Schneiderian first rank symptoms and inferior parietal lobule cortical thickness in antipsychotic-naïve schizophrenia

Resting-State Brain Activity Dysfunctions in Schizophrenia and Their Associations with Negative Symptom Domains: An fMRI Study

The aim of the present study was to examine the neurobiological correlates of the two negative symptom domains of schizophrenia, the Motivational Deficit domain (including avolition, anhedonia, and asociality) and the Expressive Deficit domain (including blunted affect and alogia), focusing on brain areas that are most commonly found to be associated with negative symptoms in previous literature. Resting-state (rs) fMRI data were analyzed in 62 subjects affected by schizophrenia (SZs) and 46 healthy controls (HCs). The SZs, compared to the HCs, showed higher rs brain activity in the right inferior parietal lobule and the right temporoparietal junction, and lower rs brain activity in the right dorsolateral prefrontal cortex, the bilateral anterior dorsal cingulate cortex, and the ventral and dorsal caudate. Furthermore, in the SZs, the rs brain activity in the left orbitofrontal cortex correlated with negative symptoms (r = -0.436, p = 0.006), in particular with the Motivational Deficit domain (r = -0.424, p = 0.002), even after controlling for confounding factors. The left ventral caudate correlated with negative symptoms (r = -0.407, p = 0.003), especially with the Expressive Deficit domain (r = -0.401, p = 0.003); however, these results seemed to be affected by confounding factors. In line with the literature, our results demonstrated that the two negative symptom domains might be underpinned by different neurobiological mechanisms.

The Static and dynamic functional connectivity characteristics of the left temporoparietal junction region in schizophrenia patients with auditory verbal hallucinations during low-frequency rTMS treatment

BACKGROUND

Auditory verbal hallucinations (AVH) are a core symptom of schizophrenia. Low-frequency (e.g., 1 Hz) repetitive transcranial magnetic stimulation (rTMS) targeting language processing regions (e.g., left TPJ) has been evident as a potential treatment for AVH. However, the underlying neural mechanisms of the rTMS treatment effect remain unclear. The present study aimed to investigate the effects of 1 Hz rTMS on functional connectivity (FC) of the temporoparietal junction area (TPJ) seed with the whole brain in schizophrenia patients with AVH.

METHODS

Using a single-blind placebo-controlled randomized clinical trial, 55 patients with AVH were randomly divided into active treatment group (n = 30) or placebo group (n = 25). The active treatment group receive 15-day 1 Hz rTMS stimulation to the left TPJ, whereas the placebo group received sham rTMS stimulation to the same site. Resting-state fMRI scans and clinical measures were acquired for all patients before and after treatment. The seed-based (left TPJ) static and DFC was used to assess the connectivity characteristics during rTMS treatment in patients with AVH.

RESULTS

Overall, symptom improvement following 1 Hz rTMS treatment was found in the active treatment group, whereas no change occurred in the placebo group. Moreover, decreased static FC (SFC) of the left TPJ with the right temporal lobes, as well as increased SFC with the prefrontal cortex and subcortical structure were observed in active rTMS group. Increased dynamic FC (DFC) of the left TPJ with frontoparietal areas was also found in the active rTMS group. However, seed-based SFC and DFC were reduced to a great extent in the placebo group. In addition, these changed FC (SFC) strengths in the active rTMS group were associated with reduced severity of clinical outcomes (e.g., positive symptoms).

CONCLUSION

The application of 1 Hz rTMS over the left TPJ may affect connectivity characteristics of the targeted region and contribute to clinical improvement, which shed light on the therapeutic effect of rTMS on schizophrenia with AVH.

Pars Triangularis Volume Asymmetry and Schneiderian First Rank Symptoms in Antipsychotic-naïve Schizophrenia

Objective

Schizophrenia is a disorder of language and self, with first-rank symptoms (FRS) as one of the predominant features in a subset of patients. Abnormal language lateralization is hypothesized to underlie the neurobiology of FRS in schizophrenia. The role of Broca's area with its right-hemispheric counterpart, consisting of pars triangularis (PTr) and pars opercularis (POp) of the inferior frontal gyrus in FRS is undetermined. We compared the volumes and asymmetries of PTr & POp in anti-psychotic-naive schizophrenia patients with FRS (FRS[＋]) with those without FRS (FRS[-]) and healthy-controls (HC) using three dimensional, interactive, semi-automated volumetric morphometry.

