Hyperglycemia and cognitive impairments anticipate the onset of an overt type 2 diabetes-like phenotype in TALLYHO/JngJ mice

Type 2 Diabetes mellitus (T2DM) is a metabolic disorder characterized by chronic hyperglycemia, resulting from deficits in insulin secretion, insulin action, or both. Whilst the role of insulin in the peripheral nervous system has been ascertained in countless studies, its role in the central nervous system (CNS) is emerging only recently. Brain insulin has been lately associated with brain disorders like Alzheimer's disease, obsessive compulsive disorder, and attention deficit hyperactivity disorder. Thus, understanding the role of insulin as a common risk factor for mental and somatic comorbidities may disclose novel preventative and therapeutic approaches. We evaluated general metabolism (glucose tolerance, insulin sensitivity, energy expenditure, lipid metabolism, and polydipsia) and cognitive capabilities (attention, cognitive flexibility, and memory), in adolescent, young adult, and adult male and female TALLYHO/JngJ mice (TH, previously reported to constitute a valid experimental model of T2DM due to impaired insulin signaling). Adult TH mice have also been studied for alterations in gut microbiota diversity and composition. While TH mice exhibited profound deficits in cognitive flexibility and altered glucose metabolism, we observed that these alterations emerged either much earlier (males) or independent of (females) a comprehensive constellation of symptoms, isomorphic to an overt T2DM-like phenotype (insulin resistance, polydipsia, higher energy expenditure, and altered lipid metabolism). We also observed significant sex-dependent alterations in gut microbiota alpha diversity and taxonomy in adult TH mice. Deficits in insulin signaling may represent a common risk factor for both T2DM and CNS-related deficits, which may stem from (partly) independent mechanisms.

A systematic review of preclinical studies exploring the role of insulin signalling in executive function and memory

Beside its involvement in somatic dysfunctions, altered insulin signalling constitutes a risk factor for the development of mental disorders like Alzheimer's disease and obsessive-compulsive disorder. While insulin-related somatic and mental disorders are often comorbid, the fundamental mechanisms underlying this association are still elusive. Studies conducted in rodent models appear well suited to help decipher these mechanisms. Specifically, these models are apt to prospective studies in which causative mechanisms can be manipulated via multiple tools (e.g., genetically engineered models and environmental interventions), and experimentally dissociated to control for potential confounding factors. Here, we provide a narrative synthesis of preclinical studies investigating the association between hyperglycaemia - as a proxy of insulin-related metabolic dysfunctions - and impairments in working and spatial memory, and attention. Ultimately, this review will advance our knowledge on the role of glucose metabolism in the comorbidity between somatic and mental illnesses.

Emotion recognition profiles in clusters of youth based on levels of callous-unemotional traits and reactive and proactive aggression

Youth with disruptive behavior showing high callous-unemotional (CU) traits and proactive aggression are often assumed to exhibit distinct impairments in emotion recognition from those showing mainly reactive aggression. Yet, reactive and proactive aggression and CU traits may co-occur to varying degrees across individuals. We aimed to investigate emotion recognition in more homogeneous clusters based on these three dimensions. In a sample of 243 youth (149 with disruptive behavior problems and 94 controls) aged 8-18 years, we used model-based clustering on self-report measures of CU traits and reactive and proactive aggression and compared the resulting clusters on emotion recognition (accuracy and response bias) and working memory. In addition to a Low and Low-Moderate symptom cluster, we identified two high CU clusters. The CU-Reactive cluster showed high reactive and low-to-medium proactive aggression; the CU-Mixed cluster showed high reactive and proactive aggression. Both CU clusters showed impaired fear recognition and working memory, whereas the CU-Reactive cluster also showed impaired recognition of disgust and sadness, partly explained by poor working memory, as well as a response bias for anger and happiness. Our results confirm the importance of CU traits as a core dimension along which youth with disruptive behavior may be characterized, yet challenge the view that high CU traits are closely linked to high proactive aggression per se. Notably, distinct neurocognitive processes may play a role in youth with high CU traits and reactive aggression with lower versus higher proactive aggression.

