Experience during adolescence shapes brain development: From synapses and networks to normal and pathological behavior

Glial Control of Cortical Neuronal Circuit Maturation and Plasticity

The brain is a highly adaptable organ that is molded by experience throughout life. Although the field of neuroscience has historically focused on intrinsic neuronal mechanisms of plasticity, there is growing evidence that multiple glial populations regulate the timing and extent of neuronal plasticity, particularly over the course of development. This review highlights recent discoveries on the role of glial cells in the establishment of cortical circuits and the regulation of experience-dependent neuronal plasticity during critical periods of neurodevelopment. These studies provide strong evidence that neuronal circuit maturation and plasticity are non-cell autonomous processes that require both glial-neuronal and glial-glial cross talk to proceed. We conclude by discussing open questions that will continue to guide research in this nascent field.

Towards a neurodevelopmental model of bipolar disorder: a critical review of trait- and state-related functional neuroimaging in adolescents and young adults

Neurodevelopmental mechanisms are increasingly implicated in bipolar disorder (BD), highlighting the importance of their study in young persons. Neuroimaging studies have demonstrated a central role for frontotemporal corticolimbic brain systems that subserve processing and regulation of emotions, and processing of reward in adults with BD. As adolescence and young adulthood (AYA) is a time when fully syndromal BD often emerges, and when these brain systems undergo dynamic maturational changes, the AYA epoch is implicated as a critical period in the neurodevelopment of BD. Functional magnetic resonance imaging (fMRI) studies can be especially informative in identifying the functional neuroanatomy in adolescents and young adults with BD (BDAYA) and at high risk for BD (HR-BDAYA) that is related to acute mood states and trait vulnerability to the disorder. The identification of early emerging brain differences, trait- and state-based, can contribute to the elucidation of the developmental neuropathophysiology of BD, and to the generation of treatment and prevention targets. In this critical review, fMRI studies of BDAYA and HR-BDAYA are discussed, and a preliminary neurodevelopmental model is presented based on a convergence of literature that suggests early emerging dysfunction in subcortical (e.g., amygdalar, striatal, thalamic) and caudal and ventral cortical regions, especially ventral prefrontal cortex (vPFC) and insula, and connections among them, persisting as trait-related features. More rostral and dorsal cortical alterations, and bilaterality progress later, with lateralization, and direction of functional imaging findings differing by mood state. Altered functioning of these brain regions, and regions they are strongly connected to, are implicated in the range of symptoms seen in BD, such as the insula in interoception, precentral gyrus in motor changes, and prefrontal cortex in cognition. Current limitations, and outlook on the future use of neuroimaging evidence to inform interventions and prevent the onset of mood episodes in BDAYA, are outlined.

Emotional engagement with close friends in adolescence predicts neural correlates of empathy in adulthood

Empathy requires the ability to understand another's point of view and is critical for motivating a person to help others. However, little is known about the link between experiences of empathic emotional engagement in close friendships during adolescence and neural correlates of empathy in adulthood. Beginning in 1998, N = 88 participants drawn from a demographically diverse community sample were observed annually from ages 13 to 21 and rated on the amount of emotional engagement displayed toward a close friend during a support task. At approximately age 24, participants underwent functional brain imaging while a partner or stranger was under distress. Contrary to predictions, greater emotional engagement with close friends during adolescence corresponded prospectively with reduced temporal pole activity (a region associated with cognitive empathy and perspective taking) while observing threats directed at others. Results have implications for understanding the neurodevelopmental roots of empathy.

Depressive symptoms during the transition to adolescence: Left hippocampal volume as a marker of social context sensitivity

The transition to adolescence is a critical period for mental health development. Socio-experiential environments play an important role in the emergence of depressive symptoms with some adolescents showing more sensitivity to social contexts than others. Drawing on recent developmental neuroscience advances, we examined whether hippocampal volume amplifies social context effects in the transition to adolescence. We analyzed 2-y longitudinal data from the Adolescent Brain Cognitive Development (ABCD®) study in a diverse sample of 11,832 youth (mean age: 9.914 y; range: 8.917 to 11.083 y; 47.8% girls) from 21 sites across the United States. Socio-experiential environments (i.e., family conflict, primary caregiver's depressive symptoms, parental warmth, peer victimization, and prosocial school environment), hippocampal volume, and a wide range of demographic characteristics were measured at baseline. Youth's symptoms of major depressive disorder were assessed at both baseline and 2 y later. Multilevel mixed-effects linear regression analyses showed that negative social environments (i.e., family conflict, primary caregiver's depressive symptoms, and peer victimization) and the absence of positive social environments (i.e., parental warmth and prosocial school environment) predicted greater increases in youth's depressive symptoms over 2 y. Importantly, left hippocampal volume amplified social context effects such that youth with larger left hippocampal volume experienced greater increases in depressive symptoms in more negative and less positive social environments. Consistent with brain-environment interaction models of mental health, these findings underscore the importance of families, peers, and schools in the development of depression during the transition to adolescence and show how neural structure amplifies social context sensitivity.

Longitudinal study of peer victimization, social support, and mental health during early adolescence

BACKGROUND

Peer victimization predicts the development of mental health symptoms in the transition to adolescence, but it is unclear whether and how parents and school environments can buffer this link.

METHODS

We analyzed two-year longitudinal data from the Adolescent Brain Cognitive Development (ABCD) study, involving a diverse sample of 11 844 children across the United States (average at baseline = 9.91 years; standard deviation = 0.63; range = 8.92-11.08; complete case sample = 8385). Longitudinal associations between peer victimization and two-year changes in mental health symptoms of major depression disorder (MDD), separation anxiety (SA), prodromal psychosis (PP), and attention-deficit/hyperactivity disorder (ADHD) were examined including a wide range of covariates. Mixed linear models were used to test for the moderating effects of parental warmth and prosocial school environment.

RESULTS

20% of children experienced peer victimization. Higher exposure to peer victimization was associated with increases in MDD, SA, and ADHD symptoms. Parental warmth was associated with decreases in MDD symptoms but did not robustly buffer the link between peer victimization and mental health symptoms. Prosocial school environment predicted decreases in PP symptoms and buffered the link between peer victimization and MDD symptoms but amplified the link between peer victimization and SA and ADHD symptoms.

CONCLUSIONS

Peer victimization is associated with increases in mental health symptoms during the transition to adolescence. Parental warmth and prosocial school environments might not be enough to counter the negative consequences of peer victimization on all mental health outcomes.

