect of numerous serious mental illnesses (SMIs) and related conditions. Despite decades of empirical research on thought disorder, our present understanding of it is poor, our clinical assessments focus on a limited set of extreme behaviors, and treatments are palliative at best. Applying a Research Domain Criteria (RDoC) framework to thought disorder research offers advantages to explicate its phenotype; isolate its mechanisms; and develop more effective assessments, treatments, and potential cures. In this commentary, we discuss ways in which thought disorder can be understood within the RDoC framework. We propose operationalizing thought disorder within the RDoC construct of language using psycholinguistic sciences, to help objectify and quantify language within individuals; technologically sophisticated paradigms, to allow naturalistic behavioral sampling techniques with unprecedented ecological validity; and computational modeling, to account for a network of interconnected and dynamic linguistic, cognitive, affective, and social functions. We also highlight challenges for understanding thought disorder within an RDoC framework. Thought disorder likely does not occur as an isomorphic dysfunction in a single RDoC construct, but rather, as multiple potential dysfunctions in a network of RDoC constructs. Moreover, thought disorder is dynamic over time and context within individuals. In sum, RDoC is a useful framework to integrate multidisciplinary research efforts aimed at operationalizing, understanding, and ameliorating thought disorder.

Association between forkhead-box P2 gene polymorphism and clinical symptoms in chronic schizophrenia in a Chinese population

The forkhead-box P2 (FOXP2) gene polymorphism has been reported to be involved in the susceptibility to schizophrenia; however, few studies have investigated the association between FOXP2 gene polymorphism and clinical symptoms in schizophrenia. This study investigated whether the FOXP2 gene was associated with the development and symptoms of schizophrenia in relatively genetically homogeneous Chinese population. The FOXP2 rs10447760 polymorphism was genotyped in 1069 schizophrenia inpatients and 410 healthy controls using a case-control design. The patients' psychopathology was assessed by the Positive and Negative Syndrome Scale (PANSS). We found no significant differences in the genotype and allele distributions between the patient and control groups. Interestingly, we found significant differences in PANSS total, positive symptom, and general psychopathology scores between genotypic subgroups in patients, with the higher score in patients with CC genotype than those with CT genotype (all p < 0.05). After adjusting demographic and clinical variables, the difference still remained significant for the PANSS positive symptom score and general psychopathology (both p < 0.05). Our findings suggest that the FOXP2 rs10447760 polymorphism may not contribute to the development of schizophrenia, but may contribute to the clinical symptoms of schizophrenia among Han Chinese.

Abnormal interactions of verbal- and spatial-memory networks in young people at familial high-risk for schizophrenia

BACKGROUND

Working memory impairment (especially in verbal and spatial domains) is the core neurocognitive impairment in schizophrenia and the familial high-risk (FHR) population. Inconsistent results have been reported in clinical and neuroimaging studies examining the verbal- and spatial-memory deficits in the FHR subjects, due to sample differences and lack of understanding on interactions of the brain regions for processing verbal- and spatial-working memory.

METHODS

Functional MRI data acquired during a verbal- vs. spatial-memory task were included from 51 young adults [26 FHR and 25 controls]. Group comparisons were conducted in brain activation patterns responding to 1) verbal-memory condition (A), 2) spatial-memory condition (B), 3) verbal higher than spatial (A-B), 4) spatial higher than verbal (B-A), 5) conjunction of brain regions that were activated during both A and B (A∧B). Group difference of the laterality index (LI) in inferior frontal lobe for condition A was also assessed.

RESULTS

Compared to controls, the FHR group exhibited significantly decreased brain activity in left inferior frontal during A, and significantly stronger involvement of ACC, PCC, paracentral gyrus for the contrast of A-B. The LI showed a trend of reduced left-higher-than-right pattern for verbal-memory processing in the HR group.

CONCLUSIONS

Our findings suggest that in the entire functional brain network for working-memory processing, verbal information processing associated brain pathways are significantly altered in people at familial high risk for developing schizophrenia. Future studies will need to examine whether these alterations may indicate vulnerability for predicting the onset of Schizophrenia.

