Surface morphology of the orbitofrontal cortex in individuals at risk of psychosis: a multicenter study

Anatomical variations in the insular cortex in individuals at a clinical high-risk state for psychosis and patients with schizophrenia

Introduction

Since the number of insular gyri is higher in schizophrenia patients, it has potential as a marker of early neurodevelopmental deviations. However, it currently remains unknown whether the features of the insular gross anatomy are similar between schizophrenia patients and individuals at risk of psychosis. Furthermore, the relationship between anatomical variations in the insular cortex and cognitive function has not yet been clarified.

Methods

The gross anatomical features (i.e., the number of gyri and development pattern of each gyrus) of the insular cortex were examined using magnetic resonance imaging, and their relationships with clinical characteristics were investigated in 57 subjects with an at-risk mental state (ARMS) and 63 schizophrenia patients in comparison with 61 healthy controls.

Results

The number of insular gyri bilaterally in the anterior subdivision was higher in the ARMS and schizophrenia groups than in the control group. The schizophrenia group was also characterized by a higher number of insular gyri in the left posterior subdivision. A well-developed right middle short insular gyrus was associated with symptom severity in first-episode schizophrenia patients, whereas chronic schizophrenia patients with a well-developed left accessory gyrus were characterized by less severe cognitive impairments in motor and executive functions. The features of the insular gross anatomy were not associated with clinical characteristics in the ARMS group.

Discussion

The features of the insular gross anatomy that were shared in the ARMS and schizophrenia groups may reflect a vulnerability to psychosis that may be attributed to anomalies in the early stages of neurodevelopment. However, the contribution of the insular gross anatomy to the clinical characteristics of schizophrenia may differ according to illness stages.

Increased inosine levels in drug-free individuals with at-risk mental state: A serum metabolomics study

AIM

At-risk mental state (ARMS) has been recently attracting attention with respect to the improvement of the management and outcome of psychiatric diseases, such as schizophrenia. Since only a few studies have reported on biological alterations in ARMS, serum metabolomics was carried out in ARMS subjects and healthy controls using liquid chromatography with high-resolution mass spectrometry.

METHODS

Serum samples were collected from ARMS subjects (n = 24; male: 12; female 12) and age- and sex-matched healthy controls (n = 23 male: 11, female: 12). After serum pre-treatment, liquid chromatography with high-resolution mass spectrometry was performed. Multivariate analyses, such as orthogonal partial least-squares discriminant and volcano plot analyses, were performed.

RESULTS

Serum inosine, lactate, taurine, 2,3-dihydroxypropanoate and glutamate levels differed between the two groups. A significant increase in inosine levels was detected in the positive- and negative-ion modes; however, significant differences were not observed in the levels of other purine-related metabolites (hypoxanthine, xanthine and urate) between the two groups.

CONCLUSION

Increased inosine levels may serve as biological markers for ARMS, in addition to alterations in the levels of lactate and certain amino acids.

Towards Deciphering the Fetal Foundation of Normal Cognition and Cognitive Symptoms From Sulcation of the Cortex

Growing evidence supports that prenatal processes play an important role for cognitive ability in normal and clinical conditions. In this context, several neuroimaging studies searched for features in postnatal life that could serve as a proxy for earlier developmental events. A very interesting candidate is the sulcal, or sulco-gyral, patterns, macroscopic features of the cortex anatomy related to the fold topology-e.g., continuous vs. interrupted/broken fold, present vs. absent fold-or their spatial organization. Indeed, as opposed to quantitative features of the cortical sheet (e.g., thickness, surface area or curvature) taking decades to reach the levels measured in adult, the qualitative sulcal patterns are mainly determined before birth and stable across the lifespan. The sulcal patterns therefore offer a window on the fetal constraints on specific brain areas on cognitive abilities and clinical symptoms that manifest later in life. After a global review of the cerebral cortex sulcation, its mechanisms, its ontogenesis along with methodological issues on how to measure the sulcal patterns, we present a selection of studies illustrating that analysis of the sulcal patterns can provide information on prenatal dispositions to cognition (with a focus on cognitive control and academic abilities) and cognitive symptoms (with a focus on schizophrenia and bipolar disorders). Finally, perspectives of sulcal studies are discussed.

Recent Advances and Future Directions in Brain MR Imaging Studies in Schizophrenia: Toward Elucidating Brain Pathology and Developing Clinical Tools