Methods

Antipsychotic naïve FRS(＋) (n = 27), FRS(-) (n = 24) and HC (n = 51) were carefully assessed with structured and semi-structured clinical tools. T1-weighted images were acquired in a 3T scanner. Volumes of regions of interest were measured independently for both sides using slicer-3D software, and asymmetry indices were calculated.

Results

FRS(＋) but not FRS(-) had a significant volume deficit in right PTr after controlling for the potential confounding effects of age, sex, and intracranial volume (p = 0.029). There was a significant leftward asymmetry of PTr in patients with FRS (i.e., leftward asymmetry in patients) (p = 0.026). No significant volume/asymmetry abnormalities were observed in POp.

Conclusion

Study findings suggest reduced right PTr volume with leftward asymmetry to be associated with FRS in schizophrenia. This is consistent with the loss of Yakovlevian torque in schizophrenia. Role of PTr in the neurobiology of schizophrenia as a disorder of self, speech, and social cognition needs further systematic evaluation in future research.

Assessment of spontaneous brain activity patterns in patients with iridocyclitis: a resting-state study

Several studies demonstrated that patients with iridocyclitis were associated with vision loss and cognitive decline, whereas alterations in spontaneous brain activity occur in iridocyclitis patients remains unknown. The study aimed to explore spontaneous brain activity changes in iridocyclitis patients. Twenty-six patients with iridocyclitis and 26 healthy controls were finally included in our study. Resting-state MRI (rs-MRI) scan was conducted on both groups and the whole brain amplitude of low-frequency fluctuations (ALFFs) value was collected to assess differences in spontaneous brain activity. A receiver operating characteristic (ROC) curve was analyzed to distinguish between the fMRI data of patients with iridocyclitis and healthy controls. Patients with iridocyclitis showed significantly lower ALFF values in the right inferior parietal lobule, right calcarine, right superior temporal gyrus and right precentral gyrus compared to healthy controls and significantly higher ALFF values in the left superior frontal gyrus (P < 0.01, false discovery rate correction). The ROC curve analysis of different brain areas showed that the accuracies of ALFF value specificity between the iridocyclitis and healthy controls of the area under the curve were over 0.8. Our study highlighted an altered spontaneous activity in multiple brain regions, including the visual cortex, default-mode network, auditory area and sensorimotor areas in iridocyclitis. This may provide valuable information about underlying pathogenic mechanisms of iridocyclitis. These findings also indicate that rs-fMRI serves as a potential tool in the disease detection and evaluation of neurologic impairment in iridocyclitis.

Neuroimaging signatures of brain plasticity in adults with prenatal exposure to polychlorinated biphenyls: Altered functional connectivity on functional MRI

Prenatal exposure to polychlorinated biphenyls (PCBs), persistent organic pollutants in food chains and environment, exerts negative effects on children's cognitive function. To study the long-term effects, we examined cognitive functions in the male children of women with substantial PCB exposure in Taiwan during 1978-1979 and investigated neural basis of cognitive function changes through structural magnetic resonance imaging (MRI) and functional MRI (fMRI), which included resting-state and task-activated fMRI with two paradigms: a 2-back task and a picture rotation task. Ten men aged 30.0 ± 3.7 years with prenatal exposure to PCBs and 11 unexposed controls aged 28.1 ± 3.1 years participated. Both groups had similar cognitive phenotypes and behavioral results. Structural MRI analysis results showed that the PCB group had increased cortical thickness over the right inferior parietal lobule. In the resting-state study, the PCB group showed alterations in the default mode network. During the tasks, the PCB group showed decreased task-induced deactivation signals in cognition-associated brain areas during the 2-back task but enhanced deactivations during the picture rotation task. This study demonstrated altered structural MRI as well as resting and task-related fMRI in men with prenatal PCB exposure, suggesting altered brain plasticity and compensatory neuropsychological performance.

[Psychological assessment of visual hemispatial neglect: standardization and approbation of the modified digit cancellation test]

AIM

To study the phenomena of visual-hemispatial neglect in healthy people and patients with brain diseases of different genesis.

MATERIAL AND METHODS

Eighty-eight patients with schizophrenia spectrum disorders, 68 patients with exogenous organic brain diseases and 240 healthy adults of different age were included in the study. The digit cancellation test modified by the authors was used.

