Meta-analysis of 41 functional neuroimaging studies of executive function in schizophrenia

Electroencephalographic Microstates in Schizophrenia and Bipolar Disorder

Schizophrenia (SCH) and bipolar disorder (BD) are characterized by many types of symptoms, damaged cognitive function, and abnormal brain connections. The microstates are considered to be the cornerstones of the mental states shown in EEG data. In our study, we investigated the use of microstates as biomarkers to distinguish patients with bipolar disorder from those with schizophrenia by analyzing EEG data measured in an eyes-closed resting state. The purpose of this article is to provide an electron directional physiological explanation for the observed brain dysfunction of schizophrenia and bipolar disorder patients. Methods: We used microstate resting EEG data to explore group differences in the duration, coverage, occurrence, and transition probability of 4 microstate maps among 20 SCH patients, 26 BD patients, and 35 healthy controls (HCs). Results: Microstate analysis revealed 4 microstates (A-D) in global clustering across SCH patients, BD patients, and HCs. The samples were chosen to be matched. We found the greater presence of microstate B in BD patients, and the less presence of microstate class A and B, the greater presence of microstate class C, and less presence of D in SCH patients. Besides, a greater frequent switching between microstates A and B and between microstates B and A in BD patients than in SCH patients and HCs and less frequent switching between microstates C and D and between microstates D and C in BD patients compared with SCH patients. Conclusion: We found abnormal features of microstate A, B in BD patients and abnormal features of microstate A, B, C, and D in SCH patients. These features may indicate the potential abnormalities of SCH patients and BD patients in distributing neural resources and influencing opportune transitions between different states of activity.

Thought Disorder on Object Sorting Test Is Associated with Executive Dysfunction in Schizophrenia

BACKGROUND

Thought disorder is considered to be central to the core disturbances in schizophrenia and was described by Goldstein as aberrant "concept formation." Executive dysfunction is another core deficit in schizophrenia. With a greater emphasis on psychopathology in nosological systems, the classical thought disorder receives less prominence. The present study aimed to understand the association between classical thought disorder (aberrant concept formation and concrete abstraction) and executive dysfunction.

METHODS

Thirty patients with schizophrenia and thirty healthy subjects, matched on age, gender, education, and socioeconomic status, were screened using MINI 5.0, following which they were assessed on object sorting test (OST) and selected tests for executive functions (EFs).

RESULTS

Individuals with schizophrenia were found to have significantly decreased performance on all domains of EFs and OST. Total peculiar scores on OST were significantly associated with mental speed, focused attention, and divided attention. Total impoverished scores on OST was significantly associated with focused attention, sustained attention, planning, set shifting, perseveration, and concept formation.

CONCLUSION

Several correlations, among performance on OST and neuropsychological tests, suggest that patterns of responses on OST can point to underlying executive dysfunction. Both thought disorder and executive dysfunction mirror similar constructs. This similarity represents a conceptual bridge between the classical and contemporary descriptions of the core deficits in schizophrenia.

An fMRI Study Using a Combined Task of Interval Discrimination and Oddball Could Reveal Common Brain Circuits of Cognitive Change

Recent functional neuroimaging studies suggest that the brain networks responsible for time processing are involved during other cognitive processes, leading to a hypothesis that time-related processing is needed to perform a range of tasks across various cognitive functions. To examine this hypothesis, we analyze whether, in healthy subjects, the brain structures activated or deactivated during performance of timing and oddball-detection type tasks coincide. To this end, we conducted two independent signed differential mapping (SDM) meta-analyses of functional magnetic resonance imaging (fMRI) studies assessing the cerebral generators of the responses elicited by tasks based on timing and oddball-detection paradigms. Finally, we undertook a multimodal meta-analysis to detect brain regions common to the findings of the two previous meta-analyses. We found that healthy subjects showed significant activation in cortical areas related to timing and salience networks. The patterns of activation and deactivation corresponding to each task type partially coincided. We hypothesize that there exists a time and change-detection network that serves as a common underlying resource used in a broad range of cognitive processes.

Cognitive performance in early, treatment-resistant psychosis patients: Could cognitive control play a role in persistent symptoms?

Approximately one third of psychosis patients fail to respond to conventional antipsychotic medication, which exerts its effect via striatal dopamine receptor antagonism. The present study aimed to investigate impaired cognitive control as a potential contributor to persistent positive symptoms in treatment resistant (TR) patients. 52 medicated First Episode Psychosis (FEP) patients (17 TR and 35 non-TR (NTR)) took part in a longitudinal study in which they performed a series of cognitive tasks and a clinical assessment at two timepoints, 12 months apart. Cognitive performance at baseline was compared to that of 39 healthy controls (HC). Across both timepoints, TR patients were significantly more impaired than NTR patients in a task of cognitive control, while performance on tasks of phonological and semantic fluency, working memory and general intelligence did not differ between patient groups. No significant associations were found between cognitive performance and psychotic symptomatology, and no significant performance changes were observed from the first to second timepoint in any of the cognitive tasks within patient groups. The results suggest that compared with NTR patients, TR patients have an exacerbated deficit specific to cognitive control, which is established early in psychotic illness and stabilises in the years following a first episode.

The VLPFC versus the DLPFC in Downregulating Social Pain Using Reappraisal and Distraction Strategies

The dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC (VLPFC) are both crucial structures involved in voluntary emotional regulation. However, it remains unclear whether the functions of these two cortical regions that are involved in emotional regulation, which are usually active in non-social situations, could be generalized to the regulation of social pain as well.

The dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC (VLPFC) are both crucial structures involved in voluntary emotional regulation. However, it remains unclear whether the functions of these two cortical regions that are involved in emotional regulation, which are usually active in non-social situations, could be generalized to the regulation of social pain as well. This study employed transcranial magnetic stimulation (TMS) to examine the causal relationship between the DLPFC/VLPFC and the emotional regulation of social pain via distraction and reappraisal. Ninety human participants (45 males and 45 females) initially underwent either active (DLPFC/VLPFC, n = 30/30) or sham (vertex, n = 30) TMS sessions. Participants were then instructed to use both distraction and reappraisal strategies to downregulate any negative emotions evoked by social exclusion pictures. Convergent results of the subjective emotional rating and electrophysiological indices demonstrated that: (1) both the DLPFC and VLPFC highly facilitate the downregulation of affective responses caused by social exclusion, revealing a causal role of these lateral PFCs in voluntary emotional regulation of both non-social and social pain; and (2) these two cortical regions showed relative functional specificity for distraction (DLPFC) and reappraisal (VLPFC) strategies, which helps to refine the cortical targeting of therapeutic protocols. In addition, the TMS effect was sustainable for at least 1 h, showcasing the potential feasibility of using this method in clinical practice. Together, these findings provide cognitive and neural evidence for the targeting of the VLPFC and/or the DLPFC to improve emotional regulation abilities, especially in social contexts.

SIGNIFICANCE STATEMENT This study aimed to examine the role of the dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC (VLPFC) in emotional regulation, particularly in response to social pain through the use of distraction and reappraisal strategies, as this is a relatively underexplored area of inquiry. This study makes a significant contribution to the literature because our results provide novel empirical information on the role of these cortical structures in the processing of negative emotions elicited within certain social contexts. As such, our findings have potential clinical implications, paving the way for future clinicians to be able to accurately target specific brain regions among patients struggling with impaired social cognition abilities, including those diagnosed with posttraumatic stress disorder, autism spectrum disorder, social anxiety disorder, and depression.

Exploring Patterns of Disturbed Eating in Psychosis: A Scoping Review

Disturbed eating behaviours have been widely reported in psychotic disorders since the early 19th century. There is also evidence that antipsychotic (AP) treatment may induce binge eating or other related compulsive eating behaviours. It is therefore possible that abnormal eating patterns may contribute to the significant weight gain and other metabolic disturbances observed in patients with psychosis. In this scoping review, we aimed to explore the underlying psychopathological and neurobiological mechanisms of disrupted eating behaviours in psychosis spectrum disorders and the role of APs in this relationship. A systematic search identified 35 studies that met our eligibility criteria and were included in our qualitative synthesis. Synthesizing evidence from self-report questionnaires and food surveys, we found that patients with psychosis exhibit increased appetite and craving for fatty food, as well as increased caloric intake and snacking, which may be associated with increased disinhibition. Limited evidence from neuroimaging studies suggested that AP-naïve first episode patients exhibit similar neural processing of food to healthy controls, while chronic AP exposure may lead to decreased activity in satiety areas and increased activity in areas associated with reward anticipation. Overall, this review supports the notion that AP use can lead to disturbed eating patterns in patients, which may contribute to AP-induced weight gain. However, intrinsic illness-related effects on eating behaviors remain less well elucidated, and many confounding factors as well as variability in study designs limits interpretation of existing literature in this field and precludes firm conclusions from being made.

