An in vivo MRI study of prefrontal cortical complexity in first-episode psychosis

Association of altered cortical gyrification and psychopathological symptoms in patients with first-episode drug-naïve schizophrenia

Altered brain gyrification in diverse cortical regions has been reported in patients with schizophrenia, which possibly reflects deviations in early neurodevelopment. The main purpose of this study was to examine the relationship between clinical symptoms and abnormal cortical gyrification in drug-naïve patients with schizophrenia in a Chinese Han population. We calculated the whole-brain cortical gyrification of 41 patients with first-episode drug-naïve schizophrenia and 30 age- and sex-matched healthy controls. The Positive and Negative Syndrome Scale (PANSS) was used to evaluate the psychopathology of patients with schizophrenia. Our results showed that compared to healthy controls, patients had higher cortical gyrification in the left lateral occipital cortex, but lower cortical gyrification in the left transverse temporal cortex. Moreover, the cortical gyrification in the left entorhinal cortex and left fusiform were both positively correlated with the general psychopathology of PANSS. Our findings indicate that abnormal cortical gyrification has occurred in the early stage of schizophrenia, suggesting that abnormal cortical gyrification may play an important role in the pathogenesis and symptomatology of schizophrenia.

Miswiring of Frontostriatal Projections in Schizophrenia

We investigated brain wiring in chronic schizophrenia and healthy controls in frontostriatal circuits using diffusion magnetic resonance imaging tractography in a novel way. We extracted diffusion streamlines in 27 chronic schizophrenia and 26 healthy controls connecting 4 frontal subregions to the striatum. We labeled the projection zone striatal surface voxels into 2 subtypes: dominant-input from a single cortical subregion, and, functionally integrative, with mixed-input from diverse cortical subregions. We showed: 1) a group difference for total striatal surface voxel number (P = .045) driven by fewer mixed-input voxels in the left (P  = .007), but not right, hemisphere; 2) a group by hemisphere interaction for the ratio quotient between voxel subtypes (P  = .04) with a left (P  = .006), but not right, hemisphere increase in schizophrenia, also reflecting fewer mixed-input voxels; and 3) fewer mixed-input voxel counts in schizophrenia (P  = .045) driven by differences in left hemisphere limbic (P  = .007) and associative (P  = .01), but not sensorimotor, striatum. These results demonstrate a less integrative pattern of frontostriatal structural connectivity in chronic schizophrenia. A diminished integrative pattern yields a less complex input pattern to the striatum from the cortex with less circuit integration at the level of the striatum. Further, as brain wiring occurs during early development, aberrant brain wiring could serve as a developmental biomarker for schizophrenia.

Increased gyrification in schizophrenia and non affective first episode of psychosis

BACKGROUND

Prefrontal cortex gyrification has been suggested to be altered in patients with schizophrenia and first episode psychosis. Therefore, it may represent a possible trait marker for these illnesses and an indirect evidence of a disrupted underlying connectivity. The aim of this study was to add further evidence to the existing literature on the role of prefrontal gyrification in psychosis by carrying out a study on a sizeable sample of chronic patients with schizophrenia and non-affective first-episode psychosis (FEP-NA) patients.

METHODS

Seventy-two patients with schizophrenia, 51 FEP-NA patients (12 who later develop schizophrenia) and 95 healthy controls (HC) underwent magnetic resonance imaging (MRI). Cortical folding was quantified using the automated gyrification index (GI). GI values were compared among groups and related to clinical variables.

RESULTS

Both FEP-NA and patients with schizophrenia showed a higher mean prefrontal GI compared to HC (all p<0.05). Interestingly, no differences have been observed between the two patients groups as well as between FEP-NA patients who did and did not develop schizophrenia.

CONCLUSIONS

Our results suggest the presence of a shared aberrant prefrontal GI in subjects with both schizophrenia and first-episode psychosis. These findings support the hypothesis that altered GI represents a neurodevelopmental trait marker for psychosis, which may be involved in the associated neurocognitive deficits.

Cortical Morphometry in the Psychosis Risk Period: A Comprehensive Perspective of Surface Features

BACKGROUND

Gyrification features reflect brain development in the early prenatal environment. Clarifying the nature of these features in psychosis can help shed light on the role of early developmental insult. However, the literature is currently widely discrepant, which may reflect confounds related to formally psychotic patient populations or overreliance on a single feature of cortical surface morphometry (CSM).

METHODS

This study compares CSM features of gyrification in clinical high-risk (n = 43) youths during the prodromal risk period to typically developing control subjects over two time points across three metrics: local gyrification index, mean curvature index, and sulcal depth (improving resolution and examination of change over 1 year).