The role of Foxo3a in neuron-mediated cognitive impairment

Cognitive impairment (COI) is a prevalent complication across a spectrum of brain disorders, underpinned by intricate mechanisms yet to be fully elucidated. Neurons, the principal cell population of the nervous system, orchestrate cognitive processes and govern cognitive balance. Extensive inquiry has spotlighted the involvement of Foxo3a in COI. The regulatory cascade of Foxo3a transactivation implicates multiple downstream signaling pathways encompassing mitochondrial function, oxidative stress, autophagy, and apoptosis, collectively affecting neuronal activity. Notably, the expression and activity profile of neuronal Foxo3a are subject to modulation via various modalities, including methylation of promoter, phosphorylation and acetylation of protein. Furthermore, upstream pathways such as PI3K/AKT, the SIRT family, and diverse micro-RNAs intricately interface with Foxo3a, engendering alterations in neuronal function. Through several downstream routes, Foxo3a regulates neuronal dynamics, thereby modulating the onset or amelioration of COI in Alzheimer's disease, stroke, ischemic brain injury, Parkinson's disease, and traumatic brain injury. Foxo3a is a potential therapeutic cognitive target, and clinical drugs or multiple small molecules have been preliminarily shown to have cognitive-enhancing effects that indirectly affect Foxo3a. Particularly noteworthy are multiple randomized, controlled, placebo clinical trials illustrating the significant cognitive enhancement achievable through autophagy modulation. Here, we discussed the role of Foxo3a in neuron-mediated COI and common cognitively impaired diseases.

Problematic Behaviors and Predicting Online Risk Behaviors in High School Students

Adolescent behavior now occurs offline and online. Frequently studied and treated independently, the relationship between offline problem behaviors and online risk taking is not well understood. This study asked whether there are any problematic behaviors predictive of online risk taking by high school students. Using a 2009 dataset of 2,077 high school students grades 9-12, five areas of offline problematic behaviors were examined: Academic problems, anxiety, behavioral wrongdoing, bullying, and social-emotional. Nine binary results were classified as online risk: Sexting, online harassment (perpetrating and experiencing), visiting sex sites, talking about sex, receiving sexual pictures, meeting offline, anything sexual happened, feeling nervous or uncomfortable. Behavioral wrongdoing (fighting, school suspension, trouble with police, theft), emerged as a significant predictor appearing in all nine models, followed by bullying experience (bully or victim) in six models. Identifying common problem behaviors that predict online risk taking are key components in developing strategies to promote adolescent health and well-being.

Multimodal neuroimaging correlates of physical-cognitive covariation in Chilean adolescents. The Cogni-Action Project

Health-related behaviours have been related to brain structural features. In developing settings, such as Latin America, high social inequality has been inversely associated with several health-related behaviours affecting brain development. Understanding the relationship between health behaviours and brain structure in such settings is particularly important during adolescence when critical habits are acquired and ingrained. In this cross-sectional study, we carry out a multimodal analysis identifying a brain region associated with health-related behaviours (i.e., adiposity, fitness, sleep problems and others) and cognitive/academic performance, independent of socioeconomic status in a large sample of Chilean adolescents. Our findings suggest that the relationship between health behaviours and cognitive/academic performance involves a particular brain phenotype that could play a mediator role. These findings fill a significant gap in the literature, which has largely focused on developed countries and raise the possibility of promoting healthy behaviours in adolescence as a means to influence brain structure and thereby cognitive/academic achievement, independently of socioeconomic factors. By highlighting the potential impact on brain structure and cognitive/academic achievement, policymakers could design interventions that are more effective in reducing health disparities in developing countries.

Interdisciplinary fetal-neonatal neurology training applies neural exposome perspectives to neurology principles and practice

An interdisciplinary fetal-neonatal neurology (FNN) program over the first 1,000 days teaches perspectives of the neural exposome that are applicable across the life span. This curriculum strengthens neonatal neurocritical care, pediatric, and adult neurology training objectives. Teaching at maternal-pediatric hospital centers optimally merges reproductive, pregnancy, and pediatric approaches to healthcare. Phenotype-genotype expressions of health or disease pathways represent a dynamic neural exposome over developmental time. The science of uncertainty applied to FNN training re-enforces the importance of shared clinical decisions that minimize bias and reduce cognitive errors. Trainees select mentoring committee participants that will maximize their learning experiences. Standardized questions and oral presentations monitor educational progress. Master or doctoral defense preparation and competitive research funding can be goals for specific individuals. FNN principles applied to practice offer an understanding of gene-environment interactions that recognizes the effects of reproductive health on the maternal-placental-fetal triad, neonate, child, and adult. Pre-conception and prenatal adversities potentially diminish life-course brain health. Endogenous and exogenous toxic stressor interplay (TSI) alters the neural exposome through maladaptive developmental neuroplasticity. Developmental disorders and epilepsy are primarily expressed during the first 1,000 days. Communicable and noncommunicable illnesses continue to interact with the neural exposome to express diverse neurologic disorders across the lifespan, particularly during the critical/sensitive time periods of adolescence and reproductive senescence. Anomalous or destructive fetal neuropathologic lesions change clinical expressions across this developmental-aging continuum. An integrated understanding of reproductive, pregnancy, placental, neonatal, childhood, and adult exposome effects offers a life-course perspective of the neural exposome. Exosome research promises improved disease monitoring and drug delivery starting during pregnancy. Developmental origins of health and disease principles applied to FNN practice anticipate neurologic diagnoses with interventions that can benefit successive generations. Addressing health care disparities in the Global South and high-income country medical deserts require constructive dialogue among stakeholders to achieve medical equity. Population health policies require a brain capital strategy that reduces the global burden of neurologic diseases by applying FNN principles and practice. This integrative neurologic care approach will prolong survival with an improved quality of life for persons across the lifespan confronted with neurological disorders.

