Linked dimensions of psychopathology and connectivity in functional brain networks

Neurobiological abnormalities associated with psychiatric disorders do not map well to existing diagnostic categories. High co-morbidity suggests dimensional circuit-level abnormalities that cross diagnoses. Here we seek to identify brain-based dimensions of psychopathology using sparse canonical correlation analysis in a sample of 663 youths. This analysis reveals correlated patterns of functional connectivity and psychiatric symptoms. We find that four dimensions of psychopathology - mood, psychosis, fear, and externalizing behavior - are associated (r = 0.68-0.71) with distinct patterns of connectivity. Loss of network segregation between the default mode network and executive networks emerges as a common feature across all dimensions. Connectivity linked to mood and psychosis becomes more prominent with development, and sex differences are present for connectivity related to mood and fear. Critically, findings largely replicate in an independent dataset (n = 336). These results delineate connectivity-guided dimensions of psychopathology that cross clinical diagnostic categories, which could serve as a foundation for developing network-based biomarkers in psychiatry.

The impact of in-scanner head motion on structural connectivity derived from diffusion MRI

Multiple studies have shown that data quality is a critical confound in the construction of brain networks derived from functional MRI. This problem is particularly relevant for studies of human brain development where important variables (such as participant age) are correlated with data quality. Nevertheless, the impact of head motion on estimates of structural connectivity derived from diffusion tractography methods remains poorly characterized. Here, we evaluated the impact of in-scanner head motion on structural connectivity using a sample of 949 participants (ages 8-23 years old) who passed a rigorous quality assessment protocol for diffusion magnetic resonance imaging (dMRI) acquired as part of the Philadelphia Neurodevelopmental Cohort. Structural brain networks were constructed for each participant using both deterministic and probabilistic tractography. We hypothesized that subtle variation in head motion would systematically bias estimates of structural connectivity and confound developmental inference, as observed in previous studies of functional connectivity. Even following quality assurance and retrospective correction for head motion, eddy currents, and field distortions, in-scanner head motion significantly impacted the strength of structural connectivity in a consistency- and length-dependent manner. Specifically, increased head motion was associated with reduced estimates of structural connectivity for network edges with high inter-subject consistency, which included both short- and long-range connections. In contrast, motion inflated estimates of structural connectivity for low-consistency network edges that were primarily shorter-range. Finally, we demonstrate that age-related differences in head motion can both inflate and obscure developmental inferences on structural connectivity. Taken together, these data delineate the systematic impact of head motion on structural connectivity, and provide a critical context for identifying motion-related confounds in studies of structural brain network development.

Structural anomalies of the peripheral olfactory system in psychosis high-risk subjects

BACKGROUND

Olfactory impairments are prominent in both schizophrenia and the preceding at-risk state. Their presence prior to illness predicts poor functional outcome. In schizophrenia, these impairments reflect peripheral olfactory structural abnormalities, which are hypothesized to arise during early embryonic development. If this is correct, then similar structural anomalies should be apparent among clinical high-risk subjects.

METHODS

Thirty-nine clinical high-risk (CR) subjects (24M/15F) were compared to 36 low-risk (LR) subjects (19M/17F). Olfactory measures derived from 3T MRI scans included olfactory bulb volume, primary olfactory cortical gray matter volume, and the depth of the olfactory sulcus overlying the bulb. Additionally, nasal cavity volumes were assessed with acoustic rhinometry.

RESULTS

Male CR subjects exhibited bilateral reductions in olfactory bulb volume and abnormal asymmetries of the posterior nasal cavities and olfactory sulci (left reduced relative to right). Post-hoc contrasts also indicated reduced left, but not right, olfactory cortical gray matter volume. Female CRs had no significant abnormalities, although they exhibited similar trend effects. Left olfactory bulb volume correlated, across all CR subjects, with negative, but not positive, symptoms. In a classification analysis, with 80% target specificity, olfactory measurements distinguished male CR from male LR subjects with 93% sensitivity. Among females, the comparable sensitivity was 69%.

CONCLUSION

Psychosis-risk youths exhibit an array of sexually dimorphic and laterally asymmetric anomalies of the peripheral olfactory system. These are consistent with a developmental disruption primarily affecting male fetuses. These structural biomarkers may enhance the identification of at-risk subjects with poor prognosis, before their clinical trajectory is apparent.

