Adolescent brain maturation and cortical folding: evidence for reductions in gyrification

Anatomical and behavioral correlates of auditory perception in developmental dyslexia

Developmental dyslexia is typically associated with difficulties in basic auditory processing and in manipulating speech sounds. However, the neuroanatomical correlates of auditory difficulties in developmental dyslexia (DD) and their contribution to individual clinical phenotypes are still unknown. Recent intracranial electrocorticography findings associated processing of sound amplitude rises and speech sounds with posterior and middle superior temporal gyrus (STG), respectively. We hypothesize that regional STG anatomy will relate to specific auditory abilities in DD, and that auditory processing abilities will relate to behavioral difficulties with speech and reading. One hundred and ten children (78 DD, 32 typically developing, age 7-15 years) completed amplitude rise time and speech in noise discrimination tasks. They also underwent a battery of cognitive tests. Anatomical MRI scans were used to identify regions in which local cortical gyrification complexity correlated with auditory behavior. Behaviorally, amplitude rise time but not speech in noise performance was impaired in DD. Neurally, amplitude rise time and speech in noise performance correlated with gyrification in posterior and middle STG, respectively. Furthermore, amplitude rise time significantly contributed to reading impairments in DD, while speech in noise only explained variance in phonological awareness. Finally, amplitude rise time and speech in noise performance were not correlated, and each task was correlated with distinct neuropsychological measures, emphasizing their unique contributions to DD. Overall, we provide a direct link between the neurodevelopment of the left STG and individual variability in auditory processing abilities in neurotypical and dyslexic populations.

Gender Incongruence and Autistic Traits: Cerebral and Behavioral Underpinnings

Gender dysphoria and autism spectrum disorder (ASD) co-occur at high rates. Yet, it is unknown whether gender dysphoria and ASD are associated with common or distinct neurobiological correlates or how they relate to experiences of gender-related body incongruence. Using the Social Responsiveness Scale, we assessed autistic traits in 99 transgender and 99 cisgender individuals and investigated their associations with gender-related body incongruence, measured via a visually based "Body Morph" test, and with cortical thickness in the brain. Autistic traits were significantly higher among transgender individuals, and those with higher autistic traits had higher body incongruence scoring. Among transgender individuals, higher autistic traits were linked with a thinner cortex bilaterally in the temporal pole and the superior and inferior temporal gyri. Autistic traits were only partly associated with cortical morphology patterns previously reported in transgender individuals; instead, they were primarily linked to temporal lobe areas mediating social cognition. While replicating the previous literature on the increased prevalence of autistic traits among transgender individuals, this study reports specific regions in the brains of transgender individuals where cortical thickness is associated with autistic traits.

Reorganization of adolescent prefrontal cortex circuitry is required for mouse cognitive maturation

Most cognitive functions involving the prefrontal cortex emerge during late development. Increasing evidence links this delayed maturation to the protracted timeline of prefrontal development, which likely does not reach full maturity before the end of adolescence. However, the underlying mechanisms that drive the emergence and fine-tuning of cognitive abilities during adolescence, caused by circuit wiring, are still unknown. Here, we continuously monitored prefrontal activity throughout the postnatal development of mice and showed that an initial activity increase was interrupted by an extensive microglia-mediated breakdown of activity, followed by the rewiring of circuit elements to achieve adult-like patterns and synchrony. Interfering with these processes during adolescence, but not adulthood, led to a long-lasting microglia-induced disruption of prefrontal activity and neuronal morphology and decreased cognitive abilities. These results identified a nonlinear reorganization of prefrontal circuits during adolescence and revealed its importance for adult network function and cognitive processing.

Preoperative serum cortisone levels are associated with cognition in preschool-aged children with tetralogy of Fallot after corrective surgery: new evidence from human populations and mice

BACKGROUND

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Children with TOF would be confronted with neurological impairment across their lifetime. Our study aimed to identify the risk factors for cerebral morphology changes and cognition in postoperative preschool-aged children with TOF.

METHODS

We used mass spectrometry (MS) technology to assess the levels of serum metabolites, Wechsler preschool and primary scale of intelligence-Fourth edition (WPPSI-IV) index scores to evaluate neurodevelopmental levels and multimodal magnetic resonance imaging (MRI) to detect cortical morphological changes.

RESULTS

Multiple linear regression showed that preoperative levels of serum cortisone were positively correlated with the gyrification index of the left inferior parietal gyrus in children with TOF and negatively related to their lower visual spaces index and nonverbal index. Meanwhile, preoperative SpO2 was negatively correlated with levels of serum cortisone after adjusting for all covariates. Furthermore, after intervening levels of cortisone in chronic hypoxic model mice, total brain volumes were reduced at both postnatal (P) 11.5 and P30 days.

CONCLUSIONS

Our results suggest that preoperative serum cortisone levels could be used as a biomarker of neurodevelopmental impairment in children with TOF. Our study findings emphasized that preoperative levels of cortisone could influence cerebral development and cognition abilities in children with TOF.

The association between cortical gyrification and sleep in adolescents and young adults

STUDY OBJECTIVES

Healthy sleep is important for adolescent neurodevelopment, and relationships between brain structure and sleep can vary in strength over this maturational window. Although cortical gyrification is increasingly considered a useful index for understanding cognitive and emotional outcomes in adolescence, and sleep is also a strong predictor of such outcomes, we know relatively little about associations between cortical gyrification and sleep. We aimed to identify developmentally invariant (stable across age) or developmentally specific (observed only during discrete age intervals) gyrification-sleep relationships in young people.

METHODS

A total of 252 Neuroimaging and Pediatric Sleep Databank participants (9-26 years; 58.3% female) completed wrist actigraphy and a structural MRI scan. Local gyrification index (lGI) was estimated for 34 bilateral brain regions. Naturalistic sleep characteristics (duration, timing, continuity, and regularity) were estimated from wrist actigraphy. Regularized regression for feature selection was used to examine gyrification-sleep relationships.

RESULTS

For most brain regions, greater lGI was associated with longer sleep duration, earlier sleep timing, lower variability in sleep regularity, and shorter time awake after sleep onset. lGI in frontoparietal network regions showed associations with sleep patterns that were stable across age. However, in default mode network regions, lGI was only associated with sleep patterns from late childhood through early-to-mid adolescence, a period of vulnerability for mental health disorders.

CONCLUSIONS

We detected both developmentally invariant and developmentally specific ties between local gyrification and naturalistic sleep patterns. Default mode network regions may be particularly susceptible to interventions promoting more optimal sleep during childhood and adolescence.

Assessing cortical features in early stage ASD children

Autism Spectrum Disorder (ASD) is defined as a neurodevelopmental disorder largely investigated in the neurologic field. Recently, neuroimaging studies have been conducted in order to investigate cerebral morphologic alterations in ASD patients, demonstrating an atypical brain development before the clinical manifestations of the disorder. Cortical Thickness (CT) and Local Gyrification Index (LGI) distribution for ASD children were investigated in this study, with the aim to evaluate possible relationship between brain measures and individual characteristics (i.e., IQ and verbal ability). 3D T1-w sequences from 129 ASD and 58 age-matched Healthy Controls (HC) were acquired and processed in order to assess CT and LGI for each subject. Intergroup differences between ASD and HC were investigated, including analyses of 2 ASD subgroups, split according to patient verbal ability and IQ. When compared to HC, ASD showed increased CT and LGI within several brain areas, both as an overall group and as verbal ability an IQ subgroups. Moreover, when comparing language characteristics of the ASD subjects, those patients with verbal ability exhibit significant CT and LGI increase was found within the occipital lobe of right hemisphere. No significant results occurred when comparing ASD patients according to their IQ value. These results support the hypothesis of abnormal brain maturation in ASD since early childhood with differences among clinical subgroups suggesting different anatomical substrates underlying an aberrant connectivity.