The catcher in the mind: validation of the brief-mentalized affectivity scale for adolescents in the Italian population

The concept of mentalized affectivity (MA) encompasses the dimensions of identifying, processing, and expressing emotions and describes the process of making sense of and reevaluating one's affects in light of autobiographical memory. This construct was developed within the theoretical framework of mentalization and, due to its interpersonal nature, added further complexity to the emotion regulation construct. This research aimed to examine the factor structure and psychometric properties of the Brief-Mentalized Affectivity Scale for adolescents (B-MAS-A) on an Italian sample of young people (aged 13-19 years). Data were collected using non-probabilistic sampling and an online survey. Participants were asked to complete a large battery of instruments, including the B-MAS-A, the Toronto Alexithymia Scale, the Reflective Functioning Questionnaire, the Epistemic Trust, Mistrust, and Credulity Questionnaire, the Strengths and Difficulties Questionnaire, and the General Self-Efficacy Scale. In study 1, factor analyses carried out on a total sample of 566 adolescents identified 3 distinct dimensions of the same components of MA found in the adult population: i) identifying; ii) processing; iii) expressing emotions. The subscales showed excellent internal consistency. Study 2 (involving a subsample of 288 participants) demonstrated good levels of construct and criterion validity. These results confirm that the B-MAS-A represents a valid and robust instrument for assessing the complex and multifaceted characteristics of MA in adolescents. The B-MAS-A can make a significant contribution to clinical practice and research and encourage systematic studies on MA in psychotherapy, taking into account the developmental stage of adolescence.

Physical activity compensates for isoflurane-induced selective impairment of neuronal progenitor cell proliferation in the young adult hippocampus

General anesthesia is considered a risk factor for postoperative cognitive dysfunction. However, it is unclear what the neuronal and cognitive consequences of general anesthesia are and whether they can be treated. One possible pathomechanism is hippocampal neurogenesis. We investigated how the anesthetic isoflurane affects adult hippocampal neurogenesis and associated cognitive functions and whether the neurogenic stimulus of physical activity reverses isoflurane-induced changes. We exposed young adult mice to isoflurane (ISO) - half had access to a running wheel (ISO-RW). Both groups were compared with a control condition (CTR; CTR-RW). Cell proliferation and survival in the dentate gyrus of the hippocampus were quantified histologically 48 h and 3 weeks after anesthesia by bromodeoxyuridine incorporation. Cell phenotype was determined by expression of neuronal markers, and the extent of continuous endogenous neuronal proliferation was estimated from the number of doublecortin-positive cells. The Morris water maze was used to test hippocampus-dependent functions. We found that isoflurane decreased proliferation of neuronal progenitor cells, whereas survival of mature neurons remained intact. Consistent with intact neuronal survival, spatial memory associated with neurogenesis also proved intact in the Morris water maze despite isoflurane exposure. Physical activity attenuated the observed neuronal changes by preventing the decrease in newborn neuronal progenitor cells and the decline in continuous endogenous neuronal proliferation in isoflurane-treated animals. In conclusion, isoflurane selectively impairs neuronal proliferation but not survival or neurogenesis-linked cognition in adult mice. The observed adverse effects can be attenuated by physical activity, a cost-effective means of preventing the neurogenic consequences of general anesthesia.

Postpartum scarcity-adversity inflicts sex-specific cerebellar adaptations and reward behaviors in adolescence

Early life adversity in the form of poor postnatal care is a major developmental stressor impacting behavior later in life. Previous studies have shown the impact of early life stress on neurobehavioral abnormalities. Specifically, research has demonstrated how limited bedding and nesting (LBN) materials can cause behavioral deficits in adulthood. There is, however, a limited understanding of how LBN influences sex-specific neurobehavioral adaptation in adolescence, a developmental stage susceptible to psychiatric diseases including substance use disorder. LBN and stress-naive c57BL/6 adolescent male and female mouse offspring were tested for a battery of behaviors including open field, novel object recognition, elevated plus maze, social preference, and morphine-induced conditioned place preference. There was a significant sex-specific deficit in social preference in male mice exposed to LBN compared to stress-naïve counterparts and both LBN males and females had a higher preference towards the drug-paired chamber in the morphine-induced conditioned place preference test. These behavioral deficits were concomitant with sex-specific increases in the transcription factor, Klf9 in the deep cerebellar nuclei (DCN) of males. Further, mRNA levels of the circadian gene Bmal1, which is known to be transcriptionally regulated by Klf9, were decreased in the DCN. Since Bmal1 has recently been implicated in extracellular matrix modulation, we examined perineuronal nets (PNN) and observed depleted PNN in the DCN of males but not female LBN mice. Overall, we provide a novel understanding of how postpartum adversity impinges on the cerebellar extracellular matrix homeostasis, likely, through disruption of the circadian axis by Klf9 that might underlie sex-specific behavioral adaptations in adolescence.

The Dysfunctional Mechanisms Throwing Tics: Structural and Functional Changes in Tourette Syndrome

Tourette Syndrome (TS) is a high-incidence multifactorial neuropsychiatric disorder characterized by motor and vocal tics co-occurring with several diverse comorbidities, including obsessive-compulsive disorder and attention-deficit hyperactivity disorder. The origin of TS is multifactorial, with strong genetic, perinatal, and immunological influences. Although almost all neurotransmettitorial systems have been implicated in TS pathophysiology, a comprehensive neurophysiological model explaining the dynamics of expression and inhibition of tics is still lacking. The genesis and maintenance of motor and non-motor aspects of TS are thought to arise from functional and/or structural modifications of the basal ganglia and related circuitry. This complex wiring involves several cortical and subcortical structures whose concerted activity controls the selection of the most appropriate reflexive and habitual motor, cognitive and emotional actions. Importantly, striatal circuits exhibit bidirectional forms of synaptic plasticity that differ in many respects from hippocampal and neocortical plasticity, including sensitivity to metaplastic molecules such as dopamine. Here, we review the available evidence about structural and functional anomalies in neural circuits which have been found in TS patients. Finally, considering what is known in the field of striatal plasticity, we discuss the role of exuberant plasticity in TS, including the prospect of future pharmacological and neuromodulation avenues.

Immediate visual reproduction negatively correlates with brain entropy of parahippocampal gyrus and inferior occipital gyrus in bipolar II disorder adolescents

BACKGROUND

Brain entropy reveals complexity and irregularity of brain, and it has been proven to reflect brain complexity alteration in disease states. Previous studies found that bipolar disorder adolescents showed cognitive impairment. The relationship between complexity of brain neural activity and cognition of bipolar II disorder (BD-II) adolescents remains unclear.

METHODS

Nineteen BD-II patients (14.63 ±1.57 years old) and seventeen age-gender matched healthy controls (HCs) (14.18 ± 1.51 years old) were enlisted. Entropy values of all voxels of the brain in resting-state functional MRI data were calculated and differences of them between BD-II and HC groups were evaluated. After that, correlation analyses were performed between entropy values of brain regions showing significant entropy differences and clinical indices in BD-II adolescents.

