A geographic cline of skull and brain morphology among individuals of European Ancestry

Mean Intracranial Volume of Brain among Patients with Normal Magnetic Resonance Imaging Referred to the Department of Radiology and Imaging of a Tertiary Care Centre

Introduction

The measurement of brain volume is an important aspect of the assessment of brain structure and function. However, limited data is available on brain volumetry in the Nepalese population. The study aimed to find the mean intracranial volume of the brain among patients with normal magnetic resonance imaging referred to the Department of Radiology and Imaging of a tertiary care centre.

Methods

A descriptive cross-sectional study was conducted among patients with normal magnetic resonance imaging referred to the Department of Radiology and Imaging in a tertiary care centre. All magnetic resonance imaging of the brain during the study period was reviewed by a radiologist. Magnetic resonance imaging with abnormal findings, clinical signs of neurological deficit, dementia and psychiatric symptoms were excluded from the study. A convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval.

Results

Among 285 Magnetic Resonance Imaging datasets, the mean intracranial volume was 1286.30±129.88 cc (1271.22-1301.38, 95% of Confidence Interval). The mean cerebral volume was 985.06±106.4 cc, cerebellar volume was 126.99±13.05 cc and brain stem volume was 19.97±2.54 cc.

Conclusions

The mean intracranial volume of the brain among patients with normal magnetic resonance imaging was found to be lower than other studies done in similar settings.

Keywords

brainstem; cerebellum; cerebrum; magnetic resonance imaging.

Anterior Skull Base Abnormalities in Congenital Anosmia

INTRODUCTION

The structures of the skull and the brain are related to each other. Prior work in individuals with isolated congenital anosmia (ICA) showed that these individuals were characterized by olfactory bulb (OB) defects. The aim of this study was to compare the morphological pattern of the anterior skull base surrounding the OB between individuals with ICA and normosmic controls. We meant to investigate whether these features can help distinguish abnormalities from normal variation.

METHODS

We conducted a retrospective study to acquire T2-weighted magnetic resonance images from individuals diagnosed with ICA (n = 31) and healthy, normosmic controls matched for age and gender (n = 62). Between both groups, we compared the depth and width of the olfactory fossa, the angle of the ethmoidal fovea, as well as the angle of the lateral lamella of the cribriform plate. Within the ICA group, we further performed subgroup analyses based on the presence or absence of the OB, to investigate whether the morphology of the anterior skull base relates to the presence of OBs. The diagnostic performance of these parameters was evaluated using receiver operating characteristic analysis.

RESULTS

Individuals with ICA exhibited a flattened ethmoid roof and shallower olfactory fossa when compared to controls. Further, the absence of the OB was found to be associated with a higher degree of flattening of the ethmoid roof and a shallow olfactory fossa. We reached the results in the following areas under the receiver operating characteristic curves: 0.80 - angle of fovea ethmoidalis, 0.76 - depth of olfactory fossa, 0.70 - angle of lateral lamella of the cribriform plate for significant differentiation between individuals with ICA and normosmic controls.

CONCLUSION

Individuals with ICA exhibited an unusual anterior skull base surrounding the OB. This study supports the idea of an integrated development of OB and anterior skull base. Hence, the morphological pattern of the anterior skull base surrounding the OB helps distinguish individuals with ICA from normosmic controls and may therefore be useful for the diagnosis of ICA, although it is certainly not an invariable sign of congenital anosmia.

Endocranial anatomy of the Guercy 1 early Neanderthal from Baume Moula-Guercy (Soyons, Ardèche, France)