Altered hippocampal-prefrontal functional network integrity in adult macaque monkeys with neonatal hippocampal lesions

The dorsolateral prefrontal cortex (DLPFC) and ventral lateral prefrontal cortex (VLPFC) play critical but different roles in working memory (WM) processes. Resting-state functional MRI (rs-fMRI) was employed to investigate the effects of neonatal hippocampal lesions on the functional connectivity (FC) between the hippocampus (H) and the DLPFC and VLPFC and its relation to WM performance in adult monkeys. Adult rhesus monkeys with neonatal H lesions (Neo-H, n = 5) and age- and gender-matched sham-operated monkeys (Neo-C, n = 5) were scanned around 10 years of age. The FC of H-DLPFC and H-VLPFC in Neo-H monkeys was significantly altered as compared to controls, but also switched from being positive in the Neo-C to negative in the Neo-H. In addition, the altered magnitude of FC between right H and bilateral DLPFC was significantly associated with the extent of the hippocampal lesions. In particular, the effects of neonatal hippocampal lesion on FC appeared to be selective to the left hemisphere of the brain (i.e. asymmetric in the two hemispheres). Finally, FC between H and DLPFC correlated with WM task performance on the SU-DNMS and the Obj-SO tasks for the control animals, but only with the H-VLPFC and SU-DNMS task for the Neo-H animals. In conclusion, the present rsfMRI study revealed that the neonatal hippocampal lesions significantly but differently altered the integrity in the functional connectivity of H-DLPFC and H-VLPFC. The similarities between the behavioral, cognitive and neural alterations in Neo-H monkeys and Schizophrenia (SZ) patients provide a strong translational model to develop new therapeutic tools for SZ.

Diagnosis- and Cell Type-Specific Mitochondrial Functional Pathway Signatures in Schizophrenia and Bipolar Disorder

OBJECTIVE

The shared risk factors and clinical features in schizophrenia and bipolar disorder may be linked via mitochondrial dysfunction. However, the severity of mitochondrial dysfunction, and/or the specific mitochondrial functional pathways affected, may differ between diagnoses, especially at the level of individual cell types.

METHODS

Transcriptomic profiling data for a gene set indexing mitochondrial functional pathways were obtained for dorsolateral prefrontal cortex (DLPFC) gray matter and layer 3 and layer 5 pyramidal neurons of subjects with schizophrenia or bipolar disorder. Analyses were conducted using a dual strategy: identification of differentially expressed genes (DEGs) and their functional pathway enrichment, and application of weighted gene coexpression network analysis. These analyses were repeated in monkeys chronically exposed to antipsychotic drugs to determine their effect on mitochondrial-related gene expression.

RESULTS

In DLPFC gray matter, 41% of mitochondrial-related genes were differentially expressed in the schizophrenia group, whereas 8% were differentially expressed in the bipolar group. In the schizophrenia group, 83% of DEGs showed lower expression, and these were significantly enriched for three functional pathways, each indexing energy production. DEGs in the bipolar disorder group were not enriched for functional pathways. This disease-related pattern of findings was also identified in pyramidal neurons. None of the gene expression alterations disrupted coexpression modules, and DEGs were not attributable to antipsychotic medications.

CONCLUSIONS

Schizophrenia and bipolar disorder do not appear to share similar mitochondrial alterations in the DLPFC. The selective and coordinated down-regulation of energy production genes in schizophrenia is consistent with the effects of chronic reductions in pyramidal neuron firing, and enhancement of this activity may serve as a therapeutic target.

Thalamic Nuclei Volumes in Psychotic Disorders and in Youths With Psychosis Spectrum Symptoms

OBJECTIVE

Thalamus models of psychosis implicate association nuclei in the pathogenesis of psychosis and mechanisms of cognitive impairment. Studies to date have provided conflicting findings for structural deficits specific to these nuclei. The authors sought to characterize thalamic structural abnormalities in psychosis and a neurodevelopmental cohort, and to determine whether nuclear volumes were associated with cognitive function.

METHODS

Thalamic nuclei volumes were tested in a cross-sectional sample of 472 adults (293 with psychosis) and the Philadelphia Neurodevelopmental Cohort (PNC), consisting of 1,393 youths (398 with psychosis spectrum symptoms and 609 with other psychopathologies), using a recently developed, validated method for segmenting thalamic nuclei and complementary voxel-based morphometry. Cognitive function was measured with the Screen for Cognitive Impairment in Psychiatry in the psychosis cohort and the Penn Computerized Neurocognitive Battery in the PNC.

RESULTS

The psychosis group had smaller pulvinar, mediodorsal, and, to a lesser extent, ventrolateral nuclei volumes compared with the healthy control group. Youths with psychosis spectrum symptoms also had smaller pulvinar volumes, compared with both typically developing youths and youths with other psychopathologies. Pulvinar volumes were positively correlated with general cognitive function.

CONCLUSIONS

The study findings demonstrate that smaller thalamic association nuclei represent a neurodevelopmental abnormality associated with psychosis, risk for psychosis in youths, and cognitive impairment. Identifying specific thalamic nuclei abnormalities in psychosis has implications for early detection of psychosis risk and treatment of cognitive impairment in psychosis.

Support vector machine-based classification of schizophrenia patients and healthy controls using structural magnetic resonance imaging from two independent sites

Structural brain alterations have been repeatedly reported in schizophrenia; however, the pathophysiology of its alterations remains unclear. Multivariate pattern recognition analysis such as support vector machines can classify patients and healthy controls by detecting subtle and spatially distributed patterns of structural alterations. We aimed to use a support vector machine to distinguish patients with schizophrenia from control participants on the basis of structural magnetic resonance imaging data and delineate the patterns of structural alterations that significantly contributed to the classification performance. We used independent datasets from different sites with different magnetic resonance imaging scanners, protocols and clinical characteristics of the patient group to achieve a more accurate estimate of the classification performance of support vector machines. We developed a support vector machine classifier using the dataset from one site (101 participants) and evaluated the performance of the trained support vector machine using a dataset from the other site (97 participants) and vice versa. We assessed the performance of the trained support vector machines in each support vector machine classifier. Both support vector machine classifiers attained a classification accuracy of >70% with two independent datasets indicating a consistently high performance of support vector machines even when used to classify data from different sites, scanners and different acquisition protocols. The regions contributing to the classification accuracy included the bilateral medial frontal cortex, superior temporal cortex, insula, occipital cortex, cerebellum, and thalamus, which have been reported to be related to the pathogenesis of schizophrenia. These results indicated that the support vector machine could detect subtle structural brain alterations and might aid our understanding of the pathophysiology of these changes in schizophrenia, which could be one of the diagnostic findings of schizophrenia.

Abnormal cognitive effort allocation and its association with amotivation in first-episode psychosis

BACKGROUND

Abnormal effort-based decision-making represents a potential mechanism underlying motivational deficits (amotivation) in psychotic disorders. Previous research identified effort allocation impairment in chronic schizophrenia and focused mostly on physical effort modality. No study has investigated cognitive effort allocation in first-episode psychosis (FEP).

METHOD

Cognitive effort allocation was examined in 40 FEP patients and 44 demographically-matched healthy controls, using Cognitive Effort-Discounting (COGED) paradigm which quantified participants' willingness to expend cognitive effort in terms of explicit, continuous discounting of monetary rewards based on parametrically-varied cognitive demands (levels N of N-back task). Relationship between reward-discounting and amotivation was investigated. Group differences in reward-magnitude and effort-cost sensitivity, and differential associations of these sensitivity indices with amotivation were explored.

RESULTS

Patients displayed significantly greater reward-discounting than controls. In particular, such discounting was most pronounced in patients with high levels of amotivation even when N-back performance and reward base amount were taken into consideration. Moreover, patients exhibited reduced reward-benefit sensitivity and effort-cost sensitivity relative to controls, and that decreased sensitivity to reward-benefit but not effort-cost was correlated with diminished motivation. Reward-discounting and sensitivity indices were generally unrelated to other symptom dimensions, antipsychotic dose and cognitive deficits.

CONCLUSION

This study provides the first evidence of cognitive effort-based decision-making impairment in FEP, and indicates that decreased effort expenditure is associated with amotivation. Our findings further suggest that abnormal effort allocation and amotivation might primarily be related to blunted reward valuation. Prospective research is required to clarify the utility of effort-based measures in predicting amotivation and functional outcome in FEP.

Differing functional mechanisms underlie cognitive control deficits in psychotic spectrum disorders

BACKGROUND

Functional underpinnings of cognitive control deficits in unbiased samples (i.e., all comers) of patients with psychotic spectrum disorders (PSD) remain actively debated. While many studies suggest hypofrontality in the lateral prefrontal cortex (PFC) and greater deficits during proactive relative to reactive control, few have examined the full hemodynamic response.

METHODS

Patients with PSD (n = 154) and healthy controls (n = 65) performed the AX continuous performance task (AX-CPT) during rapid (460 ms) functional neuroimaging and underwent full clinical characterization.

RESULTS

Behavioural results indicated generalized cognitive deficits (slower and less accurate) across proactive and reactive control conditions in patients with PSD relative to healthy controls. We observed a delayed/prolonged neural response in the left dorsolateral PFC, the sensorimotor cortex and the superior parietal lobe during proactive control for patients with PSD. These proactive hemodynamic abnormalities were better explained by negative rather than by positive symptoms or by traditional diagnoses according to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision (DSM-IV-TR), with subsequent simulations unequivocally demonstrating how these abnormalities could be erroneously interpreted as hypoactivation. Conversely, true hypoactivity, unassociated with clinical symptoms or DSM-IV-TR diagnoses, was observed within the ventrolateral PFC during reactive control.

LIMITATIONS

In spite of guidance for AX-CPT use in neuroimaging studies, one-third of patients with PSD could not perform the task above chance and were more clinically impaired.