RESULTS AND CONCLUSION

The validity of the modified digit cancellation test was approved and its age standards were obtained. In healthy right-handed people, there was the bias of attention focus to the left, the decrease of asymmetry intensity of visual-spatial inattention during physiological aging and the presence of some clinical peculiarities of neglect in schizophrenia spectrum disorders and lateralized organic damages of the brain. This variant of the test can be recommended for practical use as the sensitive psychometric tool.

Dysfunction of Magnocellular/dorsal Processing Stream in Schizophrenia

Background:

Patients with schizophrenia show not only cognitive, but also perceptual deficits. Perceptual deficits may affect different sensory modalities. Among these, the impairment of visual information processing is of particular relevance as demonstrated by the high incidence of visual disturbances. In recent years, the study of neurophysiological mechanisms that underlie visuo-perceptual, -spatial and -motor disorders in schizophrenia has increasingly attracted the interest of researchers.

Objective:

The study aims to review the existent literature on magnocellular/dorsal (occipitoparietal) visual processing stream impairment in schizophrenia. The impairment of relatively early stages of visual information processing was examined using experimental paradigms such as backward masking, contrast sensitivity, contour detection, and perceptual closure. The deficits of late processing stages were detected by examining visuo-spatial and -motor abilities.

Results:

Neurophysiological and behavioral studies support the existence of deficits in the processing of visual information along the magnocellular/dorsal pathway. These deficits appear to affect both early and late stages of visual information processing.

Conclusion:

The existence of disturbances in the early processing of visual information along the magnocellular/dorsal pathway is strongly supported by neurophysiological and behavioral observations. Early magnocellular dysfunction may provide a substrate for late dorsal processing impairment as well as higher-level cognition deficits.

Increasing the Difference in Decision Making for Oneself and for Others by Stimulating the Right Temporoparietal Junction

The right temporoparietal junction (rTPJ) has been thought to be associated with the difference in self-other decision making. In the present study, using noninvasive transcranial direct current stimulation (tDCS), we examined whether stimulating the rTPJ could modulate the self-other decision-making difference. We found that after receiving anodal stimulation of the rTPJ, participants were more likely to choose a high-value item for others than for themselves in the situations where the win probability of the high-value item was equal to or greater than that of a low-value item, indicating that elevating the cortical excitability of the rTPJ might increase the self-other decision-making difference in certain decision contexts. Our results suggest that decision making for others depends on neural activity in the rTPJ and regulation of the excitability of the rTPJ can influence the self-other decision-making difference.

Safety and Efficacy of Adjunctive Θ Burst Repetitive Transcranial Magnetic Stimulation to Right Inferior Parietal Lobule in Schizophrenia Patients With First-Rank Symptoms: A Pilot, Exploratory Study

BACKGROUND

First-rank symptoms (FRS) in schizophrenia have been found to be associated with various cognitive and biological markers. Repetitive transcranial magnetic stimulation (rTMS) has been shown to modulate such factors. We hypothesized that rTMS adjunctive to antipsychotics will be safe and effective in treatment of FRS in schizophrenia.

METHODS

Schizophrenia patients with FRS randomly received either active or sham-magnetic resonance imaging navigated continuous Θ burst stimulation (cTBS)-rTMS to right inferior parietal lobule for 2 weeks; assessments were repeated. While primary outcome variables were safety profile, FRS and overall psychopathology; secondary outcomes were γ oscillatory activity, brain-derived neurotrophic factor levels, and self-monitoring function.

RESULTS

No significant adverse events were reported in either group. None of the outcome measures showed sufficient power on the time by group analysis.

CONCLUSIONS

This study fails to demonstrate whether or not adjunctive cTBS to right inferior parietal lobule could significantly alleviate FRS. We also fail to provide evidence for whether this protocol has any effect on brain-derived neurotrophic factor levels, self-monitoring function, and right hemispheric γ oscillations.

Schneiderian first rank symptoms in schizophrenia: A developmental neuroscience evaluation

INTRODUCTION

Self disorders in schizophrenia have been suggested to have distinct neurobiological underpinnings. Using comprehensive neuro-scientific assessments including a neurophysiological, a neurochemical and a neuropsychological marker, this study assesses disordered-"self" in schizophrenia.

