Decreased number of orbital sulci in schizophrenia spectrum disorders

Birth season and gross brain morphology associated with early neurodevelopment in schizophrenia spectrum patients and healthy subjects

This MRI study examined the effects of birth seasons on gross brain characteristics, such as the prevalence/size of midline brain structures (cavum septi pellucidi and adhesio interthalamica), orbitofrontal surface morphology, and insular gross anatomy, in 135 patients with schizophrenia, 47 with schizotypal disorder, and 88 healthy controls. Birth seasons only affected the insular anatomy. Summer-born subjects (N = 110) were characterized by more developed left insular gyri than winter-born subjects; however, this effect had no diagnostic specificity. The present results do not support birth seasons affecting the neurodevelopmental pathology of schizophrenia spectrum.

Gross anatomical features of the insular cortex in schizophrenia and schizotypal personality disorder: Potential relationships with vulnerability, illness stages, and clinical subtypes

INTRODUCTION

Patients with schizophrenia have a higher number of insular gyri; however, it currently remains unclear whether the brain characteristics of patients with schizotypal personality disorder (SPD), a mild form of schizophrenia, are similar. It is also unknown whether insular gross anatomical features are associated with the illness stages and clinical subtypes of schizophrenia.

MATERIALS AND METHODS

This magnetic resonance imaging study examined gross anatomical variations in the insular cortex of 133 patients with schizophrenia, 47 with SPD, and 88 healthy controls. The relationships between the insular gross anatomy and schizophrenia subgroups (71 first-episode and 58 chronic groups, 38 deficit and 37 non-deficit subtype groups) were also investigated.

RESULTS

The number of insular gyri was higher in the schizophrenia and SPD patients than in the controls, where the patients were characterized by well-developed accessory, middle short, and posterior long insular gyri. The insular gross anatomy did not significantly differ between the first-episode and chronic schizophrenia subgroups; however, the relationship between the developed accessory gyrus and more severe positive symptoms was specific to the first-episode group. The prevalence of a right middle short gyrus was higher in the deficit schizophrenia group than in the non-deficit group.

DISCUSSION

These findings suggest that schizophrenia and SPD patients may share an altered insular gross morphology as a vulnerability factor associated with early neurodevelopmental anomalies, which may also contribute to positive symptomatology in the early illness stages and clinical subtypes of schizophrenia.

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.

The use of the orbitofrontal H-sulcus as a reference frame for value signals

Understanding the factors that drive organization and function of the brain is an enduring question in neuroscience. Using functional magnetic resonance imaging (fMRI), structure and function have been mapped in primary sensory cortices based on knowledge of the organizational principles that likely drive a given region (e.g., aspects of visual form in primary visual cortex and sound frequency in primary auditory cortex) and knowledge of underlying cytoarchitecture. The organizing principles of higher-order brain areas that encode more complex signals, such as the orbitofrontal cortex (OFC), are less well understood. One fundamental component that underlies the many functions of the OFC is the ability to compute the reward or value of a given object. There is evidence of variability in the spatial location of responses to specific categories of objects (or value of said objects) within the OFC, and several reference frames have been proposed to explain this variability, including topographic spatial gradients that correspond to axes of primary versus secondary rewards and positive versus negative reinforcers. One potentially useful structural morphometric reference frame in the OFC is the "H-sulcus," a pattern formed by medial orbital, lateral orbital and transverse orbital sulci. In 48 human subjects, we use a structural morphometric tracing procedure to localize functional activation along the H-sulcus for face and food stimuli. We report the novel finding that food-selective responses are consistently found within the caudal portion of the medial orbital sulcus, but no consistency within the H-sulcus for response to face stimuli. These results suggest that sulcogyral anatomy of the H-sulcus may be an important morphological metric that contributes to the organizing principles of the OFC response to certain stimulus categories, including food.

Increased brain gyrification in the schizophrenia spectrum

AIM

Increased brain gyrification in diverse cortical regions has been reported in patients with schizophrenia, possibly reflecting deviations in early neurodevelopment. However, it remains unknown whether patients with schizotypal disorder exhibit similar changes.

METHODS

This magnetic resonance imaging study investigated brain gyrification in 46 patients with schizotypal disorder (29 male, 17 female), 101 patients with schizophrenia (55 male, 46 female), and 77 healthy controls (44 male, 33 female). T1-weighted magnetic resonance images were obtained for each participant. Using FreeSurfer software, the local gyrification index (LGI) of the entire cortex was compared across the groups.

