The functional domain of the cerebellum has expanded beyond motor control to also include cognitive and affective functions. In line with this notion, cerebellar volume has increased over recent primate evolution, and cerebellar alterations have been linked to heritable mental disorders. To map the genetic architecture of human cerebellar morphology, we here studied a large imaging genetics sample from the UK Biobank (n discovery = 27,302; n replication: 11,264) with state-of-the art neuroimaging and biostatistics tools. Multivariate GWAS on regional cerebellar MRI features yielded 351 significant genetic loci (226 novel, 94% replicated). Lead SNPs showed positive enrichment for relatively recent genetic mutations over the last 20-40k years (i.e., overlapping the Upper Paleolithic, a period characterized by rapid cultural evolution), while gene level analyses revealed enrichment for human-specific evolution over the last ∼6-8 million years. Finally, we observed genetic overlap with major mental disorders, supporting cerebellar involvement in psychopathology.

Schizophrenia spectrum disorders (SCZspect) are associated with altered function in the auditory cortex (AC), indicated by lower N100 amplitude of the auditory evoked potential (AEP). Although the neural substrate behind lower N100 amplitude remains elusive, myelination in the AC may play a role. This study compared N100 amplitude and magnetic resonance imaging (MRI) T1 weighted and T2 weighted ratio (T1w/T2w-ratio), as a proxy of myelination, in the primary AC (AC1) and secondary AC (AC2) between SCZspect (n = 33, 48% women) and healthy controls (HC, n = 144, 49% women). We also examined the associations between N100 amplitude and T1w/T2w-ratios across groups. We finally explored N100 amplitude and T1w/T2w-ratios and the N100-T1w/T2w-ratio associations between male and female SCZspect and HC. N100 amplitude was significantly lower in male SCZspect compared to male HC (p = 0.01) and nominally lower in SCZspect compared to HC (p = 0.03). However, T1w/T2w-ratios in AC1/AC2 did not differ between groups, and no association was found between N100 amplitude and T1w/T2w-ratio in either group. These findings suggest that sex-specific effects should be considered in SCZspect neurophysiology research. Our results do not support the hypothesis of an association between lower N100 amplitude and lower T1w/T2w-ratio in the AC1/AC2 in SCZspect. More precise assessments of intracortical myelin are needed to understand the relationship between N100 amplitude and cortical myelination in the AC in SCZspect and in healthy controls.

Genetic pleiotropy is abundant across spatially distributed brain characteristics derived from one neuroimaging modality (e.g. structural, functional or diffusion magnetic resonance imaging [MRI]). A better understanding of pleiotropy across modalities could inform us on the integration of brain function, micro- and macrostructure. Here we show extensive genetic overlap across neuroimaging modalities at a locus and gene level in the UK Biobank ( N = 34,029) and ABCD Study ( N = 8607). When jointly analysing phenotypes derived from structural, functional and diffusion MRI in a genome-wide association study (GWAS) with the Multivariate Omnibus Statistical Test (MOSTest), we boost the discovery of loci and genes beyond previously identified effects for each modality individually. Cross-modality genes are involved in fundamental biological processes and predominantly expressed during prenatal brain development. We additionally boost prediction of psychiatric disorders by conditioning independent GWAS on our multimodal multivariate GWAS. These findings shed light on the shared genetic mechanisms underlying variation in brain morphology, functional connectivity, and tissue composition.

Psychiatric disorders are complex, heritable and highly polygenic. Supported by findings of abnormalities in functional magnetic resonance imaging-based measures of brain connectivity, current theoretical and empirical accounts have conceptualized them as disorders of brain connectivity and dysfunctional integration of brain signaling. However, the extent to which these findings reflect common genetic factors remains unclear. Here we performed a multivariate genome-wide association analysis of functional magnetic resonance imaging-based functional brain connectivity in a sample of 30,701 individuals from the UK Biobank and investigated the shared genetic determinants with eight major psychiatric disorders. The analysis revealed significant genetic overlap between functional brain connectivity and schizophrenia, bipolar disorder, attention-deficit/hyperactivity disorder, autism spectrum disorder, anxiety and major depression, adding further genetic support for the dysconnectivity hypothesis of psychiatric disorders and identifying potential genetic and functional targets for future studies.