Quantitative assessment of structural image quality

Data quality is increasingly recognized as one of the most important confounding factors in brain imaging research. It is particularly important for studies of brain development, where age is systematically related to in-scanner motion and data quality. Prior work has demonstrated that in-scanner head motion biases estimates of structural neuroimaging measures. However, objective measures of data quality are not available for most structural brain images. Here we sought to identify quantitative measures of data quality for T1-weighted volumes, describe how these measures relate to cortical thickness, and delineate how this in turn may bias inference regarding associations with age in youth. Three highly-trained raters provided manual ratings of 1840 raw T1-weighted volumes. These images included a training set of 1065 images from Philadelphia Neurodevelopmental Cohort (PNC), a test set of 533 images from the PNC, as well as an external test set of 242 adults acquired on a different scanner. Manual ratings were compared to automated quality measures provided by the Preprocessed Connectomes Project's Quality Assurance Protocol (QAP), as well as FreeSurfer's Euler number, which summarizes the topological complexity of the reconstructed cortical surface. Results revealed that the Euler number was consistently correlated with manual ratings across samples. Furthermore, the Euler number could be used to identify images scored "unusable" by human raters with a high degree of accuracy (AUC: 0.98-0.99), and out-performed proxy measures from functional timeseries acquired in the same scanning session. The Euler number also was significantly related to cortical thickness in a regionally heterogeneous pattern that was consistent across datasets and replicated prior results. Finally, data quality both inflated and obscured associations with age during adolescence. Taken together, these results indicate that reliable measures of data quality can be automatically derived from T1-weighted volumes, and that failing to control for data quality can systematically bias the results of studies of brain maturation.

Effects of military service and deployment on clinical symptomatology: The role of trauma exposure and social support

The Marine Resiliency Study-II examined changes in symptomatology across a deployment cycle to Afghanistan. U.S. Servicemembers (N = 1041) received clinical testing at two time points either bracketing a deployment (855) or not (186). Factor analyses were used to generate summary and change scores from Time 1 to Time 2. A between-subject design was used to examine changes across the deployment cycle with deployment (low-trauma, high-trauma, and non-deployed) and social support (low vs. high) as the grouping variables. Insomnia increased post-deployment regardless of deployment trauma (std. effect for high-trauma and low-trauma = 0.39 and 0.26, respectively). Only the high-trauma group showed increased PTSD symptoms and non-perspective-taking (std. effect = 0.40 and 0.30, respectively), while low-trauma showed decreased anxiety symptoms after deployment (std. effect = -0.17). These associations also depend on social support, with std. effects ranging from -0.22 to 0.51. When the groups were compared, the high-trauma deployed group showed significantly worse PTSD and non-perspective-taking than all other groups. Similar to studies in other military divisions, increased clinical symptoms were associated with high deployment stress in active duty Servicemembers, and social support shows promise as a moderator of said association.

Developmental increases in white matter network controllability support a growing diversity of brain dynamics

As the human brain develops, it increasingly supports coordinated control of neural activity. The mechanism by which white matter evolves to support this coordination is not well understood. Here we use a network representation of diffusion imaging data from 882 youth ages 8-22 to show that white matter connectivity becomes increasingly optimized for a diverse range of predicted dynamics in development. Notably, stable controllers in subcortical areas are negatively related to cognitive performance. Investigating structural mechanisms supporting these changes, we simulate network evolution with a set of growth rules. We find that all brain networks are structured in a manner highly optimized for network control, with distinct control mechanisms predicted in child vs. older youth. We demonstrate that our results cannot be explained by changes in network modularity. This work reveals a possible mechanism of human brain development that preferentially optimizes dynamic network control over static network architecture.

Impact of Tryptophan Depletion on Executive System Function during Menopause is Moderated by Childhood Adversity

Many healthy women with no history of cognitive dysfunction experience subjective executive difficulties during menopause. Preclinical literature suggests latent effects of early life adversity on serotonin function may play a role in this phenomenon. However, evidence in human participants regarding the mechanisms by which loss of estradiol contributes to this vulnerability is lacking. Here we examined the impact of tryptophan depletion (TD) and adverse childhood experiences (ACE) on brain activation during a working memory task in menopausal women. We hypothesized that an interactive effect between ACE and TD would be observed when women were hypogonadal, and that treatment with estradiol would attenuate this effect. Thirty-three women underwent functional imaging at four time points (123 total scans) in this double-blind, placebo controlled, cross-over study. The effects of TD, ACE, and TD × ACE were evaluated using a voxel-wise, mixed-effects, 2 × 2 ANOVA. In the absence of exogenous estradiol, a TD by ACE interaction was observed on BOLD signal in the right DLPFC such that TD increased activation in high ACE subjects but decreased activation in low ACE subjects. While a similar interaction was observed with placebo treatment, treatment with estradiol attenuated the effects of ACE and TD such that no between or within group differences were observed. Together, these results suggest that early life adversity may have a lasting impact on serotonergic circuits underlying executive function that are unmasked by loss of estradiol during menopause.