METHODS

Twenty schizophrenia patients with first rank symptoms (FRS;FRS+), 20 patients without FRS (FRS-) and 20 healthy controls (HC) were assessed for psychopathology, especially on specially designed FRS score sheets with a narrow and a broad definition. Resting state electroencephalography was acquired using 256-electrodes; gamma spectral-power was measured in 8 regions of interest. Serum BDNF and self-monitoring were also assessed. Comparative and correlation analysis were conducted in addition to a step-wise discriminant function analysis.

RESULTS

FRS+ group with greater positive symptom score and a lower negative symptom score, showed significantly increased gamma spectral power, especially on right hemispheric regions, along with lower BDNF levels and lower scores on self-monitoring compared to FRS- and HC. Serum BDNF levels and gamma spectral power in the region corresponding right inferior parietal lobule were identified as predictors that most accurately classified the defined groups.

CONCLUSIONS

Schizophrenia patients satisfying the criteria of presence of first rank symptoms represent a distinct neurodevelopmental subgroup with associated features of predominantly positive symptoms, significantly lower neurotrophin levels, aberrant resting state brain activity in the heteromodal association cortex and performing poorer on self-monitoring tasks.

A Neuropsychological Approach to Auditory Verbal Hallucinations and Thought Insertion - Grounded in Normal Voice Perception

A neuropsychological perspective on auditory verbal hallucinations (AVH) links key phenomenological features of the experience, such as voice location and identity, to functionally separable pathways in normal human audition. Although this auditory processing stream (APS) framework has proven valuable for integrating research on phenomenology with cognitive and neural accounts of hallucinatory experiences, it has not yet been applied to other symptoms presumed to be closely related to AVH – such as thought insertion (TI). In this paper, I propose that an APS framework offers a useful way of thinking about the experience of TI as well as AVH, providing a common conceptual framework for both. I argue that previous self-monitoring theories struggle to account for both the differences and similarities in the characteristic features of AVH and TI, which can be readily accommodated within an APS framework. Furthermore, the APS framework can be integrated with predictive processing accounts of psychotic symptoms; makes predictions about potential sites of prediction error signals; and may offer a template for understanding a range of other symptoms beyond AVH and TI.

Childhood trauma and childhood urbanicity in relation to psychotic disorder

BACKGROUND

Urban upbringing and childhood trauma are both associated with psychotic disorders. However, the association between childhood urbanicity and childhood trauma in psychosis is poorly understood. The urban environment could occasion a background of social adversity against which any effect of childhood trauma increases. Also, any impact of the urban environment on likelihood of exposure to childhood trauma could be stronger in children who later develop psychotic disorder. The aim of this study was twofold: (1) to investigate whether childhood urbanicity moderates the effect of childhood trauma, in a model predicting psychotic disorder; (2) to investigate whether there is an association between the urban environment and childhood trauma and whether this is moderated by genetic liability for psychotic disorder.

METHODS

Patients with a diagnosis of non-affective psychotic disorder (n = 1119) and 589 healthy controls from the Netherlands and Belgium were studied. Childhood trauma was assessed with the Dutch version of the Childhood Trauma Questionnaire Short Form. Urban exposure was defined at four levels, considering the population density, using data from Statistics Netherlands and the equivalent database in Belgium.

RESULTS

There was a significant interaction between childhood urbanicity on the one hand and childhood trauma on the other, indicating that trauma was significantly associated with psychotic disorder, with increasing odds ratios for higher levels of childhood urbanicity. In addition, there was weak evidence that childhood urbanicity was associated with childhood trauma in the patient group: higher levels of childhood urbanicity were associated with higher trauma scores.

CONCLUSION

The urban environment may moderate the risk-increasing effect of childhood trauma for psychotic disorder and childhood urbanicity may be a risk factor for childhood trauma in individuals who later develop psychotic disorder.

Mirror neuron dysfunction and ego-boundary disturbances in schizophrenia: a transcranial magnetic stimulation study

BACKGROUND

Ego-boundary disturbance (EBD) is a unique symptom cluster characterized by passivity experiences (involving thoughts, actions, emotions and sensations) attributed by patients to some external agency. The neurobiology of these "first rank" symptoms is poorly understood. Aberrant mirror neuron activation may explain impaired self-monitoring and agency attribution underlying these symptoms. We aim to study mirror neuron activity (MNA) in schizophrenia patients with and without EBD using transcranial magnetic stimulation (TMS).