RESULTS

Gyrification was stable over time, supporting the idea that gyrification reflects early insult rather than abnormal development or reorganization associated with the disease state. Each of the indices highlighted unique, aberrant features in the clinical high-risk group with respect to control subjects. Specifically, the local gyrification index reflected hypogyrification in the lateral orbitofrontal cortex, superior bank of the superior temporal sulcus, anterior isthmus of the cingulate gyrus, and temporal poles; the mean curvature index indicated sharper gyral and flatter or wider sulcal peaks in the cingulate, postcentral, and lingual gyrus; sulcal depth identified shallow features in the parietal, superior temporal sulcus, and cingulate regions. Further, both the mean curvature index and sulcal depth converged on abnormal features in the parietal cortex.

CONCLUSIONS

Gyrification metrics suggest early developmental insult and provide support for neurodevelopmental hypotheses. Observations of stable CSM features across time provide context for interpreting extant studies and speak to CSM as a promising stable marker and/or endophenotype. Collectively, findings support the importance of considering multiple CSM features.

Cortical gyrification in schizophrenia: current perspectives

The cerebral cortex of the human brain has a complex morphological structure consisting of folded or smooth cortical surfaces. These morphological features are referred to as cortical gyrification and are characterized by the gyrification index (GI). A number of cortical gyrification studies have been published using the manual tracing GI, automated GI, and local GI in patients with schizophrenia. In this review, we highlighted abnormal cortical gyrification in patients with schizophrenia, first-episode schizophrenia, siblings of patients, and high-risk and at-risk individuals. Previous researches also indicated that abnormalities in cortical gyrification may underlie the severity of clinical symptoms, neurological soft signs, and executive functions. A substantial body of research has been conducted; however, some researches showed an increased GI, which is called as "hypergyria," and others showed a decreased GI, which is called as "hypogyria." We discussed that different GI methods and a wide variety of characteristics, such as age, sex, stage, and severity of illness, might be important reasons for the conflicting findings. These issues still need to be considered, and future studies should address them.

Biological and cognitive correlates of cortical curvature in schizophrenia

Mean cortical curvature may relate to cortico-cortical connections integrity. We explored the association between prefrontal (PFC) cortical curvature and fractional anisotropy (FA) values for tracts connecting PFC and relevant cortical regions. In schizophrenia Anatomical and diffusion magnetic resonance images were obtained from 34 patients (16 of them first-episodes) and 32 healthy controls. We calculated curvature at rostral lateral prefrontal (RLPF) and superior medial prefrontal (SMPF) areas and mean FA for the tracts respectively connecting RLPF and SMPF areas with anterior caudal cingulate (ACC), superior temporal gyrus (STG) and superior parietal SP regions. Cognitive and clinical data were collected, including baseline symptoms, Clinical Global Impression change scores from baseline to follow-up, illness duration and treatment dosage. Patients showed significantly lower FA values in the tracts linking right RLPF-ACC, right SMPF-SPG and bilaterally PFC-STG. FA values in short-range cortico-cortical connections (linking PFC and ACC) were inversely associated with PFC curvature. In patients, cognitive performance was negatively associated with PFC curvature. Larger curvature values were associated to lack of clinical improvement at follow-up. We conclude that cortical curvature is influenced by integrity in short-range cortico-cortical connections and relates to cognition and clinical outcome in schizophrenia patients.

Increased Occipital Gyrification and Development of Psychotic Disorders in Individuals With an At-Risk Mental State: A Multicenter Study

BACKGROUND

Anomalies of brain gyrification have been reported in schizophrenia, possibly reflecting its neurodevelopmental pathology. However, it remains elusive whether individuals at risk for psychotic disorders exhibit deviated gyrification patterns, and whether such findings, if present, are predictive of transition to psychotic disorders.

METHODS

This multicenter magnetic resonance imaging study investigated brain gyrification and its relationship to later transition to psychotic disorders in a large sample of at-risk mental state (ARMS) individuals. T1-weighted magnetic resonance imaging scans were obtained from 104 ARMS individuals, of whom 21 (20.2%) exhibited the transition to psychotic disorders during clinical follow-up (mean = 4.9 years, SD = 2.6 years), and 104 healthy control subjects at 4 different sites. The local gyrification index (LGI) of the entire cortex was compared across the groups using FreeSurfer software.

RESULTS

Compared with the control subjects, ARMS individuals showed a significantly higher LGI in widespread cortical areas, including the bilateral frontal, temporal, parietal, and occipital regions, which was partly associated with prodromal symptomatology. ARMS individuals who exhibited the transition to psychotic disorders showed a significantly higher LGI in the left occipital region compared with individuals without transition.

CONCLUSIONS

These findings suggested that increased LGI in diverse cortical regions might represent vulnerability to psychopathology, while increased LGI in the left occipital cortex might be related to subsequent manifestation of florid psychotic disorders as a possible surrogate marker.

Forty years of structural imaging in psychosis: promises and truth

OBJECTIVE

Since the first study published in the Lancet in 1976, structural neuroimaging has been used in psychosis with the promise of imminent clinical utility. The actual impact of structural neuroimaging in psychosis is still unclear.