Neuroanatomical and Functional Dissociations between Variably Present Anterior Lateral Prefrontal Sulci

The lateral prefrontal cortex (LPFC) is an evolutionarily expanded region in humans that is critical for numerous complex functions, many of which are largely hominoid specific. Although recent work shows that the presence or absence of specific sulci in anterior LPFC is associated with cognitive performance across age groups, it is unknown whether the presence of these structures relates to individual differences in the functional organization of LPFC. To fill this gap in knowledge, we leveraged multimodal neuroimaging data from two samples encompassing 82 young adult humans (aged 22-36 years) and show that the dorsal and ventral components of the paraintermediate frontal sulcus, or pimfs, present distinct morphological (surface area), architectural (thickness and myelination), and functional (resting-state connectivity networks) properties. We further contextualize the pimfs components within classic and modern cortical parcellations. Taken together, the dorsal and ventral pimfs components mark transitions in LPFC anatomy and function, across metrics and parcellations. These results emphasize that the pimfs is a critical structure to consider when examining individual differences in the anatomical and functional organization of LPFC and suggest that future individual-level parcellations could benefit from incorporating sulcal anatomy when delineating LPFC cortical regions.

Cortical signature of depressive symptoms in frontotemporal dementia: A surface-based analysis

BACKGROUND AND OBJECTIVES

Depressive symptoms are frequently reported in patients affected by frontotemporal dementia (FTD). At structural MRI, cortical features of depressed FTD patients have been poorly described. Our objective was to investigate correlations between cortical measures and depression severity in FTD patients.

METHODS

Data were obtained from the Frontotemporal Lobar Degeneration Neuroimaging Initiative (FTLDNI) database. We included 98 controls and 92 FTD patients, n = 38 behavioral variant FTD (bvFTD), n = 26 non-fluent variant Primary Progressive Aphasia (nfvPPA), and n = 28 semantic variant Primary Progressive Aphasia (svPPA). Patients underwent clinical and cognitive evaluations, as well as a 3D T1-weighted MRI on a 3 Tesla scanner (Siemens, Trio Tim system). Depression was evaluated by means of Geriatric Depression Scale (GDS). Surface-based analysis was performed on T1-weighted images to evaluate cortical thickness, a measure of gray matter integrity, and local gyrification index (lGI), a quantitative metric of cortical folding.

RESULTS

Patients affected by svPPA were more depressed than controls at NPI and depression severity at GDS was higher in svPPA and bvFTD. Severity of depression correlated with a decrease in lGI in left precentral and superior frontal gyrus, supramarginal and postcentral gyrus and right precentral, supramarginal, superior parietal and superior frontal gyri. Furthermore, depression severity correlated positively with cortical thickness in the left medial orbitofrontal cortex.

DISCUSSION

We found that lGI was associated with depressive symptoms over brain regions involved in the pathophysiology of major depressive disorder. This finding provides novel insights into the mechanisms underlying psychiatric symptoms in FTD.

The association between cortical gyrification and sleep in adolescents and young adults

Study objectives

Healthy sleep is important for adolescent neurodevelopment, and relationships between brain structure and sleep can vary in strength over this maturational window. Although cortical gyrification is increasingly considered a useful index for understanding cognitive and emotional outcomes in adolescence, and sleep is also a strong predictor of such outcomes, we know relatively little about associations between cortical gyrification and sleep.

Methods

Using Local gyrification index (lGI) of 34 bilateral brain regions and regularized regression for feature selection, we examined gyrification-sleep relationships in the Neuroimaging and Pediatric Sleep databank (252 participants; 9-26 years; 58.3% female) and identified developmentally invariant (stable across age) or developmentally specific (observed only during discrete age intervals) brain-sleep associations. Naturalistic sleep characteristics (duration, timing, continuity, and regularity) were estimated from wrist actigraphy.

Results

For most brain regions, greater lGI was associated with longer sleep duration, earlier sleep timing, lower variability in sleep regularity, and shorter time awake after sleep onset. lGI in frontoparietal network regions showed associations with sleep patterns that were stable across age. However, in default mode network regions, lGI was only associated with sleep patterns from late childhood through early-to-mid adolescence, a period of vulnerability for mental health disorders.

Conclusions

We detected both developmentally invariant and developmentally specific ties between local gyrification and naturalistic sleep patterns. Default mode network regions may be particularly susceptible to interventions promoting more optimal sleep during childhood and adolescence.

Structural neuroimaging phenotypes and associated molecular and genomic underpinnings in autism: a review

Autism has been associated with differences in the developmental trajectories of multiple neuroanatomical features, including cortical thickness, surface area, cortical volume, measures of gyrification, and the gray-white matter tissue contrast. These neuroimaging features have been proposed as intermediate phenotypes on the gradient from genomic variation to behavioral symptoms. Hence, examining what these proxy markers represent, i.e., disentangling their associated molecular and genomic underpinnings, could provide crucial insights into the etiology and pathophysiology of autism. In line with this, an increasing number of studies are exploring the association between neuroanatomical, cellular/molecular, and (epi)genetic variation in autism, both indirectly and directly in vivo and across age. In this review, we aim to summarize the existing literature in autism (and neurotypicals) to chart a putative pathway from (i) imaging-derived neuroanatomical cortical phenotypes to (ii) underlying (neuropathological) biological processes, and (iii) associated genomic variation.

Neuroanatomical and functional dissociations between variably present anterior lateral prefrontal sulci

The lateral prefrontal cortex (LPFC) is an evolutionarily expanded region in humans that is critical for numerous complex functions, many of which are largely hominoid-specific. While recent work shows that the presence or absence of specific sulci in anterior LPFC is associated with cognitive performance across age groups, it is unknown whether the presence of these structures relates to individual differences in the functional organization of LPFC. To fill this gap in knowledge, we leveraged multimodal neuroimaging data from 72 young adult humans aged 22-36 and show that dorsal and ventral components of the paraintermediate frontal sulcus (pimfs) present distinct morphological (surface area), architectural (thickness and myelination), and functional (resting-state connectivity networks) properties. We further contextualize the pimfs components within classic and modern cortical parcellations. Taken together, the dorsal and ventral pimfs components mark transitions in anatomy and function in LPFC, across metrics and parcellations. These results emphasize that the pimfs is a critical structure to consider when examining individual differences in the anatomical and functional organization of LPFC and highlight the importance of considering individual anatomy when investigating structural and functional features of the cortex.

A cross-sectional and longitudinal study of human brain development: The integration of cortical thickness, surface area, gyrification index, and cortical curvature into a unified analytical framework

Brain maturation studies typically examine relationships linking a single morphometric feature with cognition, behavior, age, or other demographic characteristics. However, the coordinated spatiotemporal arrangement of morphological features across development and their associations with behavior are unclear. Here, we examine covariation across multiple cortical features (cortical thickness [CT], surface area [SA], local gyrification index [GI], and mean curvature [MC]) using magnetic resonance images from the NIMH developmental cohort (ages 5-25). Neuroanatomical covariance was examined using non-negative matrix factorization (NMF), which decomposes covariance resulting in a parts-based representation. Cross-sectionally, we identified six components of covariation which demonstrate differential contributions of CT, GI, and SA in hetero- vs. unimodal areas. Using this technique to examine covariance in rates of change to identify longitudinal sources of covariance highlighted preserved SA in unimodal areas and changes in CT and GI in heteromodal areas. Using behavioral partial least squares (PLS), we identified a single latent variable (LV) that recapitulated patterns of reduced CT, GI, and SA related to older age, with limited contributions of IQ and SES. Longitudinally, PLS revealed three LVs that demonstrated a nuanced developmental pattern that highlighted a higher rate of maturational change in SA and CT in higher IQ and SES females. Finally, we situated the components in the changing architecture of cortical gradients. This novel characterization of brain maturation provides an important understanding of the interdependencies between morphological measures, their coordinated development, and their relationship to biological sex, cognitive ability, and the resources of the local environment.

Altered local gyrification index and corresponding resting-state functional connectivity in individuals with high test anxiety

Previous studies have reported that test anxiety is closely related to unreasonable cognitive patterns and maladaptive emotional responses. However, its underlying brain structural and functional basis has not been thoroughly studied. This study aimed to evaluate the potential difference in local gyration index (LGI) and corresponding resting-state functional connectivity (RSFC) in individuals with high test anxiety (HTA) compared with low test anxiety (LTA). Twenty-six individuals with HTA and 28 individuals with LTA underwent T1-weighted structural and resting-state functional magnetic resonance imaging scans. Using FreeSurfer software, we contrasted the LGI between the HTA and LTA groups using a surface-based general linear model to map group contrasts on a vertex-by-vertex basis. By selecting the cortical regions with significant differences in the LGI analysis as the regions of interest, the seed-based RSFC analysis was further carried out using the Resting-State fMRI Data Analysis Toolkit to examine the differences in the functional connectivity of these cortical regions with the whole brain between the two groups. The results showed that the LGI in several cortical regions of the executive control network (ECN) and the right lateral occipital gyrus was lower in the HTA group than in the LTA group. Furthermore, compared with the LTA group, the HTA group exhibited abnormal RSFC within the ECN, between the ECN and the visual network, and between the ECN and the sensorimotor network. Our findings might provide preliminary evidence for brain morphology and functional alterations in individuals with HTA and contribute to a better understanding of the pathophysiology of TA. DATA STATEMENT: The data that support the findings of this study are available from the corresponding author upon reasonable request after completing a formal data sharing agreement.