Psychiatric disorders are complex clinical conditions with large heterogeneity and overlap in symptoms, genetic liability and brain imaging abnormalities. Building on a dimensional conceptualization of mental health, previous studies have reported genetic overlap between psychiatric disorders and population-level mental health, and between psychiatric disorders and brain functional connectivity. Here, in 30,701 participants aged 45–82 from the UK Biobank we map the genetic associations between self-reported mental health and resting-state fMRI-based measures of brain network function. Multivariate Omnibus Statistical Test revealed 10 genetic loci associated with population-level mental symptoms. Next, conjunctional FDR identified 23 shared genetic variants between these symptom profiles and fMRI-based brain network measures. Functional annotation implicated genes involved in brain structure and function, in particular related to synaptic processes such as axonal growth (e.g. NGFR and RHOA). These findings provide further genetic evidence of an association between brain function and mental health traits in the population.

Background and Hypothesis:The auditory cortex (AC) may play a central role in the pathophysiology of schizophrenia and auditory hallucinations (AH). Previous schizophrenia studies report thinner AC and impaired AC function, as indicated by decreased N100 amplitude of the auditory evoked potential. However, whether these structural and functional alterations link to AH in schizophrenia remain poorly understood.Study Design:Patients with a schizophrenia spectrum disorder (SCZspect), including patients with a lifetime experience of AH (AH+), without (AH-), and healthy controls underwent magnetic resonance imaging (39 SCZspect, 22 AH+, 17 AH-, and 146 HC) and electroencephalography (33 SCZspect, 17 AH+, 16 AH-, and 144 HC). Cortical thickness of the primary (AC1, Heschl's gyrus) and secondary (AC2, Heschl's sulcus, and the planum temporale) AC was compared between SCZspect and controls and between AH+, AH-, and controls. To examine if the association between AC thickness and N100 amplitude differed between groups, we used regression models with interaction terms.Study Results:N100 amplitude was nominally smaller in SCZspect (P = .03, d = 0.42) and in AH- (P = .020, d = 0.61), while AC2 was nominally thinner in AH+ (P = .02, d = 0.53) compared with controls. AC1 thickness was positively associated with N100 amplitude in SCZspect (t = 2.56, P = .016) and AH- (t = 3.18, P = .008), while AC2 thickness was positively associated with N100 amplitude in SCZspect (t = 2.37, P = .024) and in AH+ (t = 2.68, P = .019).Conclusions:The novel findings of positive associations between AC thickness and N100 amplitude in SCZspect, suggest that a common neural substrate may underlie AC thickness and N100 amplitude alterations.

Sleep deprivation influences several critical functions, yet how it affects human brain white matter (WM) is not well understood. The aim of the present work was to investigate the effect of 32 hours of sleep deprivation on WM microstructure compared to changes observed in a normal sleep-wake cycle (SWC). To this end, we utilised diffusion weighted imaging (DWI) including the diffusion tensor model, diffusion kurtosis imaging and the spherical mean technique, a novel biophysical diffusion model. 46 healthy adults (23 sleep deprived vs 23 with normal SWC) underwent DWI across four time points (morning, evening, next day morning and next day afternoon, after a total of 32 hours). Linear mixed models revealed significant group × time interaction effects, indicating that sleep deprivation and normal SWC differentially affect WM microstructure. Voxel-wise comparisons showed that these effects spanned large, bilateral WM regions. These findings provide important insight into how sleep deprivation affects the human brain.

Patients with schizophrenia spectrum disorders (SCZspect) and bipolar disorders (BD) show impaired function in the primary visual cortex (V1), indicated by altered visual evoked potential (VEP). While the neural substrate for altered VEP in these patients remains elusive, altered V1 structure may play a role. One previous study found a positive relationship between the amplitude of the P100 component of the VEP and V1 surface area, but not V1 thickness, in a small sample of healthy individuals. Here, we aimed to replicate these findings in a larger healthy control (HC) sample (n = 307) and to examine the same relationship in patients with SCZspect (n = 30) or BD (n = 45). We also compared the mean P100 amplitude, V1 surface area and V1 thickness between controls and patients and found no significant group differences. In HC only, we found a significant positive P100-V1 surface area association, while there were no significant P100-V1 thickness relationships in HC, SCZspect or BD. Together, our results confirm previous findings of a positive P100-V1 surface area association in HC, whereas larger patient samples are needed to further clarify the function-structure relationship in V1 in SCZspect and BD.