We provide the first comparative description of the endocranium of the Guercy 1 Early Neanderthal and examine its affinities to Preneanderthals, Neanderthals, and Homo sapiens. The Guercy 1 cranium derives from deposits chronostratigraphically and biostratigraphically dated to the Eemian Interglacial (MIS 5e). For comparative purposes, we compiled a sample of European and Southwest Asian subadult and adult Middle-to-Late Pleistocene hominins (≈MIS 12-MIS 1; N = 65). We sampled both a Preneanderthal-Neanderthal group and a Homo sapiens group. The Preneanderthal-Neanderthal group was further divided into three time-successive subgroups defined by associated MIS stages. Metric and morphological observations were made on original fossils and physical and virtual endocranial reconstructions. Guercy 1 and other Early Neanderthals, differ from Preneanderthals by increased development of the prefrontal cortex, precentral and postcentral gyri, inferior parietal lobule, and frontoparietal operculum. Early Neanderthal differ, in general, from Late Neanderthals by exhibiting less development in most of the latter brain structures. The late group additionally differentiates itself from the early group by a greater development of the rostral superior parietal lobule, angular gyrus, superior and middle temporal gyri, and caudal branches of the superior temporal gyrus. Endocranial morphology assessed along the Preneanderthal-Neanderthal sequence show that brain structures prominent in Preneanderthals are accentuated in Early-to-Late Neanderthals. However, both the Early and Late groups differentiate themselves by also showing regionally specific changes in brain development. This pattern of morphological change is consistent with a mosaic pattern of neural evolution in these Middle-to-Late Pleistocene hominins.

A single-nucleus and spatial transcriptomic atlas of the COVID-19 liver reveals topological, functional, and regenerative organ disruption in patients

The molecular underpinnings of organ dysfunction in acute COVID-19 and its potential long-term sequelae are under intense investigation. To shed light on these in the context of liver function, we performed single-nucleus RNA-seq and spatial transcriptomic profiling of livers from 17 COVID-19 decedents. We identified hepatocytes positive for SARS-CoV-2 RNA with an expression phenotype resembling infected lung epithelial cells. Integrated analysis and comparisons with healthy controls revealed extensive changes in the cellular composition and expression states in COVID-19 liver, reflecting hepatocellular injury, ductular reaction, pathologic vascular expansion, and fibrogenesis. We also observed Kupffer cell proliferation and erythrocyte progenitors for the first time in a human liver single-cell atlas, resembling similar responses in liver injury in mice and in sepsis, respectively. Despite the absence of a clinical acute liver injury phenotype, endothelial cell composition was dramatically impacted in COVID-19, concomitantly with extensive alterations and profibrogenic activation of reactive cholangiocytes and mesenchymal cells. Our atlas provides novel insights into liver physiology and pathology in COVID-19 and forms a foundational resource for its investigation and understanding.

Positional Variation of the Infraorbital Foramen in Caucasians and Black Africans from Britain: Surgical Relevance and Comparison to the Existing Literature

BACKGROUND

Midface augmentation and orbital surgery carry an inherent risk of injury to the infraorbital vascular bundle, especially the infraorbital nerve where it exits the infraorbital foramen (IOF). This can result in significant morbidity for the patient, including paresthesia and neuralgia. Studies report significant heterogeneity in IOF position according to gender, ethnicity, and laterality. A knowledge of the relationship of the IOF to regional soft tissue, bony landmarks, and its variation among ethnicities is likely to reduce iatrogenic injuries.

METHODS

A single-center retrospective computed tomography (CT)-based study was conducted. Twenty Caucasians and 20 Black Africans patients were selected from an existing radiologic database at Moorfields Eye Hospital, London, UK. DICOM image viewing software (Syngo, Siemens Healthineers) was used to record the position of the IOF using standardized sagittal and axial views.

RESULTS

There was a statistically significant difference in the horizontal position of the IOF in the 2 races (P = 0.00). The combined measurements were used to derive a rectangular zone of variability measuring 14.30 mm by 10.60 mm. This zone was found to lie 3.50 mm below the infraorbital rim, 7.10 mm medial to the piriform aperture, and 11.60 mm from the lateral orbital rim.

CONCLUSION

A sound knowledge of key facial landmarks is necessitated when performing midface augmentation and orbital surgery. An anatomical safe zone depicting the variation of the IOF will help reduce iatrogenic injury to the infraorbital nerve and prevent patient morbidity.

A geometric morphometric approach to the study of sexual dimorphism in the modern human frontal bone

OBJECTIVES

We analyzed the main anatomical traits found in the human frontal bone by using a geometric morphometric approach. The objectives of this study are to explore how the frontal bone morphology varies between the sexes and to detect which part of the frontal bone are sexually dimorphic.