Cortical Gyrification Morphology in ASD and ADHD: Implication for Further Similarities or Disorder-Specific Features?

Shared etiological pathways are suggested in ASD and ADHD given high rates of comorbidity, phenotypic overlap and shared genetic susceptibility. Given the peak of cortical gyrification expansion and emergence of ASD and ADHD symptomology in early development, we investigated gyrification morphology in 539 children and adolescents (6–17 years of age) with ASD (n=197) and ADHD (n=96) compared to typically developing controls (n=246) using the local Gyrification Index (lGI) to provide insight into contributing etiopathological factors in these two disorders. We also examined IQ effects and functional implications of gyrification by exploring the relation between lGI and ASD and ADHD symptomatology beyond diagnosis. General Linear Models yielded no group differences in lGI, and across groups, we identified an age-related decrease of lGI and greater lGI in females compared to males. No diagnosis-by-age interactions were found. Accounting for IQ variability in the model (n=484) yielded similar results. No significant associations were found between lGI and social communication deficits, repetitive and restricted behaviours, inattention or adaptive functioning. By examining both disorders and controls using shared methodology, we found no evidence of atypicality in gyrification as measured by the lGI in these conditions.

Novel Gyrification Networks Reveal Links with Psychiatric Risk Factors in Early Illness

Adult gyrification provides a window into coordinated early neurodevelopment when disruptions predispose individuals to psychiatric illness. We hypothesized that the echoes of such disruptions should be observed within structural gyrification networks in early psychiatric illness that would demonstrate associations with developmentally relevant variables rather than specific psychiatric symptoms. We employed a new data-driven method (Orthogonal Projective Non-Negative Matrix Factorization) to delineate novel gyrification-based networks of structural covariance in 308 healthy controls. Gyrification within the networks was then compared to 713 patients with recent onset psychosis or depression, and at clinical high-risk. Associations with diagnosis, symptoms, cognition, and functioning were investigated using linear models. Results demonstrated 18 novel gyrification networks in controls as verified by internal and external validation. Gyrification was reduced in patients in temporal-insular, lateral occipital, and lateral fronto-parietal networks (pFDR < 0.01) and was not moderated by illness group. Higher gyrification was associated with better cognitive performance and lifetime role functioning, but not with symptoms. The findings demonstrated that gyrification can be parsed into novel brain networks that highlight generalized illness effects linked to developmental vulnerability. When combined, our study widens the window into the etiology of psychiatric risk and its expression in adulthood.

Functional and morphological correlates of developmental dyslexia: A multimodal investigation of the ventral occipitotemporal cortex

BACKGROUND AND PURPOSE

The ventral occipitotemporal cortex (vOT) is a region crucial for reading acquisition through selective tuning to printed words. Developmental dyslexia is a disorder of reading with underlying neurobiological bases often associated with atypical neural responses to printed words. Previous studies have discovered anomalous structural development and function of the vOT in individuals with dyslexia. However, it remains unclear if or how structural abnormalities relate to functional alterations.

METHODS

In this study, we acquired structural, functional (words and faces processing), and diffusion MRI data from 26 children with dyslexia (average age = 10.4 ± 2.0 years) and 14 age-matched typically developing readers (average age = 10.4 ± 1.6 years). Morphological indices of local gyrification, neurite density (i.e., dendritic arborization structure), and orientation dispersion (i.e., dendritic arborization orientation) were analyzed within the vOT region that showed preferential activation in typically developing readers for words (as compared to face stimuli).

RESULTS

The two cohorts diverged significantly in both functional and structural measures. Compared to typically developing controls, children with dyslexia did not show selectivity for words in the left vOT (contrast: words > false fonts). This lack of tuning to printed words was associated with greater neurite dispersion heterogeneity in the dyslexia cohort, but similar neurite density. These group differences were not present in the homologous contralateral area, the right vOT.

CONCLUSIONS

Our findings provide new insight into the neurobiology of the lack of vOT word tuning in dyslexia by linking behavior, alterations in functional activation, and neurite organization.

Relationship between local gyrification index and age, intelligence quotient, symptom severity with Autism Spectrum Disorder: A large-scale MRI study

Gyrification is one of the most important characteristics in the cerebral cortex and the local gyrification index (LGI) was used to quantify the regional changes in gyrification. The aim of this study was to evaluate LGI alterations in autism spectrum disorder (ASD) individuals in comparison with typically developing (TD) controls and the association of the LGI with age, intelligence quotient (IQ), and symptom severity in a large multicenter dataset. Structural MRI datasets selected from Autism Brain Imaging Data Exchange I and II (ABIDE I and ABIDE II) repository (606 ASD individuals and 765 age-matched TD controls) were used to calculate LGI values. The correlation between the LGI and age, IQ, and other clinical measurements were assessed. No differences in LGI were found between ASD individuals and TD controls after FDR multiple comparison correction, however, LGI decreased with age in both ASD and TD groups. In the TD group, a significant positive correlation was found between the LGI and full IQ (FIQ) in the parahippocampal gyrus, parsopercularis of left hemisphere and entorhinal cortex, parahippocampal, superior temporal gyrus of right hemisphere, but was not observed in the ASD group. Furthermore, a positive correlation between the LGI and Autism Diagnostic Interview-Revised (ADI-R) Repetitive and Restrictive Behaviors (RRB) score was found in the left inferior parietal lobule, lateral occipital cortex, superior frontal gyrus and right superior frontal gyrus, inferior temporal gyrus. In summary, these results demonstrate that the ASD is a truly heterogeneous neurodevelopmental disorder. Future investigations are required that group ASD patients into more homogeneous subtypes.

Associations between long-term psychosis risk, probabilistic category learning, and attenuated psychotic symptoms with cortical surface morphometry

Neuroimaging studies have consistently found structural cortical abnormalities in individuals with schizophrenia, especially in structural hubs. However, it is unclear what abnormalities predate psychosis onset and whether abnormalities are related to behavioral performance and symptoms associated with psychosis risk. Using surface-based morphometry, we examined cortical volume, gyrification, and thickness in a psychosis risk group at long-term risk for developing a psychotic disorder (n = 18; i.e., extreme positive schizotypy plus interview-rated attenuated psychotic symptoms [APS]) and control group (n = 19). Overall, the psychosis risk group exhibited cortical abnormalities in multiple structural hub regions, with abnormalities associated with poorer probabilistic category learning, a behavioral measure strongly associated with psychosis risk. For instance, the psychosis risk group had hypogyria in a right posterior midcingulate cortical hub and left superior parietal cortical hub, as well as decreased volume in a right pericalcarine hub. Morphometric measures in all of these regions were also associated with poorer probabilistic category learning. In addition to decreased right pericalcarine volume, the psychosis risk group exhibited a number of other structural abnormalities in visual network structural hub regions, consistent with previous evidence of visual perception deficits in psychosis risk. Further, severity of APS hallucinations, delusional ideation, and suspiciousness/persecutory ideas were associated with gyrification abnormalities, with all domains associated with hypogyria of the right lateral orbitofrontal cortex. Thus, current results suggest that structural abnormalities, especially in structural hubs, are present in psychosis risk and are associated both with poor learning on a psychosis risk-related task and with APS severity.