Different whole-brain functional connectivity correlates of reactive-proactive aggression and callous-unemotional traits in children and adolescents with disruptive behaviors

BACKGROUND

Disruptive behavior in children and adolescents can manifest as reactive aggression and proactive aggression and is modulated by callous-unemotional traits and other comorbidities. Neural correlates of these aggression dimensions or subtypes and comorbid symptoms remain largely unknown. This multi-center study investigated the relationship between resting state functional connectivity (rsFC) and aggression subtypes considering comorbidities.

METHODS

The large sample of children and adolescents aged 8-18 years (n = 207; mean age = 13.30±2.60 years, 150 males) included 118 cases with disruptive behavior (80 with Oppositional Defiant Disorder and/or Conduct Disorder) and 89 controls. Attention-deficit/hyperactivity disorder (ADHD) and anxiety symptom scores were analyzed as covariates when assessing group differences and dimensional aggression effects on hypothesis-free global and local voxel-to-voxel whole-brain rsFC based on functional magnetic resonance imaging at 3 Tesla.

RESULTS

Compared to controls, the cases demonstrated altered rsFC in frontal areas, when anxiety but not ADHD symptoms were controlled for. For cases, reactive and proactive aggression scores were related to global and local rsFC in the central gyrus and precuneus, regions linked to aggression-related impairments. Callous-unemotional trait severity was correlated with ICC in the inferior and middle temporal regions implicated in empathy, emotion, and reward processing. Most observed aggression subtype-specific patterns could only be identified when ADHD and anxiety were controlled for.

CONCLUSIONS

This study clarifies that hypothesis-free brain connectivity measures can disentangle distinct though overlapping dimensions of aggression in youths. Moreover, our results highlight the importance of considering comorbid symptoms to detect aggression-related rsFC alterations in youths.

A potential osteogenic role for microRNA-181a-5p during palatogenesis

BACKGROUND

In a previous study, we found that the highly conserved hsa-miR-181a-5p is downregulated in palatal fibroblasts of non-syndromic cleft palate-only infants.

OBJECTIVES

To analyze the spatiotemporal expression pattern of mmu-miR-181a-5p during palatogenesis and identify possible mRNA targets and their involved molecular pathways.

MATERIAL AND METHODS

The expression of mmu-miR-181a-5p was analyzed in the developing palates of mouse embryos from E11 to E18 using qPCR and ISH. Mouse embryonic palatal mesenchyme cells from E13 were used to analyze mmu-miR-181a-5p expression during osteogenic differentiation. Differential mRNA expression and target identification were analyzed using whole transcriptome RNA sequencing after transfection with a mmu-miR-181a-5p mimic. Differentially expressed genes were linked with underlying pathways using gene set enrichment analysis.

RESULTS

The expression of mmm-miR-181a-5p in the palatal shelves increased from E15 and overlapped with palatal osteogenesis. During early osteogenic differentiation, mmu-miR-181a-5p was upregulated. Transient overexpression resulted in 49 upregulated mRNAs and 108 downregulated mRNAs (adjusted P-value < 0.05 and fold change > ± 1.2). Ossification (Stc1, Mmp13) and cell-cycle-related GO terms were significantly enriched for upregulated mRNAs. Analysis of possible mRNA targets indicated significant enrichment of Hippo signaling (Ywhag, Amot, Frmd6 and Serpine1) and GO terms related to cell migration and angiogenesis.

LIMITATIONS

Transient overexpression of mmu-miR-181a-5p in mouse embryonic palatal mesenchyme cells limited its analysis to early osteogenesis.

CONCLUSION

Mmu-miR-181-5p expression is increased in the developing palatal shelves in areas of bone formation and targets regulators of the Hippo signaling pathway.

Age-related brain deviations and aggression

BACKGROUND

Disruptive behavior disorders (DBD) are heterogeneous at the clinical and the biological level. Therefore, the aims were to dissect the heterogeneous neurodevelopmental deviations of the affective brain circuitry and provide an integration of these differences across modalities.

METHODS

We combined two novel approaches. First, normative modeling to map deviations from the typical age-related pattern at the level of the individual of (i) activity during emotion matching and (ii) of anatomical images derived from DBD cases (n = 77) and controls (n = 52) aged 8-18 years from the EU-funded Aggressotype and MATRICS consortia. Second, linked independent component analysis to integrate subject-specific deviations from both modalities.