RESULTS

Both schizophrenia and schizotypal disorder patients showed a significantly higher LGI in diverse cortical regions, including the bilateral prefrontal and left parietal cortices, as compared with controls, but its extent was broader in schizophrenia especially for the right prefrontal and left occipital regions. No significant correlations were found between the LGI and clinical variables (e.g., symptom severity, medication) for either of the patient groups.

CONCLUSION

Increased LGI in the frontoparietal regions was common to both patient groups and might represent vulnerability to schizophrenia, while more diverse changes in schizophrenia patients might be associated with the manifestation of florid psychosis.

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

Changes in the surface morphology of the orbitofrontal cortex (OFC), such as a fewer orbital sulci and altered sulcogyral pattern of the 'H-shaped' orbital sulcus, have been reported in schizophrenia, possibly reflecting abnormal neurodevelopment during gestation. However, whether high-risk subjects for developing psychosis also exhibit these gross morphologic anomalies is not well documented. This multicenter MRI study from four scanning sites in Japan investigated the distribution of the number of intermediate and posterior orbital sulci, as well as the OFC sulcogyral pattern, in 125 individuals with an at-risk mental state (ARMS) [of whom 22 later developed psychosis (ARMS-P) and 89 did not (ARMS-NP)] and 110 healthy controls. The ARMS group as a whole had a significantly lower number of intermediate and posterior orbital sulci compared with the controls, which was associated with prodromal symptomatology. However, there was no group difference in OFC pattern distribution. The ARMS-P and -NP groups did not differ in OFC surface morphology. These results suggest that gross morphology of the OFC in high-risk subjects may at least partly reflect neurodevelopmental pathology related to vulnerability to psychosis.

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.

Brain morphologic changes in early stages of psychosis: Implications for clinical application and early intervention

To date, a large number of magnetic resonance imaging (MRI) studies have been conducted in schizophrenia, which generally demonstrate gray matter reduction, predominantly in the frontal and temporo-limbic regions, as well as gross brain abnormalities (e.g., a deviated sulcogyral pattern). Although the causes as well as timing and course of these findings remain elusive, these morphologic changes (especially gross brain abnormalities and medial temporal lobe atrophy) are likely present at illness onset, possibly reflecting early neurodevelopmental abnormalities. In addition, longitudinal MRI studies suggest that patients with schizophrenia and related psychoses also have progressive gray matter reduction during the transition period from prodrome to overt psychosis, as well as initial periods after psychosis onset, while such changes may become almost stable in the chronic stage. These active brain changes during the early phases seem to be relevant to the development of clinical symptoms in a region-specific manner (e.g., superior temporal gyrus atrophy and positive psychotic symptoms), but may be at least partly ameliorated by antipsychotic medication. Recently, increasing evidence from MRI findings in individuals at risk for developing psychosis has suggested that those who subsequently develop psychosis have baseline brain changes, which could be at least partly predictive of later transition into psychosis. In this article, we selectively review previous MRI findings during the course of psychosis and also refer to the possible clinical applicability of these neuroimaging research findings, especially in the diagnosis of schizophrenia and early intervention for psychosis.

Brain neurodevelopmental markers related to the deficit subtype of schizophrenia

Deficit schizophrenia is a homogeneous subtype characterized by a trait-like feature of primary and prominent negative symptoms, but the etiologic factors related to this specific subtype remain largely unknown. This magnetic resonance imaging study aimed to examine gross brain morphology that probably reflects early neurodevelopment in 38 patients with deficit schizophrenia, 37 patients with non-deficit schizophrenia, and 59 healthy controls. Potential brain neurodevelopmental markers investigated in this study were the adhesio interthalamica (AI), cavum septi pellucidi (CSP), and surface morphology (i.e., olfactory sulcus depth, sulcogyral pattern, and number of orbital sulci) of the orbitofrontal cortex (OFC). The subtype classification of schizophrenia patients was based on the score of Proxy for the Deficit Syndrome. The deficit schizophrenia group had a significantly shorter AI compared with the non-deficit group and controls. The deficit group, but not the non-deficit group, was also characterized by an altered distribution of the OFC sulcogyral pattern, as well as fewer posterior orbital sulcus compared with controls. Other neurodevelopmental markers did not differentiate the deficit and non-deficit subgroups. These results suggest that the deficit subtype of schizophrenia and its clinical manifestation may be at least partly related to prominent neurodevelopmental pathology.