RESULTS

Significant differences were found in scores of immediate visual reproduction subtest (VR-I, p = 0.003) and Stroop color-word test (SCWT-1, p = 0.015; SCWT-2, p = 0.004; SCWT-3, p = 0.003) between the two groups. Compared with HCs, BD-II adolescents showed significant increased brain entropy in right parahippocampal gyrus and right inferior occipital gyrus. Besides, significant negative correlations between brain entropy values of right parahippocampal gyrus, right inferior occipital gyrus and immediate visual reproduction subtest scores were observed in BD-II adolescents.

CONCLUSIONS

The findings of the present study suggested that the disrupted function of corticolimbic system is related with cognitive abnormality of BD-II adolescents. And from the perspective temporal dynamics of brain system, the current study, brain entropy may provide available evidences for understanding the underlying neural mechanism in BD-II adolescents.

Differential alterations in brain structural network organization during addiction between adolescents and adults

BACKGROUND

The adolescent brain may be susceptible to the influences of illicit drug use. While compensatory network reorganization is a unique developmental characteristic that may restore several brain disorders, its association with methamphetamine (MA) use-induced damage during adolescence is unclear.

METHODS

Using independent component (IC) analysis on structural magnetic resonance imaging data, spatially ICs described as morphometric networks were extracted to examine the effects of MA use on gray matter (GM) volumes and network module connectivity in adolescents (51 MA users v. 60 controls) and adults (54 MA users v. 60 controls).

RESULTS

MA use was related to significant GM volume reductions in the default mode, cognitive control, salience, limbic, sensory and visual network modules in adolescents. GM volumes were also reduced in the limbic and visual network modules of the adult MA group as compared to the adult control group. Differential patterns of structural connectivity between the basal ganglia (BG) and network modules were found between the adolescent and adult MA groups. Specifically, adult MA users exhibited significantly reduced connectivity of the BG with the default network modules compared to control adults, while adolescent MA users, despite the greater extent of network GM volume reductions, did not show alterations in network connectivity relative to control adolescents.

CONCLUSIONS

Our findings suggest the potential of compensatory network reorganization in adolescent brains in response to MA use. The developmental characteristic to compensate for MA-induced brain damage can be considered as an age-specific therapeutic target for adolescent MA users.

Psychological Resilience Interventions for Adolescents during the COVID-19 Pandemic

The COVID-19 pandemic has had severe mental health effects on adolescents. Psychological resilience is the ability to recover quickly from adversity and can help adolescents cope with the stress and dangers brought by the pandemic better. Therefore, the current study aimed to explore the developmental pattern of psychological resilience in adolescents and to find the sensitive period for psychological resilience intervention to promote resilience in adolescents during the pandemic. The study measured the psychological resilience of a total of 559 adolescents using the Connor-Davidson resilience scale (CD-RISC) in four grades: grade 7 and grade 8 in a junior high school, and grade 10 and grade 11 in a high school. It was found that the resilience level of the adolescents decreased in grade 10 and then increased significantly in grade 11 (F = 4.22, p = 0.006). A 4-week resilience intervention was conducted in the four grades using both psychological course training and physical training. The results revealed that the psychological course training was effective in promoting resilience in the 7th (F = 4.79, p = 0.03) and 8th (F = 4.75, p = 0.03) grades, but not in the 10th and 11th grades. The result suggests that the 7th and 8th grades may be a critical period for psychological resilience interventions for adolescents.

Conscription and educational outcomes

Peacetime military service has both positive and negative effects on human capital. While it depreciates academic skills, it also enhances non-cognitive ones. The net effect of conscription is hard to identify due to issues of self-selection, endogenous timing and omitted variables bias. We exploit the compulsory service of men in the Republic of Cyprus preceding university enrolment to deal with the first two problems. After controlling for prior academic performance and other relevant controls in a selection on observables model, we find that duration of service has a positive and significant effect on men's subsequent academic performance as measured by grade point average. Two exogenous reforms-one at the extensive margin and one at the intensive margin of military service-allow us to deal with omitted variables bias. We estimate difference-in-differences models, where female students act as a control group, and show that an increase (reduction) in the average length of army service has a positive (negative) and significant effect on men's academic performance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00148-023-00944-2.

Embryonic exposure to PFAS causes long-term, compound-specific behavioral alterations in zebrafish

Per- and polyfluoroalkyl substances (PFAS) are commonly used as surfactants and coatings for industrial processes and consumer products. These compounds have been increasingly detected in drinking water and human tissue, and concern over their potential effects on health and development is growing. However, relatively little data are available for their potential impacts on neurodevelopment and the degree to which different compounds within this class may differ from one another in their neurotoxicity. The present study examined the neurobehavioral toxicology of two representative compounds in a zebrafish model. Zebrafish embryos were exposed to 0.1-100uM perfluorooctanoic acid (PFOA) or 0.01-1.0uM perfluorooctanesulfonic acid (PFOS) from 5 to 122 h post-fertilization. These concentrations were below threshold for producing increased lethality or overt dysmorphologies, and PFOA was tolerated at a concentration 100× higher than PFOS. Fish were maintained to adulthood, with behavioral assessments at 6 days, 3 months (adolescence) and 8 months of age (adulthood). Both PFOA and PFOS caused behavioral changes in zebrafish, but PFOS and PFOS produced strikingly different phenotypes. PFOA was associated with increased larval motility in the dark (100uM), and enhanced diving responses in adolescence (100uM) but not adulthood. PFOS was associated with a reversed light-dark response in the larval motility test (0.1-1uM), whereby the fish were more active in the light than the dark. PFOS also caused time-dependent changes in locomotor activity in the novel tank test during adolescence (0.1-1.0uM) and an overall pattern of hypoactivity in adulthood at the lowest concentration (0.01uM). Additionally, the lowest concentration of PFOS (0.01uM) reduced acoustic startle magnitude in adolescence, but not adulthood. These data suggest that PFOS and PFOA both produce neurobehavioral toxicity, but these effects are quite distinct from one another.

Transcutaneous Auricular Vagus Nerve Stimulation in Pediatric Patients: A Systematic Review of Clinical Treatment Protocols and Stimulation Parameters

BACKGROUND

Noninvasive transcutaneous vagus nerve stimulation (tVNS) has promising therapeutic potential in a wide range of applications across somatic and psychiatric conditions. Compared with invasive vagus nerve stimulation, good safety and tolerability profiles also support the use of tVNS in pediatric patients. Potential neurodevelopment-specific needs, however, raise concerns regarding the age-appropriate adjustment of treatment protocols and applied stimulation parameters.