RESULTS

While cases exhibited on average a higher activity than would be expected for their age during face processing in regions such as the amygdala when compared to controls these positive deviations were widespread at the individual level. A multimodal integration of all functional and anatomical deviations explained 23% of the variance in the clinical DBD phenotype. Most notably, the top marker, encompassing the default mode network (DMN) and subcortical regions such as the amygdala and the striatum, was related to aggression across the whole sample.

CONCLUSIONS

Overall increased age-related deviations in the amygdala in DBD suggest a maturational delay, which has to be further validated in future studies. Further, the integration of individual deviation patterns from multiple imaging modalities allowed to dissect some of the heterogeneity of DBD and identified the DMN, the striatum and the amygdala as neural signatures that were associated with aggression.

Insulin and Disorders of Behavioural Flexibility

Behavioural inflexibility is a symptom of neuropsychiatric and neurodegenerative disorders such as Obsessive-Compulsive Disorder, Autism Spectrum Disorder and Alzheimer's Disease, encompassing the maintenance of a behaviour even when no longer appropriate. Recent evidence suggests that insulin signalling has roles apart from its regulation of peripheral metabolism and mediates behaviourally-relevant central nervous system (CNS) functions including behavioural flexibility. Indeed, insulin resistance is reported to generate anxious, perseverative phenotypes in animal models, with the Type 2 diabetes medication metformin proving to be beneficial for disorders including Alzheimer's Disease. Structural and functional neuroimaging studies of Type 2 diabetes patients have highlighted aberrant connectivity in regions governing salience detection, attention, inhibition and memory. As currently available therapeutic strategies feature high rates of resistance, there is an urgent need to better understand the complex aetiology of behaviour and develop improved therapeutics. In this review, we explore the circuitry underlying behavioural flexibility, changes in Type 2 diabetes, the role of insulin in CNS outcomes and mechanisms of insulin involvement across disorders of behavioural inflexibility.

A consensus protocol for functional connectivity analysis in the rat brain

Task-free functional connectivity in animal models provides an experimental framework to examine connectivity phenomena under controlled conditions and allows for comparisons with data modalities collected under invasive or terminal procedures. Currently, animal acquisitions are performed with varying protocols and analyses that hamper result comparison and integration. Here we introduce StandardRat, a consensus rat functional magnetic resonance imaging acquisition protocol tested across 20 centers. To develop this protocol with optimized acquisition and processing parameters, we initially aggregated 65 functional imaging datasets acquired from rats across 46 centers. We developed a reproducible pipeline for analyzing rat data acquired with diverse protocols and determined experimental and processing parameters associated with the robust detection of functional connectivity across centers. We show that the standardized protocol enhances biologically plausible functional connectivity patterns relative to previous acquisitions. The protocol and processing pipeline described here is openly shared with the neuroimaging community to promote interoperability and cooperation toward tackling the most important challenges in neuroscience.

An Electrophysiological and Proteomic Analysis of the Effects of the Superoxide Dismutase Mimetic, MnTMPyP, on Synaptic Signalling Post-Ischemia in Isolated Rat Hippocampal Slices

Metabolic stress and the increased production of reactive oxygen species (ROS) are two main contributors to neuronal damage and synaptic plasticity in acute ischemic stroke. The superoxide scavenger MnTMPyP has been previously reported to have a neuroprotective effect in organotypic hippocampal slices and to modulate synaptic transmission after in vitro hypoxia and oxygen-glucose deprivation (OGD). However, the mechanisms involved in the effect of this scavenger remain elusive. In this study, two concentrations of MnTMPyP were evaluated on synaptic transmission during ischemia and post-ischemic synaptic potentiation. The complex molecular changes supporting cellular adaptation to metabolic stress, and how these are modulated by MnTMPyP, were also investigated. Electrophysiological data showed that MnTMPyP causes a decrease in baseline synaptic transmission and impairment of synaptic potentiation. Proteomic analysis performed on MnTMPyP and hypoxia-treated tissue indicated an impairment in vesicular trafficking mechanisms, including reduced expression of Hsp90 and actin signalling. Alterations of vesicular trafficking may lead to reduced probability of neurotransmitter release and AMPA receptor activity, resulting in the observed modulatory effect of MnTMPyP. In OGD, protein enrichment analysis highlighted impairments in cell proliferation and differentiation, such as TGFβ1 and CDKN1B signalling, in addition to downregulation of mitochondrial dysfunction and an increased expression of CAMKII. Taken together, our results may indicate modulation of neuronal sensitivity to the ischemic insult, and a complex role for MnTMPyP in synaptic transmission and plasticity, potentially providing molecular insights into the mechanisms mediating the effects of MnTMPyP during ischemia.