Harmonization of multi-site diffusion tensor imaging data

Diffusion tensor imaging (DTI) is a well-established magnetic resonance imaging (MRI) technique used for studying microstructural changes in the white matter. As with many other imaging modalities, DTI images suffer from technical between-scanner variation that hinders comparisons of images across imaging sites, scanners and over time. Using fractional anisotropy (FA) and mean diffusivity (MD) maps of 205 healthy participants acquired on two different scanners, we show that the DTI measurements are highly site-specific, highlighting the need of correcting for site effects before performing downstream statistical analyses. We first show evidence that combining DTI data from multiple sites, without harmonization, may be counter-productive and negatively impacts the inference. Then, we propose and compare several harmonization approaches for DTI data, and show that ComBat, a popular batch-effect correction tool used in genomics, performs best at modeling and removing the unwanted inter-site variability in FA and MD maps. Using age as a biological phenotype of interest, we show that ComBat both preserves biological variability and removes the unwanted variation introduced by site. Finally, we assess the different harmonization methods in the presence of different levels of confounding between site and age, in addition to test robustness to small sample size studies.

White matter microstructural deficits in 22q11.2 deletion syndrome

Diffusion tensor imaging (DTI) studies in 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with psychosis, report brain white matter (WM) microstructure aberrations. Several studies report that WM disruptions in 22q11DS are similar to deficits in idiopathic schizophrenia. Yet, DTI results in 22q11DS are inconsistent. We used DTI to compare WM structure in 22q11DS individuals to healthy controls (HC) and explored WM differences in 22q11DS with (+) and without (-) psychosis spectrum symptoms. We examined 39 22q11DS individuals and 39 age, sex and race equivalent HC. DTI was performed at 3T using a 64-direction protocol. Fractional anisotropy (FA) was lower, while radial diffusivity was higher in 22q11DS within the cingulum bundle. Mean diffusivity was lower in the inferior longitudinal fasciculus, while axial diffusivity (AD) was lower in the cingulum bundle, forceps major, and several posterior to anterior fasciculi. 22q11DS+ had lower FA in the cingulum bundle and lower AD in the uncinate fasciculus compared to 22q11DS-. Overall, we found aberrant WM microstructure in individuals with 22q11DS compared to age and sex matched HC and exploratory analysis indicated subtle WM deficits associated with psychosis. The findings highlight the dysfunction of WM microstructure in 22q11DS and its potential importance in elucidating WM abnormalities in psychosis.

Validation of the Cognition Test Battery for Spaceflight in a Sample of Highly Educated Adults

BACKGROUND

Neuropsychological changes that may occur due to the environmental and psychological stressors of prolonged spaceflight motivated the development of the Cognition Test Battery. The battery was designed to assess multiple domains of neurocognitive functions linked to specific brain systems. Tests included in Cognition have been validated, but not in high-performing samples comparable to astronauts, which is an essential step toward ensuring their usefulness in long-duration space missions.

METHODS

We administered Cognition (on laptop and iPad) and the WinSCAT, counterbalanced for order and version, in a sample of 96 subjects (50% women; ages 25-56 yr) with at least a Master's degree in science, technology, engineering, or mathematics (STEM). We assessed the associations of age, sex, and administration device with neurocognitive performance, and compared the scores on the Cognition battery with those of WinSCAT. Confirmatory factor analysis compared the structure of the iPad and laptop administration methods using Wald tests.

RESULTS

Age was associated with longer response times (mean β = 0.12) and less accurate (mean β = -0.12) performance, women had longer response times on psychomotor (β = 0.62), emotion recognition (β = 0.30), and visuo-spatial (β = 0.48) tasks, men outperformed women on matrix reasoning (β = -0.34), and performance on an iPad was generally faster (mean β = -0.55). The WinSCAT appeared heavily loaded with tasks requiring executive control, whereas Cognition assessed a larger variety of neurocognitive domains.