Distribution of Response Time, Cortical, and Cardiac Correlates during Emotional Interference in Persons with Subclinical Psychotic Symptoms

A psychosis phenotype can be observed below the threshold of clinical detection. The study aimed to investigate whether subclinical psychotic symptoms are associated with deficits in controlling emotional interference, and whether cortical brain and cardiac correlates of these deficits can be detected using functional near-infrared spectroscopy (fNIRS). A data set derived from a community sample was obtained from the Zurich Program for Sustainable Development of Mental Health Services. 174 subjects (mean age 29.67 ± 6.41, 91 females) were assigned to four groups ranging from low to high levels of subclinical psychotic symptoms (derived from the Symptom Checklist-90-R). Emotional interference was assessed using the emotional Stroop task comprising neutral, positive, and negative conditions. Statistical distributional methods based on delta plots [behavioral response time (RT) data] and quantile analysis (fNIRS data) were applied to evaluate the emotional interference effects. Results showed that both interference effects and disorder-specific (i.e., group-specific) effects could be detected, based on behavioral RTs, cortical hemodynamic signals (brain correlates), and heart rate variability (cardiac correlates). Subjects with high compared to low subclinical psychotic symptoms revealed significantly reduced amplitudes in dorsolateral prefrontal cortices (interference effect, p < 0.001) and middle temporal gyrus (disorder-specific group effect, p < 0.001), supported by behavioral and heart rate results. The present findings indicate that distributional analyses methods can support the detection of emotional interference effects in the emotional Stroop. The results suggested that subjects with high subclinical psychosis exhibit enhanced emotional interference effects. Based on these observations, subclinical psychosis may therefore prove to represent a valid extension of the clinical psychosis phenotype.

Contextual predictability enhances reading performance in patients with schizophrenia

In the present work we analyzed fixation duration in 40 healthy individuals and 18 patients with chronic, stable SZ during reading of regular sentences and proverbs. While they read, their eye movements were recorded. We used lineal mixed models to analyze fixation durations. The predictability of words N-1, N, and N+1 exerted a strong influence on controls and SZ patients. The influence of the predictabilities of preceding, current, and upcoming words on SZ was clearly reduced for proverbs in comparison to regular sentences. Both controls and SZ readers were able to use highly predictable fixated words for an easier reading. Our results suggest that SZ readers might compensate attentional and working memory deficiencies by using stored information of familiar texts for enhancing their reading performance. The predictabilities of words in proverbs serve as task-appropriate cues that are used by SZ readers. To the best of our knowledge, this is the first study using eyetracking for measuring how patients with SZ process well-defined words embedded in regular sentences and proverbs. Evaluation of the resulting changes in fixation durations might provide a useful tool for understanding how SZ patients could enhance their reading performance.

Language deficits in schizophrenia and autism as related oscillatory connectomopathies: An evolutionary account

Schizophrenia (SZ) and autism spectrum disorders (ASD) are characterised by marked language deficits, but it is not clear how these arise from gene mutations associated with the disorders. Our goal is to narrow the gap between SZ and ASD and, ultimately, give support to the view that they represent abnormal (but related) ontogenetic itineraries for the human faculty of language. We will focus on the distinctive oscillatory profiles of the SZ and ASD brains, in turn using these insights to refine our understanding of how the brain implements linguistic computations by exploring a novel model of linguistic feature-set composition. We will argue that brain rhythms constitute the best route to interpreting language deficits in both conditions and mapping them to neural dysfunction and risk alleles of the genes. Importantly, candidate genes for SZ and ASD are overrepresented among the gene sets believed to be important for language evolution. This translational effort may help develop an understanding of the aetiology of SZ and ASD and their high prevalence among modern populations.

Word processing during reading sentences in patients with schizophrenia: evidences from the eyetracking technique

PURPOSE

The current study analyze the effect of word properties (i.e., word length, word frequency and word predictability) on the eye movement behavior of patients with schizophrenia (SZ) compared to age-matched controls.

METHOD

18 SZ patients and 40 age matched controls participated in the study. Eye movements were recorded during reading regular sentences by using the eyetracking technique. Eye movement analyses were performed using linear mixed models.

FINDINGS

Analysis of eye movements revealed that patients with SZ decreased the amount of single fixations, increased their total number of second pass fixations compared with healthy individuals (Controls). In addition, SZ patients showed an increase in gaze duration, compared to Controls. Interestingly, the effects of current word frequency and current word length processing were similar in Controls and SZ patients. The high rate of second pass fixations and its low rate in single fixation might reveal impairments in working memory when integrating neighbor words. In contrast, word frequency and length processing might require less complex mechanisms, which were functioning in SZ patients.

CONCLUSION

To the best of our knowledge, this is the first study measuring how patients with SZ process dynamically well-defined words embedded in regular sentences. The findings suggest that evaluation of the resulting changes in eye movement behavior may supplement current symptom-based diagnosis.