The Bi-directional Relationship Between Sleep and Inflammation in Muscular Dystrophies: A Narrative Review

Muscular dystrophies vary in presentation and severity, but are associated with profound disability in many people. Although characterised by muscle weakness and wasting, there is also a very high prevalence of sleep problems and disorders which have significant impacts on quality of life in these individuals. There are no curative therapies for muscular dystrophies, with the only options for patients being supportive therapies to aid with symptoms. Therefore, there is an urgent need for new therapeutic targets and a greater understanding of pathogenesis. Inflammation and altered immunity are factors which have prominent roles in some muscular dystrophies and emerging roles in others such as type 1 myotonic dystrophy, signifying a link to pathogenesis. Interestingly, there is also a strong link between inflammation/immunity and sleep. In this review, we will explore this link in the context of muscular dystrophies and how it may influence potential therapeutic targets and interventions.

Trauma-induced human glucocorticoid receptor expression increases predict subsequent HPA-axis blunting in a prospective longitudinal design

One of the hallmarks of post-traumatic stress disorder (PTSD) is abnormalities in the HPA-axis. This includes alterations in its negative feedback regulation. Although altered glucocorticoid receptor (GR) mRNA expression is thought to play a crucial role herein, direct longitudinal evidence in humans is lacking to support this assumption. The current prospective longitudinal study assessed the consequence of repeated trauma exposure on GR mRNA expression from saliva samples in early-career police recruits (n = 112) by assessing them before and after trauma exposure. We did not observe a relationship between change in GR mRNA expression and development of PTSD symptom severity. However, the more traumatic events were experienced during police training the stronger GR mRNA expression was increased. Moreover, increases in GR mRNA expression were associated with blunted HPA-axis stress-reactivity at follow-up compared to baseline. This study provides the first longitudinal evidence of a dose-response relationship between trauma and human GR mRNA expression (extracted from saliva) changes; therefore, replication is warranted. Our finding might contribute a possible explanatory framework for blunted HPA-axis function associated with PTSD.

Clinical improvement of DM1 patients reflected by reversal of disease-induced gene expression in blood

BACKGROUND

Myotonic dystrophy type 1 (DM1) is an incurable multisystem disease caused by a CTG-repeat expansion in the DM1 protein kinase (DMPK) gene. The OPTIMISTIC clinical trial demonstrated positive and heterogenous effects of cognitive behavioral therapy (CBT) on the capacity for activity and social participations in DM1 patients. Through a process of reverse engineering, this study aims to identify druggable molecular biomarkers associated with the clinical improvement in the OPTIMISTIC cohort.

METHODS

Based on full blood samples collected during OPTIMISTIC, we performed paired mRNA sequencing for 27 patients before and after the CBT intervention. Linear mixed effect models were used to identify biomarkers associated with the disease-causing CTG expansion and the mean clinical improvement across all clinical outcome measures.

RESULTS

We identified 608 genes for which their expression was significantly associated with the CTG-repeat expansion, as well as 1176 genes significantly associated with the average clinical response towards the intervention. Remarkably, all 97 genes associated with both returned to more normal levels in patients who benefited the most from CBT. This main finding has been replicated based on an external dataset of mRNA data of DM1 patients and controls, singling these genes out as candidate biomarkers for therapy response. Among these candidate genes were DNAJB12, HDAC5, and TRIM8, each belonging to a protein family that is being studied in the context of neurological disorders or muscular dystrophies. Across the different gene sets, gene pathway enrichment analysis revealed disease-relevant impaired signaling in, among others, insulin-, metabolism-, and immune-related pathways. Furthermore, evidence for shared dysregulations with another neuromuscular disease, Duchenne muscular dystrophy, was found, suggesting a partial overlap in blood-based gene dysregulation.

CONCLUSIONS

DM1-relevant disease signatures can be identified on a molecular level in peripheral blood, opening new avenues for drug discovery and therapy efficacy assessments.