DISCUSSION

Overall results supported the interpretation of Cognition scores as measuring their intended constructs in high performing astronaut analog samples.Moore TM, Basner M, Nasrini J, Hermosillo E, Kabadi S, Roalf DR, McGuire S, Ecker AJ, Ruparel K, Port AM, Jackson CT, Dinges DF, Gur RC. Validation of the Cognition Test Battery for spaceflight in a sample of highly educated adults. Aerosp Med Hum Perform. 2017; 88(10):937-946.

Common Dimensional Reward Deficits Across Mood and Psychotic Disorders: A Connectome-Wide Association Study

OBJECTIVE

Anhedonia is central to multiple psychiatric disorders and causes substantial disability. A dimensional conceptualization posits that anhedonia severity is related to a transdiagnostic continuum of reward deficits in specific neural networks. Previous functional connectivity studies related to anhedonia have focused on case-control comparisons in specific disorders, using region-specific seed-based analyses. Here, the authors explore the entire functional connectome in relation to reward responsivity across a population of adults with heterogeneous psychopathology.

METHOD

In a sample of 225 adults from five diagnostic groups (major depressive disorder, N=32; bipolar disorder, N=50; schizophrenia, N=51; psychosis risk, N=39; and healthy control subjects, N=53), the authors conducted a connectome-wide analysis examining the relationship between a dimensional measure of reward responsivity (the reward sensitivity subscale of the Behavioral Activation Scale) and resting-state functional connectivity using multivariate distance-based matrix regression.

RESULTS

The authors identified foci of dysconnectivity associated with reward responsivity in the nucleus accumbens, the default mode network, and the cingulo-opercular network. Follow-up analyses revealed dysconnectivity among specific large-scale functional networks and their connectivity with the nucleus accumbens. Reward deficits were associated with decreased connectivity between the nucleus accumbens and the default mode network and increased connectivity between the nucleus accumbens and the cingulo-opercular network. In addition, impaired reward responsivity was associated with default mode network hyperconnectivity and diminished connectivity between the default mode network and the cingulo-opercular network.

CONCLUSIONS

These results emphasize the centrality of the nucleus accumbens in the pathophysiology of reward deficits and suggest that dissociable patterns of connectivity among large-scale networks are critical to the neurobiology of reward dysfunction across clinical diagnostic categories.

Modular Segregation of Structural Brain Networks Supports the Development of Executive Function in Youth

The human brain is organized into large-scale functional modules that have been shown to evolve in childhood and adolescence. However, it remains unknown whether the underlying white matter architecture is similarly refined during development, potentially allowing for improvements in executive function. In a sample of 882 participants (ages 8-22) who underwent diffusion imaging as part of the Philadelphia Neurodevelopmental Cohort, we demonstrate that structural network modules become more segregated with age, with weaker connections between modules and stronger connections within modules. Evolving modular topology facilitates global network efficiency and is driven by age-related strengthening of hub edges present both within and between modules. Critically, both modular segregation and network efficiency are associated with enhanced executive performance and mediate the improvement of executive functioning with age. Together, results delineate a process of structural network maturation that supports executive function in youth.

Temporal Lobe Volume Decrements in Psychosis Spectrum Youths

Structural brain abnormalities have been amply demonstrated in schizophrenia. These include volume decrements in the perirhinal/entorhinal regions of the ventromedial temporal lobe, which comprise the primary olfactory cortex. Olfactory impairments, which are a hallmark of schizophrenia, precede the onset of illness, distinguish adolescents experiencing prodromal symptoms from healthy youths, and may predict the transition from the prodrome to frank psychosis. We therefore examined temporal lobe regional volumes in a large adolescent sample to determine if structural deficits in ventromedial temporal lobe areas were associated, not only with schizophrenia, but also with a heightened risk for psychosis. Seven temporal lobe regional volumes (amygdala [AM], hippocampus, inferior temporal gyrus, parahippocampal gyrus, superior temporal gyrus, temporal pole, and entorhinal cortex [EC]) were measured in 386 psychosis spectrum adolescents, 521 adolescents with other types of psychopathology, and 359 healthy adolescents from the Philadelphia Neurodevelopment Cohort. Total intracranial and left EC volumes, which were both smallest among the psychosis spectrum, were the only measures that distinguished all 3 groups. Left AM was also smaller in psychosis spectrum compared with healthy subjects. EC volume decrement was strongly correlated with impaired cognition and less robustly associated with heightened negative/disorganized symptoms. AM volume decrement correlated with positive symptoms (persecution/special abilities). Temporal lobe volumes classified psychosis spectrum youths with very high specificity but relatively low sensitivity. These MRI measures may therefore serve as important confirmatory biomarkers denoting a worrisome preclinical trajectory among at-risk youths, and the specific pattern of deficits may predict specific symptom profiles.