Morphological and Age-Related Changes in the Narcolepsy Brain

Morphological changes in the cortex of narcolepsy patients were investigated by surface-based morphometry analysis in this study. Fifty-one type 1 narcolepsy patients and 60 demographically group-matched healthy controls provided resting-state functional and high-resolution 3T anatomical magnetic resonance imaging scans. Vertex-level cortical thickness (CT), gyrification, and voxel-wise functional connectivity were calculated. Adolescent narcolepsy patients showed decreased CT in bilateral frontal cortex and left precuneus. Adolescent narcolepsy demonstrated increased gyrification in left occipital lobe, left precuneus, and right fusiform but decreased gyrification in left postcentral gyrus, whereas adult narcolepsy exhibited increased gyrification in left temporal lobe and right frontal cortex. Furthermore, sleepiness severity was associated with altered CT and gyrification. Increased gyrification was associated with reduced long-range functional connectivity. In adolescent patients, those with more severe sleepiness showed increased right postcentral gyrification. Decreased frontal and occipital gyrification was found in cases with hallucination. In adult patients, a wide range of regions showed reduced gyrification in those with adolescence-onset compared adult-onset narcolepsy patients. Particularly the frontal lobes showed altered brain morphology, being a thinner cortex and more gyri. The impact of narcolepsy on age-related brain morphological changes may remain from adolescence to young adulthood, and it was especially exacerbated in adolescence.

New insights into the dynamic development of the cerebral cortex in childhood and adolescence: Integrating macro- and microstructural MRI findings

Through dynamic transactional processes between genetic and environmental factors, childhood and adolescence involve reorganization and optimization of the cerebral cortex. The cortex and its development plays a crucial role for prototypical human cognitive abilities. At the same time, many common mental disorders appear during these critical phases of neurodevelopment. Magnetic resonance imaging (MRI) can indirectly capture several multifaceted changes of cortical macro- and microstructure, of high relevance to further our understanding of the neural foundation of cognition and mental health. Great progress has been made recently in mapping the typical development of cortical morphology. Moreover, newer less explored MRI signal intensity and specialized quantitative T2 measures have been applied to assess microstructural cortical development. We review recent findings of typical postnatal macro- and microstructural development of the cerebral cortex from early childhood to young adulthood. We cover studies of cortical volume, thickness, area, gyrification, T1-weighted (T1w) tissue contrasts such a grey/white matter contrast, T1w/T2w ratio, magnetization transfer and myelin water fraction. Finally, we integrate imaging studies with cortical gene expression findings to further our understanding of the underlying neurobiology of the developmental changes, bridging the gap between ex vivo histological- and in vivo MRI studies.

Cortical structural changes related to early antiretroviral therapy (ART) interruption in perinatally HIV-infected children at 5 years of age

ART interruption in children can occur especially in resource-limited settings for reasons including poor adherence, stock-outs, ART intolerance of non-pediatric formulas and pill size, as well as ultimately to test for HIV remission. Although early ART initiation is now standard of care in pediatric HIV management, very little is known on the effect of early ART initiation or subsequent interruption on brain development. This study aimed to investigate the effect of ART interruption on brain cortical thickness (CT) and folding in a subset of children from the Children with HIV Early antiRetroviral therapy (CHER) trial cohort who all started ART before 18 months of age. CHER participants in the neuroimaging follow-up study had magnetic resonance (MRI) scans on a 3T Siemens Allegra brain scanner at age 5.44 ± 0.37 years. MR images were processed using the automated cross-sectional stream in FreeSurfer v6.0 and vertex wise comparisons of CT and local gyrification indices (LGIs) were performed between HIV+ children and HIV- controls, as well as between HIV+ children on interrupted or continuous ART and controls. HIV+ children (n = 46) showed thicker cortex than HIV- children (n = 29) in bilateral frontal and left temporo-insular regions but lower LGIs in left superior and bilateral medial orbitofrontal cortex extending into rostral anterior cingulate. Children on interrupted ART (n = 21) had thicker cortex than HIV- controls in left frontal and right insular regions, but children on continuous treatment (n = 25) showed no difference from controls. Children on both interrupted and continuous ART showed region-specific alterations in LGI relative to controls. Cortical folding appears more sensitive than CT to early life events including early ART and interruption. However, immune health resilience in children can translate to long term preservation of morphometric brain development, especially for those on early and continuous treatment.

Brain Structure and Subclinical Symptoms: A Dimensional Perspective of Psychopathology in the Depression and Anxiety Spectrum

Human psychopathology is the result of complex and subtle neurobiological alterations. Categorial DSM or ICD diagnoses do not allow a biologically founded and differentiated description of these diverse processes across a spectrum or continuum, emphasising the need for a scientific and clinical paradigm shift towards a dimensional psychiatric nosology. The subclinical part of the spectrum is, however, of special interest for early detection of mental disorders. We review the current evidence of brain structural correlates (grey matter volume, cortical thickness, and gyrification) in non-clinical (psychiatrically healthy) subjects with minor depressive and anxiety symptoms. We identified 16 studies in the depressive spectrum and 20 studies in the anxiety spectrum. These studies show effects associated with subclinical symptoms in the hippocampus, anterior cingulate cortex, and anterior insula similar to major depression and changes in amygdala similar to anxiety disorders. Precuneus and temporal areas as parts of the default mode network were affected specifically in the subclinical studies. We derive several methodical considerations crucial to investigations of brain structural correlates of minor psycho(patho)logical symptoms in healthy participants. And we discuss neurobiological overlaps with findings in patients as well as distinct findings, e.g. in areas involved in the default mode network. These results might lead to more insight into the early pathogenesis of clinical significant depression or anxiety and need to be enhanced by multi-centre and longitudinal studies.

A Connectomic Hypothesis for the Hominization of the Brain

Cognitive abilities of the human brain, including language, have expanded dramatically in the course of our recent evolution from nonhuman primates, despite only minor apparent changes at the gene level. The hypothesis we propose for this paradox relies upon fundamental features of human brain connectivity, which contribute to a characteristic anatomical, functional, and computational neural phenotype, offering a parsimonious framework for connectomic changes taking place upon the human-specific evolution of the genome. Many human connectomic features might be accounted for by substantially increased brain size within the global neural architecture of the primate brain, resulting in a larger number of neurons and areas and the sparsification, increased modularity, and laminar differentiation of cortical connections. The combination of these features with the developmental expansion of upper cortical layers, prolonged postnatal brain development, and multiplied nongenetic interactions with the physical, social, and cultural environment gives rise to categorically human-specific cognitive abilities including the recursivity of language. Thus, a small set of genetic regulatory events affecting quantitative gene expression may plausibly account for the origins of human brain connectivity and cognition.

Cortical Gyrification Morphology in Individuals with ASD and ADHD across the Lifespan: A Systematic Review and Meta-Analysis

Autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) are common neurodevelopmental disorders (NDDs) that may impact brain maturation. A number of studies have examined cortical gyrification morphology in both NDDs. Here we review and when possible pool their results to better understand the shared and potentially disorder-specific gyrification features. We searched MEDLINE, PsycINFO, and EMBASE databases, and 24 and 10 studies met the criteria to be included in the systematic review and meta-analysis portions, respectively. Meta-analysis of local Gyrification Index (lGI) findings across ASD studies was conducted with SDM software adapted for surface-based morphometry studies. Meta-regressions were used to explore effects of age, sex, and sample size on gyrification differences. There were no significant differences in gyrification across groups. Qualitative synthesis of remaining ASD studies highlighted heterogeneity in findings. Large-scale ADHD studies reported no differences in gyrification between cases and controls suggesting that, similar to ASD, there is currently no evidence of differences in gyrification morphology compared with controls. Larger, longitudinal studies are needed to further clarify the effects of age, sex, and IQ on cortical gyrification in these NDDs.

Differential Patterns of Gyral and Sulcal Morphological Changes During Normal Aging Process

The cerebral cortex is a highly convoluted structure with distinct morphologic features, namely the gyri and sulci, which are associated with the functional segregation or integration in the human brain. During the lifespan, the brain atrophy that is accompanied by cognitive decline is a well-accepted aging phenotype. However, the detailed patterns of cortical folding change during aging, especially the changing age-dependencies of gyri and sulci, which is essential to brain functioning, remain unclear. In this study, we investigated the morphology of the gyral and sulcal regions from pial and white matter surfaces using MR imaging data of 417 healthy participants across adulthood to old age (21–92 years). To elucidate the age-related changes in the cortical pattern, we fitted cortical thickness and intrinsic curvature of gyri and sulci using the quadratic model to evaluate their age-dependencies during normal aging. Our findings show that comparing to gyri, the sulcal thinning is the most prominent pattern during the aging process, and the gyrification of pial and white matter surfaces were also affected differently, which implies the vulnerability of functional segregation during aging. Taken together, we propose a morphological model of aging that may provide a framework for understanding the mechanisms underlying gray matter degeneration.

Cortical gyrification morphology in PTSD: A neurobiological risk factor for severity?