Schizophrenia is a common severe psychiatric disorder that affects approximately 1% of general population through the life course. Historically, in Kraepelin's time, schizophrenia was a disease unit conceptualized as dementia praecox; however, since then, the disease concept has changed. Recent MRI studies had shown that the neuropathology of the brain in this disorder was characterized by mild progression before and after the onset of the disease, and that the brain alterations were relatively smaller than assumed. Although genetic factors contribute to the brain alterations in schizophrenia, which are thought to be trait differences, other changes include factors that are common in psychiatric diseases. Furthermore, it has been shown that the brain differences specific to schizophrenia were relatively small compared to other changes, such as those caused by brain development, aging, and gender. In addition, compared to the disease and participant factors, machine and imaging protocol differences could affect MRI signals, which should be addressed in multi-site studies. Recent advances in MRI modalities, such as multi-shell diffusion-weighted imaging, magnetic resonance spectroscopy, and multimodal brain imaging analysis, may be candidates to sharpen the characterization of schizophrenia-specific factors and provide new insights. The Brain/MINDS Beyond Human Brain MRI (BMB-HBM) project has been launched considering the differences and noises irrespective of the disease pathologies and includes the future perspectives of MRI studies for various psychiatric and neurological disorders. The sites use restricted MRI machines and harmonized multi-modal protocols, standardized image preprocessing, and traveling subject harmonization. Data sharing to the public will be planned in FY 2024. In the future, we believe that combining a high-quality human MRI dataset with genetic data, randomized controlled trials, and MRI for non-human primates and animal models will enable us to understand schizophrenia, elucidate its neural bases and therapeutic targets, and provide tools for clinical application at bedside.

Heschl's Gyrus Duplication Pattern in Individuals at Risk of Developing Psychosis and Patients With Schizophrenia

An increased prevalence of duplicated Heschl’s gyrus (HG), which may reflect an early neurodevelopmental pathology, has been reported in schizophrenia (Sz). However, it currently remains unclear whether individuals at risk of psychosis exhibit similar brain morphological characteristics. This magnetic resonance imaging study investigated the distribution of HG gyrification patterns [i.e., single HG, common stem duplication (CSD), and complete posterior duplication (CPD)] and their relationship with clinical characteristics in 57 individuals with an at-risk mental state (ARMS) [of whom 5 (8.8%) later developed Sz], 63 patients with Sz, and 61 healthy comparisons. The prevalence of duplicated HG patterns (i.e., CSD or CPD) bilaterally was significantly higher in the ARMS and Sz groups than in the controls, whereas no significant differences were observed in HG patterns between these groups. The left CSD pattern, particularly in the Sz group, was associated with a verbal fluency deficit. In the ARMS group, left CSD pattern was related to a more severe general psychopathology. The present results suggest that an altered gyrification pattern on the superior temporal plane reflects vulnerability factors associated with Sz, which may also contribute to the clinical features of high-risk individuals, even without the onset of psychosis.

Increased Heschl's Gyrus Duplication in Schizophrenia Spectrum Disorders: A Cross-Sectional MRI Study

Duplicated Heschl's gyrus (HG) is prevalent in patients with schizophrenia and may reflect early neurodevelopmental anomalies. However, it currently remains unclear whether patients with schizotypal disorder, a prototypic disorder within the schizophrenia spectrum, exhibit a similar HG gyrification pattern. In this magnetic resonance imaging study, HG gyrification patterns were examined in 47 patients with schizotypal disorder, 111 with schizophrenia, and 88 age- and sex-matched healthy subjects. HG gyrification patterns were classified as single, common stem duplication (CSD), or complete posterior duplication (CPD). The prevalence of the duplicated HG patterns (CSD or CPD) bilaterally was higher in the schizophrenia and schizotypal groups than in healthy controls, whereas no significant difference was observed between the schizophrenia and schizotypal groups. Schizophrenia patients with the right CPD pattern had less severe positive symptoms, whereas the right single HG pattern was associated with higher doses of antipsychotic medication in schizotypal patients. The present study demonstrated shared HG gyrification patterns in schizophrenia spectrum disorders, which may reflect a common biological vulnerability factor. HG patterns may also be associated with susceptibility to psychopathology.

Orbitofrontal sulcogyral morphology in patients with cocaine use disorder

Orbitofrontal cortex (OFC) is thought to be involved in appropriate processing of rewarding stimuli, and abnormal OFC structure and function has been found in patients with substance use disorders. Atypical patterns of the H-sulcus in the OFC have been primarily identified with schizophrenia, but also with bipolar disorder, both of which are associated with comorbid substance use. Given the high rates of substance use within Axis I psychiatric disorders, it is reasonable to consider how frequencies of OFC patterns in populations with only substance use compare to controls. This information is crucial to disentangle whether atypical frequencies of H-sulcus sulcogyral patterns within psychopathology are associated with the psychiatric or substance use phenotype. Here, we present the first analysis of H-sulcus sulcogyral patterns in a population of adult black men with (n = 84) and without (n = 24) cocaine use disorder (CUD). We find that OFC sulcogyral patterns are not significantly different from the control group, indicating that OFC sulcogyral patterns are not disrupted in patients with CUD. As exploratory analyses, we describe OFC sulcogyral pattern subtypes in this cohort as well as an additional control group (n = 52), in order to add to the growing body of literature on OFC sulcogyral pattern characterization.