Cognitive functioning of adolescent and young adult cannabis users in the Philadelphia Neurodevelopmental Cohort

Cannabis use in youth is rising and has been linked to deficits in cognitive functioning. However, cognitive findings have primarily been based on small samples of users seeking treatment, and few studies have evaluated cognition in occasional cannabis users. Here, we examined 4,568 adolescents and young adults (ages 14-21 years) drawn from the Philadelphia Neurodevelopmental Cohort, a prospective, population-based study. Participants were classified as cannabis Non-Users (n = 3,401), Occasional Users (twice per week or less; n = 940), or Frequent Users (>3 times per week; n = 227). Mixed-model analyses examined main effects of cannabis use and interactions between age and cannabis use on cognitive functioning. There was a significant interaction between cannabis group and age such that adolescent (but not young adult) Frequent Users performed worse than Non-Users on measures of executive control (p = .002). Earlier age of cannabis use was associated with worse performance in executive control in Occasional Users (p = .04). Unexpectedly, Occasional Users exhibited better executive control, memory, and social cognition than Non-Users (ps < .05). Although mild executive control deficits in adolescent frequent users and a relation between early cannabis initiation and cognitive performance are partially consistent with prior research, cognitive deficits were not found in other hypothesized domains in this community-based sample. Moreover, occasional cannabis users displayed equivalent or even slightly better executive control, social-cognitive, and memory abilities compared with nonusers, suggesting complex relationships between cannabis use and cognition in youth. Longitudinal studies with community samples are needed to identify variables affecting risk and resilience to cognitive deficits associated with cannabis. (PsycINFO Database Record

Face Processing Measures of Social Cognition: A Dimensional Approach to Developmental Psychopathology

BACKGROUND

Social cognition impairments in neurodevelopmental disorders impact functioning. Face processing is the most extensively studied aspect of social cognition, commonly indexing this construct in neuropsychiatric disorders compared with typically developing youths. Applying social cognition measures as a Research Domain Criteria concept in the clinical arena requires establishing cutoffs for intervention and identifying vulnerability for psychopathology across disorders. This can be accomplished by comparing extreme performers across multiple clinical symptom features.

METHODS

The Philadelphia Neurodevelopmental Cohort (N = 9498), a community sample of youths (8-21 years old), was assessed with a structured interview (Kiddie Schedule for Affective Disorders and Schizophrenia). The Penn Computerized Neurocognitive Battery was administered measuring accuracy and response time on Executive, Episodic Memory, Complex Cognition, and Social Cognition domains. We parsed participants by performance on social cognition into tertiles and examined their neurocognitive and clinical profiles.

RESULTS

The top social cognition group outperformed the bottom group in face memory and complex reasoning. Concerning symptoms, the top performing group did not differ from the middle group, but the bottom performing group had higher externalizing and psychosis symptoms. There were sex differences in social cognition and symptom profiles but no sex × performance or sex × diagnosis × domain interactions.

CONCLUSIONS

Social cognition is supported by strong face memory and complex reasoning skills. Poor performance portends more severe externalizing and psychosis symptoms. That average performance is sufficient for normative symptomatology suggests that interventions aimed at ameliorating social cognition deficits, as measured here, could be effective in normalizing level of symptoms.

Benchmarking of participant-level confound regression strategies for the control of motion artifact in studies of functional connectivity

Since initial reports regarding the impact of motion artifact on measures of functional connectivity, there has been a proliferation of participant-level confound regression methods to limit its impact. However, many of the most commonly used techniques have not been systematically evaluated using a broad range of outcome measures. Here, we provide a systematic evaluation of 14 participant-level confound regression methods in 393 youths. Specifically, we compare methods according to four benchmarks, including the residual relationship between motion and connectivity, distance-dependent effects of motion on connectivity, network identifiability, and additional degrees of freedom lost in confound regression. Our results delineate two clear trade-offs among methods. First, methods that include global signal regression minimize the relationship between connectivity and motion, but result in distance-dependent artifact. In contrast, censoring methods mitigate both motion artifact and distance-dependence, but use additional degrees of freedom. Importantly, less effective de-noising methods are also unable to identify modular network structure in the connectome. Taken together, these results emphasize the heterogeneous efficacy of existing methods, and suggest that different confound regression strategies may be appropriate in the context of specific scientific goals.