Post-traumatic stress disorder (PTSD) is a prevalent psychiatric disorder, particularly among military personnel and veterans. Cortical gyrification, as a specific metric derived from structural MRI, is an index of the convoluted folding and patterning of the gyri and sulci, and is thought to facilitate the efficiency of local neuronal wiring. It has the potential to act as a neurobiological risk factor for emergent psychiatric disorders – to date, it has been understudied in PTSD. Here, using a local measure of the degree of gyrification (local Gyrification Index, lGI) we investigate cortical gyrification morphology in 48 adult male soldiers with (n = 23) and without (n = 25) a PTSD diagnosis. We also examine the relation between lGI and PTSD severity within the PTSD group. General linear models yielded significant between-group differences with greater lGI found in PTSD in a cluster located in the medial occipito-parietal lobe on the left hemisphere and reduced lGI in a cluster located on the lateral surface of the parietal lobe on the right hemisphere. Brain-behaviour analyses within the PTSD group yielded significant positive associations between lGI and PTSD severity in a cluster located in the frontal cortex of the left hemisphere and scattered clusters located within all lobes of the right hemisphere. After accounting for the effects of comorbid psychiatric symptoms common in PTSD, the associations in the right hemisphere reduced to clusters only located in the frontal lobe, while the cluster in the left hemisphere remained significant. Our results suggest that atypical cortical gyrification in parietal and occipital regions may be implicated in the psychopathology of PTSD diagnosis, and properties of prefrontal gyrification associated with the emergent severity of PTSD after trauma. The importance of these regions in PTSD may be attributed to a pre-existing neurobiological risk factor, or neuromorphological changes after trauma precipitating emergent psychiatric illness. Our brain-behaviour relations provide support for the existing literature by highlighting the importance of the frontal lobe in the pathogenesis of PTSD. Future large-scale longitudinal studies including female participants may infer causal implications of atypical gyrification in PTSD and shed light on the potential effect of sex on this brain metric.

A gyrification analysis approach based on Laplace Beltrami eigenfunction level sets

An accurate measure of the complexity of patterns of cortical folding or gyrification is necessary for understanding normal brain development and neurodevelopmental disorders. Conventional gyrification indices (GIs) are calculated based on surface curvature (curvature-based GI) or an outer hull surface of the cortex (outer surface-based GI). The latter is dependent on the definition of the outer hull surface and a corresponding function between surfaces. In the present study, we propose the Laplace Beltrami-based gyrification index (LB-GI). This is a new curvature-based local GI computed using the first three Laplace Beltrami eigenfunction level sets. As with outer surface-based GI methods, this method is based on the hypothesis that gyrification stems from a flat surface during development. However, instead of quantifying gyrification with reference to corresponding points on an outer hull surface, LB-GI quantifies the gyrification at each point on the cortical surface with reference to their surrounding gyral points, overcoming several shortcomings of existing methods. The LB-GI was applied to investigate the cortical maturation profile of the human brain from preschool to early adulthood using the PING database. The results revealed more detail in patterns of cortical folding than conventional curvature-based methods, especially on frontal and posterior tips of the brain, such as the frontal pole, lateral occipital, lateral cuneus, and lingual. Negative associations of cortical folding with age were observed at cortical regions, including bilateral lingual, lateral occipital, precentral gyrus, postcentral gyrus, and superior frontal gyrus. The results also indicated positive significant associations between age and the LB-GI of bilateral insula, the medial orbitofrontal, frontal pole and rostral anterior cingulate regions. It is anticipated that the LB-GI will be advantageous in providing further insights in the understanding of brain development and degeneration in large clinical neuroimaging studies.

Developmental Alterations in Cortical Organization and Socialization in Adolescents Who Sustained a Traumatic Brain Injury in Early Childhood

This study investigated patterns of cortical organization in adolescents who had sustained a traumatic brain injury (TBI) during early childhood to determine ways in which early head injury may alter typical brain development. Increased gyrification in other patient populations is associated with polymicrogyria and aberrant development, but this has not been investigated in TBI. Seventeen adolescents (mean age = 14.1 ± 2.4) who sustained a TBI between 1-8 years of age, and 17 demographically-matched typically developing children (TDC) underwent a high-resolution, T1-weighted 3-Tesla magnetic resonance imaging (MRI) at 6-15 years post-injury. Cortical white matter volume and organization was measured using FreeSurfer's Local Gyrification Index (LGI). Despite a lack of significant difference in white matter volume, participants with TBI demonstrated significantly increased LGI in several cortical regions that are among those latest to mature in normal development, including left parietal association areas, bilateral dorsolateral and medial frontal areas, and the right posterior temporal gyrus, relative to the TDC group. Additionally, there was no evidence of increased surface area in the regions that demonstrated increased LGI. Higher Vineland-II Socialization scores were associated with decreased LGI in right frontal and temporal regions. The present results suggest an altered pattern of expected development in cortical gyrification in the TBI group, with changes in late-developing frontal and parietal association areas. Such changes in brain structure may underlie cognitive and behavioral deficits associated with pediatric TBI. Alternatively, increased gyrification following TBI may represent a compensatory mechanism that allows for typical development of cortical surface area, despite reduced brain volume.

A Longitudinal Study of Local Gyrification Index in Young Boys With Autism Spectrum Disorder

Local gyrification index (LGI), a metric quantifying cortical folding, was evaluated in 105 boys with autism spectrum disorder (ASD) and 49 typically developing (TD) boys at 3 and 5 years-of-age. At 3 years-of-age, boys with ASD had reduced gyrification in the fusiform gyrus compared with TD boys. A longitudinal evaluation from 3 to 5 years revealed that while TD boys had stable/decreasing LGI, boys with ASD had increasing LGI in right inferior temporal gyrus, right inferior frontal gyrus, right inferior parietal lobule, and stable LGI in left lingual gyrus. LGI was also examined in a previously defined neurophenotype of boys with ASD and disproportionate megalencephaly. At 3 years-of-age, this subgroup exhibited increased LGI in right dorsomedial prefrontal cortex, cingulate cortex, and paracentral cortex, and left cingulate cortex and superior frontal gyrus relative to TD boys and increased LGI in right paracentral lobule and parahippocampal gyrus, and left precentral gyrus compared with boys with ASD and normal brain size. In summary, this study identified alterations in the pattern and development of LGI during early childhood in ASD. Distinct patterns of alterations in subgroups of boys with ASD suggests that multiple neurophenotypes exist and boys with ASD and disproportionate megalencephaly should be evaluated separately.

Neighborhood deprivation, prefrontal morphology and neurocognition in late childhood to early adolescence

Background:

Neighborhood deprivation adversely effects neurodevelopment and cognitive function; however, mechanisms remain unexplored. Neighborhood deprivation could be particularly impactful in late childhood/early adolescence, in neural regions with protracted developmental trajectories, e.g., prefrontal cortex (PFC).

Methods:

The Adolescent Brain Cognitive Development (ABCD) study recruited 10,205 youth. Geocoded residential history was used to extract individual neighborhood characteristics. A general cognitive ability index and MRI scans were completed. Associations with neurocognition were examined. The relation of PFC surface area and cortical thickness to neighborhood deprivation was tested. PFC subregions and asymmetry, with putative differential environmental susceptibility during key developmental periods, were explored. Analyses tested PFC area as a possible mediating mechanism.

Results:

Neighborhood deprivation predicted neurocognitive performance (β = −0.11), even after accounting for parental education and household income (β = −0.07). Higher neighborhood deprivation related to greater overall PFC surface area (η²_p = 0.003), and differences in leftward asymmetry were observed for area (η²_p = 0.001), and thickness (η²_p = 0.003). Subregion analyses highlighted differences among critical areas that are actively developing in late childhood/early adolescence and are essential to modulating high order cognitive function. These included orbitofrontal, superior frontal, rostral middle frontal, and frontal pole regions (Cohen’s d = 0.03–0.09). PFC surface area partially mediated the relation between neighborhood deprivation and neurocognition.

Discussion:

Neighborhood deprivation related to cognitive function (a foundational skill tied to a range of lifetime outcomes) and PFC morphology, with evidence found for partial mediation of PFC on neurocognitive function. Results inform public health conceptualizations of development and environmental vulnerability.