CONCLUSION

Current findings question the utility of the AX-CPT for neuroimaging-based appraisal of cognitive control across the full spectrum of patients with PSD. Previously reported lateral PFC "hypoactivity" during proactive control may be more indicative of a delayed/prolonged neural response, important for rehabilitative purposes. Negative symptoms may better explain certain behavioural and hemodynamic abnormalities in patients with PSD relative to DSM-IV-TR diagnoses.

Amphetamine-induced alteration to gaze parameters: A novel conceptual pathway and implications for naturalistic behavior

Amphetamine produces a multiplicity of well-documented end-order biochemical, pharmacological and biobehavioural effects. Mechanistically, amphetamine downregulates presynaptic and postsynaptic striatal monoamine (primarily dopaminergic) systems, producing alterations to key brain regions which manifest as stereotyped ridged behaviour which occurs under both acute and chronic dosing schedules and persists beyond detoxification. Despite evidence of amphetamine-induced visual attentional dysfunction, no conceptual synthesis has yet captured how characteristic pharmaco-behavioural processes are critically implicated via these pathways, nor described the potential implications for safety-sensitive behaviours. Drawing on known pathomechanisms, we propose a cross-disciplinary, novel conceptual functional system framework for delineating the biobehavioural consequences of amphetamine use on visual attentional capacity and discuss the implications for functional and behavioural outcomes. Specifically, we highlight the manifest implications for behaviours that are conceptually driven and highly dependent on visual information processing for timely execution of visually-guided movements. Following this, we highlight the potential impact on safety-sensitive, but common behaviours, such as driving a motor vehicle. The close pathophysiological relationship between oculomotor control and higher-order cognitive processes further suggests that dynamic measurement of movement related to the motion of the eye (gaze behaviour) may be a simple, effective and direct measure of behavioural performance capabilities in naturalistic settings. Consequently, we discuss the potential efficacy of ocular monitoring for the detection and monitoring of driver states for this drug user group, and potential wider application. Significance statement: We propose a novel biochemical-physiological-behavioural pathway which delineates how amphetamine use critically alters oculomotor function, visual-attentional performance and information processing capabilities. Given the manifest implications for behaviours that are conceptually driven and highly dependent on these processes, we recommend oculography as a novel means of detecting and monitoring gaze behaviours during naturalistic tasks such as driving. Real-word examination of gaze behaviour therefore present as an effective means to detect driver impairment and prevent performance degradation due to these drugs.

Predicting psychosis risk using a specific measure of cognitive control: a 12-month longitudinal study

BACKGROUND

Identifying risk factors of individuals in a clinical-high-risk state for psychosis are vital to prevention and early intervention efforts. Among prodromal abnormalities, cognitive functioning has shown intermediate levels of impairment in CHR relative to first-episode psychosis and healthy controls, highlighting a potential role as a risk factor for transition to psychosis and other negative clinical outcomes. The current study used the AX-CPT, a brief 15-min computerized task, to determine whether cognitive control impairments in CHR at baseline could predict clinical status at 12-month follow-up.

METHODS

Baseline AX-CPT data were obtained from 117 CHR individuals participating in two studies, the Early Detection, Intervention, and Prevention of Psychosis Program (EDIPPP) and the Understanding Early Psychosis Programs (EP) and used to predict clinical status at 12-month follow-up. At 12 months, 19 individuals converted to a first episode of psychosis (CHR-C), 52 remitted (CHR-R), and 46 had persistent sub-threshold symptoms (CHR-P). Binary logistic regression and multinomial logistic regression were used to test prediction models.

RESULTS

Baseline AX-CPT performance (d-prime context) was less impaired in CHR-R compared to CHR-P and CHR-C patient groups. AX-CPT predictive validity was robust (0.723) for discriminating converters v. non-converters, and even greater (0.771) when predicting CHR three subgroups.

CONCLUSIONS

These longitudinal outcome data indicate that cognitive control deficits as measured by AX-CPT d-prime context are a strong predictor of clinical outcome in CHR individuals. The AX-CPT is brief, easily implemented and cost-effective measure that may be valuable for large-scale prediction efforts.

Precuneus and insular hypoactivation during cognitive processing in first-episode psychosis: Systematic review and meta-analysis of fMRI studies

INTRODUCTION

The neural correlates of the cognitive dysfunction in first-episode psychosis (FEP) are still unclear. The present review and meta-analysis provide an update of the location of the abnormalities in the fMRI-measured brain response to cognitive processes in individuals with FEP.

METHODS

Systematic review and voxel-based meta-analysis of cross-sectional fMRI studies comparing neural responses to cognitive tasks between individuals with FEP and healthy controls (HC) according to PRISMA guidelines.

RESULTS

Twenty-six studies were included, comprising 598 individuals with FEP and 567 HC. Individual studies reported statistically significant hypoactivation in the dorsolateral prefrontal cortex (6 studies), frontal lobe (8 studies), cingulate (6 studies) and insula (5 studies). The meta-analysis showed statistically significant hypoactivation in the left anterior insula, precuneus and bilateral striatum.

CONCLUSIONS

While the studies tend to highlight frontal hypoactivation during cognitive tasks in FEP, our meta-analytic results show that the left precuneus and insula primarily display aberrant activation in FEP that may be associated with salience attribution to external stimuli and related to deficits in perception and regulation.

Thalamocortical Anatomical Connectivity in Schizophrenia and Psychotic Bipolar Disorder

BACKGROUND

Anatomical connectivity between the thalamus and cortex, including the prefrontal cortex (PFC), is abnormal in schizophrenia. Overlapping phenotypes, including deficits in executive cognitive abilities dependent on PFC-thalamic circuitry, suggest dysrupted thalamocortical anatomical connectivity may extend to psychotic bipolar disorder. We tested this hypothesis and examined the impact of illness stage to inform when in the illness course thalamocortical dysconnectivity emerges.

METHODS

Diffusion-weighted imaging data were collected on 70 healthy individuals and 124 people with a psychotic disorder (schizophrenia spectrum = 75; psychotic bipolar disorder = 49), including 62 individuals in the early stage of psychosis. Anatomical connectivity between major divisions of the cortex and thalamus was quantified using probabilistic tractography and compared between groups. Associations between PFC-thalamic anatomical connectivity and executive cognitive abilities were examined using regression analysis.

RESULTS

Psychosis was associated with lower PFC-thalamic and elevated somatosensory-thalamic anatomical connectivity. Follow-up analyses established that lower PFC-thalamic and elevated somatosensory-thalamic anatomical connectivity were present in both schizophrenia and psychotic bipolar disorder. Lower PFC-thalamic anatomical connectivity was also present in early-stage and chronic psychosis. Contrary to expectations, lower PFC-thalamic anatomical connectivity was not associated with impaired executive cognitive abilities.

CONCLUSIONS

Altered thalamocortical anatomical connectivity, especially reduced PFC-thalamic connectivity, is a transdiagnostic feature of psychosis detectable in the early stage of illness. Further work is required to elucidate the functional consequences of the full spectrum of thalamocortical connectivity abnormalities in psychosis.

One-Year Stability of Frontoparietal Cognitive Control Network Connectivity in Recent Onset Schizophrenia: A Task-Related 3T fMRI Study

Kraepelinian theory posits that schizophrenia (SZ) is a degenerative disorder that worsens throughout the lifespan. Behavioral studies of cognition have since challenged that viewpoint, particularly in the early phases of illness. Nonetheless, the extent to which cognition remains functionally stable during the early course of illness is unclear, particularly with regard to task-associated connectivity in cognition-related brain networks. In this study, we examined the 1-year stability of the frontoparietal control network during the AX-Continuous Performance Task (AX-CPT) from a new baseline sample of 153 participants scanned at 3T, of which 29 recent onset individuals with SZ and 42 healthy control (HC) participants had follow-up data available for analysis. Among individuals that had both baseline and follow-up data, reduced functional connectivity in SZ was observed between the dorsolateral prefrontal cortex (DLPFC) and superior parietal cortex (SPC) during the high control (B cue) condition. Furthermore, this deficit was stable over time, as no significant time × diagnosis interaction or effects of time were observed and intraclass correlation coefficients were greater than 0.6 in HCs and SZ. Previous 1.5T findings showing stable deficits with no evidence of degeneration in performance or DLPFC activation in an independent SZ sample were replicated. Overall, these results suggest that the neuronal circuitry supporting cognitive control is stably impaired during the early course of illness in SZ across multiple levels of analysis with no evidence of functional decline.

Non-Invasive Brain Stimulation Does Not Improve Working Memory in Schizophrenia: A Meta-Analysis of Randomised Controlled Trials

Poor working memory functioning is commonly found in schizophrenia. A number of studies have now tested whether non-invasive brain stimulation can improve this aspect of cognitive functioning. This report used meta-analysis to synthesise the results of these studies to examine whether transcranial electrical stimulation (tES) or repetitive transcranial magnetic stimulation (rTMS) can improve working memory in schizophrenia. The studies included in this meta-analysis were sham-controlled, randomised controlled trials that utilised either tES or rTMS to treat working memory problems in schizophrenia. A total of 22 studies were included in the review. Nine studies administered rTMS and 13 administered tES. Meta-analysis revealed that compared to sham/placebo stimulation, neither TMS nor tES significantly improved working memory. This was found when working memory was measured with respect to the accuracy on working memory tasks (TMS studies: Hedges' g = 0.112, CI₉₅: -0.082, 0.305, p = .257; tES studies Hedges' g = 0.080, CI₉₅: -0.117, 0.277, p = .427) or the speed working memory tasks were completed (rTMS studies: Hedges' g = 0.233, CI₉₅: -0.212, 0.678, p = .305; tES studies Hedges' g = -0.016, CI₉₅: -0.204, 0.173, p = .871). For tES studies, meta-regression analysis found that studies with a larger number of stimulation sessions were associated with larger treatment effects. This association was not found for TMS studies. At present, rTMS and tES is not associated with a reliable improvement in working memory for individuals with schizophrenia.