Uncovering the genetic architecture of broad antisocial behavior through a genome-wide association study meta-analysis

Despite the substantial heritability of antisocial behavior (ASB), specific genetic variants robustly associated with the trait have not been identified. The present study by the Broad Antisocial Behavior Consortium (BroadABC) meta-analyzed data from 28 discovery samples (N = 85,359) and five independent replication samples (N = 8058) with genotypic data and broad measures of ASB. We identified the first significant genetic associations with broad ASB, involving common intronic variants in the forkhead box protein P2 (FOXP2) gene (lead SNP rs12536335, p = 6.32 × 10-10). Furthermore, we observed intronic variation in Foxp2 and one of its targets (Cntnap2) distinguishing a mouse model of pathological aggression (BALB/cJ strain) from controls (BALB/cByJ strain). Polygenic risk score (PRS) analyses in independent samples revealed that the genetic risk for ASB was associated with several antisocial outcomes across the lifespan, including diagnosis of conduct disorder, official criminal convictions, and trajectories of antisocial development. We found substantial genetic correlations of ASB with mental health (depression rg = 0.63, insomnia rg = 0.47), physical health (overweight rg = 0.19, waist-to-hip ratio rg = 0.32), smoking (rg = 0.54), cognitive ability (intelligence rg = -0.40), educational attainment (years of schooling rg = -0.46) and reproductive traits (age at first birth rg = -0.58, father's age at death rg = -0.54). Our findings provide a starting point toward identifying critical biosocial risk mechanisms for the development of ASB.

Deviant circadian rhythmicity, corticosterone variability and trait testosterone levels in aggressive mice

Although aggression has been linked to disturbances of circadian rhythm, insight into the neural substrate of this association is currently lacking. The suprachiasmatic nucleus (SCN) of the hypothalamus, the master circadian clock, is regulated by clock genes and known to influence the secretion of cortisosterone and testosterone, important hormones implicated in aggression. Here, we investigated deviations in the regulation of the locomotor circadian rhythm and hormonal levels in a mouse model of abnormal aggression. We tested aggressive BALB/cJ and control BALB/cByJ mice in the resident–intruder paradigm and compared them on their locomotor circadian rhythm during a 12 h light/12 h dark cycle and constant darkness. State (serum) corticosterone and trait (hair) corticosterone and testosterone levels were determined, and immunohistochemistry was performed to assess the expression of important clock proteins, PER1 and PER2, in the core and shell of the SCN at the start of their active phase. Compared with BALB/cByJ mice, aggressive BALB/cJ mice displayed: (1) a shorter free‐running period in constant darkness; (2) reduced state corticosterone variability between circadian peak and trough but no differences in corticosterone trait levels; (3) lower testosterone trait levels; (4) higher PER1 expression in the SCN shell with no changes in PER2 in either SCN subregion during the early dark phase. Together, these results suggest that aggressive BALB/cJ mice have disturbances in different components encompassing the circadian and hormonal cycle, emphasizing their value for future investigation of the causal relationship between SCN function, circadian clocks and aggression.

The effects of callous-unemotional traits and aggression subtypes on amygdala activity in response to negative faces

BACKGROUND

Brain imaging studies have shown altered amygdala activity during emotion processing in children and adolescents with oppositional defiant disorder (ODD) and conduct disorder (CD) compared to typically developing children and adolescents (TD). Here we aimed to assess whether aggression-related subtypes (reactive and proactive aggression) and callous-unemotional (CU) traits predicted variation in amygdala activity and skin conductance (SC) response during emotion processing.

METHODS

We included 177 participants (n = 108 cases with disruptive behaviour and/or ODD/CD and n = 69 TD), aged 8-18 years, across nine sites in Europe, as part of the EU Aggressotype and MATRICS projects. All participants performed an emotional face-matching functional magnetic resonance imaging task.

RESULTS

Differences between cases and TD in affective processing, as well as specificity of activation patterns for aggression subtypes and CU traits, were assessed. Simultaneous SC recordings were acquired in a subsample (n = 63). Cases compared to TDs showed higher amygdala activity in response to negative faces (fearful and angry) v. shapes. Subtyping cases according to aggression-related subtypes did not significantly influence on amygdala activity; while stratification based on CU traits was more sensitive and revealed decreased amygdala activity in the high CU group. SC responses were significantly lower in cases and negatively correlated with CU traits, reactive and proactive aggression.