Quantitative MRI-Based Analysis Identifies Developmental Limbic Abnormalities in PCDH19 Encephalopathy

Protocadherin-19 (PCDH19) is a calcium dependent cell-adhesion molecule involved in neuronal circuit formation with prevalent expression in the limbic structures. PCDH19-gene mutations cause a developmental encephalopathy with prominent infantile onset focal seizures, variably associated with intellectual disability and autistic features. Diagnostic neuroimaging is usually unrevealing. We used quantitative MRI to investigate the cortex and white matter in a group of 20 PCDH19-mutated patients. By a statistical comparison between quantitative features in PCDH19 brains and in a group of age and sex matched controls, we found that patients exhibited bilateral reductions of local gyrification index (lGI) in limbic cortical areas, including the parahippocampal and entorhinal cortex and the fusiform and lingual gyri, and altered diffusivity features in the underlying white matter. In patients with an earlier onset of seizures, worse psychiatric manifestations and cognitive impairment, reductions of lGI and diffusivity abnormalities in the limbic areas were more pronounced. Developmental abnormalities involving the limbic structures likely represent a measurable anatomic counterpart of the reduced contribution of the PCDH19 protein to local cortical folding and white matter organization and are functionally reflected in the phenotypic features involving cognitive and communicative skills as well as local epileptogenesis.

Alcohol use in young adults associated with cortical gyrification

BACKGROUND

Young adulthood has the highest rates of alcohol use and high-risk drinking behavior. This period is also a critical neurodevelopmental stage, with neural insults having a profound neurotoxic effect on the brain. Cortical gyrification is thought, in part, to reflect early brain maturation (e.g., hypogyrification in fetal alcohol syndrome). There is also evidence that cortical gyrification is sensitive to later-life events (e.g., fluctuations in malnutrition in young adults). However, no study has examined how alcohol use in young adulthood is associated with cortical gyrification.

METHODS

We examined the associations between cortical gyrification with lifetime alcohol use and past year hangover symptoms in young adults (N = 78).

RESULTS

Lifetime alcohol use was associated with hypogyria in multiple cortical regions (rs ≤ -.27, ps ≤ .0159; right orbitofrontal, right temporal pole, and left lateral occipital). Further, past year hangover symptoms were associated with hypogyria (rs ≤ -.27, ps ≤ .0034), overlapping with lifetime alcohol use (right orbitofrontal and left lateral occipital). Hangover symptoms were also uniquely associated with hypogyria of other cortical regions (rs ≤ -.30, ps ≤ .0002; right parahippocampal gyrus, left inferior temporal/parahippocampal gyrus and right anterior insula).

CONCLUSIONS

Thus, results suggest that young adulthood is a critical period for targeted prevention and intervention, especially for individuals exhibiting heavy alcohol consumption and high-risk drinking behavior.

Brain morphometric differences in youth with and without perinatally-acquired HIV: A cross-sectional study

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We performed vertex-wise analyses comparing grey matter in youth with and without perinatally-acquired HIV (PHIV).

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PHIV youth had reduced cortical thickness, surface area, and gyrification compared to control youth.

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PHIV youth did not exhibit the same pattern of inverse grey matter-age relationships that were observed in control youth.

Youth with perinatally-acquired HIV (PHIV) experience specific and global cognitive deficits at increased rates compared to typically-developing HIV-uninfected youth. In youth with PHIV, HIV infects the brain early in development. Neuroimaging studies have demonstrated altered grey matter morphometry in youth with PHIV compared to typically-developing youth. This study examined cortical thickness, surface area, and gyrification of grey matter in youth (age 11–20 years old) with PHIV (n = 40) from the Pediatric HIV/AIDS Cohort Study (PHACS) compared to typically-developing presumed HIV uninfected and unexposed youth (n = 80) from the Pediatric Imaging, Neurocognition and Genetics Study (PING) using structural magnetic resonance imaging. This study also examined the relationship between grey matter morphometry and age. Youth with PHIV had reduced cortical thickness, surface area, and gyrification compared to typically-developing youth. In addition, an inverse relationship between age and grey matter volume was found in typically-developing youth, but was not observed in youth with PHIV. Longitudinal studies are necessary to understand the neurodevelopmental trajectory of youth with PHIV.

Altered Cortical Gyrification in Adults Who Were Born Very Preterm and Its Associations With Cognition and Mental Health

BACKGROUND

The last trimester of pregnancy is a critical period for the establishment of cortical gyrification, and altered folding patterns have been reported following very preterm birth (< 33 weeks of gestation) in childhood and adolescence. However, research is scant on the persistence of such alterations in adulthood and their associations with cognitive and psychiatric outcomes.

METHODS

We studied 79 very preterm and 81 age-matched full-term control adults. T1-weighted magnetic resonance images were used to measure a local gyrification index (LGI), indicating the degree of folding across multiple vertices of the reconstructed cortical surface. Group and group-by-sex LGI differences were assessed by means of per-vertex adjustment for cortical thickness and overall intracranial volume. Within-group correlations were also computed between LGI and functional outcomes, including general intelligence (IQ) and psychopathology.

RESULTS

Very preterm adults had significantly reduced LGI in extensive cortical regions encompassing the frontal, anterior temporal, and occipitoparietal lobes. Alterations in lateral fronto-temporal-parietal and medial occipitoparietal regions were present in both men and women, although men showed more extensive alterations. In both very preterm and control adults, higher LGI was associated with higher IQ and lower psychopathology scores, with the spatial distribution of these associations substantially differing between the two groups.

CONCLUSIONS

Very preterm adults' brains are characterized by significant and widespread local hypogyria, and these alterations might be implicated in cognitive and psychiatric outcomes. Gyrification reflects an early developmental process and provides a fingerprint for very preterm birth.

Visualizing the neuroanatomical changes in Han Chinese adulthood: A pseudo-longitudinal study based on age-related large-scale statistical Chinese brain atlases

Objective:

Understanding how brain changes over lifetime provides the basis for new insights into neurophysiology and neuropathology. In this study, we carried out a pseudo-longitudinal study based on age-related Chinese brain atlases (i.e., Chinese2020) constructed from large-scale volumetric brain MRI data collected in normal Han Chinese adults at varying ages.

Methods:

In order to quantify the deformation and displacement of brains for each voxel as age increases, optical flow algorithm was employed to compute motion vectors between every two consecutive brain templates of the age-related brain atlas, i.e., Chinese2020.

Results:

Dynamic age-related neuroanatomical changes in a standardized brain space were shown. Overall, our results demonstrate that brain inward deformation (mainly due to atrophy) can appear in adulthood and this trend generally accelerates as age increases, affecting multiple regions including frontal cortex, temporal cortex, parietal cortex, and cerebellum, whereas occipital cortex is least affected by aging, and even showed some degree of outward deformation in the midlife.

Conclusion:

Our findings indicated more complicated age-related changes instead of a simple trend of brain volume decrease, which may be in line with the recently increasing interests in the age-related cortical complexity with other morphometry measures.

Brain Development in School-Age and Adolescent Girls: Effects of Turner Syndrome, Estrogen Therapy, and Genomic Imprinting

BACKGROUND

The study of Turner syndrome (TS) offers a unique window of opportunity for advancing scientific knowledge of how X chromosome gene imprinting, epigenetic factors, hormonal milieu, and chronologic age affect brain development in females.

METHODS

We described brain growth trajectories in 55 girls with TS and 53 typically developing girls (258 magnetic resonance imaging datasets) spanning 5 years. Using novel nonparametric and mixed effects analytic approaches, we evaluated influences of X chromosome genomic imprinting and hormone replacement therapy on brain development.

RESULTS

Parieto-occipital gray and white matter regions showed slower growth during typical pubertal timing in girls with TS relative to typically developing girls. In contrast, some basal ganglia, cerebellar, and limited cortical areas showed enhanced volume growth with peaks around 10 years of age.

CONCLUSIONS

The parieto-occipital finding suggests that girls with TS may be particularly vulnerable to altered brain development during adolescence. Basal ganglia regions may be relatively preserved in TS owing to their maturational growth before or early in typical pubertal years. Taken together, our findings indicate that particular brain regions are more vulnerable to TS genetic and hormonal effects during puberty. These specific alterations in neurodevelopment may be more likely to affect long-term cognitive behavioral outcomes in young girls with this common genetic condition.

Age effects on basic symptoms in the community: A route to gain new insight into the neurodevelopment of psychosis?