Correspondence between adolescent and informant reports of substance use: Findings from the Philadelphia Neurodevelopmental Cohort

Inclusion of collateral informant reports is common in adolescent psychopathology research and clinical assessment, yet few studies have examined agreement on ratings of adolescent substance use or factors that may be associated with reporter agreement. The present study aimed to extend prior work on the correspondence between adolescent and informant reports of adolescent substance use with data from a large (n=5214), diverse, community-based sample of youth aged 11-17 (mean age=14.53, SD=1.98; 52% female). Specifically, we examined: (a) agreement between adolescent and collateral informant reports of adolescent use of alcohol, marijuana, cocaine, inhalants, and stimulants and (b) potential correlates of reporter agreement. Agreement ranged from low (κ=0.007, p=0.053) for inhalant use to moderate (κ=0.414, p<0.001) for marijuana use. Disagreements were mainly driven by collateral underestimation of adolescent substance use. Older adolescent age was associated with poorer agreement across all substances (Odds Ratios [ORs]≤0.80, ps<0.05) except inhalants (OR=1.28, p<0.001). Reporter agreement on alcohol and marijuana use was lower for male than female adolescents (ORs≤0.85, ps<0.05). Adolescent psychopathology was associated with poorer agreement on all substances (ORs≤0.62, ps<0.01). For alcohol and marijuana, past year frequency of use was associated with better reporter agreement (ORs≥1.54, ps<0.001). For marijuana, older age at first use was related to poorer agreement (OR=0.81, p=0.01). Our results suggest that collateral reports of adolescent substance use may be ineffective proxies for adolescent self-reports in community samples, particularly for low base rate substances. Findings also highlight important factors to consider when collecting substance use information from multiple informants.

Persistence of psychosis spectrum symptoms in the Philadelphia Neurodevelopmental Cohort: a prospective two-year follow-up

Prospective evaluation of youths with early psychotic-like experiences can enrich our knowledge of clinical, biobehavioral and environmental risk and protective factors associated with the development of psychotic disorders. We aimed to investigate the predictors of persistence or worsening of psychosis spectrum features among US youth through the first large systematic study to evaluate subclinical symptoms in the community. Based on Time 1 screen of 9,498 youth (age 8-21) from the Philadelphia Neurodevelopmental Cohort, a subsample of participants was enrolled based on the presence (N=249) or absence (N=254) of baseline psychosis spectrum symptoms, prior participation in neuroimaging, and current neuroimaging eligibility. They were invited to participate in a Time 2 assessment two years on average following Time 1. Participants were administered the Structured Interview for Prodromal Syndromes, conducted blind to initial screen status, along with the Schizotypal Personality Questionnaire and other clinical measures, computerized neurocognitive testing, and neuroimaging. Clinical and demographic predictors of symptom persistence were examined using logistic regression. At Time 2, psychosis spectrum features persisted or worsened in 51.4% of youths. Symptom persistence was predicted by higher severity of subclinical psychosis, lower global functioning, and prior psychiatric medication at baseline. Youths classified as having psychosis spectrum symptoms at baseline but not at follow-up nonetheless exhibited comparatively higher symptom levels and lower functioning at both baseline and follow-up than typically developing youths. In addition, psychosis spectrum features emerged in a small number of young people who previously had not reported significant symptoms but who had exhibited early clinical warning signs. Together, our findings indicate that varying courses of psychosis spectrum symptoms are evident early in US youth, supporting the importance of investigating psychosis risk as a dynamic developmental process. Neurocognition, brain structure and function, and genomics may be integrated with clinical data to provide early indices of symptom persistence and worsening in youths at risk for psychosis.

Defining and validating a short form Montreal Cognitive Assessment (s-MoCA) for use in neurodegenerative disease

INTRODUCTION

Screening for cognitive deficits is essential in neurodegenerative disease. Screening tests, such as the Montreal Cognitive Assessment (MoCA), are easily administered, correlate with neuropsychological performance and demonstrate diagnostic utility. Yet, administration time is too long for many clinical settings.