CONCLUSIONS

Our results showed differences in amygdala activity and SC responses to emotional faces between cases with ODD/CD and TD, while CU traits moderate both central (amygdala) and peripheral (SC) responses. Our insights regarding subtypes and trait-specific aggression could be used for improved diagnostics and personalized treatment.

Subgrouping children and adolescents with disruptive behaviors: symptom profiles and the role of callous-unemotional traits

Disruptive behavior during childhood and adolescence is heterogeneous and associated with several psychiatric disorders. The identification of more homogeneous subgroups might help identify different underlying pathways and tailor treatment strategies. Children and adolescents (aged 8-18) with disruptive behaviors (N = 121) and healthy controls (N = 100) were included in a European multi-center cognition and brain imaging study. They were assessed via a battery of standardized semi-structured interviews and questionnaires. K-means cluster-model analysis was carried out to identify subgroups within the group with disruptive behaviors, based on clinical symptom profiles, callous-unemotional (CU) traits, and proactive and reactive aggression. The resulting subgroups were then compared to healthy controls with regard to these clinical variables. Three distinct subgroups were found within the group with disruptive behaviors. The High CU Traits subgroup presented elevated scores for CU traits, proactive aggression and conduct disorder (CD) symptoms, as well as a higher proportion of comorbidities (CD + oppositional defiant disorder + attention deficit hyperactivity disorder (ADHD). The ADHD and Affective Dysregulation subgroup showed elevated scores for internalizing and ADHD symptoms, as well as a higher proportion of females. The Low Severity subgroup had relatively low levels of psychopathology and aggressive behavior compared to the other two subgroups. The High CU Traits subgroup displayed more antisocial behaviors than the Low Severity subgroup, but did not differ when compared to the ADHD and Affective Dysregulation subgroup. All three subgroups differed significantly from the healthy controls in all the variables analyzed. The present study extends previous findings on subgrouping children and adolescents with disruptive behaviors using a multidimensional approach and describes levels of anxiety, affective problems, ADHD, proactive aggression and CU traits as key factors that differentiate conclusively between subgroups.

Memantine treatment does not affect compulsive behavior or frontostriatal connectivity in an adolescent rat model for quinpirole-induced compulsive checking behavior

RATIONALE

Compulsivity often develops during childhood and is associated with elevated glutamate levels within the frontostriatal system. This suggests that anti-glutamatergic drugs, like memantine, may be an effective treatment.

OBJECTIVE

Our goal was to characterize the acute and chronic effect of memantine treatment on compulsive behavior and frontostriatal network structure and function in an adolescent rat model of compulsivity.

METHODS

Juvenile Sprague-Dawley rats received repeated quinpirole, resulting in compulsive checking behavior (n = 32; compulsive) or saline injections (n = 32; control). Eight compulsive and control rats received chronic memantine treatment, and eight compulsive and control rats received saline treatment for seven consecutive days between the 10th and 12th quinpirole/saline injection. Compulsive checking behavior was assessed, and structural and functional brain connectivity was measured with diffusion MRI and resting-state fMRI before and after treatment. The other rats received an acute single memantine (compulsive: n = 12; control: n = 12) or saline injection (compulsive: n = 4; control: n = 4) during pharmacological MRI after the 12th quinpirole/saline injection. An additional group of rats received a single memantine injection after a single quinpirole injection (n = 8).

RESULTS

Memantine treatment did not affect compulsive checking nor frontostriatal structural and functional connectivity in the quinpirole-induced adolescent rat model. While memantine activated the frontal cortex in control rats, no significant activation responses were measured after single or repeated quinpirole injections.

CONCLUSIONS

The lack of a memantine treatment effect in quinpirole-induced compulsive adolescent rats may be partly explained by the interaction between glutamatergic and dopaminergic receptors in the brain, which can be evaluated with functional MRI.

Longitudinal Assessment of Strength, Functional Capacity, Oropharyngeal Function, and Quality of Life in Oculopharyngeal Muscular Dystrophy

BACKGROUND AND OBJECTIVES

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, progressive muscle disease. Disease progression is known to be slow, but details on the natural history remain unknown. We aimed to examine the natural history of OPMD in a large nationwide cohort to determine clinical outcome measures that capture disease progression and can be used in future clinical trials.