MATERIALS AND METHODS

50 right-handed schizophrenia patients (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) were evaluated using the Mini-International Neuropsychiatric Interview and the Positive and Negative Syndrome Scale. They completed a TMS experiment to assess putative premotor MNA. Motor evoked potential (MEP) was recorded in the right first dorsal interosseous muscle (FDI) with (a) 120% of resting motor threshold (RMT), (b) stimulus intensity set to evoke MEP of motor threshold 1 mV amplitude (MT1), (c) two paired pulse paradigms (short- and long interval intra-cortical inhibition). These were done in three states: Actual observation of an action using the FDI, virtual-observation (video) of this action and resting state. The percent change of MEP from resting to action-observation states formed the measure of putative MNA.

RESULTS

MNA measured using MT1 and 120% RMT paradigms was significantly lower in the 18 patients with EBD (thought-broadcast/withdrawal/insertion, made-act/impulse/affect and somatic passivity) than the 32 patients without EBD (t = 2.431, P = 0.020; t = 2.051, P = 0.04 respectively for the two paradigms). The two groups did not differ on age, gender, education and total symptom scores.

CONCLUSION

Schizophrenia patients with EBD have lower premotor MNA. This highlights the role of MNA dysfunction in the pathophysiology of this unique and intriguing symptom cluster in schizophrenia.

Psychotic disorder and educational achievement: a family-based analysis

BACKGROUND

Early social and cognitive alterations in psychotic disorder, associated with familial liability and environmental exposures, may contribute to lower than expected educational achievement. The aims of the present study were to investigate (1) how differences in educational level between parents and their children vary across patients, their healthy siblings, and healthy controls (effect familial liability), and across two environmental risk factors for psychotic disorder: childhood trauma and childhood urban exposure (effect environment) and (2) to what degree the association between familial liability and educational differential was moderated by the environmental exposures.

METHODS

Patients with a diagnosis of non-affective psychotic disorder (n = 629), 552 non-psychotic siblings and 326 healthy controls from the Netherlands and Belgium were studied. Participants reported their highest level of education and that of their parents. Childhood trauma was assessed with the Dutch version of the Childhood Trauma Questionnaire-Short Form. Urban exposure, expressed as population density, was rated across five levels.

RESULTS

Overall, participants had a higher level of education than their parents. This difference was significantly reduced in the patient group, and the healthy siblings displayed intergenerational differences that were in between those of controls and patients. Higher levels of childhood urban exposure were also associated with a smaller intergenerational educational differential. There was no evidence for differential sensitivity to childhood trauma and childhood urbanicity across the three groups.

CONCLUSION

Intergenerational difference in educational achievements is decreased in patients with psychotic disorder and to a lesser extent in siblings of patients with psychotic disorder, and across higher levels of childhood urban exposure. More research is required to better understand the dynamics between early social and cognitive alterations in those at risk in relation to progress through the educational system and to understand the interaction between urban environment and educational outcomes.

Structural MRI Differences between Patients with and without First Rank Symptoms: A Delusion?

OBJECTIVE

It has been suggested that specific psychotic symptom clusters may be explained by patterns of biological abnormalities. The presence of first rank symptoms (FRS) has been associated with cognitive abnormalities, e.g., deficits in self-monitoring or in the experience of agency, suggesting that a specific network of neural abnormalities might underlie FRS. Here, we investigate differences in cortical and subcortical brain volume between patients with and without FRS.

METHODS

Three independent patient samples (referred to as A, B, and C) with different mean ages and in different illness stages were included, leading to a total of 348 patients within the schizophrenia-spectrum. All underwent magnetic resonance imaging of the brain. In addition, the presence of FRS was established using a diagnostic interview. Patients with (FRS+, A: n = 63, B: n = 129, and C: n = 96) and without FRS (FRS-, A: n = 35, B: n = 17, and C: n = 8) were compared on global and local cortical volumes as well as subcortical volumes, using a whole brain (cerebrum) approach.

RESULTS

Nucleus accumbens volume was significantly smaller in FRS+ as compared with FRS- in sample A (p < 0.005). Furthermore, FRS+ showed a smaller volume of the pars-opercularis relative to FRS- in sample B (p < 0.001). No further significant differences were found in cortical and subcortical volumes between FRS+ and FRS- in either one of the three samples after correction for multiple comparison.