OBJECTIVE

In this study, we aimed to review registered trials and published studies to synthesize existing tVNS treatment protocols and stimulation parameters applied in pediatric patients.

MATERIALS AND METHODS

A systematic search of electronic data bases (PubMed, Scopus, MEDLINE, Cochrane Library, and PsycINFO) and ClinicalTrials was conducted. Information on patient and study-level characteristics (eg, clinical condition, sample size), the tVNS device (eg, brand name, manufacturer), stimulation settings (eg, pulse width, stimulation intensity), and stimulation protocol (eg, duration, dosage of stimulation) was extracted.

RESULTS

We identified a total of 15 publications (four study protocols) and 15 registered trials applying tVNS in pediatric patients (<18 years of age). Most of these studies did not exclusively address pediatric patients. None of the studies elaborated on neurodevelopmental aspects or justified the applied protocol or stimulation parameters for use in pediatric patients.

CONCLUSIONS

No dedicated pediatric tVNS devices exist. Neither stimulation parameters nor stimulation protocols for tVNS are properly justified in pediatric patients. Evidence on age-dependent stimulation effects of tVNS under a neurodevelopment framework is warranted. We discuss the potential implications of these findings with clinical relevance, address some of the challenges of tVNS research in pediatric populations, and point out key aspects in future device development and research in addition to clinical studies on pediatric populations.

Development of morning-eveningness in adolescence: implications for brain development and psychopathology

BACKGROUND

Morning-evening preference is defined as an individual's preference for a morning- or evening-oriented rhythm. Across adolescence, a preference for eveningness becomes more predominant. Although eveningness is cross-sectionally associated with internalizing and externalizing psychopathology, few studies have examined developmental changes in eveningness and its potential biological substrates. Here, we investigated the longitudinal relationships among the trajectory of eveningness preference, internalizing and externalizing psychopathology and white matter development, across adolescence.

METHODS

Two-hundred and nine adolescents (49% male) were assessed longitudinally at four separate time points between 12 and 19 years of age. Morning-evening preference and internalizing and externalizing symptoms were assessed at each time point. Diffusion-weighted images were acquired on a subset of participants at the final two time points to estimate changes in global mean fractional anisotropy (FA). Linear mixed models were performed to estimate the change in eveningness over time. A series of linear regression models assessed the influence of change in eveningness on psychopathology and white matter development at age 19.

RESULTS

Across the sample, a preference for eveningness became more predominant by 19 years of age. Greater individual-level change towards eveningness significantly predicted greater severity in externalizing, but not internalizing, symptoms at 19 years of age. In contrast, change in psychopathology from 12 to 19 years of age was not associated with morning-eveningness at age 19. A change towards eveningness predicted an attenuated increase in FA between 17 and 19 years of age.

CONCLUSIONS

This study suggests that developmental changes in morning-evening preference may predict both neurodevelopmental and psychological outcomes in adolescents.

Enhancing the resolution of behavioral measures: Key observations during a forty year career in behavioral neuroscience

This manuscript reviews several key observations from the research program of Professor John P. Bruno that are believed to have significantly advanced our understanding of the brain's mediation of behavior. This review focuses on findings within several important research areas in behavioral neuroscience, including a) age-dependent neurobehavioral plasticity following brain damage; b) the role of the cortical cholinergic system in attentional processing and cognitive flexibility; and c) the design and validation of animal models of cognitive deficits in schizophrenia. In selecting these observations, emphasis was given to examples in which the heuristic potency was increased by maximizing the resolution and microanalysis of behavioral assays in the same fashion as one typically refines neuronal manipulations. Professor Bruno served the International Behavioral Neuroscience Society (IBNS) as an IBNS Fellow (1995-present) and President of the IBNS (2001-02).

Beneficial effects of enriched environment on behavior, cognitive functions, and hippocampal brain-derived neurotrophic factor level following postnatal serotonin depletion in male rats

The neurotransmitter serotonin (5-HT) is one of the most important modulators of neural circuitry and has a critical role in neural development and functions. Previous studies indicated that changes in serotonergic system signaling in early life critically impact mental health, behavior, the morphology of hippocampal neurons, and cognitive functions across the lifespan. The enriched environment (EE) has indicated beneficial effects on behavior and cognitive functions in the developmental period of life, but its impacts on cognitive impairments and behavioral changes following postnatal serotonin depletion are unknown. Therefore, the present study aimed to evaluate the influences of the EE housing (postnatal days [PNDs] 21-60) following postnatal serotonin depletion (by para-chlorophenylalanine [PCPA], 100 mg/kg, s.c, in PNDs 10-20) on anxiety-related behaviors, cognitive functions, and brain-derived neurotrophic factor (BDNF) mRNA expression in the hippocampus of male rats. Memory and behavioral parameters were examined in early adulthood and after that, the hippocampi of rats were removed to determine the BDNF mRNA expression by PCR (PNDs 60-70). The findings of the present work indicated that adolescent EE exposure alleviated memory impairment, decreased BDNF levels, and anxiety disorders induced by experimental depletion of serotonin. Overall, these results indicate that serotonergic system dysregulation during the developmental periods can be alleviated by adolescent EE exposure.

Cannabis in Adolescence: Lasting Cognitive Alterations and Underlying Mechanisms

Cannabis consumption during adolescence is an area of particular concern, owing to changes in the social and political perception of the drug, and presents a scientific, medical, and economic challenge. Major social and economic interests continue to push toward cannabis legalization as well as pharmaceutical development. As a result, shifting perceptions of both legal and illicit cannabis use across the population have changed the collective evaluation of the potential dangers of the product. The wave of cannabis legalization therefore comes with new responsibility to educate the public on potential risks and known dangers associated with both recreational and medical cannabis. Among these is the risk of long-term cognitive and psychological consequences, particularly following early-life initiation of use, compounded by high-potency and/or synthetic cannabis, and heavy/frequent use of the drug. Underlying these cognitive and psychiatric consequences are lasting aberrations in the development of synaptic function, often secondary to epigenetic changes. Additional factors such as genetic risk and environmental influences or nondrug toxic insults during development are also profound contributors to these long-term functional alterations following adolescent cannabis use. Preclinical studies indicate that exposure to cannabinoids during specific windows of vulnerability (e.g., adolescence) impacts neurodevelopmental processes and behavior by durably changing dendritic structure and synaptic functions, including those normally mediated by endogenous cannabinoids and neuronal circuits.