METHODS

Patients invited by their treating physicians or identified from the national neuromuscular database and invited family members were examined twice 20 months apart with fixed dynamometry; Medical Research Council (MRC) grading; maximum bite force and isometric tongue strength; Motor Function Measure (MFM); 10-step stair test; maximum swallowing, chewing, and speech tasks; and quality of life assessments.

RESULTS

Disease progression was captured by 8 of 18 measures over 20 months in 43 patients with genetically confirmed OPMD. The largest deterioration was seen in deltoid muscle strength (-27% [range -17% to -37%]), followed by the quadriceps (-14% [range -6 to -23%]), iliopsoas (-12.2%), tongue (-9.9%), and MRC sum score (-2.5%). The 10-step stair test (-12.5%), MFM part D1 (-7.1%), and maximum repetition rate of /pa/ (-5.3%) showed a significant decrease as well (all p < 0.05). The Physical Functioning domain of the Short Form-36 Health Survey significantly deteriorated (p = 0.044). No relationship was found between disease progression and genotype or disease duration (p > 0.05).

DISCUSSION

Despite the slow disease progression of OPMD, this study showed that several outcome measures detected progression within 20 months. Deltoid muscle strength, measured by fixed dynamometry, showed the greatest decline. These longitudinal data provide clinical outcome measures that can be used as biomarkers in future clinical trials.

Moral strategies and psychopathic traits

Psychopathy is a personality construct encompassing impaired interpersonal-affective functioning, combined with the inclination to lead an erratic lifestyle and to engage in antisocial acts. Individuals with elevated psychopathic traits often make decisions that have a negative impact on others. Some findings suggest that a lack of empathy and guilt is a key explanatory factor, while other results point toward a decreased sense of fairness in individuals with elevated psychopathic traits. The goal of the present study was to directly compare these hypotheses. Eighty-six healthy individuals completed the Self-Report Psychopathy scale and performed the Hidden Multiplier Trust Game, a socioeconomic decision-making task designed to untangle the roles of guilt and fairness during decision-making. Computational modeling of choice data identified five types of moral decision strategies: inequity aversion, guilt aversion, moral opportunism, greed, and generosity. The model-free results demonstrated that psychopathic traits were associated with lower levels of reciprocity. The model-based results suggested that a reduced sense of fairness, associated with affective traits, was driving this behavior. Our findings stress the importance of treating guilt and fairness as independent concepts, and highlight the importance of improving conceptual precision in untangling the individual impact of fairness and guilt, as this could help explain the mixed results in moral decision-making literature. Elucidating the psychological motivations underlying the relationship between psychopathic traits and poor social decision-making opens new avenues for research on the underlying cognitive mechanisms. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Aggression subtypes relate to distinct resting state functional connectivity in children and adolescents with disruptive behavior

There is increasing evidence for altered brain resting state functional connectivity in adolescents with disruptive behavior. While a considerable body of behavioral research points to differences between reactive and proactive aggression, it remains unknown whether these two subtypes have dissociable effects on connectivity. Additionally, callous-unemotional traits are important specifiers in subtyping aggressive behavior along the affective dimension. Accordingly, we examined associations between two aggression subtypes along with callous-unemotional traits using a seed-to-voxel approach. Six functionally relevant seeds were selected to probe the salience and the default mode network, based on their presumed role in aggression. The resting state sequence was acquired from 207 children and adolescents of both sexes [mean age (standard deviation) = 13.30 (2.60); range = 8.02-18.35] as part of a Europe-based multi-center study. One hundred eighteen individuals exhibiting disruptive behavior (conduct disorder/oppositional defiant disorder) with varying comorbid attention-deficit/hyperactivity disorder (ADHD) symptoms were studied, together with 89 healthy controls. Proactive aggression was associated with increased left amygdala-precuneus coupling, while reactive aggression related to hyper-connectivities of the posterior cingulate cortex (PCC) to the parahippocampus, the left amygdala to the precuneus and to hypo-connectivity between the right anterior insula and the nucleus caudate. Callous-unemotional traits were linked to distinct hyper-connectivities to frontal, parietal, and cingulate areas. Additionally, compared to controls, cases demonstrated reduced connectivity of the PCC and left anterior insula to left frontal areas, the latter only when controlling for ADHD scores. Taken together, this study revealed aggression-subtype-specific patterns involving areas associated with emotion, empathy, morality, and cognitive control.