CONCLUSION

Brain volume differences between patients with and without FRS are, when present, subtle, and not consistent between three independent samples. Brain abnormalities related to FRS may be too subtle to become visible through structural brain imaging.

Evaluation of spontaneous dense array gamma oscillatory activity and minor physical anomalies as a composite neurodevelopmental endophenotype in schizophrenia

OBJECTIVE

Minor physical anomalies (MPAs) and gamma oscillatory activity have been proposed as associated endophenotypes in schizophrenia. Combining these endophenotypes to create a composite endophenotype may help identify those at risk for schizophrenia better. The present study aims to investigate MPAs and gamma oscillatory activity in schizophrenia patients, their unaffected first degree relatives and healthy controls and appreciate whether they can be used together as a composite endophenotype.

METHODS

This was a cross sectional family study conducted at a tertiary care mental health setup. Ninety participants including schizophrenia patients, their first degree relatives and controls (thirty each) were assessed for MPAs on the Extended Waldrop Scale. All participants underwent an awake, resting 192-channel EEG recording. Spectral power and coherence in 30-100Hz gamma bands were estimated using Welch's averaged periodogram method. One-way ANOVA, chi square test were used for comparing socio-demographic-clinical variables. MANOVA supplemented by one-way ANOVAs (post hoc Tukey HSD) were done for comparison of spectral measures. Pearson's correlation, step-by-step linear discriminant functional and intra-familial correlation analysis were subsequently performed.

RESULTS

An endophenotype pattern of finding was found for MPAs in the craniofacial region, the total number of MPAs, spectral power in right temporal region on all bands and in the right parietal region in 50-70Hz and 70-100Hz gamma bands. The three groups were most accurately classified when MPA total score, right temporal 30-50Hz gamma power and right occipital 'intra hemispheric' 50-70Hz gamma coherence were considered together than when considered independently. Significant intra familial correlation was seen for MPA total score and right temporal gamma 30-50Hz power.

CONCLUSION

Composite evaluation of two developmentally linked markers i.e. MPAs and gamma spectral measures may prove useful in categorizing schizophrenia and identifying at-risk individuals.

Schneiderian first rank symptoms and gamma oscillatory activity in neuroleptic naïve first episode schizophrenia: a 192 channel EEG study

OBJECTIVE

Schneiderian first-rank symptoms (FRS) and abnormal EEG gamma activity in schizophrenia have been reported independently to have a neurodevelopmental basis. We aimed to investigate spontaneous gamma power in two groups of first episode schizophrenia patients (those who experience FRS and those who do not).

METHODS

A comparative hospital based study having 37neuroleptic naïve male patients with schizophrenia divided into two groups-FRS(+) and FRS(-) groups based on the presence of FRS. Thirty age, sex, education and handedness matched individuals served as controls (N). All participants underwent a 192-channel resting Electroencephalography (EEG) recording. Gamma spectral power was calculated for low- (30-50 Hz) and high-gamma 1 & 2 (51-70 and 71-100 Hz) bands. Spectral power was compared between three groups using MANOVA and supplementary one-way ANOVA with Bonferroni test controlling for multiple comparisons. Linear regression was used to identifying predictor variables for FRS. Pearson correlation coefficient was computed between spectral power parameters and various clinical variables.

RESULTS

Significantly higher high gamma band-1 power was observed over right frontal (p<0.05), parietal (p<0.05) and temporal (p<0.05) regions in FRS(+) than FRS(-) group and normal controls. Right parietal high gamma-1 power and paranoid cluster on PANSS significantly predicted number of FRS in total schizophrenia patients; paranoid cluster on PANSS showed significant correlation with number of FRS in FRS(+) group.

CONCLUSION

Findings of our study add to the evidence that areas contained within the hetero modal association cortex are associated with FRS. The study findings also strengthen the neurodevelopmental basis of FRS in schizophrenia.

Negative correlation between leftward bias in line bisection and schizotypal features in healthy subjects

Introduction: Recent studies have found a lack of normal pseudoneglect in schizophrenia patients and in their first degree relatives. Similarly, several contributions have reported that measures of schizotypy in the healthy population may be related to signs of right-sided lateralization, but most of these studies differ greatly in methodology (sample size, choice of schizotypy scales, and laterality tasks) and, consequently, the results cannot be compared and so definitive conclusion cannot be drawn. In this study, our purpose is to investigate whether some tasks of spatial attention may be related to different dimensions of schizotypy not only in a larger sample of healthy subjects (HS), but testing the same people with several supposedly related measures several times.