MATERIALS AND METHODS

The sample is composed of 161 skulls of European and North American individuals of known sex. For each cranium, we collected 3D landmarks and semilandmarks on the frontal bone, to examine the entire morphology and separate modules (frontal squama, supraorbital ridges, glabellar region, temporal lines, and mid-sagittal profile). We used Procrustes ANOVAs and LDAs (linear discriminant analyses) to evaluate the relation between frontal bone morphology and sexual dimorphism and to calculate precision and accuracy in the classification of sex.

RESULTS

All the frontal bone traits are influenced by sexual dimorphism, though each in a different manner. Variation in shape and size differs between the sexes, and this study confirmed that the supraorbital ridges and glabella are the most important regions for sex determination, although there is no covariation between them. The variable size does not contribute significantly to the discrimination between sexes. Thanks to a geometric morphometric analysis, it was found that the size variable is not an important element for the determination of sex in the frontal bone.

CONCLUSION

The usage of geometric morphometrics in analyzing the frontal bone has led to new knowledge on the morphological variations due to sexual dimorphism. The proposed protocol permits to quantify morphological covariation between modules, to calculate the shape variations related to sexual dimorphism including or omitting the variable size.

The effect of bilingualism on brain development from early childhood to young adulthood

Bilingualism affects the structure of the brain in adults, as evidenced by experience-dependent grey and white matter changes in brain structures implicated in language learning, processing, and control. However, limited evidence exists on how bilingualism may influence brain development. We examined the developmental patterns of both grey and white matter structures in a cross-sectional study of a large sample (n = 711 for grey matter, n = 637 for white matter) of bilingual and monolingual participants, aged 3–21 years. Metrics of grey matter (thickness, volume, and surface area) and white matter (fractional anisotropy and mean diffusivity) were examined across 41 cortical and subcortical brain structures and 20 tracts, respectively. We used generalized additive modelling to analyze whether, how, and where the developmental trajectories of bilinguals and monolinguals might differ. Bilingual and monolingual participants manifested distinct developmental trajectories in both grey and white matter structures. As compared to monolinguals, bilinguals showed: (a) more grey matter (less developmental loss) starting during late childhood and adolescence, mainly in frontal and parietal regions (particularly in the inferior frontal gyrus pars opercularis, superior frontal cortex, inferior and superior parietal cortex, and precuneus); and (b) higher white matter integrity (greater developmental increase) starting during mid-late adolescence, specifically in striatal–inferior frontal fibers. The data suggest that there may be a developmental basis to the well-documented structural differences in the brain between bilingual and monolingual adults.

Generalized Score Functions for Causal Discovery

Discovery of causal relationships from observational data is a fundamental problem. Roughly speaking, there are two types of methods for causal discovery, constraint-based ones and score-based ones. Score-based methods avoid the multiple testing problem and enjoy certain advantages compared to constraint-based ones. However, most of them need strong assumptions on the functional forms of causal mechanisms, as well as on data distributions, which limit their applicability. In practice the precise information of the underlying model class is usually unknown. If the above assumptions are violated, both spurious and missing edges may result. In this paper, we introduce generalized score functions for causal discovery based on the characterization of general (conditional) independence relationships between random variables, without assuming particular model classes. In particular, we exploit regression in RKHS to capture the dependence in a non-parametric way. The resulting causal discovery approach produces asymptotically correct results in rather general cases, which may have nonlinear causal mechanisms, a wide class of data distributions, mixed continuous and discrete data, and multidimensional variables. Experimental results on both synthetic and real-world data demonstrate the efficacy of our proposed approach.

Association of genetic ancestry with striatal dopamine D2/D3 receptor availability

Despite ethnic differences in allele frequencies of variants in dopaminergic genes associated with dopamine D2/D3 receptor availability (D2R), no study to date has investigated the relationship between genetic ancestry and striatal D2R. Here, we show that ancestry-informative markers significantly predict dorsal striatal D2R in 117 healthy ethnically diverse residents of the New York metropolitan area using Positron Emission Tomography (PET) with [¹¹C]raclopride (P<0.0001), while correcting for age, sex, BMI, education, smoking status, and estimated socioeconomic status (ZIP codes). Effects of ethnicity on D2R were not driven by variation in dopaminergic candidate genes. Instead, candidate gene associations with striatal D2R were diminished when correcting for ancestry. These findings imply that future studies investigating D2 receptor genes should covary for genetic ancestry or study homogeneous populations. Moreover, ancestry studies on human neurobiology should control for socioeconomic differences between ethnic groups.