Reports of limited clinical significance of attenuated psychotic symptoms before age 15/16 indicate an important role of neurodevelopment in the early detection of psychoses. Therefore, we examined if age also exerts an influence on the prevalence and clinical significance of the 14 cognitive and perceptive basic symptoms (BS) used in psychosis-risk criteria and conceptualized as the most direct self-experienced expression of neurobiological aberrations. A random representative general population sample of the Swiss canton Bern (N = 689, age 8-40 years, 06/2011-05/2014) was interviewed for BS, psychosocial functioning, and current mental disorder. BS were reported by 18% of participants, mainly cognitive BS (15%). In regression analyses, age affected perceptive and cognitive BS differently, indicating an age threshold for perceptive BS in late adolescence (around age 18) and for cognitive BS in young adulthood (early twenties)-with higher prevalence, but a lesser association with functional deficits and the presence of mental disorder in the below-threshold groups. Thereby, interaction effects between age and BS on functioning and mental disorder were commonly stronger than individual effects of age and BS. Indicating support of the proposed "substrate-closeness" of BS, differential age effects of perceptual and cognitive BS seem to follow normal brain maturation processes, in which they might occur as infrequent and temporary non-pathological disturbances. Their persistence or occurrence after conclusion of main brain maturation processes, however, might signify aberrant maturation or neurodegenerative processes. Thus, BS might provide important insight into the pathogenesis of psychosis and into differential neuroprotective or anti-inflammatory targets.

Cortical surface morphology in long-term cannabis users: A multi-site MRI study

Cannabis exerts its psychoactive effect through cannabinoid receptors that are widely distributed across the cortical surface of the human brain. It is suggested that cannabis use may contribute to structural alterations across the cortical surface. In a large, multisite dataset of 120 controls and 141 cannabis users, we examined whether differences in key characteristics of the cortical surface - including cortical thickness, surface area, and gyrification index were related to cannabis use characteristics, including (i) cannabis use vs. non-use, (ii) cannabis dependence vs. non-dependence vs. non-use, and (iii) early adolescent vs. late adolescent onset of cannabis use vs. non-use. Our results revealed that cortical morphology was not associated with cannabis use, dependence, or onset age. The lack of effect of regular cannabis use, including problematic use, on cortical structure in our study is contrary to previous evidence of cortical morphological alterations (particularly in relation to cannabis dependence and cannabis onset age) in cannabis users. Careful reevaluation of the evidence on cannabis-related harm will be necessary to address concerns surrounding the long-term effects of cannabis use and inform policies in a changing cannabis regulation climate.

Cortical Contributions to Distinct Symptom Dimensions of Catatonia

Catatonia is a central aspect of schizophrenia spectrum disorders (SSD) and most likely associated with abnormalities in affective, motor, and sensorimotor brain regions. However, contributions of different cortical features to the pathophysiology of catatonia in SSD are poorly understood. Here, T1-weighted structural magnetic resonance imaging data at 3 T were obtained from 56 right-handed patients with SSD. Using FreeSurfer version 6.0, we calculated cortical thickness, area, and local gyrification index (LGI). Catatonic symptoms were examined on the Northoff catatonia rating scale (NCRS). Patients with catatonia (NCRS total score ≥3; n = 25) showed reduced surface area in the parietal and medial orbitofrontal gyrus and LGI in the temporal gyrus (P < .05, corrected for cluster-wise probability [CWP]) as well as hypergyrification in rostral cingulate and medial orbitofrontal gyrus when compared with patients without catatonia (n = 22; P < .05, corrected for CWP). Following a dimensional approach, a negative association between NCRS motor and behavior scores and cortical thickness in superior frontal, insular, and precentral cortex was found (34 patients with at least 1 motor and at least 1 other affective or behavioral symptom; P < .05, corrected for CWP). Positive associations were found between NCRS motor and behavior scores and surface area and LGI in superior frontal, posterior cingulate, precentral, and pericalcarine gyrus (P < .05, corrected for CWP). The data support the notion that cortical features of distinct evolutionary and genetic origin differently contribute to catatonia in SSD. Catatonia in SSD may be essentially driven by cortex variations in frontoparietal regions including regions implicated in the coordination and goal-orientation of behavior.

Gyrification abnormalities in presymptomatic c9orf72 expansion carriers

OBJECTIVE

To investigate in-vivo cortical gyrification patterns measured by the local gyrification index (lGI) in presymptomatic c9orf72 expansion carriers compared with healthy controls, and investigate relationships between lGI and cortical thickness, an established morphometric measure of neurodegeneration.

METHODS

We assessed cortical gyrification and thickness patterns in a cohort of 15 presymptomatic c9orf72 expansion carriers (age 43.7 ± 10.2 years, 9 females) compared with 67 (age 42.4 ± 12.4 years, 36 females) age and sex matched healthy controls using the dedicated Freesurfer pipeline.

RESULTS

Compared with controls, presymptomatic carriers showed significantly lower lGI in left frontal and right parieto-occipital regions. Interestingly, those areas with abnormal gyrification in presymptomatic carriers showed no concomitant cortical thickness abnormality. Overall, for both presymptomatic carriers and healthy controls, gyrification and cortical thickness measures were not correlated, suggesting that gyrification captures a feature distinct from cortical thickness.

CONCLUSIONS

Presymptomatic c9orf72 expansion carriers show regions of abnormally low gyrification as early as their 30s, decades before expected symptom onset. Cortical gyrification represents a novel grey matter metric distinctive from grey matter thickness or volume and detects differences in presymptomatic carriers at an early age.

Parallel Changes in Cognitive Function and Gray Matter Volume After Multi-Component Training of Cognitive Control (MTCC) in Adolescents

Adolescence is a unique period in which higher cognition develops to adult-level, while plasticity of neuron and behavior is at one of its peak. Notably, cognitive training studies for adolescents has been sparse and neural correlates of the training effects yet to be established. This study investigated the effects of multi-component training of cognitive control (MTCC) in order to examine whether the training enhanced adolescents' cognitive control ability and if the effects were generalizable to other cognitive domains. Cognitive control refers to the ability to adjust a series of thoughts and behaviors in correspondence to an internal goal, and involves inhibition, working memory, shifting, and dual tasking as subcomponents. The participants were middle school students (aged 11-14) and randomly assigned to either a training group or an active control group. The training group performed 30 min of MTCC per day for 6 weeks. To identify the training effects, we examined the cognitive performance, regional gray matter, and their relationship. The training group showed modest improvement in a visuospatial fluid intelligence test (Block Design) after MTCC, which was not significant after correcting for multiple comparisons. In addition, the training effect on the gray matter volume (time × group interaction) was observed in the right inferior cortex (rIFC). While the control group showed a typical reduction in the rIFC volume, the training group showed a relative increase in the homologous region. The relative change in rIFC volume was associated with the change in Stroop performance. These results imply that MTCC may affect brain structure relevant to inhibitory control process.

Cortical morphometry in anorexia nervosa: An out-of-sample replication study

BACKGROUND

Acute anorexia nervosa (AN) is frequently accompanied by reduced global cortical volume. Investigations of local cortical alterations in AN have revealed widespread reduction in cortical thickness, gyrification, and curvature. The aim of the present study was to combine data from two previous studies to replicate previous findings.

METHODOLOGY

Magnetic resonance imaging (MRI) images from 46 adult women with AN and 54 age-matched healthy comparison (HC) women were analysed using FreeSurfer. Group differences in cortical volume and local cortical measures, including gyrification, curvature, thickness, and area, were examined controlling for dataset and age.

RESULTS

The AN group had reduced global cortical volume relative to the HC group. The AN group also had reduction in local cortical gyrification, small localised clusters of reduced cortical thickness, in the occipital and parietal cortices, and surface area in the frontal and temporal cortices. The AN group also had increased cortical thickness in the ACC relative to the HC participants.

CONCLUSIONS

The present findings replicate and validate previous findings of reduced global cortical volume and local gyrification in acute AN. The findings highlight the need for further investigation of local cortical folding, thickness, and surface area in AN to gain further insight into the biological underpinnings of AN.