Materials and Methods: In the first part of the study (Part I), the performance on “paper and pencil” line bisection (LB) tasks in 205 HS was investigated. Each task was repeated three times. In the second part of the study (Part II), a subgroup of 80 subjects performed a computerized version of the LB test and of the mental number line bisection (MNL) test. In both parts of the study, every subject completed the 74-item version of the Schizotypal Personality Questionnaire (SPQ) and the Edinburgh Handedness Inventory (EHI).

Results: In both parts of the study, high scores on the subscale “magical thinking” of SPQ have resulted in being closely linked to a decreased pseudoneglect as assessed by the LB task. On the contrary, right handedness is related to an increased leftward bias at the same task. No association was found between MNL and the other variables.

Discussion: The main finding of this study is that a decreased spatial leftward bias at the LB task correlates with positive schizotypy in the healthy population. This finding supports the hypothesis that a deviation from leftward hemispatial visual preference may be related to the degree of psychosis-like schizotypal signs in non-clinical population and should be investigated as a possible marker of psychosis.

Relationship between Brain-Derived Neurotrophic Factor and Schneiderian First Rank Symptoms in Antipsychotic-Naïve Schizophrenia

Neurodevelopmental aberrations influenced by neurotrophic factors are among the important paradigms to understand schizophrenia pathogenesis. Among various neurotrophic factors, Brain-Derived Neurotrophic Factor (BDNF) is strongly implicated by previous research studies. Evaluating co-morbidity free, antipsychotic-naïve schizophrenia patients for BDNF levels and examining the correlates of this factor with symptoms might facilitate elucidation of its pathogenetic role without confounds of potential influencing factors. In this study, 59 co-morbidity free, antipsychotic-naïve schizophrenia patients were compared with 60 healthy controls for serum BDNF levels. In addition, the relationship between Schneiderian First Rank Symptoms (FRS) and BDNF level in patients was examined. As a group, schizophrenia patients (28.8 ± 11.7 ng/mL) had significantly lower serum BDNF than healthy controls (34.9 ± 8.2 ng/mL) after controlling for the potential confounding effects of age and sex (F = 7.8; p = 0.006). Further analyses revealed FRS status to have significant effect on plasma BDNF after controlling for the potential confounding effects of age and sex (F = 4.5; p = 0.01). Follow-up post hoc analyses revealed FRS(+) patients to have significant deficit in plasma BDNF level in comparison with healthy controls (p = 0.002); however, FRS(-) patients did not differ from healthy controls (p = 0.38). Our study observations add further support to the role for BDNF in schizophrenia pathogenesis and suggest a potential novel link between deficient BDNF and FRS.

Perceptual pseudoneglect in schizophrenia: candidate endophenotype and the role of the right parietal cortex

Several contributions have reported an altered expression of pseudoneglect in psychiatric disorders, highlighting the existence of an anomalous brain lateralization in affected subjects. Surprisingly, no studies have yet investigated pseudoneglect in first-degree relatives (FdR) of psychiatric patients. We investigated performance on "paper and pencil" line bisection (LB) tasks in 68 schizophrenic patients (SCZ), 42 unaffected FdR, 41 unipolar depressive patients (UP), and 103 healthy subjects (HS). A subgroup of 20 SCZ and 16 HS underwent computerized LB and mental number line bisection (MNL) tasks requiring judgment of prebisected lines and numerical intervals. Moreover, we evaluated, in a subgroup of 15 SCZ, performance on LB and MNL before and after parietal transcranial direct current stimulation (tDCS). In comparison to HS and UP, SCZ showed a systematic rightward bias on LB, partially corrected by selective right posterior parietal tDCS. Interestingly, even FdR showed a lack of pseudoneglect on LB, expressing a mean error lying in the middle between those of HS and SCZ. On the other hand, our results showed no significant difference between the performance of SCZ and HS on MNL. Both groups showed a comparable leftward bias that could not be significantly altered after left or right parietal tDCS. These findings confirm the existence of reduced lateralization in SCZ, suggesting specific impaired functioning of the right parietal lobule. Notably, we report a lack of pseudoneglect not only in SCZ but also in FdR, raising the hypothesis that an inverted laterality pattern may be considered a concrete marker of schizotypal traits.