Adolescent alcohol exposure alters threat avoidance in adulthood

Adolescent binge-like alcohol exposure impairs cognitive function and decision making in adulthood and may be associated with dysfunction of threat avoidance, a critical mechanism of survival which relies upon executive function. The present study investigated the impact of binge-like alcohol exposure during adolescence on active avoidance in adulthood. Male and female rats were subjected to adolescent intermittent ethanol (AIE) exposure by vapor inhalation and then tested in adulthood using a platform-mediated avoidance task. After training to press a lever to receive a sucrose reward, the rats were conditioned to a tone that co-terminated with a foot-shock. A motivational conflict was introduced by the presence of an escape platform that isolated the rat from the shock, but also prevented access to the sucrose reward while the rat was on the platform. During the task training phase, both male and female rats exhibited progressive increases in active avoidance (platform escape) in response to the conditioned tone, whereas innate fear behavior (freezing) remained relatively constant over training days. A history of AIE exposure did not impact either active avoidance or freezing behavior during task acquisition. On the test day following platform acquisition training, female rats exhibited higher levels of both active avoidance and freezing compared to male rats, while AIE-exposed male but not female rats exhibited significantly greater levels of active avoidance compared to controls. In contrast, neither male nor female AIE-exposed rats exhibited alterations in freezing compared to controls. Following 5 days of extinction training, female rats continued to display higher levels of active avoidance and freezing during tone presentation compared to males. Male AIE-exposed rats also had higher levels of both active avoidance and freezing compared to the male control rats. Together, the results demonstrate that female rats exhibit elevated levels of active avoidance and freezing compared to males and further reveal a sex-specific impact of AIE on threat responding in adulthood.

Adolescent brain maturation and the neuropathological effects of binge drinking: A critical review

Adolescence is a transitional stage marked by continued brain development. This period is accompanied by physical and neurochemical modifications in the shape and function of the hippocampus, prefrontal cortex, and other limbic system structures. Brain maturation during adolescence, which is typically governed by intrinsic factors, can be dramatically altered by environmental influences such as drugs and alcohol. Unlike many other addictive substances, binge drinking is very common and normative among teenagers and young adults. This repeated pattern of excessive alcohol consumption in adolescents has been shown to cause behavioral changes and neurocognitive impairments that include increased anxiety, risky decision-making, and learning deficits, which could lead to the development of alcohol use disorder (AUD). This manuscript highlights factors that lead to adolescent binge drinking, discusses maturational changes that occur in an adolescent's brain, and then evaluates the effect of adolescent alcohol consumption on brain structure, function, and neurocognitive abilities in both human studies and animal models. The impact of gender/sex and COVID-19 are briefly discussed. Understanding the factors that promote the onset of adolescent binge drinking and its undesirable consequences could serve as a catalyst for developing therapeutic agents that would decrease or eradicate the damaging effects of alcohol on an adolescent brain.

Significant age by childhood trauma interactions on grey matter volumes: A whole brain VBM analysis

BACKGROUND

Childhood trauma is deleterious to long term brain development. The changes are variable, and depend on gender, age and the nature of the trauma. In this exploratory analysis, we investigated the effects of exposure to emotional trauma on grey matter (GM) volumes in adolescent females.

METHODS

We explored GM volumes in non-clinical females aged 12-17 years who had been exposed to either higher (HET; N = 75) or minimal (MET; N = 127) emotional trauma. High-resolution T1-weighted structural images were analysed with an optimised FSL-VBM protocol. The General Linear Model was run on HET versus MET with continuous age as an interaction. Mean GM volumes were extracted from significant corrected age interaction statistical maps and scrutinised with SPSS®.

RESULTS

We observed greater HET*age than MET*age interactions (corrected p-value = 0.0002), in 4 separate bilateral cortical regions associated with mood disorders. Scrutiny of these regions showed significant GM volume enlargements in the early adolescent HET group (p = 0.017) and reductions in the late adolescent HET group (p < 0.0001). Notably, there were no differences in middle adolescence (p > 0.05).

LIMITATIONS

Causality cannot be inferred from this cross-sectional study and the onset of trauma cannot be determined using retrospective measures.

CONCLUSIONS

Whilst GM volumes diminish from early adolescence onwards, our results show that HET impacts this brain development, perhaps first via unstable adaptative mechanisms, followed by maladaptive processes in late adolescence. This suggests that compromises of emotional and cognitive self-regulation in mood disorders may underpin the structural abnormalities observed across multiple brain regions in these teenage girls.

Pubertal development underlies optimization of inhibitory control through specialization of ventrolateral prefrontal cortex

Inhibitory control improves into young adulthood after specialization of relevant brain systems during adolescence. However, the biological mechanisms supporting this unique transition are not well understood. Given that adolescence is defined by puberty, we examined relative contributions of chronological age and pubertal maturation to inhibitory control development. 105 8-19-year-olds completed 1-5 longitudinal visits (227 visits total) in which pubertal development was assessed via self-reported Tanner stage and inhibitory control was assessed with an in-scanner antisaccade task. As expected, percentage and latency of correct antisaccade responses improved with age and pubertal stage. When controlling for pubertal stage, chronological age was distinctly associated with correct response rate. In contrast, pubertal stage was uniquely associated with antisaccade latency even when controlling for age. Chronological age was associated with fMRI task activation in several regions including the right dorsolateral prefrontal cortex, while puberty was associated with right ventrolateral prefrontal cortex (VLPFC) activation. Furthermore, task-related connectivity between VLPFC and cingulate was associated with both pubertal stage and response latency. These results suggest that while age-related developmental processes may support maturation of brain systems underlying the ability to inhibit a response, puberty may play a larger role in the effectiveness of generating cognitive control responses.

Immune signaling as a node of interaction between systems that sex-specifically develop during puberty and adolescence

Adolescence is pivotal for neural and behavioral development across species. During this period, maturation occurs in several biological systems, the most well-recognized being activation of the hypothalamic-pituitary-gonadal axis marking pubertal onset. Increasing comparative studies of sex differences have enriched our understanding of systems integration during neurodevelopment. In recent years, immune signaling has emerged as a key node of interaction between a variety of biological signaling processes. Herein, we review the age- and sex-specific changes that occur in neural, hypothalamic-pituitary, and microbiome systems during adolescence. We then describe how immune signaling interacts with these systems, and review recent preclinical evidence indicating that immune signaling may play a central role in integrating changes in their typical and atypical development during adolescence. Finally, we discuss the translational relevance of these preclinical studies to human health and wellness.