Neanderthal-Derived Genetic Variation Shapes Modern Human Cranium and Brain

Before their disappearance from the fossil record approximately 40,000 years ago, Neanderthals, the ancient hominin lineage most closely related to modern humans, interbred with ancestors of present-day humans. The legacy of this gene flow persists through Neanderthal-derived variants that survive in modern human DNA; however, the neural implications of this inheritance are uncertain. Here, using MRI in a large cohort of healthy individuals of European-descent, we show that the amount of Neanderthal-originating polymorphism carried in living humans is related to cranial and brain morphology. First, as a validation of our approach, we demonstrate that a greater load of Neanderthal-derived genetic variants (higher “NeanderScore”) is associated with skull shapes resembling those of known Neanderthal cranial remains, particularly in occipital and parietal bones. Next, we demonstrate convergent NeanderScore-related findings in the brain (measured by gray- and white-matter volume, sulcal depth, and gyrification index) that localize to the visual cortex and intraparietal sulcus. This work provides insights into ancestral human neurobiology and suggests that Neanderthal-derived genetic variation is neurologically functional in the contemporary population.

ENIGMA and the individual: Predicting factors that affect the brain in 35 countries worldwide

In this review, we discuss recent work by the ENIGMA Consortium (http://enigma.ini.usc.edu) - a global alliance of over 500 scientists spread across 200 institutions in 35 countries collectively analyzing brain imaging, clinical, and genetic data. Initially formed to detect genetic influences on brain measures, ENIGMA has grown to over 30 working groups studying 12 major brain diseases by pooling and comparing brain data. In some of the largest neuroimaging studies to date - of schizophrenia and major depression - ENIGMA has found replicable disease effects on the brain that are consistent worldwide, as well as factors that modulate disease effects. In partnership with other consortia including ADNI, CHARGE, IMAGEN and others¹, ENIGMA's genomic screens - now numbering over 30,000 MRI scans - have revealed at least 8 genetic loci that affect brain volumes. Downstream of gene findings, ENIGMA has revealed how these individual variants - and genetic variants in general - may affect both the brain and risk for a range of diseases. The ENIGMA consortium is discovering factors that consistently affect brain structure and function that will serve as future predictors linking individual brain scans and genomic data. It is generating vast pools of normative data on brain measures - from tens of thousands of people - that may help detect deviations from normal development or aging in specific groups of subjects. We discuss challenges and opportunities in applying these predictors to individual subjects and new cohorts, as well as lessons we have learned in ENIGMA's efforts so far.

Adolescent Development of Cortical and White Matter Structure in the NCANDA Sample: Role of Sex, Ethnicity, Puberty, and Alcohol Drinking

Brain structural development continues throughout adolescence, when experimentation with alcohol is often initiated. To parse contributions from biological and environmental factors on neurodevelopment, this study used baseline National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA) magnetic resonance imaging (MRI) data, acquired in 674 adolescents meeting no/low alcohol or drug use criteria and 134 adolescents exceeding criteria. Spatial integrity of images across the 5 recruitment sites was assured by morphological scaling using Alzheimer's disease neuroimaging initiative phantom-derived volume scalar metrics. Clinical MRI readings identified structural anomalies in 11.4%. Cortical volume and thickness were smaller and white matter volumes were larger in older than in younger adolescents. Effects of sex (male > female) and ethnicity (majority > minority) were significant for volume and surface but minimal for cortical thickness. Adjusting volume and area for supratentorial volume attenuated or removed sex and ethnicity effects. That cortical thickness showed age-related decline and was unrelated to supratentorial volume is consistent with the radial unit hypothesis, suggesting a universal neural development characteristic robust to sex and ethnicity. Comparison of NCANDA with PING data revealed similar but flatter, age-related declines in cortical volumes and thickness. Smaller, thinner frontal, and temporal cortices in the exceeds-criteria than no/low-drinking group suggested untoward effects of excessive alcohol consumption on brain structural development.