METHOD

We present here a critical review of studies involving structural magnetic resonance imaging techniques in patients with psychosis published between 1976 and 2015 in selected journals of relevance for the field. For each study, we extracted summary descriptive variables. Additionally, we qualitatively described the main structural findings of each article in summary notes and we employed a biomarker rating system based on quality of evidence (scored 1-4) and effect size (scored 1-4).

RESULTS

Eighty studies meeting the inclusion criteria were retrieved. The number of studies increased over time, reflecting an increased structural imaging research in psychosis. However, quality of evidence was generally impaired by small samples and unclear biomarker definitions. In particular, there was little attempt of replication of previous findings. The effect sizes ranged from small to modest. No diagnostic or prognostic biomarker for clinical use was identified.

CONCLUSIONS

Structural neuroimaging in psychosis research has not yet delivered on the clinical applications that were envisioned.

The XY gene hypothesis of psychosis: origins and current status

Sex differences in psychosis and their interaction with laterality (systematic departures from 50:50 left-right symmetry across the antero-posterior neural axis) are reviewed in the context of the X-Y gene hypothesis. Aspects of laterality (handedness/cerebral asymmetry/the torque) predict (1) verbal and non-verbal ability in childhood and across adult life and (2) anatomical, physiological, and linguistic variation relating to psychosis. Neuropsychological and MRI evidence from individuals with sex chromosome aneuploidies indicates that laterality is associated with an X-Y homologous gene pair. Within each mammalian species the complement of such X-Y gene pairs reflects their potential to account for taxon-specific sexual dimorphisms. As a consequence of the mechanism of meiotic suppression of unpaired chromosomes such X-Y gene pairs generate epigenetic variation around a species defining motif that is carried to the zygote with potential to initiate embryonic gene expression in XX or XY format. The Protocadherin11XY (PCDH11XY) gene pair in Xq21.3/Yp11.2 in probable coordination with a gene or genes within PAR2 (the second pseudo-autosomal region) is the prime candidate in relation to cerebral asymmetry and psychosis in Homo sapiens. The lately-described pattern of sequence variation associated with psychosis on the autosomes may reflect a component of the human genome's adjustment to selective pressures generated by the sexually dimorphic mate recognition system.

Prediction for human intelligence using morphometric characteristics of cortical surface: partial least square analysis

A number of imaging studies have reported neuroanatomical correlates of human intelligence with various morphological characteristics of the cerebral cortex. However, it is not yet clear whether these morphological properties of the cerebral cortex account for human intelligence. We assumed that the complex structure of the cerebral cortex could be explained effectively considering cortical thickness, surface area, sulcal depth and absolute mean curvature together. In 78 young healthy adults (age range: 17-27, male/female: 39/39), we used the full-scale intelligence quotient (FSIQ) and the cortical measurements calculated in native space from each subject to determine how much combining various cortical measures explained human intelligence. Since each cortical measure is thought to be not independent but highly inter-related, we applied partial least square (PLS) regression, which is one of the most promising multivariate analysis approaches, to overcome multicollinearity among cortical measures. Our results showed that 30% of FSIQ was explained by the first latent variable extracted from PLS regression analysis. Although it is difficult to relate the first derived latent variable with specific anatomy, we found that cortical thickness measures had a substantial impact on the PLS model supporting the most significant factor accounting for FSIQ. Our results presented here strongly suggest that the new predictor combining different morphometric properties of complex cortical structure is well suited for predicting human intelligence.

Williams syndrome: a relationship between genetics, brain morphology and behaviour

BACKGROUND

Genetically Williams syndrome (WS) promises to provide essential insight into the pathophysiology of cortical development because its ∼28 deleted genes are crucial for cortical neuronal migration and maturation. Phenotypically, WS is one of the most puzzling childhood neurodevelopmental disorders affecting most intellectual deficiencies (i.e. low-moderate intelligence quotient, visuospatial deficits) yet relatively preserving what is uniquely human (i.e. language and social-emotional cognition). Therefore, WS provides a privileged setting for investigating the relationship between genes, brain and the consequent complex human behaviour.

METHODS

We used in vivo anatomical magnetic resonance imaging analysing cortical surface-based morphometry, (i.e. surface area, cortical volume, cortical thickness, gyrification index) and cortical complexity, which is of particular relevance to the WS genotype-phenotype relationship in 22 children (2.27-14.6 years) to compare whole hemisphere and lobar surface-based morphometry between WS (n = 10) and gender/age matched normal controls healthy controls (n = 12).

RESULTS

Compared to healthy controls, WS children had a (1) relatively preserved Cth; (2) significantly reduced SA and CV; (3) significantly increased GI mostly in the parietal lobe; and (4) decreased CC specifically in the frontal and parietal lobes.

CONCLUSION

Our findings are then discussed with reference to the Rakic radial-unit hypothesis of cortical development, arguing that WS gene deletions may spare Cth yet affecting the number of founder cells/columns/radial units, hence decreasing the SA and CV. In essence, cortical brain structure in WS may be shaped by gene-dosage abnormalities.