Low VGF is associated with executive dysfunction in patients with major depressive disorder

OBJECTIVES

Executive dysfunction is considered to be one of the cognitive impairment dimensions that are easily observed in depression, but its underlying molecular mechanism is still unclear. Study have shown that the neuropeptide VGF (non-acronymic) plays an important role in the regulation of hippocampal neurogenesis and neuroplasticity. Previous studies have shown that VGF may be related to the psychopathology of depression and cognitive impairment. However, the correlation between VGF and executive dysfunction in MDD has not been investigated.

METHODS

A total of 35 MDD patients and 31 healthy control patients were enrolled in this study. The 17-item Hamilton Depression Rating Scale (HDRS) was used to measure the severity of depression, and the Wisconsin Card Sorting Test (WCST) was used to assess executive dysfunction. Double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was used to determine serum VGF in peripheral blood.

RESULTS

The level of serum VGF in MDD patients was significantly lower compared to that in the healthy control group (p < 0.001). Moreover, Response Administered (RA) scores, Response preservative errors (RPE), and Non-response preservative errors (NRPE) were all higher in the MDD group (all p < 0.05). In contrast, Categories Completed (CC) and Response Correct (RC) scores were lower (all p < 0.05). Further results showed a significant correlation between serum VGF with RA (r = -0.372, p = 0.028) and RPE scores (r = 0.507, p = 0.002) in patients with depression, while serum VGF showed no correlation with the severity of depression in either group.

CONCLUSIONS

VGF may play an important role in executive function dysfunction in MDD patients, and VGF levels may become a new marker for predicting executive function dysfunction in depression.

Psychometric Properties and Measurement Invariance of the Childhood Trauma Questionnaire (Short Form) Across Genders, Time Points and Presence of Major Depressive Disorder Among Chinese Adolescents

Purpose

The Childhood Trauma Questionnaire-Short Form (CTQ-SF) is a widely used self-report tool designed to assess juveniles' experiences of abuse and neglect. The current study examined the psychometric properties, particularly measurement invariance of the CTQ-SF in Chinese non-clinical adolescents and adolescents with major depressive disorder (MDD).

Methods

Participants included 1,507 high school students (non-clinical sample) from Hunan Province and 281 adolescent patients with major depressive disorder (MDD sample) from The Second Xiangya Hospital. We examined the reliability and validity of CTQ-SF, confirm the five-factor model of the CTQ-SF. Multiple-group confirmatory factor analysis (CFA) was used to examine the measurement invariance across genders, presence of depression, and over time.

Results

The CTQ-SF had good internal consistency in a non-clinical sample (Cronbach's α = 0.85) and MDD sample (Cronbach's α = 0.86). Good test-retest reliability (ICC = 0.72) and Adequate validity were also observed. Good fit of the five-factor CTQ-SF model was confirmed in both samples. Multiple-group CFA confirmed that the CTQ-SF had the scalar invariance across genders and the presence of MDD, as well as over time.

Conclusion

The CTQ-SF is an effective and reliable tool for assessing child maltreatment in Chinese adolescents (non-clinical sample and MDD sample). The results suggest that the horizontal and longitudinal invariance of CTQ-SF are strongly established, which means CTQ-SF can be meaningfully used to compare outcomes among Chinese adolescents (non-clinical sample and MDD sample). The experience of child maltreatment, especially neglect (emotional and physical), was found to be common in Chinese adolescents.

Brief Maternal Separation Inoculates Against the Effects of Social Stress on Depression-Like Behavior and Cocaine Reward in Mice

Exposure to intermittent repeated social defeat (IRSD) increases the vulnerability of mice to the rewarding effects of cocaine in the conditioned place preference (CPP) paradigm. According to the "inoculation of stress" hypothesis, a brief period of maternal separation (MS) can provide protection against the negative effects of IRSD. The aim of the present study was to assess whether exposure to a brief episode of MS prevents the subsequent short-term effects of IRSD on depression- and anxiety-like behaviors and to explore its long-term effects on cocaine CPP in mice. Four groups of male C57BL/6 mice were employed; two groups were separated from their mother [6 h on postnatal day (PND) 9], while the other two groups were not (controls). On PND 47, 50, 53 and 56, mice that had experienced MS were exposed to social defeat in the cage of an aggressive resident mouse (MS + IRSD group) or were allowed to explore an empty cage (MS + EXPL group). The same procedure was performed with control mice that had not experienced MS (CONTROL + IRSD and CONTROL + EXPL groups). On PND57-58, all the mice performed the elevated plus maze and the hole-board, social interaction and splash tests. Three weeks after the last episode of defeat, all the mice underwent the CPP procedure with cocaine (1 mg/kg). Irrespective of whether or not MS had taken place, a reduction in open arms measures, dips, and social interaction was observed in mice that experienced IRSD. A higher latency of grooming and acquisition of cocaine-induced CPP were observed only in mice exposed to IRSD alone (CONTROL + IRSD). These results suggest that exposure to a brief episode of stress early in life increases the subsequent resilience of animals to the effects of social stress on vulnerability to cocaine.

Differential extrinsic brain network connectivity and social cognitive task-specific demands in Autism Spectrum Disorder (ASD)

Few studies have used task-based functional connectivity (FC) magnetic resonance imaging to examine emotion-processing during the critical neurodevelopmental period of adolescence in Autism Spectrum Disorders (ASDs). Moreover, task designs with pervasive confounds (e.g., lack of appropriate controls) persist because they activate neural circuits of interest reliably. As an alternative approach to "subtracting" activity from putative control conditions, we propose examining FC across an entire task run. By pivoting our analysis and interpretation of existing paradigms, we may better understand neural response to non-focal instances of socially-relevant stimuli that approximate real-world experiences more closely. Hence, using two well-established affective tasks (face-viewing, face-matching) with diverging social-cognitive demands, we investigated extrinsic FC from amygdala (AMG) and fusiform gyrus (FG) seeds in typically-developing (TD; N = 17) and ASD (N = 17) male adolescents (10-18 yo) and clinical correlations (Social Communication Questionnaire; SCQ) of group FC differences. Participant data (4TD, 6ASD) with excessive head-motion were excluded from final analysis. Direct between-group comparisons revealed significant differences between groups for neural response but not task performance (accuracy, reaction time). During face-viewing, we found greater FC from AMG and FG seeds for ASD participants (ASD > TD) in regions involved in the Default Mode and Fronto-Parietal Task Control Networks. During face-matching, we found greater FC from AMG and FG seeds for TD participants (TD > ASD), in regions associated with the Salience, Dorsal Attention, and Somatosensory Networks. SCQ scores correlated positively with regions with group differences on the face-viewing task and negatively with regions identified for the face-matching task. Task-dependent group differences in FC despite comparable behavioral performance suggest that high-functioning ASD may wield compensatory strategies; clinically-correlated FC patterns may associate with differential task-demands, ecological validity, and context-dependent processing. Employing this novel approach may further the development of targeted therapeutic interventions informed by individual differences in the highly heterogeneous ASD population.