Investigation of orbitofrontal sulcogyral pattern in chronic schizophrenia

Abnormalities of orbitofrontal cortex (OFC) pattern type distribution have been associated with schizophrenia-spectrum disorders. We investigated OFC pattern type in a large sample of chronic schizophrenia patients and healthy controls. We found an increased frequency of Type II but no difference in Type I or III folding pattern in the schizophrenia group in comparison to controls. Further large studies are required to investigate the diagnostic specificity of altered OFC pattern type and to confirm the distribution of pattern type in the normal population.

Revisiting classic clines in Drosophila melanogaster in the age of genomics

Adaptation to spatially varying environments has been studied for decades, but advances in sequencing technology are now enabling researchers to investigate the landscape of genetic variation underlying this adaptation genome wide. In this review we highlight some of the decades-long research on local adaptation in Drosophila melanogaster from well-studied clines in North America and Australia. We explore the evidence for parallel adaptation and identify commonalities in the genes responding to clinal selection across continents as well as discussing instances where patterns differ among clines. We also investigate recent studies utilizing whole-genome data to identify clines in D. melanogaster and several other systems. Although connecting segregating genomic variation to variation in phenotypes and fitness remains challenging, clinal genomics is poised to increase our understanding of local adaptation and the selective pressures that drive the extensive phenotypic diversity observed in nature.

Modeling the 3D geometry of the cortical surface with genetic ancestry

Knowing how the human brain is shaped by migration and admixture is a critical step in studying human evolution [1, 2], as well as in preventing the bias of hidden population structure in brain research [3, 4]. Yet, the neuroanatomical differences engendered by population history are still poorly understood. Most of the inference relies on craniometric measurements, because morphology of the brain is presumed to be the neurocranium's main shaping force before bones are fused and ossified [5]. Although studies have shown that the shape variations of cranial bones are consistent with population history [6-8], it is unknown how much human ancestry information is retained by the human cortical surface. In our group's previous study, we found that area measures of cortical surface and total brain volumes of individuals of European descent in the United States correlate significantly with their ancestral geographic locations in Europe [9]. Here, we demonstrate that the three-dimensional geometry of cortical surface is highly predictive of individuals' genetic ancestry in West Africa, Europe, East Asia, and America, even though their genetic background has been shaped by multiple waves of migratory and admixture events. The geometry of the cortical surface contains richer information about ancestry than the areal variability of the cortical surface, independent of total brain volumes. Besides explaining more ancestry variance than other brain imaging measurements, the 3D geometry of the cortical surface further characterizes distinct regional patterns in the folding and gyrification of the human brain associated with each ancestral lineage.