A multimodal magnetoencephalography 7 T fMRI and 7 T proton MR spectroscopy study in first episode psychosis

We combined magnetoencephalography (MEG), 7 T proton magnetic resonance spectroscopy (MRS), and 7 T fMRI during performance of a task in a group of 23 first episode psychosis (FEP) patients and 26 matched healthy controls (HC). We recorded both the auditory evoked response to 40 Hz tone clicks and the resting state in MEG. Neurometabolite levels were obtained from the anterior cingulate cortex (ACC). The fMRI BOLD response was obtained during the Stroop inhibitory control task. FEP showed a significant increase in resting state low frequency theta activity (p < 0.05; Cohen d = 0.69), but no significant difference in the 40 Hz auditory evoked response compared to HC. An across-groups whole brain analysis of the fMRI BOLD response identified eight regions that were significantly activated during task performance (p < 0.01, FDR-corrected); the mean signal extracted from those regions was significantly different between the groups (p = 0.0006; d = 1.19). In the combined FEP and HC group, there was a significant correlation between the BOLD signal during task performance and MEG resting state low frequency activity (p < 0.05). In FEP, we report significant alteration in resting state low frequency MEG activity, but no alterations in auditory evoked gamma band response, suggesting that the former is a more robust biomarker of early psychosis. There were no correlations between gamma oscillations and GABA levels in either HC or FEP. Finally, in this study, each of the three imaging modalities differentiated FEP from HC; fMRI with good and MEG and MRS with moderate effect size.

Abnormal Contingent Negative Variation Drifts During Facial Expression Judgment in Schizophrenia Patients

Schizophrenia patients often show impaired facial expression recognition, which leads to difficulties in adaptation to daily life. However, it remains unclear whether the deficit is at the perceptual or higher cognitive level of facial emotion processing. Recent studies have shown that earlier face-evoked event-related potential (ERP) components such as N170 and P100 can effectively distinguish schizophrenia patients from healthy controls; however, findings for later waveforms are ambiguous. To clarify this point, in this study we compared electroencephalographic signals in schizophrenia patients and control subjects during a facial expression judgment task. We found that group effects of the occipital N170 and frontal lobe contingent negative variation (CNV) were both significant. The effect sizes (ESs) of N170 and CNV amplitudes were generally medium or small, whereas that of CNV slope for an upright face was large (>0.8). Moreover, N170 amplitude and CNV slope but not CNV amplitude was correlated with Personal and Social Performance (PSP) Scale score. These results suggest that the slope of CNV drift during facial expression processing has a potential clinical value for schizophrenia.

Aberrant Auditory Steady-State Response of Awake Mice After Single Application of the NMDA Receptor Antagonist MK-801 Into the Medial Geniculate Body

BACKGROUND

Systemic administration of noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonists such as MK-801 is widely used to model psychosis of schizophrenia (SZ). Acute systemic MK-801 in rodents caused an increase of the auditory steady-state responses (ASSRs), the oscillatory neural responses to periodic auditory stimulation, while most studies in patients with SZ reported a decrease of ASSRs. This inconsistency may be attributable to the comprehensive effects of systemic administration of MK-801. Here, we examined how the ASSR is affected by selectively blocking NMDAR in the thalamus.

METHODS

We implanted multiple electrodes in the auditory cortex (AC) and prefrontal cortex to simultaneously record the local field potential and spike activity (SA) of multiple sites from awake mice. Click-trains at a 40-Hz repetition rate were used to evoke the ASSR. We compared the mean trial power and phase-locking factor and the firing rate of SA before and after microinjection of MK-801 (1.5 µg) into the medial geniculate body (MGB).

RESULTS

We found that both the AC and prefrontal cortex showed a transient local field potential response at the onset of click-train stimulus, which was less affected by the application of MK-801 in the MGB. Following the onset response, the AC also showed a response continuing throughout the stimulus period, corresponding to the ASSR, which was suppressed by the application of MK-801.

CONCLUSION

Our data suggest that the MGB is one of the generators of ASSR, and NMDAR hypofunction in the thalamocortical projection may account for the ASSR deficits in SZ.

Subcortical neural tracks play an important role in executive function in schizophrenia: An experimental study among patients with schizophrenia and healthy comparisons

The literature has long emphasized the involvement of cortical and subcortical networks in executive function impairments among patients with schizophrenia. However, previous studies have not examined the relative involvement of monocular (mostly subcortical) versus binocular (mostly cortical) neural tracks in patients' EF deficits.

Patients with schizophrenia and healthy comparisons were administered a dichotic version of the Stroop task, in which eye-of-origin manipulation was employed to isolate the involvement of monocular (mostly subcortical; thalamic regions) versus binocular (mostly cortical; extrastriate cortex) visual pathways. The eye-of-origin manipulation, in which a color patch (e.g., a green patch) was presented to one eye, and a word (e.g., “RED”) to the other eye, enabled a split of the conflicting information between the two monocular channels. This results in the presentation of conflicting information to the higher cortical regions, but not to the lower subcortical structures. In the Stroop color task, when the monocular neural channels were not exposed to the conflicting information, the differences in task performance between the patients and the HCs significantly increased, and only the patients exhibited larger task conflict. When monocular neural channels were not exposed to the conflicting information, a robust dysfunction of the patients' group was observed. This abnormality might result from impairments in cortical regions or reduced computational power available for solving the conflict. However, additional studies that take into account the resolution of monocular and binocular neural channels are needed to enrich our understanding of the interplay between cortical and subcortical mechanisms in patients' EF deficits.

Deficits and compensation: Attentional control cortical networks in schizophrenia

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Examined attention systems in SzP with resting-state connectivity and task fMRI.

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SzP have functional connectivity deficits in late visual cortex and prefrontal areas.

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Task performance correlated with ventral attention network deactivation in SzP only.

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This relationship is mediated by connectivity of key attentional control components.

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Results reveal deficits and potential compensation in SzP visual processing/attention.

Visual processing and attention deficits are responsible for a substantial portion of the disability caused by schizophrenia, but the source of these deficits remains unclear. In 35 schizophrenia patients (SzP) and 34 healthy controls (HC), we used a rapid serial visual presentation (RSVP) visual search task designed to activate/deactivate the cortical components of the attentional control system (i.e. the dorsal and ventral attention networks, lateral prefrontal regions in the frontoparietal network, and cingulo-opercular/salience networks), along with resting state functional connectivity, to examine the integrity of these components. While we find that behavioral performance and activation/deactivation of the RSVP task are largely similar between groups, SzP exhibited decreased functional connectivity within late visual components and between prefrontal and other components. We also find that performance correlates with the deactivation of the ventral attention network in SzP only. This relationship is mediated by the functional connectivity of critical components of the attentional control system. In summary, our results suggest that the attentional control system is potentially used to compensate for visual cortex deficits. Furthermore, prefrontal deficits in SzP may interfere with this compensatory use of the attentional control system. In addition to highlighting focal deficits and potential compensatory mechanisms in visual processing and attention, our findings point to the attentional control system as a potential target for rehabilitation and neuromodulation-based treatments for visual processing deficits in SzP.

Reconfiguration of Dynamic Functional Connectivity in Sensory and Perceptual System in Schizophrenia

Schizophrenia is thought as a self-disorder with dysfunctional brain connectivity. This self-disorder is often attributed to high-order cognitive impairment. Yet due to the frequent report of sensorial and perceptual deficits, it has been hypothesized that self-disorder in schizophrenia is dysfunctional communication between sensory and cognitive processes. To further verify this assumption, the present study comprehensively examined dynamic reconfigurations of resting-state functional connectivity (rsFC) in schizophrenia at voxel level, region level, and network levels (102 patients vs. 124 controls). We found patients who show consistently increased rsFC variability in sensory and perceptual system, including visual network, sensorimotor network, attention network, and thalamus at all the three levels. However, decreased variability in high-order networks, such as default mode network and frontal-parietal network were only consistently observed at region and network levels. Taken together, these findings highlighted the rudimentary role of elevated instability of information communication in sensory and perceptual system and attenuated whole-brain integration of high-order network in schizophrenia, which provided novel neural evidence to support the hypothesis of disrupted perceptual and cognitive function in schizophrenia. The foci of effects also highlighted that targeting perceptual deficits can be regarded as the key to enhance our understanding of pathophysiology in schizophrenia and promote new treatment intervention.