Orbitofrontal Sulcogyral Pattern as a Transdiagnostic Trait Marker of Early Neurodevelopment in the Social Brain

Objective. To systematically assess previous findings on the orbitofrontal sulcogyral pattern in psychiatric disorders and to address the utility of this pattern as a transdiagnostic trait marker of early neurodevelopment in the social brain. Methods. An online literature search was conducted using the PubMed database from inception to August 2019. Studies included in this review were based on the Chiavaras's original classification method of this H-shaped sulcus (type I, II, and III), intermediate orbital sulcus (IOS), and posterior orbital sulcus (POS). Results. Twenty-six studies were included in the review. Sixteen studies (62%) focused on schizophrenia spectrum (Sz) disorders, and the remaining studies focused on autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), history of extremely preterm and extremely low birth weight, bipolar disorder (BD), panic disorder, obsessive-compulsive disorder, cannabis users, and pathological gambling. In Sz, compared with healthy controls, the orbitofrontal sulcogyral pattern was decreased in type I, increased in type II and III, and there were fewer numbers of IOS and POS reported, although specificity in sex and hemispheric dominance was not consistent. BD and neurodevelopmental disorders in ASD and ADHD showed a similar pattern of alteration to that observed in the Sz. Conclusions. The present review of the orbitofrontal sulcogyral pattern indicated that type I expression might reflect a neurodevelopmental protective marker, and type II and III expressions, as well as fewer numbers of IOS and POS, might reflect neurodevelopmental risk markers. These trait markers may be transdiagnostic among socially disabling diseases.

Association between olfactory sulcus morphology and olfactory functioning in schizophrenia and psychosis high-risk status

Olfactory impairment has been reported in patients with schizophrenia and individuals with a high risk of psychosis, but its neural basis is largely unknown. We used magnetic resonance imaging to investigate the morphology of the olfactory sulcus (an indicator of olfactory system development) and its relation to olfactory function in 38 persons with an at-risk mental state (ARMS), 62 patients with schizophrenia, and 61 healthy controls. Odor detection and identification were examined with a T & T olfactometer. Compared with the controls, the olfactory sulcus was significantly shallower and odor identification was inferior among the ARMS and schizophrenia subjects. Across all subjects, but not within each group, the olfactory sulcus depth was significantly related to better identification of odors. Our results support the concept that olfactory sulcus morphology reflects the neurodevelopmental process of the olfactory system.

Altered orbitofrontal sulcogyral patterns in gambling disorder: a multicenter study

Gambling disorder is a serious psychiatric condition characterized by decision-making and reward processing impairments that are associated with dysfunctional brain activity in the orbitofrontal cortex (OFC). However, it remains unclear whether OFC functional abnormalities in gambling disorder are accompanied by structural abnormalities. We addressed this question by examining the organization of sulci and gyri in the OFC. This organization is in place very early and stable across life, such that OFC sulcogyral patterns (classified into Types I, II, and III) can be regarded as potential pre-morbid markers of pathological conditions. We gathered structural brain data from nine existing studies, reaching a total of 165 individuals with gambling disorder and 159 healthy controls. Our results, supported by both frequentist and Bayesian statistics, show that the distribution of OFC sulcogyral patterns is skewed in individuals with gambling disorder, with an increased prevalence of Type II pattern compared with healthy controls. Examination of gambling severity did not reveal any significant relationship between OFC sulcogyral patterns and disease severity. Altogether, our results provide evidence for a skewed distribution of OFC sulcogyral patterns in gambling disorder and suggest that pattern Type II might represent a pre-morbid structural brain marker of the disease. It will be important to investigate more closely the functional implications of these structural abnormalities in future work.

Potential role of orbitofrontal surface morphology on social and cognitive functions in high-risk subjects for psychosis and schizophrenia patients

This MRI study examined the surface morphology of the orbitofrontal cortex (OFC) and its relation to social and cognitive functions in 38 individuals with at-risk mental state (ARMS) and 63 schizophrenia patients in comparison with 61 healthy controls. The ARMS and schizophrenia groups had increased right OFC Type III expression and fewer orbital sulci, which were partly associated with social and cognitive impairments. OFC underdevelopment may underlie vulnerability to psychosis, as well as the core clinical features of the illness.

No regional gray matter volume reduction observed in young Japanese people at ultra-high risk for psychosis: A voxel-based morphometry study

OBJECTIVES

Structural brain magnetic resonance imaging studies of individuals at ultra-high risk (UHR) for psychosis have shown subtle but widespread reductions in baseline gray matter volume (GMV) in the frontal, temporal, and limbic regions compared with healthy controls (HC). These regions coincide with regions of reduced GMV in patients with established psychosis and have led to the consideration of structural changes in UHR as a potential biomarker for future transition to psychosis. However, most studies have been from Europe, North America, and Australia, with few reports from other regions, and two recent studies from Asian countries have failed to detect regional GMV reduction in UHR, suggesting the need for further analysis of an Asian sample. In this study, we investigated GMV reduction in Japanese UHR subjects.

RESULTS

The study used voxel-based morphometry to compare magnetic resonance imaging brain scans between 45 UHR individuals recruited by a specialist and 33 HCs. This showed no significant GMV reduction in the UHR group compared with the healthy control group. This negative result may be attributable to characteristics of Asian samples, such as a low prevalence of illicit drug use, or to the heterogeneous nature of UHR subjects.