Neuropathological similarities and differences between schizophrenia and bipolar disorder: a flow cytometric postmortem brain study

Recent studies suggest that schizophrenia (SCH) and bipolar disorder (BPD) may share a similar etiopathology. However, their precise neuropathological natures have rarely been characterized in a comprehensive and quantitative fashion. We have recently developed a rapid, quantitative cell-counting method for frozen unfixed postmortem brains using a flow cytometer. In the present study, we not only counted stained nuclei, but also measured their sizes in the gray matter of frontopolar cortices (FPCs) and inferior temporal cortices (ITCs) from patients with SCH or BPD, as well as in that from normal controls. In terms of NeuN(+) neuronal nuclei size, particularly in the reduced densities of small NeuN(+) nuclei, we found abnormal distributions present in the ITC gray matter of both patient groups. These same abnormalities were also found in the FPCs of SCH patients, whereas in the FPCs of BPD patients, a reduction in oligodendrocyte lineage (olig2(+)) cells was much more common. Surprisingly, in the SCH FPC, normal left-greater-than-right asymmetry in neural nuclei densities was almost completely reversed. In the BPD FPC, this asymmetry, though not obvious, differed significantly from that in the SCH FPC. These findings indicate that while similar neuropathological abnormalities are shared by patients with SCH or BPD, differences also exist, mainly in the FPC, which may at least partially explain the differences observed in many aspects in these disorders.

Cognition and lobar morphology in full mutation boys with fragile X syndrome

The aims of the present study are twofold: (1) to examine cortical morphology (CM) associated with alterations in cognition in fragile X syndrome (FXS); (2) to characterize the CM profile of FXS versus FXS with an autism diagnosis (FXS+Aut) as a preliminary attempt to further elucidate the behavioral distinctions between the two sub-groups. We used anatomical magnetic resonance imaging surface-based morphometry in 21 male children (FXS N=11 and age [2.27-13.3] matched controls [C] N=10). We found (1) increased whole hemispheric and lobar cortical volume, cortical thickness and cortical complexity bilaterally, yet insignificant changes in hemispheric surface area and gyrification index in FXS compared to C; (2) linear regression analyses revealed significant negative correlations between CM and cognition; (3) significant CM differences between FXS and FXS+Aut associated with their distinctive behavioral phenotypes. These findings are critical in understanding the neuropathophysiology of one of the most common intellectual deficiency syndromes associated with altered cognition as they provide human in vivo information about genetic control of CM and cognition.

Reduction of gyrification index in the cerebellar vermis in schizophrenia: a post-mortem study

OBJECTIVES

In schizophrenia, alterations of the gyrification index (GI) have been measured in cortical brain regions and are related to neurodevelopmental disturbances. Cerebellar regions have been implicated in the pathophysiology of schizophrenia; however, the GI has not been investigated here so far.

METHODS

Hence, in a post-mortem study we investigated the GI separately from the vermis, left and right hemisphere of the medial posterior cerebellum in nine schizophrenia patients and 10 healthy controls. GI was defined as length of the inner contour inclusively depth of the sulci divided by length of the outer contour of the cerebellar surface and measured by tracing contours on images obtained by a stereological workstation.

RESULTS

In the vermis, GI was reduced in schizophrenia patients according to the methods of Zilles (P = 0.020) and Vogeley (P = 0.015). In the hemispheres, no differences have been observed. GI obtained by the two methods showed a high correlation (P < 0.001). Correlation analysis showed no influence of gender, postmortem interval and age.

CONCLUSIONS

Decreased GI in the vermis of schizophrenia patients may result from neurodevelopmental disturbances, since folding of the brain occurs mainly during the perinatal period. MRI studies using automated GI processing in larger samples are needed to confirm our results.

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

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

Folding of the prefrontal cortex in schizophrenia: regional differences in gyrification

BACKGROUND

Anatomy of prefrontal cortex in schizophrenia has been studied previously by quantifying the degree of gyrification. Conflicting results exist, with some studies showing hypergyria and others showing hypogyria. It is likely that regional variations in cortical folding exist within the prefrontal cortex that could be explored by studying the anatomical subdivisions formed by the sulci and gyri. With surface reconstructions from magnetic resonance imaging, we studied the gyrification within anatomically meaningful subdivisions of prefrontal cortex in schizophrenia.

METHODS

Prefrontal cortex was studied with an automated method to obtain Local Gyrification Index, reflecting the degree of cortical folding in 57 patients with schizophrenia and 42 control subjects. Regional differences within prefrontal cortex were compared between the two groups with a sulcogyral atlas. Effects of hemisphere and age were subsequently assessed.

RESULTS

Patients with schizophrenia had significant hypogyria in most prefrontal regions except the frontomarginal region, which showed hypergyria. The normal left > right pattern of prefrontal gyrification was reversed in schizophrenia. Patients with schizophrenia also showed significant age-related reduction in gyrification at the hypogyric regions.