A Human-Specific Schizophrenia Risk Tandem Repeat Affects Alternative Splicing of a Human-Unique Isoform AS3MTd2d3 and Mushroom Dendritic Spine Density

Recent advances in functional genomics have facilitated the identification of multiple genes and isoforms associated with the genetic risk of schizophrenia, yet the causal variations remain largely unclear. A previous study reported that the schizophrenia risk single-nucleotide polymorphism (SNP) rs7085104 at 10q24.32 was in high linkage disequilibrium (LD) with a human-specific variable number of tandem repeat (VNTR), and both were significantly associated with the brain mRNA expression of a human-unique AS3MTd2d3 isoform in Europeans and African Americans. In this study, we have shown the direct regulation of the AS3MTd2d3 mRNA expression by this VNTR through an in vitro minigene splicing assay, suggesting that it is likely a causative functional variation. Intriguingly, we have further confirmed that the VNTR and rs7085104 are significantly associated with AS3MTd2d3 mRNA expression in brains of Han Chinese donors, and rs7085104 is also associated with risk of schizophrenia in East Asians. Finally, the overexpression of AS3MTd2d3 in cultured primary hippocampal neurons results in significantly reduced densities of mushroom dendritic spines, implicating its potential functional impact. Considering the crucial roles of dendritic spines in neuroplasticity, these results reveal the potential regulatory impact of the schizophrenia risk VNTR on AS3MTd2d3 and provide insights into the underlying biological mechanisms.

Relational Memory in the Early Stage of Psychosis: A 2-Year Follow-up Study

BACKGROUND

Relational memory, the ability to bind information into complex memories, is moderately impaired in early psychosis and severely impaired in chronic schizophrenia, suggesting relational memory may worsen throughout the course of illness.

METHODS

We examined relational memory in 66 early psychosis patients and 64 healthy control subjects, with 59 patients and 52 control subjects assessed longitudinally at baseline and 2-year follow-up. Relational memory was assessed with 2 complementary tasks, to test how individuals learn relationships between items (face-scene binding task) and make inferences about trained relationships (associative inference task).

RESULTS

The early psychosis group showed impaired relational memory in both tasks relative to the healthy control group. The ability to learn relationships between items remained impaired in early psychosis patients, while the ability to make inferences about trained relationships improved, although never reaching the level of healthy control performance. Early psychosis patients who did not progress to schizophrenia at follow-up had better relational memory than patients who did.

CONCLUSIONS

Relational memory impairments, some of which improve and are less severe in patients who do not progress to schizophrenia, are a target for intervention in early psychosis.

Cognitive Brain Signatures of Youth With Early Onset and Relatives With Schizophrenia: Evidence From fMRI Meta-analyses

Deficits in cognitive function are a major characteristic of schizophrenia. Many functional magnetic resonance imaging (fMRI) studies examine brain correlates of cognitive function in adults with schizophrenia, showing altered implication of associative areas such as the prefrontal cortex and temporal cortex. fMRI studies also examine brain representation of cognitive function in adolescents with early onset schizophrenia and those at risk of the disorder, yet results are often inconsistent. We compile and analyze data from eligible fMRI studies using quantitative meta-analyses to reveal concordant brain activity associated with adolescent relatives of patients with schizophrenia and those with early onset schizophrenia. Results show similar functional hubs of brain activity (eg, precuneus) yet in opposite hemispheres and clusters in ventrolateral rather than dorsolateral prefrontal cortices. Other areas of altered implication include the middle temporal gyrus, insula, and cerebellum. We discuss the findings in reference to the protracted maturation of the prefrontal cortex and possible effects due to the medication status of the two groups.

Decreased interhemispheric connectivity and increased cortical excitability in unmedicated schizophrenia: A prefrontal interleaved TMS fMRI study

BACKGROUND

Prefrontal abnormalities in schizophrenia have consistently emerged from resting state and cognitive neuroimaging studies. However, these correlative findings require causal verification via combined imaging/stimulation approaches. To date, no interleaved transcranial magnetic stimulation and functional magnetic resonance imaging study (TMS fMRI) has probed putative prefrontal cortex abnormalities in schizophrenia.

OBJECTIVE

/Hypothesis: We hypothesized that subjects with schizophrenia would show significant hyperexcitability at the site of stimulation (BA9) and decreased interhemispheric functional connectivity.

METHODS

We enrolled 19 unmedicated subjects with schizophrenia and 22 controls. All subjects underwent brain imaging using a 3T MRI scanner with a SENSE coil. They also underwent a single TMS fMRI session involving motor threshold (rMT) determination, structural imaging, and a parametric TMS fMRI protocol with 10 Hz triplet pulses at 0, 80, 100 and 120% rMT. Scanning involved a surface MR coil optimized for bilateral prefrontal cortex image acquisition.

RESULTS

Of the original 41 enrolled subjects, 8 subjects with schizophrenia and 11 controls met full criteria for final data analyses. At equal TMS intensity, subjects with schizophrenia showed hyperexcitability in left BA9 (p = 0.0157; max z-score = 4.7) and neighboring BA46 (p = 0.019; max z-score = 4.47). Controls showed more contralateral functional connectivity between left BA9 and right BA9 through increased activation in right BA9 (p = 0.02; max z-score = 3.4). GM density in subjects with schizophrenia positively correlated with normalized prefrontal to motor cortex ratio of the corresponding distance from skull to cortex ratio (S-BA9/S-MC) (r = 0.83, p = 0.004).

CONCLUSIONS

Subjects with schizophrenia showed hyperexcitability in left BA9 and impaired interhemispheric functional connectivity compared to controls. Interleaved TMS fMRI is a promising tool to investigate prefrontal dysfunction in schizophrenia.

Adolescents at clinical high risk for psychosis show qualitatively altered patterns of activation during rule learning

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Novel investigation of novel rule learning in psychosis risk.

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Failed to replicate previous study comparing novel and practiced rule learning.

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No significant group differences, but effect size comparison revealed differences.

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Results suggest that psychosis risk group may rely on different rule retrieval strategies.

Background

The ability to flexibly apply rules to novel situations is a critical aspect of adaptive human behavior. While executive function deficits are known to appear early in the course of psychosis, it is unclear which specific facets are affected. Identifying whether rule learning is impacted at the early stages of psychosis is necessary for truly understanding the etiology of psychosis and may be critical for designing novel treatments. Therefore, we examined rule learning in healthy adolescents and those meeting criteria for clinical high risk (CHR) for psychosis.

Methods

24 control and 22 CHR adolescents underwent rapid, high-resolution fMRI while performing a paradigm which required them to apply novel or practiced task rules.

Results

Previous work has suggested that practiced rules rely on rostrolateral prefrontal cortex (RLPFC) during rule encoding and dorsolateral prefrontal cortex (DLPFC) during task performance, while novel rules show the opposite pattern. We failed to replicate this finding, with greater activity for novel rules during performance. Comparing the HC and CHR group, there were no statistically significant effects, but an effect size analysis found that the CHR group showed less activation during encoding and greater activation during performance. This suggests the CHR group may use less efficient reactive control to retrieve task rules at the time of task performance, rather than proactively during rule encoding.

Conclusions

These findings suggest that flexibility is qualitatively altered in the clinical high risk state, however, more data is needed to determine whether these deficits predict disease progression.

Relationships between abnormal neural activities and cognitive impairments in patients with drug-naive first-episode schizophrenia

BACKGROUND

Prior resting state functional Magnetic Resonance Imaging studies (rs-fMRI) via the regional homogeneity (ReHo) method have demonstrated inconsistent and conflicting results because of several confounding factors, such as small sample size, medicinal influence, and illness duration. Relationships between ReHo measures and cognitive impairments in patients with drug-naive First-Episode Schizophrenia (dn-FES) are rarely reported. This study was conducted to explore the correlations between ReHo measures and cognitive deficits and clinical symptoms in patients with dn-FES.

METHODS

A total of 69 patients with dn-FES and 74 healthy controls were recruited. MATRICS Consensus Cognitive Battery (MCCB), Wechsler Adult Intelligence Scale (WAIS), and Positive And Negative Syndrome Scale (PANSS) were used to assess cognitive function, Intelligence Quotient (IQ), and clinical symptoms, respectively. The correlations between ReHo maps and cognitive deficits and the severity of symptoms were examined using strict correlation analysis.

RESULTS

ReHo values in right Middle Frontal Gyrus (MFG) and Superior Frontal Gyrus (SFG) increased in dn-FES group, whereas ReHo values in right cuneus decreased. Correlation analysis showed that the ReHo values in right MFG positively correlated with attention/vigilance impairments, social cognition deficits, and the severity of clinical manifestations.

CONCLUSIONS

These findings suggested that abnormal spontaneous activities in right MFG reflect illness severity and cognitive deficits, which also serve as a basis for establishing objective diagnostic markers and might be a clinical intervention target for treating patients with schizophrenia.

Altered core networks of brain connectivity and personality traits in internet gaming disorder

BACKGROUND AND AIMS

Although the Internet has provided convenience and efficiency in many areas of everyday life, problems stemming from Internet use have also been identified, such as Internet gaming disorder (IGD). Internet addiction, which includes IGD, can be viewed as a behavioral addiction or impulse control disorder. This study investigated the altered functional and effective connectivity of the core brain networks in individuals with IGD compared to healthy controls (HCs).

METHODS

Forty-five adults with IGD and 45 HCs were included in this study. To examine the brain networks related to personality traits that influence problematic online gaming, the left and right central executive network (CEN) and the salience network (SN) were included in the analysis. Also, to examine changes in major brain network topographies, we analyzed the default mode network (DMN).