Clinical Outcome Evaluations and CBT Response Prediction in Myotonic Dystrophy

BACKGROUND

The European OPTIMISTIC clinical trial has demonstrated a significant, yet heterogenous effect of Cognitive Behavioural Therapy (CBT) for Myotonic Dystrophy type 1 (DM1) patients. One of its remaining aims was the assessment of efficacy and adequacy of clinical outcome measures, including the relatively novel primary trial outcome, the DM1-Activ-c questionnaire.

OBJECTIVES

Assessment of the relationship between the Rasch-built DM1-Activ-c questionnaire and 26 commonly used clinical outcome measurements. Identification of variables associated with CBT response in DM1 patients.

METHODS

Retrospective analysis of the to date largest clinical trial in DM1 (OPTIMISTIC), comprising of 255 genetically confirmed DM1 patients randomized to either standard care or CBT with optionally graded exercise therapy. Correlations of 27 different outcome measures were calculated at baseline (cross-sectional) and of their respective intervention induced changes (longitudinal). Bootstrap enhanced Elastic-Net (BeEN) regression was validated and implemented to select variables associated with CBT response.

RESULTS

In cross-sectional data, DM1-Activ-c correlated significantly with the majority of other outcome measures, including Six Minute Walk Test and Myotonic Dystrophy Health Index. Fewer and weaker significant longitudinal correlations were observed. Nine variables potentially associated with CBT response were identified, including measures of disease severity, executive cognitive functioning and perceived social support.

CONCLUSIONS

The DM1-Activ-c questionnaire appears to be a well suited cross-sectional instrument to assess a variety of clinically relevant dimensions in DM1. Yet, apathy and experienced social support measures were less well captured. CBT response was heterogenous, requiring careful selection of outcome measures for different disease aspects.

A central role for anterior cingulate cortex in the control of pathological aggression

Controlling aggression is a crucial skill in social species like rodents and humans and has been associated with anterior cingulate cortex (ACC). Here, we directly link the failed regulation of aggression in BALB/cJ mice to ACC hypofunction. We first show that ACC in BALB/cJ mice is structurally degraded: neuron density is decreased, with pervasive neuron death and reactive astroglia. Gene-set enrichment analysis suggested that this process is driven by neuronal degeneration, which then triggers toxic astrogliosis. cFos expression across ACC indicated functional consequences: during aggressive encounters, ACC was engaged in control mice, but not BALB/cJ mice. Chemogenetically activating ACC during aggressive encounters drastically suppressed pathological aggression but left species-typical aggression intact. The network effects of our chemogenetic perturbation suggest that this behavioral rescue is mediated by suppression of amygdala and hypothalamus and activation of mediodorsal thalamus. Together, these findings highlight the central role of ACC in curbing pathological aggression.

Psychopathic traits influence threat avoidance in a community sample independent of testosterone

Psychopathy is a personality construct that encompasses a constellation of traits reflecting emotional dysfunction and antisocial behavior. Individuals with elevated levels of psychopathic traits have shown abnormal affective processing. Studies with psychopathic offenders suggested that this is a result of altered automatic social approach-avoidance tendencies. The goal of the current study was to increase the insight into the underlying mechanism of affective processes in community-dwelling individuals with a high level of psychopathic traits by studying approach and avoidance behavior in an experimental setting. Furthermore, given its link with aggression and threat approach, testosterone was measured to investigate a possible mediatory role. Eighty-seven healthy individuals performed a computerized affective approach-avoidance task in which they pushed or pulled emotional faces using a joystick. The results showed that high levels of psychopathic traits corresponded with diminished threat avoidance to angry faces, as was found previously in psychopathic offenders. Although endogenous testosterone was positively associated with the level of psychopathic traits, it did not mediate the effect of psychopathic traits on threat avoidance. We propose that an increased understanding of the interplay between different neuroendocrine mechanisms could lead to a better insight into the underlying mechanism of abnormal threat avoidance in individuals with high levels of psychopathic traits. (PsycInfo Database Record (c) 2021 APA, all rights reserved).