Dimensional approaches to schizophrenia: A comparison of the Bern Psychopathology scale and the five-factor model of the Positive and Negative Syndrome Scale

The aim was to examine to what extent the dimensions of the BPS map the five factors derived from the PANSS in order to explore the level of agreement of these alternative dimensional approaches in patients with schizophrenia. 149 inpatients with schizophrenia spectrum disorders were recruited. Psychopathological symptoms were assessed with the Bern Psychopathology Scale (BPS) and the Positive and Negative Syndrome Scale (PANSS). Linear regression analyses were conducted to explore the association between the factors and the items of the BPS. The robustness of patterns was evaluated. An understandable overlap of both approaches was found for positive and negative symptoms and excitement. The PANSS positive factor was associated with symptoms of the affect domain in terms of both inhibition and disinhibition, the PANSS negative factor with symptoms of all three domains of the BPS as an inhibition and the PANSS excitement factor with an inhibition of the affect domain and a disinhibition of the language and motor domains. The results show that here is only a partial overlap between the system-specific approach of the BPS and the five-factor PANSS model. A longitudinal assessment of psychopathological symptoms would therefore be of interest.

Association between impaired brain activity and volume at the sub-region of Broca's area in ultra-high risk and first-episode schizophrenia: A multi-modal neuroimaging study

Recent studies have suggested that functional abnormalities in Broca's area, which is important in language production (speech and thoughts before speech), play an important role in the pathophysiology of schizophrenia. While multi-modal approaches have proved useful in revealing the specific pathophysiology of psychosis, the association of functional abnormalities with gray matter volume (GMV) here in subjects with an ultra-high risk (UHR) of schizophrenia, those with first-episode schizophrenia (FES), and healthy controls has yet to be clarified. Therefore, the relationship between cortical activity measured using functional near-infrared spectroscopy (fNIRS) during a verbal fluency task, and GMV in the Broca's area assessed using a manual tracing in magnetic resonance imaging (MRI), which considers individual structural variation, was examined for 57 subjects (23 UHR/18 FES/16 controls). The UHR and FES group showed significantly reduced brain activity compared to control group in the left pars triangularis (PT) (P=.036, .003, respectively). Furthermore in the FES group, the reduced brain activity significantly positively correlated with the volume in the left PT (B=0.29, P=.027), while significant negative association was evident for all subjects (B=-0.18, P=.010). This correlation remained significant after adjusting for antipsychotics dosage, and voxel-wise analysis could not detect any significant correlation between impaired cortical activity and volume. The significant relationship between neural activity and GMV in the left PT may reflect a specific pathophysiology related to the onset of schizophrenia.

You looking at me?: Interpreting social cues in schizophrenia

BACKGROUND

Deficits in the perception of social cues are common in schizophrenia and predict functional outcome. While effective communication depends on deciphering both verbal and non-verbal features, work on non-verbal communication in the disorder is scarce.

METHOD

This behavioural study of 29 individuals with schizophrenia and 25 demographically matched controls used silent video-clips to examine gestural identification, its contextual modulation and related metacognitive representations.

RESULTS

In accord with our principal hypothesis, we observed that individuals with schizophrenia exhibited a preserved ability to identify archetypal gestures and did not differentially infer communicative intent from incidental movements. However, patients were more likely than controls to perceive gestures as self-referential when confirmatory evidence was ambiguous. Furthermore, the severity of their current hallucinatory experience inversely predicted their confidence ratings associated with these self-referential judgements.

CONCLUSIONS

These findings suggest a deficit in the contextual refinement of social-cue processing in schizophrenia that is potentially attributable to impaired monitoring of a mirror mechanism underlying intentional judgements, or to an incomplete semantic representation of gestural actions. Non-verbal communication may be improved in patients through psychotherapeutic interventions that include performance and perception of gestures in group interactions.

Psychopathological Symptoms Assessed by a System-Specific Approach Are Related to Global Functioning in Schizophrenic Disorders

BACKGROUND

By mostly using a positive-negative approach, several studies have identified factors that influence day-to-day functioning. We applied a different, system-specific approach to expand the knowledge of this issue.

SAMPLING AND METHODS

We recruited a sample of 100 inpatients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder. Psychopathological characteristics were assessed with the Bern Psychopathology Scale (BPS) and functional characteristics with the Global Assessment of Functioning (GAF) scale. Linear regression analyses were performed with the GAF score as the dependent variable and the global values of the BPS subscores as independent variables. The model was controlled for confounding variables. Spearman rank correlation analyses were used to identify associations between the relevant BPS subdomains and global functioning.