RESULTS

IGD participants showed lower functional connectivity between the dorsal lateral prefrontal cortex (DLPFC) and other regions in the CEN than HC participants during resting state. Also, IGD participants revealed reduced functional connectivity between the dorsal anterior cingulate cortex and other regions in the SN and lower functional connectivity in the medial prefrontal cortex of the anterior DMN. Notably, in IGD individuals but not HC individuals, there was a positive correlation between IGD severity and effective connectivity and a positive correlation between reward sensitivity and effective connectivity within the ventral striatum of the SN.

CONCLUSIONS

Problematic online gaming was associated with neurofunctional alterations, impairing the capacity of core brain networks.

Dysfunctional connectivity in posterior brain regions involved in cognitive control in schizophrenia: A preliminary fMRI study

Cognitive control, the ability to use goal-directed information to guide behaviour, is impaired in schizophrenia, and mainly related to dysfunctions within the fronto-posterior brain network. However, cognitive control is a broad cognitive function encompassing distinct sub-processes that, until now, studies have failed to separate and relate to specific brain regions. The goal of this preliminary fMRI study is to investigate the functional specialization of posterior brain regions, and their functional interaction with lateral prefrontal cortex (LPFC) regions, in schizophrenia. Fourteen healthy participants and 15 matched schizophrenic patients participated in this fMRI study. We used a task paradigm that differentiates two cognitive control sub-processes according to the temporal framing of information, namely the control of immediate context (present cues) vs. temporal episode (past instructions). We found that areas activated during contextual and episodic controls were in dorsal posterior regions and that activations did not significantly differ between schizophrenic patients and healthy participants. However, while processing contextual signals, patients with schizophrenia failed to show decreased connectivity between caudal LPFC and areas located in ventral posterior regions. The absence of group difference in the functional specialization of posterior regions is difficult to interpret due to our small sample size. One interpretation for our connectivity results is that patients present an inefficient extinction of posterior regions involved in attention shifting by prefrontal areas involved in the top-down control of contextual signals. Further studies with larger sample sizes will be needed to ascertain those observations.

Frequency-dependent gating of feedforward inhibition in thalamofrontal synapses

Thalamic recruitment of feedforward inhibition is known to enhance the fidelity of the receptive field by limiting the temporal window during which cortical neurons integrate excitatory inputs. Feedforward inhibition driven by the mediodorsal nucleus of the thalamus (MD) has been previously observed, but its physiological function and regulation remain unknown. Accumulating evidence suggests that elevated neuronal activity in the prefrontal cortex is required for the short-term storage of information. Furthermore, the elevated neuronal activity is supported by the reciprocal connectivity between the MD and the medial prefrontal cortex (mPFC). Therefore, detailed knowledge about the synaptic connections during high-frequency activity is critical for understanding the mechanism of short-term memory. In this study, we examined how feedforward inhibition of thalamofrontal connectivity is modulated by activity frequency. We observed greater short-term synaptic depression during disynaptic inhibition than in thalamic excitatory synapses during high-frequency activities. The strength of feedforward inhibition became weaker as the stimulation continued, which, in turn, enhanced the range of firing jitter in a frequency-dependent manner. We postulated that this phenomenon was primarily due to the increased failure rate of evoking action potentials in parvalbumin-expressing inhibitory neurons. These findings suggest that the MD-mPFC pathway is dynamically regulated by an excitatory-inhibitory balance in an activity-dependent manner. During low-frequency activities, excessive excitations are inhibited, and firing is restricted to a limited temporal range by the strong feedforward inhibition. However, during high-frequency activities, such as during short-term memory, the activity can be transferred in a broader temporal range due to the decreased feedforward inhibition.

Examining Specificity of Neural Correlates of Childhood Psychotic-like Experiences During an Emotional n-Back Task

BACKGROUND

Psychotic-like experiences (PLEs) during childhood are associated with greater risk of developing a psychotic disorder in adulthood, highlighting the importance of identifying neural correlates of childhood PLEs. Furthermore, impairment of cognitive functions, such as working memory and emotion regulation, has also been linked to psychosis risk as well as to disruptions in several brain regions. However, impairments in these domains have also been linked to other disorders, including depression. Therefore, the aim of the current study was to examine whether neural impairments in regions associated with working memory and implicit emotion regulation impairments are specific to PLEs versus depression.

METHODS

The current study used an emotional n-back task to examine the relationship between childhood PLEs and neural activation of regions involved in both working memory and implicit emotion regulation using data from 8805 9- to 11-year-olds in the Adolescent Brain Cognitive Development (ABCD) Study 2.0 release. To examine specificity, we also analyzed associations with depressive symptoms.

RESULTS

Our results indicated that increased PLEs during middle childhood were associated with decreased activation of the dorsolateral prefrontal cortex, striatum, and pallidum during trials requiring working memory. In contrast, increased activation of the parahippocampus, caudate, nucleus accumbens, and rostral anterior cingulate during face-viewing trials was associated with increased depressive symptoms.

CONCLUSIONS

These results support the dimensional view of psychosis across the lifespan, providing evidence that neural correlates of PLEs, such as decreased activation during working memory, are present during middle childhood. Furthermore, these correlates are specific to psychotic-like symptoms as compared with depressive symptoms.

Current challenges and possible future developments in personalized psychiatry with an emphasis on psychotic disorders

A personalized medicine approach seems to be particularly applicable to psychiatry. Indeed, considering mental illness as deregulation, unique to each patient, of molecular pathways, governing the development and functioning of the brain, seems to be the most justified way to understand and treat disorders of this medical category. In order to extract correct information about the implicated molecular pathways, data can be drawn from sampling phenotypic and genetic biomarkers and then analyzed by a machine learning algorithm. This review describes current difficulties in the field of personalized psychiatry and gives several examples of possibly actionable biomarkers of psychotic and other psychiatric disorders, including several examples of genetic studies relevant to personalized psychiatry. Most of these biomarkers are not yet ready to be introduced in clinical practice. In a next step, a perspective on the path personalized psychiatry may take in the future is given, paying particular attention to machine learning algorithms that can be used with the goal of handling multidimensional datasets.

Electrical status epilepticus in sleep affects intrinsically connected networks in patients with benign childhood epilepsy with centrotemporal spikes

BACKGROUND

Although outcomes of benign childhood epilepsy with centrotemporal spikes (BECTS) are frequently excellent, some atypical forms of BECTS, especially electrical status epilepticus in sleep (ESES), are characterized by worse outcomes and negative impacts on cognitive development.

METHODS

To explore specific ESES-related brain networks in patients with BECTS, we used resting-state functional magnetic resonance imaging (fMRI) to scan patients with BECTS with ESES (n = 9), patients with BECTS without ESES (n = 17), and healthy controls (n = 36). Unbiased seed-based whole-brain functional connectivity (FC) was adopted to explore the connectivity mode of three resting-state cerebral networks: the default mode network (DMN), salience network (SN), and central executive network (CEN).

RESULTS

Compared with the other two groups, patients with BECTS with ESES showed FC in the SN or in the CEN decreased, but not in the DMN. Moreover, we found the FC in the CEN in patients with BECTS without ESES decreased when compared with controls. Our currently intrinsically defined anticorrelated networks strength was disrupted in BECTS and connote greater deactivation than the results from FC for a seed region in children with BECTS.

CONCLUSION

These results indicated that children with BECTS with ESES showed brain activity altered in the CEN and the SN. The difference of impairment in the SN and CEN may lead to improve the understanding of the underlying neuropathophysiology, and to assess the activity of patients with BECTS with ESES, which is crucial for measuring disease activity, improving patient care, and assessing the effect of antiepilepsy therapy.

Partitioning heritability analyses unveil the genetic architecture of human brain multidimensional functional connectivity patterns

Resting-state functional connectivity profiles have been increasingly shown to be important endophenotypes that are tightly linked to human cognitive functions and psychiatric diseases, yet the genetic architecture of this multidimensional trait is barely understood. Using a unique sample of 1,704 unrelated, young and healthy Chinese Han individuals, we revealed a significant heritability of functional connectivity patterns in the whole brain and several subnetworks. We further proposed a partitioned heritability analysis for multidimensional functional connectivity patterns, which revealed the common and unique enrichment patterns of the genetic contributions to brain connectivity patterns for several gene sets linked to brain functions, including the genes expressed preferentially in the central nervous system and those associated with intelligence, educational attainment, attention-deficit/hyperactivity disorder, and schizophrenia. These results for the first time reveal the genetic architecture of multidimensional brain connectivity patterns across different networks and advance our understanding of the complex relationship between gene sets, neural networks, and behaviors.

Intra-Regional Glu-GABA vs Inter-Regional Glu-Glu Imbalance: A 1H-MRS Study of the Neurochemistry of Auditory Verbal Hallucinations in Schizophrenia

Glutamate (Glu), gamma amino-butyric acid (GABA), and excitatory/inhibitory (E/I) imbalance have inconsistently been implicated in the etiology of schizophrenia. Elevated Glu levels in language regions have been suggested to mediate auditory verbal hallucinations (AVH), the same regions previously associated with neuronal hyperactivity during AVHs. It is, however, not known whether alterations in Glu levels are accompanied by corresponding GABA alterations, nor is it known if Glu levels are affected in brain regions with known neuronal hypo-activity. Using magnetic resonance spectroscopy (MRS), we measured Glx (Glu+glutamine) and GABA+ levels in the anterior cingulate cortex (ACC), left and right superior temporal gyrus (STG), and left inferior frontal gyrus (IFG), in a sample of 77 schizophrenia patients and 77 healthy controls. Two MRS-protocols were used. Results showed a marginally significant positive correlation in the left STG between Glx and AVHs, whereas a significant negative correlation was found in the ACC. In addition, high-hallucinating patients as a group showed decreased ACC and increased left STG Glx levels compared to low-hallucinating patients, with the healthy controls in between the 2 hallucinating groups. No significant differences were found for GABA+ levels. It is discussed that reduced ACC Glx levels reflect an inability of AVH patients to cognitively inhibit their "voices" through neuronal hypo-activity, which in turn originates from increased left STG Glu levels and neuronal hyperactivity. A revised E/I-imbalance model is proposed where Glu-Glu imbalance between brain regions is emphasized rather than Glu-GABA imbalance within regions, for the understanding of the underlying neurochemistry of AVHs.