CONCLUSIONS

The differences between reported findings regarding prefrontal gyrification might reflect regional variation in the nature of the abnormal process of gyrification in schizophrenia. Prefrontal gyrification is significantly influenced by age in schizophrenia, in addition to the influence of neurodevelopmental factors.

Gyrification and neural connectivity in schizophrenia

There is emerging evidence for a connection between the surface morphology of the brain and its underlying connectivity. The foundation for this relationship is thought to be established during brain development through the shaping influences of tension exerted by viscoelastic nerve fibers. The tension-based morphogenesis results in compact wiring that enhances efficient neural processing. Individuals with schizophrenia present with multiple symptoms that can include impaired thought, action, perception, and cognition. The global nature of these symptoms has led researchers to explore a more global disruption of neuronal connectivity as a theory to explain the vast array of clinical and cognitive symptoms in schizophrenia. If cerebral function and form are linked through the organization of neural connectivity, then a disruption in neural connectivity may also alter the surface morphology of the brain. This paper reviews developmental theories of gyrification and the potential interaction between gyrification and neuronal connectivity. Studies of gyrification abnormalities in children, adolescents, and adults with schizophrenia demonstrate a relationship between disrupted function and altered morphology in the surface patterns of the cerebral cortex. This altered form may provide helpful clues in understanding the neurobiological abnormalities associated with schizophrenia.

Increased parahippocampal and lingual gyrification in first-episode schizophrenia

OBJECTIVE

Cerebral gyrification is attributed to a large extent to genetic and intrauterine/perinatal factors. Hence, investigating gyrification might offer important evidence for disturbed neurodevelopmental mechanisms in schizophrenia. As an extension of recent ROI analyses of gyrification in schizophrenia the present study is the first to compare on a node-by-node basis mean curvature as a sensitive parameter for the identification of local gyrification changes of the whole cortex in first-episode schizophrenia.

METHODS

A group of 54 patients with first-episode schizophrenia according to DSM-IV and 54 age and gender matched healthy control subjects were included. All participants underwent high-resolution T1-weighted MRI scans on a 1.5 T scanner. Mean curvature was calculated dividing the sum of the principal curvatures by two at each point of the curved surface as implemented in the Freesurfer Software package. Statistical cortical maps were created to estimate gyrification differences between groups based on a clustering approach.

RESULTS

A significantly increased gyrification was observed in first-episode schizophrenia patients relative to controls in a right parahippocampal-lingual cortex area. The cluster encompassed a surface area of 750 mm². A further analysis of cortical thickness of this cluster demonstrated concurrent significant reduced cortical thickness of this area.

CONCLUSIONS

This is the first study to reveal an aberrant gyrification of the medial surface in first-episode schizophrenia. This finding is in line with substantial evidence showing medial temporal lobe abnormalities in schizophrenia. The present morphometric data provide further support for an early disruption of cortical maturation in schizophrenia.

Volume reduction and altered sulco-gyral pattern of the orbitofrontal cortex in first-episode schizophrenia

BACKGROUND

Although clinical and neuropsychological findings have implicated functional deficits of the orbitofrontal cortex (OFC) in schizophrenia, structural magnetic resonance imaging (MRI) studies of this region have yielded inconsistent findings. In addition, it remains elusive whether the OFC morphology in first-episode patients is related to their clinical features.

METHOD

MR images were acquired from 42 (24 males, 18 females) first-episode schizophrenia patients and 35 (20 males, 15 females) age-, gender-, and parental socio-economic status (SES)-matched healthy subjects. The OFC sub-regions (orbital gyrus and straight gyrus) were measured on contiguous 1-mm-thick coronal slices. The OFC sulco-gyral pattern was also evaluated for each subject. Furthermore, the relationships between OFC morphology and clinical measures were examined.

RESULTS

The volumes of the bilateral orbital gyri were significantly reduced in schizophrenia patients compared with healthy subjects, whereas the volumes of the straight gyri did not show differences between the groups. Among the schizophrenia patients, the volume of the left orbital gyrus was inversely correlated with their SES and illness duration. The OFC sulco-gyral patterns were significantly different between the patients and controls in the right hemisphere.

CONCLUSION

This study demonstrated morphologic abnormalities of the OFC in first-episode schizophrenia patients, which may have reflected neurodevelopmental aberrations and neurodegenerative changes during the first episode of the illness. Our findings also suggest that such brain structural changes are related to the social dysfunction observed in schizophrenia.