A potential relationship between dysregulation of immune/inflammatory pathways and cognitive impairment has been suggested in severe mental illnesses (SMI), such as schizophrenia (SZ) and bipolar (BD) spectrum disorders. However, multivariate relationships between peripheral inflammatory/immune-related markers and cognitive domains are unclear, and many studies do not account for inter-individual variance in both cognitive functioning and inflammatory/immune status. This study aimed to investigate covariance patterns between inflammatory/immune-related markers and cognitive domains and further elucidate heterogeneity in a large SMI and healthy control (HC) cohort (SZ = 343, BD = 289, HC = 770). We applied canonical correlation analysis (CCA) to identify modes of maximum covariation between a comprehensive selection of cognitive domains and inflammatory/immune markers. We found that poor verbal learning and psychomotor processing speed was associated with higher levels of interleukin-18 system cytokines and beta defensin 2, reflecting enhanced activation of innate immunity, a pattern augmented in SMI compared to HC. Applying hierarchical clustering on covariance patterns identified by the CCA revealed a high cognition—low immune dysregulation subgroup with predominantly HC (24% SZ, 45% BD, 74% HC) and a low cognition—high immune dysregulation subgroup predominantly consisting of SMI patients (76% SZ, 55% BD, 26% HC). These subgroups differed in IQ, years of education, age, CRP, BMI (all groups), level of functioning, symptoms and defined daily dose (DDD) of antipsychotics (SMI cohort). Our findings suggest a link between cognitive impairment and innate immune dysregulation in a subset of individuals with severe mental illness.

OBJECTIVEMental disorders are heritable and polygenic, and genome-wide genetic correlations (rg) have indicated widespread shared genetic risk across multiple disorders and related traits, mirroring their overlapping clinical characteristics. However, rg may underestimate the shared genetic underpinnings of mental disorders and related traits because it does not differentiate mixtures of concordant and discordant genetic effects from an absence of genetic overlap. Using novel statistical genetics tools, the authors aimed to evaluate the genetic overlap between mental disorders and related traits when accounting for mixed effect directions.METHODSThe authors applied the bivariate causal mixture model (MiXeR) to summary statistics for four mental disorders, four related mental traits, and height from genome-wide association studies (Ns ranged from 53,293 to 766,345). MiXeR estimated the number of "causal" variants for a given trait ("polygenicity"), the number of variants shared between traits, and the genetic correlation of shared variants (rgs). Local rg was investigated using LAVA.RESULTSAmong mental disorders, ADHD was the least polygenic (5.6K "causal" variants), followed by bipolar disorder (8.6K), schizophrenia (9.6K), and depression (14.5K). Most variants were shared across mental disorders (4.4K-9.3K) and between mental disorders and related traits (5.2K-12.8K), but with disorder-specific variations in rg and rgs. Overlap with height was small (0.7K-1.1K). MiXeR estimates correlated with LAVA local rg (r=0.88, p<0.001).CONCLUSIONSThere is extensive genetic overlap across mental disorders and related traits, with mixed effect directions and few disorder-specific variants. This suggests that genetic risk for mental disorders is predominantly differentiated by divergent effect distributions of pleiotropic genetic variants rather than disorder-specific variants. This represents a conceptual advance in our understanding of the landscape of shared genetic architecture across mental disorders, which may inform genetic discovery, biological characterization, nosology, and genetic prediction.