RESULTS

Higher absolute global values of the BPS domains language (px2009; = x2009;0.038) and motor behavior (px2009; = x2009;0.049) were significantly associated with lower GAF scores. These findings remained stable after adjusting for potential confounding variables. A statistically significant negative correlation was found between both qualitative symptoms (rx2009; = x2009;-0.273, px2009; = x2009;0.006) and indirect signs (rx2009; = x2009;-0.269, px2009; = x2009;0.007) of the language domain and GAF scores. Also, quantitative (rx2009; = x2009;-0.211, px2009; = x2009;0.035) and qualitative symptoms (rx2009; = x2009;-0.214, px2009; = x2009;0.033) in the motor behavior domain were associated with poorer functioning.

CONCLUSIONS

A system-specific approach can describe subgroups of patients with poor functioning. Identifying such subgroups could help to utilize targeted treatment opinions in a timely manner. Another goal of future research is to clarify the underlying neurobiological deficits.

Task-independent effects are potential confounders in longitudinal imaging studies of learning in schizophrenia

Learning impairment is a core deficit in schizophrenia that impacts on real-world functioning and yet, elucidating its underlying neural basis remains a challenge. A key issue when interpreting learning-task experiments is that task-independent changes may confound interpretation of task-related signal changes in neuroimaging studies. The nature of these task-independent changes in schizophrenia is unknown. Therefore, we examined task-independent “time effects” in a group of participants with schizophrenia contrasted with healthy participants in a longitudinal fMRI learning-experiment designed to allow for examination of non-specific effects of time. Flanking the learning portions of the experiment with a task-of-no-interest allowed us to extract task-independent BOLD changes. Task-independent effects occurred in both groups, but were more robust in the schizophrenia group. There was a significant interaction effect between group and time in a distributed activity pattern that included inferior and superior temporal regions, frontal areas (left anterior insula and superior medial gyri), and parietal areas (posterior cingulate cortices and precuneus). This pattern showed task-independent linear decrease in BOLD amplitude over the two scanning sessions for the schizophrenia group, but showed either opposite effect or no activity changes for the control group. There was a trend towards a correlation between task-independent effects and the presence of more negative symptoms in the schizophrenia group.

The strong interaction between group and time suggests that both the scanning experience as a whole and the transition between task-types evokes a different response in persons with schizophrenia and may confound interpretation of learning-related longitudinal imaging experiments if not explicitly considered.

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A robust method was used to identify task-independent fMRI BOLD changes in a multiday learning experiment in schizophrenia

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Task-independent effects were apparent in healthy control group and schizophrenia but differed in direction and magnitude

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In schizophrenia they were greater in magnitude and most prominent in areas of the salience and default mode networks

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Unless properly accounted for, these effects will compromise precise interpretation of fMRI learning data in schizophrenia.

Neural activity changes in unaffected children of patients with schizophrenia: A resting-state fMRI study

Previous neuroimaging studies have suggested that individuals at risk for schizophrenia exhibit structural and functional brain abnormalities. However, few studies focus on resting state baseline activity in individuals with genetic high-risk for schizophrenia (HR). We examined cerebral spontaneous neural activity in HR by measuring the amplitude of low frequency fluctuations (ALFF) in the blood oxygen level-dependent (BOLD) functional magnetic resonance signal during resting state. Using a 3T MRI scanner, 28 non-psychotic young adult participants with at least one parent with schizophrenia and 44 matched unrelated healthy comparison subjects (HC) were scanned during the resting-state. The ALFF of the BOLD signal for each participant was calculated, and these values were then compared between-groups using voxel-based analysis of the ALFF maps. The HR group showed significantly increased ALFF compared to the HC group in the striatum, including the left caudate nucleus extending to the putamen and the right caudate nucleus. There was also increased ALFF in HR relative to controls in the left medial temporal region including hippocampus, parahippocampal gyrus and the fusiform gyrus, as well as regions including the left lateral thalamus, bilateral ventral and dorsal anterior cingulate cortex, bilateral calcarine sulcus and precuneus. There was significantly decreased ALFF in the HR group relative to controls in the left inferior parietal lobule/postcentral gyrus. Our findings suggest that altered intrinsic neuronal activity in cortico-striato-thalamic networks may represent genetic vulnerability for the development of schizophrenia.

Dysfunctional resting-state connectivities of brain regions with structural deficits in drug-naive first-episode schizophrenia adolescents

OBJECTIVE

Individuals with adolescent-onset schizophrenia (AOS) are a subgroup of patients who present clinical symptoms between 13 and 18years of age. Little is known about neurodevelopmental abnormalities in this patient population. The present study was to examine possible resting-state dysfunctional connectivity of brain regions with altered gray matter volume in AOS.

METHODS

Gray matter volume was investigated by voxel-based morphometry (VBM) analysis. Resting-state functional connectivity analysis was used to examine the correlations between regions with structural deficits and the remaining regions.