Dissociable morphometric differences of the inferior parietal lobule in schizophrenia

Inferior parietal lobule (IPL) forms an integral part of a critical frontoparietal network, which has been implicated in various clinical symptoms and cognitive deficits seen in schizophrenia. Despite its functional relevance, the relatively few studies that have investigated the structural changes in the IPL report inconsistent findings concerning the nature and localization of these changes. We employed a blinded, automated labelling procedure to measure cortical thickness, surface area and the degree of cortical folding of the two distinct subregions of the IPL (Angular Gyrus and Supramarginal Gyrus) in 57 patients with schizophrenia and 41 controls using high-resolution magnetic resonance imaging. Within the IPL, we observed more pronounced morphological changes in supramarginal gyrus compared to angular gyrus in schizophrenia. While supramarginal gyrus in patients showed reduced gyrification, contracted surface area and thinning, the morphometric changes in angular gyrus were largely confined to a reduction in surface area. Significant hemispheric asymmetry was observed in the gyrification of the supramarginal gyrus. Our findings suggest that in addition to abnormalities in the neurodevelopmental processes that contribute to regional surface area and cortical thickness, a specific defect in cortical folding, especially affecting the left hemisphere, is likely to occur in schizophrenia.

Neuroimaging studies in schizophrenia: an overview of research from Asia

Neuroimaging studies in schizophrenia help clarify the neural substrates underlying the pathogenesis of this neuropsychiatric disorder. Contemporary brain imaging in schizophrenia is predominated by magnetic resonance imaging (MRI)-based research approaches. This review focuses on the various imaging studies from India and their relevance to the understanding of brain abnormalities in schizophrenia. The existing studies are predominantly comprised of structural MRI reports involving region-of-interest and voxel-based morphometry approaches, magnetic resonance spectroscopy and single-photon emission computed tomography/positron emission tomography (SPECT/PET) studies. Most of these studies are significant in that they have evaluated antipsychotic-naïve schizophrenia patients--a relatively difficult population to obtain in contemporary research. Findings of these studies offer robust support to the existence of significant brain abnormalities at very early stages of the disorder. In addition, theoretically relevant relationships between these brain abnormalities and developmental aberrations suggest possible neurodevelopmental basis for these brain deficits.

Cortical thickness, neuron density and size in the inferior parietal lobe in schizophrenia

The inferior parietal lobe (IPL) is a center of multisensory integration, and both functional and structural MRI studies have found evidence that pathology in this region may contribute to disrupted sensory perception in schizophrenia. To further define this pathology, we used postmortem samples from the left and right IPL, to compare the thickness and volume of the upper (I-III) and lower (IV-VI) cortical layers. The samples were divided into supramarginal and angular gyri, and neuron density and size were measured in the supramarginal gyrus. The laminar thickness and volume measurements did not demonstrate significant changes in schizophrenia, but did show that the angular gyrus was thinner than the supramarginal gyrus, due to a difference mainly in the lower layers. Measurements of cortical thickness, neuron size and neuron density all showed some evidence of previously reported normal hemispheric differences. These asymmetries were reduced in schizophrenia, but the small changes were at the threshold of detection, and are discussed in the context of the sensitivity of the methods applied.

Putative structural neuroimaging endophenotypes in schizophrenia: a comprehensive review of the current evidence

The genetic contribution to schizophrenia etiopathogenesis is underscored by the fact that the best predictor of developing schizophrenia is having an affected first-degree relative, which increases lifetime risk by tenfold, as well as the observation that when both parents are affected, the risk of schizophrenia increases to approximately 50%, compared with 1% in the general population. The search to elucidate the complex genetic architecture of schizophrenia has employed various approaches, including twin and family studies to examine co-aggregation of brain abnormalities, studies on genetic linkage and studies using genome-wide association to identify genetic variations associated with schizophrenia. ‘Endophenotypes’, or ‘intermediate phenotypes’, are potentially narrower constructs of genetic risk. Hypothetically, they are intermediate in the pathway between genetic variation and clinical phenotypes and can supposedly be implemented to assist in the identification of genetic diathesis for schizophrenia and, possibly, in redefining clinical phenomenology.