Cortical microstructure is influenced by circadian rhythm and sleep deprivation, yet the precise underpinnings of these effects remain unclear. The ratio between T1-weighted and T2-weighted magnetic resonance images (T1w/T2w ratio) has been linked to myelin levels and dendrite density and may offer novel insight into the intracortical microstructure of the sleep deprived brain. Here, we examined intracortical T1w/T2w ratio in 41 healthy young adults (26 women) before and after 32 h of either sleep deprivation (n = 18) or a normal sleep-wake cycle (n = 23). Linear models revealed significant group differences in T1w/T2w ratio change after 32 h in four clusters, including bilateral effects in the insular, cingulate, and superior temporal cortices, comprising regions involved in attentional, auditory and pain processing. Across clusters, the sleep deprived group showed an increased T1w/T2w ratio, while the normal sleep-wake group exhibited a reduced ratio. These changes were not explained by in-scanner head movement, and 95% of the effects across clusters remained significant after adjusting for cortical thickness and hydration. Compared with a normal sleep-wake cycle, 32 h of sleep deprivation yields intracortical T1w/T2w ratio increases. While the intracortical changes detected by this study could reflect alterations in myelin or dendritic density, or both, histological analyses are needed to clarify the precise underlying cortical processes.

Background Several lines of research suggest that impairments in long-term potentiation (LTP)-like synaptic plasticity might be a key pathophysiological mechanism in schizophrenia (SZ) and bipolar disorder type I (BDI) and II (BDII). Using modulations of visually evoked potentials (VEP) of the electroencephalogram, impaired LTP-like visual cortical plasticity has been implicated in patients with BDII, while there has been conflicting evidence in SZ, a lack of research in BDI, and mixed results regarding associations with symptom severity, mood states, and medication. Methods We measured the VEP of patients with SZ spectrum disorders (n=31), BDI (n=34), BDII (n=33), and other BD spectrum disorders (n=2), and age-matched healthy control participants (n=200) before and after prolonged visual stimulation. Results Compared to healthy controls, modulation of VEP component N1b, but not C1 or P1, was impaired both in patients within the SZ spectrum (χ 2 =35.1, p=3.1×10 −9 ) and BD spectrum (χ 2 =7.0, p=8.2×10 −3 ), including BDI (χ 2 =6.4, p=0.012), but not BDII (χ 2 =2.2, p=0.14). N1b modulation was also more severely impaired in SZ spectrum than BD spectrum patients (χ 2 =14.2, p=1.7×10 −4 ). The reduction in N1b modulation was related to PANSS total scores (χ 2 =10.8, p=1.0×10 −3 ), and nominally to number of psychotic episodes (χ 2 =4.9, p=0.027). Conclusions. These results suggest that LTP-like plasticity is impaired in SZ and BDI, but not BDII, and related to psychotic symptom severity. Adding to previous genetic, pharmacological, and anatomical evidence, these results implicate aberrant synaptic plasticity as a mechanism underlying SZ and BD.

Rationale: For visual perspective taking (VPT) using the avatar task, examinations of neural processes using event related potentials (ERP) indicate a distinction between an early posterior perspective calculation process (P3) and a later frontal process (LFSW) managing perspective conflict. While it is unknown if these neural processes are affected in clinical populations, it is unclear if the avatar task can be applied to this group, due to the long duration and sensitivity to data loss. Thus, we performed a methodological study of the avatar task, testing the feasibility of a shortened experimental paradigm. Objective: To investigate whether previously reported behavioural and ERP effects in the avatar task can also be seen if analysing all trials (matching/non-matching) jointly, and whether they remain robust if only a subset of the data is analysed. Method: Healthy individuals (n = 20) completed the avatar task with ERP measurement. ERP components (P3, LFSW) and behavioural data were investigated by A) comparing use of only matching trials (n = 384) versus all trials (n = 768), and B) examining if reduced duration of assessment, by analysing only a subset of the data, impacts ERP findings. Results: We observed minimal differences when analysing data from only matching trial types compared to all trial types. Further, ERP amplitudes and latency findings were replicated when analysing only a subset of the data. Conclusions: The duration of the avatar task can be reduced to avoid long testing times, thus making it better suited for use in clinical populations.

This chapter is focused on two pillars of statistics: the study design and analysis of data. The statistical design helps us to understand variety of ways how clinical studies and experiments can be conducted so that the research question at hand can be answered. Data analysis methods are crucial to unravel the knowledge from the collected data. Both design and analysis are important part of statistics, and they are underpinned by the statistical science and theory of probability.