RESULTS

Thirty-seven first-episode schizophrenia adolescents and 30 healthy controls were enrolled. Compared to the controls, the patients showed significantly decreased gray matter volumes in the right superior temporal gyrus (STG) and middle temporal gyrus (MTG) (ps<0.05). With the right STG as seed, significantly reduced connectivities were found within the frontal-temporal networks in the patient group (ps<0.05). With the right MTG as seed, the patient group showed significantly reduced connectivities in the default-mode networks and visual networks (ps<0.05). Compared to significant correlations in the controls (p=0.02), the patients had no observed correlations between functional connectivity of the right STG and gray matter volume of this region. Significant positive correlations were found between functional connectivity of the right STG with the left middle frontal gyrus and the Positive and Negative Syndrome Scale total scores (p=0.048) after controlling the confounding variables.

CONCLUSIONS

These findings show dysfunctional resting-state connectivities of the right STG and MTG with decreased gray matter volume in adolescents with AOS, suggesting that neurodevelopmental abnormalities may be present in AOS.

A possible contributory mechanism for impaired idiom perception in schizophrenia

In this review, we focus on the ability of people with schizophrenia to correctly perceive the meaning of idioms; figurative language expressions in which intended meaning is not derived from the meaning of constituent words. We collate evidence on how idiom perception is impaired, ascertain the clinical relevance of this impairment, and consider possible psychological and neural mechanisms behind the impairment. In reviewing extant literature, we searched the PubMed database, from 1975-2014, focussing on articles that directly concerned schizophrenia and idioms, with follow up searches to explore the viability of possible underlying mechanisms. We learn that there is clear evidence of impairment, with a tendency to err towards literal interpretations unless the figurative meaning is salient, and despite contextual cues to figurative interpretations. Given the importance of idioms in everyday language, the potential impact is significant. Clinically, impaired idiom perception primarily relates to positive symptoms of schizophrenia, but also to negative symptoms. The origins of the impairment remain speculation, with impaired executive function, impaired semantic functions, and impaired context processing all proposed to explain the phenomenon. We conclude that a possible contributory mechanism at the neural level is an impaired dorsolateral prefrontal cortex system for cognitive control over semantic processing.

Factor structure of the Bern Psychopathology Scale in a sample of patients with schizophrenia spectrum disorders

BACKGROUND

The Bern Psychopathology Scale (BPS) is based on a system-specific approach to classifying the psychopathological symptom pattern of schizophrenia. It consists of subscales for three domains (language, affect and motor behaviour) that are hypothesized to be related to specific brain circuits. The aim of the study was to examine the factor structure of the BPS in patients with schizophrenia spectrum disorders.

METHODS

One hundred and forty-nine inpatients with schizophrenia spectrum disorders were recruited at the Department of Psychiatry II, Ulm University, Germany (n=100) and at the University Hospital of Psychiatry, Bern, Switzerland (n=49). Psychopathology was assessed with the BPS. The VARCLUS procedure of SAS(®) (a type of oblique component analysis) was used for statistical analysis.

RESULTS

Six clusters were identified (inhibited language, inhibited motor behaviour, inhibited affect, disinhibited affect, disinhibited language/motor behaviour, inhibited language/motor behaviour) which explained 40.13% of the total variance of the data. A binary division of attributes into an inhibited and disinhibited cluster was appropriate, although an overlap was found between the language and motor behaviour domains. There was a clear distinction between qualitative and quantitative symptoms.

CONCLUSIONS

The results argue for the validity of the BPS in identifying subsyndromes of schizophrenia spectrum disorders according to a dimensional approach. Future research should address the longitudinal assessment of dimensional psychopathological symptoms and elucidate the underlying neurobiological processes.

Reduced functional connectivity during controlled semantic integration in schizophrenia: A multivariate approach

Impairment in controlled semantic association is a central feature of schizophrenia, and the goal of the current functional magnetic resonance imaging study was to identify the neural correlates of this impairment. Thirty people with schizophrenia and 30 healthy age- and gender-matched control subjects performed a task requiring participants to match word pairs that varied in semantic distance (distant vs. close). A whole-brain multivariate connectivity analysis revealed three functional brain networks of primary interest engaged by the task: two configurations of a multiple demands network, in which brain activity did not differ between groups, and a semantic integration network, in which coordinated activity was reduced in schizophrenia patients relative to healthy controls, for distantly relative to closely related word pairs. The hypoactivity during controlled semantic integration in schizophrenia reported here, combined with hyperactivity in automatic semantic association reported in the literature, suggests an imbalance between controlled integration and automatic association. This provides a biological basis for Bleuler's concept of schizophrenia as a "split mind" arising from an impaired ability to form coherent associations between semantic concepts.