Comprehensive mapping of cytochrome c oxidase activity in the rat brain after sub-chronic ketamine administration

Ketamine is a noncompetitive antagonist of glutamatergic N-methyl-d-aspartate receptors. Its acute effects on healthy volunteers and schizophrenia patients mimic some acute psychotic, but also cognitive and negative symptoms of schizophrenia, and subchronic treatment with ketamine has been used as an animal model of psychotic disorders. Glutamatergic neurotransmission is tightly coupled to oxidative metabolism in the brain. Quantitative histochemical mapping of cytochrome c oxidase (COX) activity, which reflect long-term energy metabolism, was carried out in rats that received a daily subanaesthetic dose (30 mg/kg) of ketamine for 10 days. In total, COX activity was measured in 190 brain regions to map out metabolic adaptations to the subchronic administration of ketamine. Ketamine treatment was associated with elevated COX activity in nine brain sub-regions in sensory thalamus, basal ganglia, cortical areas, hippocampus and superior colliculi. Changes in pairwise correlations between brain regions were studied with differential correlation analysis. Ketamine treatment was associated with the reduction of positive association between brain regions in 66 % of the significant comparisons. Different layers of the superior colliculi showed the strongest effects. Changes in other visual and auditory brain centres were also of note. The locus coeruleus showed opposite pattern of increased coupling to mainly limbic brain regions in ketamine-treated rats. Our study replicated commonly observed activating effects of ketamine in the hippocampus, cingulate cortex, and basal ganglia. The current study is the first to extensively map the oxidative metabolism in the CNS in the ketamine model of schizophrenia. It shows that ketamine treatment leads to the re-organization of activity in sensory and memory-related brain circuits.

Altered functional connectivity of the thalamus induced by modified electroconvulsive therapy for schizophrenia

BACKGROUND

Electroconvulsive therapy (ECT) has been shown to be effective in schizophrenia (SZ), particularly in drug-refractory cases or when rapid symptom relief is needed. However, its precise mechanisms of action remain largely unclear. To clarify the mechanisms underlying modified electroconvulsive therapy (mECT) for SZ, we conducted a longitudinal cohort study evaluating functional connectivity of the thalamus before and after mECT treatment using sub-regions of thalamus as regions of interest (ROIs).

METHODS

Twenty-one SZ individuals taking only antipsychotics (DSZ group) for 4 weeks and 21 SZ patients receiving a regular course of mECT combining with antipsychotics (MSZ group) were observed in parallel. All patients underwent magnetic resonance imaging scans at baseline (t1) and follow-up (t2, ~4 weeks) time points. Data were compared to a matched healthy control group (HC group) consisting of 23 persons who were only scanned at baseline. Group differences in changes of thalamic functional connectivity between two SZ groups over time, as well as in functional connectivity among two SZ groups and HC group were assessed.

RESULTS

Significant interaction of group by time was found in functional connectivity of the right thalamus to right putamen during the course of about 4-week treatment. Post-hoc analysis showed a significantly enhanced functional connectivity of the right thalamus to right putamen in the MSZ group contrasting to the DSZ group. In addition, a decreased and an increased functional connectivity of the thalamus to sensory cortex were observed within the MSZ and DSZ group after 4-week treatment trial, respectively.

CONCLUSION

Our findings suggest that changes in functional connectivity of the thalamus may be associated with the brain mechanisms of mECT for schizophrenia.

Perinatal complications and executive dysfunction in early-onset schizophrenia

BACKGROUND

The present study examined the association between perinatal obstetric complications and executive dysfunction in early-onset schizophrenia (EOS), compared to healthy controls. Higher incidences of obstetric complications and more severe executive dysfunctions characterize EOS. Research shows extensive brain maturation in newborns, suggesting them to be particularly vulnerable for perinatal insults. Executive function is mainly mediated by the prefrontal cortex, an area that matures last during pregnancy. Thus, exposure to perinatal complications may influence executive dysfunction in EOS.

METHODS

The participants were 19 EOS patients and 54 healthy controls. Executive function was assessed with the D-KEFS Color Word Interference Test and the Wisconsin Card Sorting Test. Information on perinatal obstetric complications and Apgar 5-min scores were obtained from the Norwegian Medical Birth Registry. Associations between perinatal conditions and executive function were studied using stepwise regression analyses.

RESULTS

Perinatal complications, and especially shorter gestational lengths, were significantly associated with significant executive dysfunctions in EOS. Perinatal complications did not affect executive function among healthy controls. A significant relationship between lower Apgar 5-min scores and executive dysfunction was found among both EOS patients and healthy controls.

CONCLUSIONS

Exposure to perinatal complications, and particularly a shorter gestational length, was associated with increased executive dysfunction in EOS. Exposed healthy controls did not exhibit similar executive difficulties, suggesting that the EOS patients seemed especially vulnerable for executive deficits due to perinatal insults. The findings indicate that EOS youths learn more slowly and experience more difficulty with problem-solving, which carry important implications for clinical practice. Lower Apgar 5-min scores were associated with executive dysfunction in both groups. Low Apgar score at 5 min may therefore be an important early indicator of executive difficulties among adolescents, independent of diagnosis.

Effectiveness of integrated psychological therapy on cognitive function among Lebanese patients with schizophrenia: a pilot study

Background: The integrated term emphasises the need for cognitive therapy to always be embedded into an extended treatment concept adapted to cognitive resources and deficits and to patient rehabilitation. One of the first approaches is integrated psychological therapy (IPT).Aim: To assess the effect of the IPT Programme compared to the Treatment as Usual (TaU) in terms of cognitive performance and social skills among a group of schizophrenic patients.Methods: This randomised controlled study enrolled 20 patients in each group. Patients attended 60-min sessions, 3 days/week.Results: When considering the TaU group, the bivariate results showed that significantly higher means of attention scores, lower means in social dysfunction and aggression, social adaptation scores were found after IPT compared to before. The effect size for all tests was found to be weak. When considering the IPT group, significantly higher means attention score, lower means cognitive disorders, social dysfunction, aggression and social adaptation scores were found after IPT compared to before. The effect size for all tests was found to be high.Conclusion: The therapeutic combination of the IPT programme with medical treatment has shown additional beneficial effects on the schizophrenic patients' treatment, enabling them, as far as possible, to reintegrate into the community.KEY POINTSIn cases, a significantly higher GZ-F and KL scores and a lower SDAS-9 and SDAS-6 scores were found post-IPT respectively.In controls, a significant increase in the GZ-F and KL subscales and a decrease in all other scales was found post-IPT respectively.This therapeutic combination of the integrative programme with medical treatment has shown additive beneficial effects in patients with schizophreniaThe treatment approach would allow them, as far as possible, to reintegrate within the community.

Failure of activation of striatum during the performance of executive function tasks in adult patients with bipolar disorder

BACKGROUND

Although numerous studies have used functional neuroimaging to identify executive dysfunction in patients with bipolar disorder (BD), the findings are not consistent. The aim of this meta-analysis is to identify the most reliable functional anomalies in BD patients during performance of Executive Function (EF) tasks.

METHODS

A web-based search was performed on publication databases to identify functional magnetic resonance imaging studies of BD patients performing EF tasks and a voxel-based meta-analytic method known as anisotropic Effect Size Signed Differential Mapping (ES-SDM) was used to identify brain regions which showed anomalous activity in BD patients compared with healthy controls (HC).

RESULTS

Twenty datasets consisting of 463 BD patients and 484 HC were included. Compared with HC, BD patients showed significant hypo-activation or failure of activation in the left striatum (p = 0.00007), supplementary motor area (BA 6, p = 0.00037), precentral gyrus (BA 6, p = 0.0014) and cerebellum (BA 37, p = 0.0019), and hyper-activation in the left gyrus rectus (BA 11, p ≈ 0) and right middle temporal gyrus (BA 22, p = 0.00031) during performance of EF tasks. Sensitivity and subgroup analyses showed that the anomaly of left striatum is consistent across studies and present in both euthymic and BD I patients.

CONCLUSIONS

Patients with BD consistently showed abnormal activation in the cortico-striatal system during performance of EF tasks compared with HC. Failure of activation of the striatum may be a reliable marker for impairment in performance of especially inhibition tasks by patients with BD.