2014 Update of the Alzheimer's Disease Neuroimaging Initiative: A review of papers published since its inception

The Alzheimer's Disease Neuroimaging Initiative (ADNI) is an ongoing, longitudinal, multicenter study designed to develop clinical, imaging, genetic, and biochemical biomarkers for the early detection and tracking of Alzheimer's disease (AD). The initial study, ADNI-1, enrolled 400 subjects with early mild cognitive impairment (MCI), 200 with early AD, and 200 cognitively normal elderly controls. ADNI-1 was extended by a 2-year Grand Opportunities grant in 2009 and by a competitive renewal, ADNI-2, which enrolled an additional 550 participants and will run until 2015. This article reviews all papers published since the inception of the initiative and summarizes the results to the end of 2013. The major accomplishments of ADNI have been as follows: (1) the development of standardized methods for clinical tests, magnetic resonance imaging (MRI), positron emission tomography (PET), and cerebrospinal fluid (CSF) biomarkers in a multicenter setting; (2) elucidation of the patterns and rates of change of imaging and CSF biomarker measurements in control subjects, MCI patients, and AD patients. CSF biomarkers are largely consistent with disease trajectories predicted by β-amyloid cascade (Hardy, J Alzheimer's Dis 2006;9(Suppl 3):151-3) and tau-mediated neurodegeneration hypotheses for AD, whereas brain atrophy and hypometabolism levels show predicted patterns but exhibit differing rates of change depending on region and disease severity; (3) the assessment of alternative methods of diagnostic categorization. Currently, the best classifiers select and combine optimum features from multiple modalities, including MRI, [(18)F]-fluorodeoxyglucose-PET, amyloid PET, CSF biomarkers, and clinical tests; (4) the development of blood biomarkers for AD as potentially noninvasive and low-cost alternatives to CSF biomarkers for AD diagnosis and the assessment of α-syn as an additional biomarker; (5) the development of methods for the early detection of AD. CSF biomarkers, β-amyloid 42 and tau, as well as amyloid PET may reflect the earliest steps in AD pathology in mildly symptomatic or even nonsymptomatic subjects and are leading candidates for the detection of AD in its preclinical stages; (6) the improvement of clinical trial efficiency through the identification of subjects most likely to undergo imminent future clinical decline and the use of more sensitive outcome measures to reduce sample sizes. Multimodal methods incorporating APOE status and longitudinal MRI proved most highly predictive of future decline. Refinements of clinical tests used as outcome measures such as clinical dementia rating-sum of boxes further reduced sample sizes; (7) the pioneering of genome-wide association studies that leverage quantitative imaging and biomarker phenotypes, including longitudinal data, to confirm recently identified loci, CR1, CLU, and PICALM and to identify novel AD risk loci; (8) worldwide impact through the establishment of ADNI-like programs in Japan, Australia, Argentina, Taiwan, China, Korea, Europe, and Italy; (9) understanding the biology and pathobiology of normal aging, MCI, and AD through integration of ADNI biomarker and clinical data to stimulate research that will resolve controversies about competing hypotheses on the etiopathogenesis of AD, thereby advancing efforts to find disease-modifying drugs for AD; and (10) the establishment of infrastructure to allow sharing of all raw and processed data without embargo to interested scientific investigators throughout the world.

Genetic analysis of quantitative phenotypes in AD and MCI: imaging, cognition and biomarkers

The Genetics Core of the Alzheimer's Disease Neuroimaging Initiative (ADNI), formally established in 2009, aims to provide resources and facilitate research related to genetic predictors of multidimensional Alzheimer's disease (AD)-related phenotypes. Here, we provide a systematic review of genetic studies published between 2009 and 2012 where either ADNI APOE genotype or genome-wide association study (GWAS) data were used. We review and synthesize ADNI genetic associations with disease status or quantitative disease endophenotypes including structural and functional neuroimaging, fluid biomarker assays, and cognitive performance. We also discuss the diverse analytical strategies used in these studies, including univariate and multivariate analysis, meta-analysis, pathway analysis, and interaction and network analysis. Finally, we perform pathway and network enrichment analyses of these ADNI genetic associations to highlight key mechanisms that may drive disease onset and trajectory. Major ADNI findings included all the top 10 AD genes and several of these (e.g., APOE, BIN1, CLU, CR1, and PICALM) were corroborated by ADNI imaging, fluid and cognitive phenotypes. ADNI imaging genetics studies discovered novel findings (e.g., FRMD6) that were later replicated on different data sets. Several other genes (e.g., APOC1, FTO, GRIN2B, MAGI2, and TOMM40) were associated with multiple ADNI phenotypes, warranting further investigation on other data sets. The broad availability and wide scope of ADNI genetic and phenotypic data has advanced our understanding of the genetic basis of AD and has nominated novel targets for future studies employing next-generation sequencing and convergent multi-omics approaches, and for clinical drug and biomarker development.