En situation nucléaire, radiologique ou chimique, l'administration d'antidotes en zone contaminée est une priorité lorsqu'il y a un risque vital imminent. Les équipements de protection individuelle portés par les personnels positionnés à l'avant réduisent leur visibilité et compliquent les gestes de motricité fine, rendant difficiles les reconstitutions médicamenteuses, notamment d'antidotes. C'est pourquoi une équipe pharmaceutique dédiée à la reconstitution d'antidotes serait positionnée en zone de soutien. Cette équipe, sensibilisée aux gestes de reconstitution, mais non entraînée régulièrement, avait rencontré lors des deux derniers exercices interzonaux de la zone Sud des difficultés à organiser la répartition des tâches entre les manipulateurs, qui avaient chacun reconstitué chaque antidote du début à la fin (méthode classique). Ceci nous a incités à comparer deux organisations différentes pour reconstituer les trois antidotes utilisés dans les intoxications aux neurotoxiques organophosphorés, l'objectif étant de définir la méthode la plus adaptée en termes de temps de reconstitution. Nous avons donc sollicité des étudiants en pharmacie, répartis en deux groupes de six : -Le groupe 1 appliquant une méthode dite classique, où chaque membre reconstitue chaque antidote, du début à la fin. - Le groupe 2 appliquant une méthode dite fractionnée où chaque membre se positionne à une étape de la chaîne de reconstitution et se voit attribuer une tâche précise et répétitive. Les résultats montrent que la méthode fractionnée est plus rapide pour la reconstitution de l'intégralité des trois antidotes. Cette méthode aurait de plus l'avantage de limiter les erreurs de manipulation (asepsie, erreurs de dosage). Cependant, selon la nature et le degré d'intoxication des victimes, il est parfois plus opportun de prioriser un antidote par rapport à l'autre. D'autres études seront nécessaires afin de définir un nombre optimal de personnes affectées à chaque tâche.In nuclear, radiological or chemical situations, the administration of antidotes in contaminated areas is a priority when there is an imminent life-threatening situation. The personal protective equipment worn by front-line personnel reduces their visibility and complicates fine motor movements, making it difficult to reconstitute drugs, particularly antidotes. This is why a pharmaceutical team dedicated to the reconstitution of antidotes would be positioned in the support area. This team, aware of the gestures of reconstitution, but not trained regularly, had encountered during the last two interzonal exercises in the South zone difficulties in organizing the distribution of tasks between the manipulators, who had each reconstituted each antidote from beginning to end (classic method). This prompted us to compare two different organizations in order to reconstitute the three antidotes used in organophosphorus neurotoxicity, the objective being to define the most suitable method in term of reconstitution time. We therefore solicited pharmacy students, divided into two groups of six : - Group 1 applying a classical method, where each member reconstitutes each antidote from beginning to end. - Group 2 applying a fractionated method where each member is positioned at a step in the reconstitution chain and is assigned a precise and repetitive task. The results show that the fractionated method is faster for the reconstitution of all three antidotes. This method would also have the advantage of limiting handling errors (asepsis, dosing errors). However, depending on the nature and degree of intoxication of the victims, it is sometimes more appropriate to prioritize one antidote over the other. Further studies will be necessary to define an optimal number of people assigned to each task.

The folding of the human cerebral cortex is a highly genetically regulated process that allows for a much larger surface area to fit into the cranial vault and optimizes functional organization. Sulcal depth is a robust yet understudied measure of localized folding, previously associated with multiple neurodevelopmental disorders. Here, we report the first genome-wide association study of sulcal depth. Through the multivariate omnibus statistical test (MOSTest) applied to vertex-wise measures from 33,748 U.K. Biobank participants (mean age, 64.3 years; 52.0% female), we identified 856 genome-wide significant loci (P < 5 × 10−8). Comparisons with cortical thickness and surface area indicated that sulcal depth has higher locus yield, heritability, and effective sample size. There was a large amount of genetic overlap between these traits, with gene-based analyses indicating strong associations with neurodevelopmental processes. Our findings demonstrate sulcal depth is a promising neuroimaging phenotype that may enhance our understanding of cortical morphology.

