Task-related neural mechanisms of persecutory ideation in schizophrenia and community monozygotic twin-pairs.

Perceptions of spiteful behavior are common, distinct from rational fear, and may undergird persecutory ideation. To test this hypothesis and investigate neural mechanisms of persecutory ideation, we employed a novel economic social decision-making task, the Minnesota Trust Game (MTG), during neuroimaging in patients with schizophrenia (n = 30) and community monozygotic (MZ) twins (n = 38; 19 pairs). We examined distinct forms of mistrust, task-related brain activation and connectivity, and investigated relationships with persecutory ideation. We tested whether co-twin discordance on these measurements was correlated to reflect a common source of underlying variance. Across samples persecutory ideation was associated with reduced trust only during the suspiciousness condition, which assessed spite sensitivity given partners had no monetary incentive to betray. Task-based activation contrasts for specific forms of mistrust were limited and unrelated to persecutory ideation. However, task-based connectivity contrasts revealed a dorsal cingulate anterior insula network sensitive to suspicious mistrust, a left frontal-parietal (lF-P) network sensitive to rational mistrust, and a ventral medial/orbital prefrontal (vmPFC/OFC) network that was sensitive to the difference between these forms of mistrust (all p < .005). Higher persecutory ideation was predicted only by reduced connectivity between the vmPFC/OFC and lF-P networks (p = .005), which was only observed when the intentions of the other player were relevant. Moreover, co-twin differences in persecutory ideation predicted co-twin differences in both spite sensitivity and in vmPFC/OFC-lF-P connectivity. This work found that interconnectivity may be particularly important to the complex neurobiology underlying persecutory ideation, and that unique environmental variance causally linked persecutory ideation, decision-making, and brain connectivity.

Associations between cortical thickness and general intelligence in children, adolescents and young adults.

Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral performance correlates of normative gray matter thinning during adolescence.

Associations between cortical thickness and verbal fluency in childhood, adolescence, and young adulthood.

Neuroimaging studies of normative human brain development indicate that the brain matures at differing rates across time and brain regions, with some areas maturing into young adulthood. In particular, changes in cortical thickness may index maturational progressions from an overabundance of neuropil toward efficiently pruned neural networks. Developmental changes in structural MRI measures have rarely been examined in relation to discrete neuropsychological functions. In this study, healthy right-handed adolescents completed MRI scanning and the Controlled Oral Word Association Test (COWAT). Associations of task performance and cortical thickness were assessed with cortical-surface-based analyses. Significant correlations between increasing COWAT performances and decreasing cortical thickness were found in left hemisphere language regions, including perisylvian regions surrounding Wernicke's and Broca's areas. Task performance was also correlated with regions associated with effortful verbal processing, working memory, and performance monitoring. Structure-function associations were not significantly different between older and younger subjects. Decreases in cortical thicknesses in regions that comprise the language network likely reflect maturation toward adult-like cortical organization and processing efficiency. The changes in cortical thicknesses that support verbal fluency are apparent by middle childhood, but with regionally separate developmental trajectories for males and females, consistent with other studies of adolescent development.

Neuropsychological characterization of three adolescent females with anti-NMDA receptor encephalitis in the acute, post-acute, and chronic phases: an inter-institutional case series.

OBJECTIVE: Anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis is an acute, immune-mediated paraneoplastic syndrome that often presents with psychobehavioral changes, abnormal movements, autonomic instability, seizures, and cognitive dysfunction. While the disease continues to be more readily identified and appropriately treated, the course of cognitive deficits from the acute to post-acute to chronic phase has not been well described, particularly in the pediatric population. This case series describes the neuropsychological functioning of three adolescent females with anti-NMDA receptor encephalitis from its early presentation to long-term follow-up. METHOD: All three cases are adolescent females with antibody-confirmed anti-NMDA receptor encephalitis. A review of the literature is provided summarizing the disorder and its known cognitive sequelae, pathophysiology, treatment, and prognostic factors, as well as each patient's relevant history, symptom presentation, and disease course. Neuropsychological functioning of each patient was evaluated from her initial inpatient hospitalization to long-term follow-up (3.5-12 months after acute evaluation). RESULTS: All three patients demonstrated clear improvement in cognitive functioning during the course of their recovery, though selected deficits in executive functioning, fine motor dexterity, language, and memory were observed at long-term follow-up in some of our patients. CONCLUSIONS: Findings are consistent with studies in adults that found cognitive deficits following anti-NMDA receptor encephalitis. Though gradual recovery was noted over time, all three patients reported no clinically significant difficulties during their final evaluation, despite showing mild impairment in some areas, emphasizing the importance of ongoing neuropsychological follow-up.

Age-related changes in the intrinsic functional connectivity of the human ventral vs. dorsal striatum from childhood to middle age.

The striatum codes motivated behavior. Delineating age-related differences within striatal circuitry can provide insights into neural mechanisms underlying ontogenic behavioral changes and vulnerabilities to mental disorders. To this end, a dual ventral/dorsal model of striatal function was examined using resting state intrinsic functional connectivity (iFC) imaging in 106 healthy individuals, ages 9-44. Broadly, the dorsal striatum (DS) is connected to prefrontal and parietal cortices and contributes to cognitive processes; the ventral striatum (VS) is connected to medial orbitofrontal and anterior cingulate cortices, and contributes to affective valuation and motivation. Findings revealed patterns of age-related changes that differed between VS and DS iFCs. We found an age-related increase in DS iFC with posterior cingulate cortex (pCC) that stabilized after the mid-twenties, but a decrease in VS iFC with anterior insula (aIns) and dorsal anterior cingulate cortex (dACC) that persisted into mid-adulthood. These distinct developmental trajectories of VS vs. DS iFC might underlie adolescents' unique behavioral patterns and vulnerabilities to psychopathology, and also speaks to changes in motivational networks that extend well past 25 years old.

Dopaminergic modulation of incentive motivation in adolescence: age-related changes in signaling, individual differences, and implications for the development of self-regulation.

Behavioral activation that is associated with incentive-reward motivation increases in adolescence relative to childhood and adulthood. This quadratic developmental pattern is generally supported by behavioral and experimental neuroscience findings. It is suggested that a focus on changes in dopamine neurotransmission is informative in understanding the mechanism for this adolescent increase in reward-related behavioral activation and subsequent decline into adulthood. Evidence is presented to indicate that incentive-reward motivation is modulated by mesoaccumbens dopamine, and that it increases in adolescence before declining into adulthood because of normative developmental changes at the molecular level. Potential mechanisms of variation in functional mesoaccumbens dopamine transmission are discussed with a focus on the interplay between tonic and phasic modes of dopamine transmission in modulating both general incentive-motivational biases and the efficacy of reward learning during exposure to novel reward experiences. Interactions between individual difference factors and these age-related trends are discussed.