The Alzheimer's Disease Neuroimaging Initiative: a review of papers published since its inception

The Alzheimer's Disease Neuroimaging Initiative (ADNI) is an ongoing, longitudinal, multicenter study designed to develop clinical, imaging, genetic, and biochemical biomarkers for the early detection and tracking of Alzheimer's disease (AD). The study aimed to enroll 400 subjects with early mild cognitive impairment (MCI), 200 subjects with early AD, and 200 normal control subjects; $67 million funding was provided by both the public and private sectors, including the National Institute on Aging, 13 pharmaceutical companies, and 2 foundations that provided support through the Foundation for the National Institutes of Health. This article reviews all papers published since the inception of the initiative and summarizes the results as of February 2011. The major accomplishments of ADNI have been as follows: (1) the development of standardized methods for clinical tests, magnetic resonance imaging (MRI), positron emission tomography (PET), and cerebrospinal fluid (CSF) biomarkers in a multicenter setting; (2) elucidation of the patterns and rates of change of imaging and CSF biomarker measurements in control subjects, MCI patients, and AD patients. CSF biomarkers are consistent with disease trajectories predicted by β-amyloid cascade (Hardy, J Alzheimers Dis 2006;9(Suppl 3):151-3) and tau-mediated neurodegeneration hypotheses for AD, whereas brain atrophy and hypometabolism levels show predicted patterns but exhibit differing rates of change depending on region and disease severity; (3) the assessment of alternative methods of diagnostic categorization. Currently, the best classifiers combine optimum features from multiple modalities, including MRI, [(18)F]-fluorodeoxyglucose-PET, CSF biomarkers, and clinical tests; (4) the development of methods for the early detection of AD. CSF biomarkers, β-amyloid 42 and tau, as well as amyloid PET may reflect the earliest steps in AD pathology in mildly symptomatic or even nonsymptomatic subjects, and are leading candidates for the detection of AD in its preclinical stages; (5) the improvement of clinical trial efficiency through the identification of subjects most likely to undergo imminent future clinical decline and the use of more sensitive outcome measures to reduce sample sizes. Baseline cognitive and/or MRI measures generally predicted future decline better than other modalities, whereas MRI measures of change were shown to be the most efficient outcome measures; (6) the confirmation of the AD risk loci CLU, CR1, and PICALM and the identification of novel candidate risk loci; (7) worldwide impact through the establishment of ADNI-like programs in Europe, Asia, and Australia; (8) understanding the biology and pathobiology of normal aging, MCI, and AD through integration of ADNI biomarker data with clinical data from ADNI to stimulate research that will resolve controversies about competing hypotheses on the etiopathogenesis of AD, thereby advancing efforts to find disease-modifying drugs for AD; and (9) the establishment of infrastructure to allow sharing of all raw and processed data without embargo to interested scientific investigators throughout the world. The ADNI study was extended by a 2-year Grand Opportunities grant in 2009 and a renewal of ADNI (ADNI-2) in October 2010 through to 2016, with enrollment of an additional 550 participants.

Sulcogyral patterns and morphological abnormalities of the orbitofrontal cortex in psychosis

Three types of OFC sulcogyral patterns have been identified in the general population. The distribution of these three types has been found altered in individuals at genetic risk of psychosis, first episode psychosis (FEP) and chronic schizophrenia. The aim of this study was to replicate and extend previous research by additionally investigating: intermediate and posterior orbital sulci, cortical thickness, and degree of gyrification/folding of the OFC, in a large sample of FEP patients and healthy controls. OFC pattern type was classified based on a method previously devised, using T1-weighted magnetic resonance images. Cortical thickness and local gyrification indices were calculated using FreeSurfer. Occurrence of Type I pattern was decreased and Type II pattern was increased in FEP patients for the right hemisphere. Interestingly, controls displayed an OFC pattern type distribution that was disparate to that previously reported. Significantly fewer intermediate orbital sulci were observed in the left hemisphere of patients. Grey matter thickness of orbitofrontal sulci was reduced bilaterally, and left hemisphere reductions were related to OFC pattern type in patients. There was no relationship between pattern type and degree of OFC gyrification. An interaction was found between the number of intermediate orbital sulci and OFC gyrification; however this group difference was specific to only the small subsample of people with three intermediate orbital sulci. Given that cortical folding is largely determined by birth, our findings suggest that Type II pattern may be a neurodevelopmental risk marker while Type I pattern may be somewhat protective. This finding, along with compromised orbitofrontal sulci thickness, may reflect early abnormalities in cortical development and point toward a possible endophenotypic risk marker of schizophrenia-spectrum disorders.