A selective review of volumetric and morphometric imaging in schizophrenia

Brain imaging studies have long supported that schizophrenia is a disorder of the brain, involving many discrete and widely spread regions. Generally, studies have shown decreases in cortical gray matter (GM) volume. Here, we selectively review recent papers studying GM volume changes in schizophrenia subjects, both first-episode (FE) and chronic, in an attempt to quantify and better understand differences between healthy and patient groups. We focused on the cortical GM of the prefrontal cortex, limbic and paralimbic structures, temporal lobe, and one subcortical structure (the caudate nucleus). We performed a search of the electronic journal database PsycINFO using the keywords "schizophrenia" and "MRI," and selected for papers published between 2001 and 2008. We then screened for only those studies utilizing manual or manually edited tracing methodologies for determining regions of interest (ROIs). Each region of interest was indexed independently; thus, one paper might yield results for numerous brain regions. Our review found that in almost all ROIs, cortical GM volume was decreased in the patient populations. The only exception was the caudate nucleus - most studies reviewed showed no change, while one study showed an increase in volume; this region, however, is particularly sensitive to medication effects. The reductions were seen in both FE and chronic schizophrenia. These results clearly support that schizophrenia is an anatomical disorder of the brain, and specifically that schizophrenia patients tend to have decreased cortical GM in regions involved in higher cognition and emotional processing. That these reductions were found in both FE and chronic subjects supports that brain abnormalities are present at the onset of illness, and are not simply a consequence of chronicity. Additional studies assessing morphometry at different phases of the illness, including prodromal stages, together with longitudinal studies will elucidate further the role of progression in this disorder.

The Italian guidelines for early intervention in schizophrenia: development and conclusions

AIM

The effectiveness of early intervention in schizophrenia is still under discussion. The guidelines described in the present paper were aimed at contributing to the current debate by providing Italian practitioners, families, patients and health managers with evidence-based information on early intervention. They also examined the diagnostic tools that are currently available for assessing different stages of psychotic disorders.

METHODS

A multidisciplinary panel of experts (the Guidelines Development Group) used a set of key-questions to develop an explicit search strategy to conduct a systematic review of the literature published from January 2000 to June 2006. Trained personnel then selected papers from those yielded by the literature search. The Guidelines Development Group's final recommendations were scaled according to the Italian National Guidelines System grading system.

RESULTS

The evidence available up to the time of the literature search does not allow for recommendation of early intervention targeting prodromal or at-risk patients to prevent progression from the prodromal phase to acute, full-blown psychosis, nor to improve prognosis. Conversely, identification and timely treatment of first-episode psychotic patients through specific early intervention programmes are highly recommended.

CONCLUSIONS

The Italian Guidelines on early intervention in schizophrenia are based on a comprehensive assessment of an updated, large-scale body of literature. They draw specific, evidence-based conclusions to assist clinicians and stakeholders in the planning and implementation of appropriate intervention programmes. Further research is needed to ascertain the effectiveness of early intervention in delaying or preventing the conversion to psychosis and improving prognosis in prodromal or at-risk patients. Further investigation is also required for first-episode and critical period patients.

Major psychoses with mixed psychotic and mood symptoms: are mixed psychoses associated with different neurobiological markers?

OBJECTIVE

Evidence related to overlapping clinical and genetic risk factors in schizophrenia and bipolar disorder (BD) have raised concerns about the validity of 'Kraepelinian dichotomy'. As controversies mainly arise in mixed psychoses that occupy the intermediate zone between schizophrenia and BD, investigating neurobiological markers of mixed psychoses may be relevant to understanding the nature of psychotic disorders.

METHOD

In this article, we review studies comparing magnetic resonance imaging, neuropsychological and electrophysiological findings in mixed psychoses with each other, as well as with more prototypical cases of schizophrenia and BD.

RESULTS

The evidence reviewed suggests that mixed psychoses may be associated with different genetic and neurobiological markers compared with prototypical forms of schizophrenia and BD.

CONCLUSION

These findings may be compatible with more sophisticated versions of dimensional and continuum models or, alternatively, they may suggest that there is an intermediate third category between prototypical schizophrenia and BD.

Brain size and cortical structure in the adult human brain

We investigated the scale relationship between size and cortical structure of human brains in a large sample of magnetic resonance imaging data. Cortical structure was estimated with several measures (cortical volume, surface area, and thickness, sulcal depth, and absolute mean curvature in sulcal regions and sulcal walls) using three-dimensional surface-based methods in 148 normal subjects (n [men/women]: 83/65, age [mean +/- standard deviation]: 25.0 +/- 4.9 years). We found significantly larger scaling exponents than geometrically predicted for cortical surface area, absolute mean curvature in sulcal regions and in sulcal walls, and smaller ones for cortical volume and thickness. As brain size increases, the cortex thickens only slightly, but the degree of sulcal convolution increases dramatically, indicating that human cortices are not simply scaled versions of one another. Our results are consistent with previous hypotheses that greater local clustering of interneuronal connections would be required in a larger brain, and fiber tension between local cortical areas would induce cortical folds. We suggest that sex effects are explained by brain size effects in cortical structure at a macroscopic and lobar regional level, and that it is necessary to consider true relationships between cortical measures and brain size due to the limitations of linear stereotaxic normalization.