METHODS

Item response theory and computerised adaptive testing simulation were employed to establish an abbreviated MoCA in 1850 well-characterised community-dwelling individuals with and without neurodegenerative disease.

RESULTS

8 MoCA items with high item discrimination and appropriate difficulty were identified for use in a short form (s-MoCA). The s-MoCA was highly correlated with the original MoCA, showed robust diagnostic classification and cross-validation procedures substantiated these items.

DISCUSSION

Early detection of cognitive impairment is an important clinical and public health concern, but administration of screening measures is limited by time constraints in demanding clinical settings. Here, we provide as-MoCA that is valid across neurological disorders and can be administered in approximately 5 min.

Elevated Amygdala Perfusion Mediates Developmental Sex Differences in Trait Anxiety

BACKGROUND

Adolescence is a critical period for emotional maturation and is a time when clinically significant symptoms of anxiety and depression increase, particularly in females. However, few studies relate developmental differences in symptoms of anxiety and depression to brain development. Cerebral blood flow is one brain phenotype that is known to have marked developmental sex differences.

METHODS

We investigated whether developmental sex differences in cerebral blood flow mediated sex differences in anxiety and depression symptoms by capitalizing on a large sample of 875 youths who completed cross-sectional imaging as part of the Philadelphia Neurodevelopmental Cohort. Perfusion was quantified on a voxelwise basis using arterial spin-labeled magnetic resonance imaging at 3T. Perfusion images were related to trait and state anxiety using general additive models with penalized splines, while controlling for gray matter density on a voxelwise basis. Clusters found to be related to anxiety were evaluated for interactions with age, sex, and puberty.

RESULTS

Trait anxiety was associated with elevated perfusion in a network of regions including the amygdala, anterior insula, and fusiform cortex, even after accounting for prescan state anxiety. Notably, these relationships strengthened with age and the transition through puberty. Moreover, higher trait anxiety in postpubertal females was mediated by elevated perfusion of the left amygdala.

CONCLUSIONS

Taken together, these results demonstrate that differences in the evolution of cerebral perfusion during adolescence may be a critical element of the affective neurobiological characteristics underlying sex differences in anxiety and mood symptoms.

Polygraphy and Functional Magnetic Resonance Imaging in Lie Detection: A Controlled Blind Comparison Using the Concealed Information Test

OBJECTIVE

Intentional deception is a common act that often has detrimental social, legal, and clinical implications. In the last decade, brain activation patterns associated with deception have been mapped with functional magnetic resonance imaging (fMRI), significantly expanding our theoretical understanding of the phenomenon. However, despite substantial criticism, polygraphy remains the only biological method of lie detection in practical use today. We conducted a blind, prospective, and controlled within-subjects study to compare the accuracy of fMRI and polygraphy in the detection of concealed information. Data were collected between July 2008 and August 2009.

METHOD

Participants (N = 28) secretly wrote down a number between 3 and 8 on a slip of paper and were questioned about what number they wrote during consecutive and counterbalanced fMRI and polygraphy sessions. The Concealed Information Test (CIT) paradigm was used to evoke deceptive responses about the concealed number. Each participant's preprocessed fMRI images and 5-channel polygraph data were independently evaluated by 3 fMRI and 3 polygraph experts, who made an independent determination of the number the participant wrote down and concealed.

RESULTS

Using a logistic regression, we found that fMRI experts were 24% more likely (relative risk = 1.24, P < .001) to detect the concealed number than the polygraphy experts. Incidentally, when 2 out of 3 raters in each modality agreed on a number (N = 17), the combined accuracy was 100%.

CONCLUSIONS

These data justify further evaluation of fMRI as a potential alternative to polygraphy. The sequential or concurrent use of psychophysiology and neuroimaging in lie detection also deserves new consideration.