Schizophrenia (SCZ) spectrum and bipolar disorder (BD) are severe mental disorders with unknown pathophysiology. Altered visual evoked potential (VEP), an electroencephalogram signal reflecting function in the primary visual cortex (V1), abnormal visual processing and visual hallucinations reported in these patients, all point towards V1 dysfunction. While the mechanisms contributing to V1 dysfunction remain unknown, structural alterations are possible candidates. Lack of insight into neural substrates of structure and functional in V1 has limited our ability to determine implications of altered V1 function. While combining VEP and magnetic resonance imaging has increased our understanding of the structure-function relationship in V1 in healthy individuals, no previous study has examined the same structure-function relationship in patients with SCZ spectrum and BD. Here, we aimed to confirm previous findings of a selective positive correlation between the amplitude of the P100 component of the VEP and V1 surface area (SA) in 307 healthy individuals and to examine whether this relationship was altered in patients with SCZ spectrum (n=30) and BD (n=45). The correlation between the P100 amplitude and the total, (r=0.16, p=0.006), right (r=0.14, p=0.013) and left V1 surface area (r=0.13, p=0.02) was significant in healthy individuals, but not in patients. The current results support previous findings of a selective relationship between P100 amplitude and V1 surface area in healthy individuals and suggests that other factors than V1 surface area or thickness explain V1 dysfunction reported in these patients.

Genome-wide association studies (GWAS) and family-based studies have revealed partly overlapping genetic architectures between various psychiatric disorders. Given clinical overlap between disorders, our knowledge of the genetic architectures underlying specific symptom profiles and risk factors is limited. Here, we aimed to derive distinct profiles relevant to mental health in healthy individuals and to study how these genetically relate to each other and to common psychiatric disorders. Using independent component analysis, we decomposed self-report mental health questionnaires from 136,678 healthy individuals of the UK Biobank, excluding data from individuals with a diagnosed neurological or psychiatric disorder, into 13 distinct profiles relevant to mental health, capturing different symptoms as well as social and risk factors underlying reduced mental health. Utilizing genotypes from 117,611 of those individuals with White British ancestry, we performed GWAS for each mental health profile and assessed genetic correlations between these profiles, and between the profiles and common psychiatric disorders and cognitive traits. We found that mental health profiles were genetically correlated with a wide range of psychiatric disorders and cognitive traits, with strongest effects typically observed between a given mental health profile and a disorder for which the profile is common (e.g. depression symptoms and major depressive disorder, or psychosis and schizophrenia). Strikingly, although the profiles were phenotypically uncorrelated, many of them were genetically correlated with each other. This study provides evidence that statistically independent mental health profiles partly share genetic underpinnings and show genetic overlap with psychiatric disorders, suggesting that shared genetics across psychiatric disorders cannot be exclusively attributed to the known overlapping symptomatology between the disorders.

1 Phenotypically independent mental health symptom profiles are genetically related 1 Daniel Roelfs1,*, MSc, Dag Alnæs1, PhD, Oleksandr Frei1, PhD, Dennis van der Meer1,2, PhD, Olav B. 2 Smeland1, PhD, Ole A. Andreassen1, PhD, Lars T. Westlye1,3, PhD, Tobias Kaufmann1,*, PhD 3 4 1 NORMENT, KG Jebsen Centre for Neurodevelopmental Disorders, Division of Mental Health and 5 Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway 6 2 School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht 7 University, Maastricht, The Netherlands 8 3 Department of Psychology, University of Oslo, Oslo, Norway 9 10 * Correspondence: Daniel Roelfs & Tobias Kaufmann, Ph.D. 11 Email: daniel.roelfs@medisin.uio.no, tobias.kaufmann@medisin.uio.no 12 Postal address: OUS, PO Box 4956 Nydalen, 0424 Oslo, Norway 13 Telephone: +47 23 02 73 50, Fax: +47 23 02 73 33 14 15 Counts: Main: 3464 words | Abstract: 350 words | Figures: 4 | References: 41 16 All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 30, 2020. ; https://doi.org/10.1101/2020.03.30.20045591 doi: medRxiv preprint

Cortical excitability dysregulation is one of the leading candidate mechanisms in schizophrenia (SCZ) and bipolar disorders (BD). In the present study, we investigated whether cortical excitability as indexed by the rate of decline in EEG power with increasing frequency – the 1/f-like spectral slope – differs between individuals with SCZ, BD, and healthy controls (HC).