Asymmetry of prefrontal cortical convolution complexity in males with attention-deficit/hyperactivity disorder using fractal information dimension

BACKGROUND AND PURPOSE

Prefrontal cortex, known to be a crucial region for the function of attention, is generally thought to be largely associated with the pathogenesis of attention-deficit hyperactivity disorder (ADHD). Most previous structural imaging studies of ADHD reported abnormality of grey matter volume in prefrontal region. However, volume measure is affected by the size of the interrogated brain, which may cause the inconsistence of the volume based findings. The purpose of the current paper is to use a scale-free measure, fractal information dimension (FID), to assess the prefrontal cortical convolution complexity and asymmetry in ADHD patients.

METHODS

MRI scans from 12 boys with ADHD and 11 controls were carefully processed. Prefrontal cortex was outlined manually. FIDs of bilateral prefrontal cortical surface were examined in each case. Group differences of the bilateral prefrontal cortical convolution complexities and the asymmetry pattern were statistically tested.

RESULTS

We found a left-greater-than-right prefrontal cortical convolution complexity pattern in both groups. However, compared with healthy controls, the left prefrontal cortical convolution complexities of ADHD patients were significantly reduced, resulting in significant reduction of the normal left-greater-than-right cortical convolution complexity asymmetry pattern.

CONCLUSION

This study confirms and extends the existing anatomical knowledge about the brains of people with ADHD. The cortical convolution analysis method may also be applied to quantitatively assess changes in other neuropsychiatric syndromes as well.

Cerebral Disconnectivity: An Early Event in Schizophrenia

Neuroimaging and electrophysiological investigations have demonstrated numerous differences in brain morphology and function of chronic schizophrenia patients compared to healthy controls. Studying patients at the beginning of their disease without the confounding effects of chronicity, medication, and institutionalization may provide a better understanding of schizophrenia. Recently, at many institutions around the world, special projects have been launched for specialized treatment and research of this interesting patient group. Using the PubMed search engine in this update, the authors summarize recent investigations between January 2002 and September 2006 that focus on whether signs of disconnectivity already exist early in the disease process. They discuss gray and white matter changes, their impact on symptomatology, electroencephalogram-based studies on connectivity, and possible influences of medication. NEUROSCIENTIST 14(1):19—45, 2008. DOI: 10.1177/1073858406298391

Cortical folding abnormalities in schizophrenia patients with resistant auditory hallucinations

Gray matter volume and functional abnormalities have been reported in language-related cortex in schizophrenia patients with auditory hallucinations. Such abnormalities might denote abnormal cortical folding development, which can now be investigated using gyrification measures. Anatomic magnetic resonance images (MRIs) were obtained from 30 schizophrenia patients screened for resistant auditory hallucinations and 28 control subjects. We searched for overall gyrification abnormalities in the whole cortex as well as localized abnormalities in language-related cortex, assuming that gyrification is associated with brain sulcation. A fully automated method was applied to MRIs to extract, label and measure the sulcus area in the whole cortex. Gyrification was assessed using both global and local sulcal indices, respectively the ratio between total sulcal area, or area of each labeled sulcus, and outer cortex area. For both hemispheres, the patients had a lower global sulcal index. The local sulcal index decrease was not homogeneous across the whole cortex. It was more significant in the superior temporal sulcus bilaterally, in the left middle frontal sulcus and in the diagonal branch of left sylvian fissure (Broca's area). Findings suggest abnormalities in cortical gyrification in these patients. Sulcal abnormalities in language-related cortex might underlie these patients' particular vulnerability to hallucinations.

Deconstructing psychosis with human brain imaging

This review synthesizes our current knowledge on the neurobiology of psychosis from an array of in vivo brain-imaging studies. The evidence base consists of hundreds of studies of patients with schizophrenia and fewer on bipolar disorder but rarely providing direct comparisons between the disorders or integration across methods. Replicated findings in schizophrenia include reduced whole-brain and hippocampal volume as potential vulnerability markers, with further progression at onset; reduced N-acetyl aspartate concentrations in hippocampus and prefrontal cortex; striatal dopamine D(2) receptors upregulation; and alteration in the relation between frontal and temporal activation. These findings are not attributable to medication effects but are of unclear specificity and may apply across the psychosis spectrum. There are consistently replicated associations of psychotic symptoms and cognitive impairment in both structural and functional imaging in schizophrenia but not, as yet, in bipolar disorder. Therefore, it would be premature to dispense with current diagnostic categories because direct comparisons among them are rare, insufficient studies have examined longitudinal changes, and long-term imaging outcome studies in first-episode psychosis have not yet been done. To address these issues and make neuroimaging "clinically relevant," investigators will need to standardize their approaches to data acquisition and analysis, and construct the necessary range of "human brain maps," to implement studies that are sufficiently powered to provide reliable data pertinent to deconstructing psychosis.

Localised reductions in gyrification in the posterior cingulate: schizophrenia and controls

Several authors report changes in the volume and degree of cortical folding in several presumptive regions of schizophrenia patients. However, no research, to our knowledge, has looked for schizophrenia related differences in cortical volume and degree of cortical folding in post-mortem posterior cingulate cortex (PCCx).