Local Cortical Gyrification is Increased in Children With Autism Spectrum Disorders, but Decreases Rapidly in Adolescents

Extensive MRI evidence indicates early brain overgrowth in autism spectrum disorders (ASDs). Local gyrification may reflect the distribution and timing of aberrant cortical expansion in ASDs. We examined MRI data from (Study 1) 64 individuals with ASD and 64 typically developing (TD) controls (7-19 years), and from (Study 2) an independent sample from the Autism Brain Imaging Data Exchange (n = 31/group). Local Gyrification Index (lGI), cortical thickness (CT), and surface area (SA) were measured. In Study 1, differences in lGI (ASD > TD) were found in left parietal and temporal and right frontal and temporal regions. lGI decreased bilaterally with age, but more steeply in ASD in left precentral, right lateral occipital, and middle frontal clusters. CT differed between groups in right perisylvian cortex (TD > ASD), but no differences were found for SA. Partial correlations between lGI and CT were generally negative, but associations were weaker in ASD in several clusters. Study 2 results were consistent, though less extensive. Altered gyrification may reflect unique information about the trajectory of cortical development in ASDs. While early overgrowth tends to be undetectable in later childhood in ASDs, findings may indicate that a trace of this developmental abnormality could remain in a disorder-specific pattern of gyrification.

MRI Indices of Cortical Development in Young People With Psychotic Experiences: Influence of Genetic Risk and Persistence of Symptoms

Background

Psychotic experiences (PEs) are considered part of an extended psychosis phenotype and are associated with an elevated risk of developing a psychotic disorder. Risk of transition increases with persistence of PEs, and this is thought to be modulated by genetic and environmental factors. However, it is unclear if persistence is associated with progressive schizophrenia-like changes in neuroanatomy.

Methods

We examined cortical morphometry using MRI in 247 young adults, from a population-based cohort, assessed for the presence of PEs at ages 18 and 20. We then incorporated a polygenic risk score for schizophrenia (PRS) to elucidate the effects of high genetic risk. Finally, we used atlas-based tractography data to examine the underlying white matter.

Results

Individuals with persisting PEs showed reductions in gyrification (local gyrification index: lGI) in the left temporal gyrus as well as atypical associations with brain volume (TBV) in the left occipital and right prefrontal gyri. No main effect was found for the PRS, but interaction effects with PEs were identified in the orbitofrontal, parietal, and temporal regions. Examination of underlying white matter did not provide strong evidence of further disturbances.

Conclusions

Disturbances in lGI were similar to schizophrenia but findings were mostly limited to those with persistent PEs. These could reflect subtle changes that worsen with impending psychosis or reflect an early vulnerability associated with the persistence of PEs. The lack of clear differences in underlying white matter suggests our findings reflect early disturbances in cortical expansion rather than progressive changes in brain structure.

Nutritional Status Affects Cortical Folding: Lessons Learned From Anorexia Nervosa

BACKGROUND

Cortical folding is thought to remain relatively invariant after birth. Therefore, differences seen in psychiatric disorders have been proposed as early biomarkers or used as intermediate phenotypes in imaging genetics studies. Anorexia nervosa (AN) is associated with drastic and rapid structural brain alterations and thus may be an ideal model disorder to study environmental influences on cortical folding.

METHODS

To date, the only two studies in AN applied different methods (local gyrification index and mean curvature) and found seemingly discordant results. We computed both vertexwise measures in a sizable sample of acutely underweight female AN patients (n = 87, mean age 16.5 years), long-term recovered patients (n = 58, mean age 22 years), and healthy control participants (n = 141, mean age 19.5 years). The majority of acutely ill patients were scanned longitudinally (n = 57) again after partial weight normalization (>14% body mass index increase).

RESULTS

While gyrification was broadly reduced in acutely ill patients, normal values were restored in most brain regions after partial weight restoration (≈3 months), and after full recovery no significant differences were evident relative to control participants. Increased gyrification was largely predicted by weight restoration alone. Results for absolute mean curvature analyses complemented those obtained using the local gyrification index.

CONCLUSIONS

Together, these findings indicate that nutritional status affects cortical folding and suggest that gyrification studies may need to better control for environmental factors. Moreover, they provide novel support for the likelihood that macroscopic changes in the cortical organization in AN are more reflective of nutritional state than premorbid trait markers or permanent scars.

Myelin Water Fraction Imaging Reveals Hemispheric Asymmetries in Human White Matter That Are Associated with Genetic Variation in PLP1

Myelination of axons in the central nervous system is critical for human cognition and behavior. The predominant protein in myelin is proteolipid protein-making PLP1, the gene that encodes for proteolipid protein, one of the primary candidate genes for white matter structure in the human brain. Here, we investigated the relation of genetic variation within PLP1 and white matter microstructure as assessed with myelin water fraction imaging, a neuroimaging technique that has the advantage over conventional diffusion tensor imaging in that it allows for a more direct assessment of myelin content. We observed significant asymmetries in myelin water fraction that were strongest and rightward in the parietal lobe. Importantly, these parietal myelin water fraction asymmetries were associated with genetic variation in PLP1. These findings support the assumption that genetic variation in PLP1 affects white matter myelination in the healthy human brain.

The neurocognitive correlates of academic diligence in adolescent girls

Academic diligence is the ability to regulate behavior in the service of goals, and a predictor of educational attainment. Here we combined behavioral, structural MRI, functional MRI and connectivity data to investigate the neurocognitive correlates of diligence. We assessed whether individual differences in diligence are related to the interplay between frontal control and striatal reward systems, as predicted by the dual-systems hypothesis of adolescent development. We obtained behavioral measures of diligence from 40 adolescent girls (aged 14-15 years) using the Academic Diligence Task. We collected structural imaging data for each participant, as well as functional imaging data during an emotional go-no-go self-control task. As predicted by the dual-systems hypothesis, we found that inferior frontal activation and gyrification correlated with academic diligence. However, neither striatal activation nor structure, nor fronto-striatal connectivity, showed clear associations with diligence. Instead, we found prominent activation of temporal areas during the go-no-go task. This suggests that academic diligence is associated with an extended network of brain regions.

The Structural and Functional Signature of Action Control

Individuals differ in their ability to initiate self- and emotional-control mechanisms. These differences have been explicitly described in Kuhl’s action-control theory. Although interindividual differences in action control make a major contribution to our everyday life, their neural foundation remains unknown. Here, we measured action control in a sample of 264 healthy adults and related interindividual differences in action control to variations in brain structure and resting-state connectivity. Our results demonstrate a significant negative correlation between decision-related action orientation (AOD) and amygdala volume. Further, we showed that the functional resting-state connectivity between the amygdala and the dorsal anterior cingulate cortex was significantly associated with AOD. Specifically, stronger functional connectivity was associated with higher AOD scores. These findings are the first to show that interindividual differences in action control, namely AOD, are based on the anatomical architecture and functional network of the amygdala.

Gyrification changes are related to cognitive strengths in autism

Background

Behavioral, cognitive and functional particularities in autism differ according to autism subgroups and might be associated with domain-specific cognitive strengths. It is unknown whether structural changes support this specialization. We investigated the link between cortical folding, its maturation and cognitive strengths in autism subgroups presenting verbal or visuo-spatial peaks of abilities.

Methods

We measured gyrification, a structural index related to function, in 55 autistic participants with (AS-SOD, N = 27) or without (AS-NoSOD, N = 28) a speech onset delay (SOD) with similar symptom severity but respectively perceptual and verbal cognitive strengths, and 37 typical adolescents and young adults matched for intelligence and age. We calculated the local Gyrification Index (lGI) throughout an occipito-temporal region of interest and independently modeled age and peak of ability effects for each group.

Results

Unique gyrification features in both autistic groups were detected in localized clusters. When comparing the three groups, gyrification was found lower in AS-SOD in a fusiform visual area, whereas it was higher in AS-NoSOD in a temporal language-related region. These particular areas presented age-related gyrification differences reflecting contrasting local maturation pathways in AS. As expected, peaks of ability were found in a verbal subtest for the AS-NoSOD group and in the Block Design IQ subtest for the AS-SOD group.

Conclusions

Irrespective of their direction, regional gyrification differences in visual and language processing areas respectively reflect AS-SOD perceptual and AS-NoSOD language-oriented peaks. Unique regional maturation trajectories in the autistic brain may underline specific cognitive strengths, which are key variables for understanding heterogeneity in autism.

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Subgrouping the autism spectrum (AS) partly accounts for its heterogeneity.

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AS individuals with a speech onset delay (SOD) show perceptual cognitive strengths.

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AS individuals without a SOD show language-related cognitive strengths.

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AS subgroups show unique gyrification patterns in areas related to their strengths.

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Cortical structural maturation may be related to domain-specific strengths in AS.