Striatal and Thalamic Auditory Response During Deep Brain Stimulation for Essential Tremor: Implications for Psychosis

INTRODUCTION

The P50, a positive auditory-evoked potential occurring 50 msec after an auditory click, has been characterized extensively with electroencephalography (EEG) to detect aberrant auditory electrophysiology in disorders like schizophrenia (SZ) where 61-74% have an auditory gating deficit. The P50 response occurs in primary auditory cortex and several thalamocortical regions. In rodents, the gated P50 response has been identified in the reticular thalamic nucleus (RT)-a deep brain structure traversed during deep brain stimulation (DBS) targeting of the ventral intermediate nucleus (VIM) of the thalamus to treat essential tremor (ET) allowing for interspecies comparison. The goal was to utilize the unique opportunity provided by DBS surgery for ET to map the P50 response in multiple deep brain structures in order to determine the utility of intraoperative P50 detection for facilitating DBS targeting of auditory responsive subterritories.

MATERIALS AND METHODS

We developed a method to assess P50 response intraoperatively with local field potentials (LFP) using microelectrode recording during routine clinical electrophysiologic mapping for awake DBS surgery in seven ET patients. Recording sites were mapped into a common stereotactic space.

RESULTS

Forty significant P50 responses of 155 recordings mapped to the ventral thalamus, RT and CN head/body interface at similar rates of 22.7-26.7%. P50 response exhibited anatomic specificity based on distinct positions of centroids of positive and negative responses within brain regions and the fact that P50 response was not identified in the recordings from either the internal capsule or the dorsal thalamus.

CONCLUSIONS

Detection of P50 response intraoperatively may guide DBS targeting RT and subterritories within CN head/body interface-DBS targets with the potential to treat psychosis and shown to modulate schizophrenia-like aberrancies in mouse models.

A longitudinal comparison of two neurocognitive test batteries in patients with schizophrenia and healthy volunteers: Time effects on neuropsychological performance and their relation to functional outcome

Cognitive impairment is a major unmet need in the treatment of schizophrenia. Over the last decade, the MATRICS Consensus Cognitive Battery (MCCB) has been used to assess the effects of novel treatments for cognitive impairment in schizophrenia. However, other cognitive-neuroscience-based cognitive batteries, such as the Cambridge Neuropsychological Test Automated Battery (CANTAB) have been suggested as an alternative to the MCCB. Although both batteries purport to assess cognitive function in psychosis, no previous study has attempted to examine their validity longitudinally and the potential overlap between the two batteries over time. The aim of the current study was to assess the relationship between the MCCB and the CANTAB in the longitudinal assessment of cognitive impairment in schizophrenia. A sample of 39 stable schizophrenia outpatients and 18 controls completed the MCCB and the CANTAB battery at baseline, and at 2, 4 and 8-weeks follow-up. Correlation analyses and a mixed-model repeated measures approach were used. We found no significant effect of time in the MCCB. In contrast, for the CANTAB a significant effect of time consistent with practice effects for the attention domain in the control group and for the visual learning, reasoning and problem-solving, and social cognition domains in patients, with subjects performing better at follow-up. In particular, a significant time ∗ battery interaction was found for those cognitive domains. These findings suggest there are specific differences across cognitive tests to assess cognitive impairments in schizophrenia and that measures derived from the CANTAB appear to be more prone to practice effects in these patients.

Roles of the medial prefrontal cortex, mediodorsal thalamus, and their combined circuit for performance of the odor span task in rats: analysis of memory capacity and foraging behavior

Working memory (WM), the capacity for short-term storage of small quantities of information for immediate use, is thought to depend on activity within the prefrontal cortex. Recent evidence indicates that the prefrontal neuronal activity supporting WM is driven by thalamocortical connections arising in mediodorsal thalamus (mdThal). However, the role of these connections has not been studied using olfactory stimuli leaving open the question of whether this circuit extends to all sensory modalities. Additionally, manipulations of the mdThal in olfactory memory tasks have yielded mixed results. In the present experiment, we investigated the role of connections between the rat medial prefrontal cortex (mPFC) and mdThal in the odor span task (OST) using a pharmacological contralateral disconnection technique. Inactivation of either the mPFC or mdThal alone both significantly impaired memory performance in the OST, replicating previous findings with the mPFC and confirming that the mdThal plays an essential role in intact OST performance. Contralateral disconnection of the two structures impaired OST performance in support of the idea that the OST relies on mPFC-mdThal connections, but ipsilateral control infusions also impaired performance, complicating this interpretation. We also performed a detailed analysis of rats’ errors and foraging behavior and found a dissociation between mPFC and mdThal inactivation conditions. Inactivation of the mdThal and mPFC caused a significant reduction in the number of approaches rats made per odor, whereas only mdThal inactivation or mPFC-mdThal disconnection caused significant increases in choice latency. Our results confirm that the mdThal is necessary for performance of the OST and that it may critically interact with the mPFC to mediate OST performance. Additionally, we have provided evidence that the mPFC and mdThal play dissociable roles in mediating foraging behavior.

Neural Correlates Underlying the Precision of Visual Working Memory

The neural mechanisms associated with the limited capacity of working memory (WM) has long been studied, but it is still unclear which neural regions are associated with the precision of visual WM. Here, an orientation recall task for estimating the trial-wise precision of visual WM was performed and then repeated two weeks later in an fMRI scanner. Results showed that activity in frontal and parietal regions during WM maintenance scaled with WM load, but not with the precision of WM (i.e., recall error in radians). Conversely, activity in the lateral occipital complex (LOC) during WM maintenance was not affected by memory load, but rather, correlated with WM precision on a trial-by-trial basis. Moreover, activity in LOC also correlated with the individual participant's precision of WM from a separate behavioral experiment. Interestingly, a region within the prefrontal cortex, the inferior frontal junction (IFJ), exhibited greater functional connectivity with LOC when the WM load increased. Together, our findings provide unique evidence that the LOC supports visual WM precision, while communication between the IFJ and LOC varies based on WM load demands. These results suggest an intriguing possibility that distinct neural mechanisms may be associated with general content (load) or detailed information (precision) of WM.

Differential Roles of Mediodorsal Nucleus of the Thalamus and Prefrontal Cortex in Decision-Making and State Representation in a Cognitive Control Task Measuring Deficits in Schizophrenia

The mediodorsal nucleus of the thalamus (MD) is reciprocally connected with the prefrontal cortex (PFC), and although the MD has been implicated in a range of PFC-dependent cognitive functions (Watanabe and Funahashi, 2012; Mitchell and Chakraborty, 2013; Parnaudeau et al., 2018), little is known about how MD neurons in the primate participate specifically in cognitive control, a capability that reflects the ability to use contextual information (such as a rule) to modify responses to environmental stimuli. To learn how the MD-PFC thalamocortical network is engaged to mediate forms of cognitive control that are selectively disrupted in schizophrenia, we trained male monkeys to perform a variant of the AX continuous performance task, which reliably measures cognitive control deficits in patients (Henderson et al., 2012) and used linear multielectrode arrays to record neural activity in the MD and PFC simultaneously. We found that the two structures made clearly different contributions to distributed processing for cognitive control: MD neurons were specialized for decision-making and response selection, whereas prefrontal neurons were specialized to preferentially encode the environmental state on which the decision was based. In addition, we observed that functional coupling between MD and PFC was strongest when the decision as to which of the two responses in the task to execute was being made. These findings delineate unique contributions of MD and PFC to distributed processing for cognitive control and characterized neural dynamics in this network associated with normative cognitive control performance.SIGNIFICANCE STATEMENT Cognitive control is fundamental to healthy human executive functioning (Miller and Cohen, 2001) and deficits in patients with schizophrenia relate to decreased functional activation of the MD thalamus and the prefrontal cortex (Minzenberg et al., 2009), which are reciprocally linked (Goldman-Rakic and Porrino, 1985; Xiao et al., 2009). We carry out simultaneous neural recordings in the MD and PFC while monkeys perform a cognitive control task translated from patients with schizophrenia to relate thalamocortical dynamics to cognitive control performance. Our data suggest that state representation and decision-making computations for cognitive control are preferentially performed by PFC and MD, respectively. This suggests experiments to parse decision-making and state representation deficits in patients while providing novel computational targets for future therapies.

Neurovascular Uncoupling in Schizophrenia: A Bimodal Meta-Analysis of Brain Perfusion and Glucose Metabolism

The use of modern neuroimaging approaches has demonstrated resting-state regional cerebral blood flow (rCBF) to be tightly coupled to resting cerebral glucose metabolism (rCMRglu) in healthy brains. In schizophrenia, several lines of evidence point toward aberrant neurovascular coupling, especially in the prefrontal regions. To investigate this, we used Signed Differential Mapping to undertake a voxel-based bimodal meta-analysis examining the relationship between rCBF and rCMRglu in schizophrenia, as measured by arterial spin labeling (ASL) and ¹⁸Flurodeoxyglucose positron emission tomography (FDG-PET) respectively. We used 19 studies comprised of data from 557 patients and 584 controls. Our results suggest that several key regions implicated in the pathophysiology of schizophrenia such as the frontoinsular cortex, dorsal ACC, putamen, and temporal pole show conjoint metabolic and perfusion abnormalities in patients. In contrast, discordance between metabolism and perfusion were seen in superior frontal gyrus and cerebellum, indicating that factors contributing to neurovascular uncoupling (e.g. inflammation, mitochondrial dysfunction, oxidative stress) are likely operates at these loci. Studies enrolling patients on high doses of antipsychotics had showed larger rCBF/rCMRglu effects in patients in the left dorsal striatum. Hybrid ASL-PET studies focusing on these regions could confirm our proposition regarding neurovascular uncoupling at superior frontal gyrus in schizophrenia.