METHOD

Brain tissues from 9 people who suffered from schizophrenia (DSM-IV) and 9 controls were cut into 3 mm coronal slices. Three alternative PCCx blocks were available for research. The 3 PCCx blocks were cut into 50 microm sections. The volume and gyrification index (GI) were measured in 15 tissue sections per brain (5 sections per block).

RESULTS

People who suffered with schizophrenia showed significant reductions in GI in rostral PCCx, trend reductions were seen in medial and caudal PCCx. In addition, the average volume of the rostral tissue sections was significantly lower in the schizophrenia cohort, suggesting that schizophrenia is associated with reduced volume in the rostral PCCx. However, a true volumetric assessment of the whole PCCx, rather than a limited number of sections from three alternative blocks, is needed to confirm such a hypothesis.

Resting hypofrontality in schizophrenia: A study using near-infrared time-resolved spectroscopy

Hypofrontality has been a major finding obtained from functional neuroimaging studies on schizophrenia, although there have also been contradictory results that have questioned the reality of hypofrontality. In our previous study, we confirmed the existence of activation hypofrontality by using a 2-channel continuous-wave-type (CW-type) near-infrared spectroscopy (NIRS) instrument. In this study, we employed a single-channel time-resolved spectroscopy (TRS) instrument, which can quantify hemoglobin (Hb) concentrations based on the photon diffusion theory, to investigate resting hypofrontality. A pair of incident and detecting light guides was placed on either side of the forehead at approximately Fp2-F8 or Fp1-F7 alternately in 14 male schizophrenic patients and 16 age-matched male control subjects to measure Hb concentrations at rest. The patients were also measured with a 2-channel CW-type NIRS instrument during the performance of a random number generation (RNG) task. A reduced total hemoglobin concentration (t-Hb) less than 60 microM (the mean value of the control subjects-1.5 SD) was observed bilaterally in 4 patients and only in the left side in 3 patients. Activation hypofrontality was more manifest in these patients than in the remaining 7 patients despite the same task performance. This decreased t-Hb was related to the duration of illness, and it was not observed in patients whose duration of illness was less than 10 years. These results indicate that resting hypofrontality is a chronically developed feature of schizophrenia. This does not necessarily represent frontal dysfunction, but may reflect anatomical and/or functional changes in frontal microcirculation.

Neuroimaging-genetic paradigms: a new approach to investigate the pathophysiology and treatment of cognitive deficits in schizophrenia

Cognitive impairment is a prominent and debilitating feature of schizophrenia. Genetic predisposition likely accounts for a large proportion of these cognitive deficits. Direct associations between candidate genes and cognitive dysfunction have been difficult to establish, however, largely due to the subtle effects of these genes on observable behavior. Neuroimaging techniques can provide a sensitive means to bridge the neurobiology of genes and behavior. Here we illustrate the use of neuroimaging-genetics paradigms to elaborate the relationship between genes and cognitive dysfunction in schizophrenia. After reviewing principles important for the selection of genes, neuroimaging techniques, and subjects, we describe how imaging-genetics investigations have helped clarify the contribution of five candidate genes (COMT, GRM3, G72, DISC1, and BDNF) to cognitive deficits in schizophrenia. The potential of this approach for improving patient care will depend on its ability to predict outcomes with greater accuracy and sensitivity than current clinical measures.

Paracingulate sulcus morphology and fMRI activation detection in schizophrenia patients

OBJECTIVE

Altered anterior cingulate cortex activity has been consistently detected by functional imaging in schizophrenia patients. In the present study, we hypothesized that the detection of such local hypoactivity varies when the subjects' local gyrification is monitored. Using a group-statistical approach, we investigated whether the presence or absence of a paracingulate sulcus (PCS) does influence the detection of the activation patterns in the cognitive division of the anterior cingulate cortex (ACcd).

METHOD

fMRI data were acquired using an event-related paradigm during a task involving both priming and interference between stimuli. In the fMRI dataset collected from 13 schizophrenia patients and 16 healthy subjects, subgroups were defined according to the presence or absence of a PCS. Regional activations during interference between stimuli were examined in the ACcd of each hemisphere, using for each region of interest both voxel-based random-effects and non-parametric analyses.

RESULTS

ACcd activation was left-sided in healthy subjects with a PCS, and right-sided in healthy subjects devoid of a PCS. ACcd activations were detected bilaterally in schizophrenia patients with a PCS, whereas left ACcd was deactivated in patients without a PCS. Subgroup comparisons revealed no difference between healthy subjects with a PCS and patients with a PCS, whereas in the subgroups devoid of PCS, the patients exhibited a bilateral ACcd hypoactivation relative to healthy subjects.

CONCLUSIONS

PCS presence or absence influences the detection of ACcd activations in group-analysis of schizophrenia patients.