Neurocognitive profile in psychotic versus nonpsychotic individuals with 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome (22q11DS) is associated with increased rates of psychotic disorders and cognitive deficits, but large scale studies are needed to elucidate their interaction. The objective of this two-center study was to identify the neurocognitive phenotype of individuals with 22q11DS and psychotic disorders. We hypothesized that psychotic 22q11DS individuals compared to nonpsychotic deleted individuals would have more severe neurocognitive deficits, especially in executive function and social cognition. These deficits would be present when compared to IQ- matched individuals with Williams Syndrome (WS). Three groups were ascertained from the Tel Aviv and Philadelphia centers: 22q11DS individuals with a psychotic disorder (n=31), nonpsychotic 22q11DS (n=86) and typically-developing controls (TD, n=828). In Tel Aviv a group of individuals with WS (n=18) matched in IQ to the 22q11DS psychotic group was also included. The Penn Computerized Neurocognitive Battery (CNB) was used to assess a wide-range of cognitive functions and all patients underwent structured psychiatric evaluations. 22q11DS individuals performed poorly on all CNB domains compared to TD. Participants with 22q11DS and psychosis, compared to nonpsychotic 22q11DS, had more severe deficits in global neurocognitive performance (GNP), executive function, social cognition and episodic memory domains. The primary deficits were also significant when comparing the Tel Aviv 22q11DS psychotic group to IQ-matched individuals with WS. In conclusion, 22q11DS individuals with a psychotic disorder have specific neurocognitive deficits that are reliably identified cross nationality using the CNB. These cognitive dysfunctions should be further studied as potential endophenotypes of psychosis in 22q11DS and as targets for intervention.

Divergent relationship of depression severity to social reward responses among patients with bipolar versus unipolar depression

Neuroimaging studies of mood disorders demonstrate abnormalities in brain regions implicated in reward processing. However, there is a paucity of research investigating how social rewards affect reward circuit activity in these disorders. Here, we evaluated the relationship of both diagnostic category and dimensional depression severity to reward system function in bipolar and unipolar depression. In total, 86 adults were included, including 24 patients with bipolar depression, 24 patients with unipolar depression, and 38 healthy comparison subjects. Participants completed a social reward task during 3T BOLD fMRI. On average, diagnostic groups did not differ in activation to social reward. However, greater depression severity significantly correlated with reduced bilateral ventral striatum activation to social reward in the bipolar depressed group, but not the unipolar depressed group. In addition, decreased left orbitofrontal cortical activation correlated with more severe symptoms in bipolar depression, but not unipolar depression. These differential dimensional effects resulted in a significant voxelwise group by depression severity interaction. Taken together, these results provide initial evidence that deficits in social reward processing are differentially related to depression severity in the two disorders.

Disrupted anatomic networks in the 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome (22q11DS) is an uncommon genetic disorder with an increased risk of psychosis. Although the neural substrates of psychosis and schizophrenia are not well understood, aberrations in cortical networks represent intriguing potential mechanisms. Investigations of anatomic networks within 22q11DS are sparse. We investigated group differences in anatomic network structure in 48 individuals with 22q11DS and 370 typically developing controls by analyzing covariance patterns in cortical thickness among 68 regions of interest using graph theoretical models. Subjects with 22q11DS had less robust geographic organization relative to the control group, particularly in the occipital and parietal lobes. Multiple global graph theoretical statistics were decreased in 22q11DS. These results are consistent with prior studies demonstrating decreased connectivity in 22q11DS using other neuroimaging methodologies.

Nicotine withdrawal alters neural responses to psychosocial stress

INTRODUCTION

Psychosocial stress is considered to be an important mechanism underlying smoking behavior and relapse. Thus, understanding the effects of acute nicotine withdrawal on responses to stress is important to intervene to prevent stress-induced relapse. The current study investigated the neural correlates of psychosocial stress during acute nicotine withdrawal in chronic smokers.

METHODS

Thirty-nine treatment-seeking smokers were randomized to one of two conditions (abstinent 24 h (n = 21) or smoking as usual (n = 18)). They were then exposed to the Montreal Imaging Stress Task (MIST), a psychosocial stress task consisting of difficult mental arithmetic problems while receiving negative performance feedback while undergoing functional magnetic resonance imaging (fMRI).

RESULTS

Subjective measures of stress increased following the MIST, compared to baseline. Whole brain between-group analysis identified significant activation clusters in four regions for the stress induction minus control contrast: inferior frontal gyrus (IFG), anterior/para cingulate cortex (ACC), precuneus, and supramarginal gyrus (SMG). In all regions, the deprived group showed significantly greater activation compared to the non-deprived group. No significant correlations were found between subjective stress and BOLD signal activation (ps > 0.07).

CONCLUSIONS

This study provides new evidence that brain regions previously shown to be predictive of relapse, such as the precuneus and IFG, display heightened neural responses to stress during nicotine deprivation. These data identify the brain regions that may be associated with withdrawal-related stress responses. Increased stress-related activation during nicotine withdrawal may identify those most vulnerable to relapse and represent a target for novel pharmacological intervention.