Application of Three-Dimensional Pseudocontinuous Arterial Spin Labeling Perfusion Imaging in the Brains of Children With Autism

Objective

To explore the application of three-dimensional pseudocontinuous arterial spin labeling (3D-PCASL) perfusion imaging in the brains of children with autism and to understand the characteristics of cerebral blood perfusion in children with autism.

Methods

A total of 320 children with autism (160 men and 160 women) aged between 2 and 18 years and 320 age- and sex-matched healthy children participated in the study. All children were scanned by 3.0 T magnetic resonance axial T1 fluid-attenuated inversion recovery (FLAIR), T2 FLAIR, 3D-T1, and 3D-PCASL sequences. After postprocessing, cerebral blood flow (CBF) values in each brain region of children with autism and healthy children at the same age were compared and analyzed. Furthermore, CBF characteristics in each brain region of autistic children at various ages were determined.

Results

The CBF values of the frontal lobe, hippocampus, temporal lobe, and caudate nucleus of children with autism are lower than those of healthy children (P < 0.05). Additionally, as the ages of children with autism increase, the number of brain regions with decreased CBF values gradually increases. A receiver operating characteristic (ROC) analysis results show that the CBF values of the frontal lobe, hippocampus, temporal lobe, and caudate nucleus can distinguish children with autism [area under the ROC curve (AUC) > 0.05, P < 0.05].

Conclusion

The 3D-PCASL shows lower brain CBF values in children with autism.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier: ChiCTR2000034356.

Consequences of Inadequate Caregiving for Children's Attachment, Neurobiological Development, and Adaptive Functioning

Given that human infants are almost fully reliant on caregivers for survival, the presence of parents who provide sensitive, responsive care support infants and young children in developing the foundation for optimal biological functioning. Conversely, when parents are unavailable or insensitive, there are consequences for infants' and children's attachment and neurobiological development. In this paper, we describe effects of inadequate parenting on children's neurobiological and behavioral development, with a focus on developing capacities for executive functioning, emotion regulation, and other important cognitive-affective processes. Most prior research has examined correlational associations among these constructs. Given that interventions tested through randomized clinical trials allow for causal inferences, we review longitudinal intervention effects on children's biobehavioral and cognitive-affective outcomes. In particular, we provide an overview of the Bucharest Early Intervention Project, a study in which children were randomized to continue in orphanage care (typically the most extreme condition of privation) or were placed into the homes of trained, supported foster parents. We also discuss findings regarding Attachment and Biobehavioral Catch-up, an intervention enhancing sensitivity among high-risk parents. We conclude by suggesting future directions for research in this area.

The Danish High-Risk and Resilience Study-VIA 15 - A Study Protocol for the Third Clinical Assessment of a Cohort of 522 Children Born to Parents Diagnosed With Schizophrenia or Bipolar Disorder and Population-Based Controls

BACKGROUND

Children born to parents with severe mental illness have gained more attention during the last decades because of increasing evidence documenting that these children constitute a population with an increased risk of developing mental illness and other negative life outcomes. Because of high-quality research with cohorts of offspring with familial risk and increased knowledge about gene-environment interactions, early interventions and preventive strategies are now being developed all over the world. Adolescence is a period characterized by massive changes, both in terms of physical, neurologic, psychological, social, and behavioral aspects. It is also the period of life with the highest risk of experiencing onset of a mental disorder. Therefore, investigating the impact of various risk and resilience factors in adolescence is important.

METHODS

The Danish High-Risk and Resilience Study started data collection in 2012, where 522 7-year-old children were enrolled in the first wave of the study, the VIA 7 study. The cohort was identified through Danish registers based on diagnoses of the parents. A total of 202 children had a parent diagnosed with schizophrenia, 120 children had a parent diagnosed with bipolar disorder, and 200 children had parents without these diagnoses. At age 11 years, all children were assessed for the second time in the VIA 11 study, with a follow-up retention rate of 89%. A comprehensive assessment battery covering domains of psychopathology, neurocognition, social cognition and behavior, motor development and physical health, genetic analyses, attachment, stress, parental functioning, and home environment was carried out at each wave. Magnetic resonance imaging scans of the brain and electroencephalograms were included from age 11 years. This study protocol describes the third wave of assessment, the VIA 15 study, participants being 15 years of age and the full, 3-day-long assessment battery this time including also risk behavior, magnetoencephalography, sleep, and a white noise paradigm. Data collection started on May 1, 2021.

DISCUSSION

We will discuss the importance of longitudinal studies and cross-sectional data collection and how studies like this may inform us about unmet needs and windows of opportunity for future preventive interventions, early illness identification, and treatment in the future.

Aberrant maturation and connectivity of prefrontal cortex in schizophrenia-contribution of NMDA receptor development and hypofunction

The neurobiology of schizophrenia involves multiple facets of pathophysiology, ranging from its genetic basis over changes in neurochemistry and neurophysiology, to the systemic level of neural circuits. Although the precise mechanisms associated with the neuropathophysiology remain elusive, one essential aspect is the aberrant maturation and connectivity of the prefrontal cortex that leads to complex symptoms in various stages of the disease. Here, we focus on how early developmental dysfunction, especially N-methyl-D-aspartate receptor (NMDAR) development and hypofunction, may lead to the dysfunction of both local circuitry within the prefrontal cortex and its long-range connectivity. More specifically, we will focus on an "all roads lead to Rome" hypothesis, i.e., how NMDAR hypofunction during development acts as a convergence point and leads to local gamma-aminobutyric acid (GABA) deficits and input-output dysconnectivity in the prefrontal cortex, which eventually induce cognitive and social deficits. Many outstanding questions and hypothetical mechanisms are listed for future investigations of this intriguing hypothesis that may lead to a better understanding of the aberrant maturation and connectivity associated with the prefrontal cortex.

Adolescent enriched environment exposure alleviates cognitive impairment in sleep-deprived male rats: Role of hippocampal BDNF

Developmental life experience has long-lasting influences on the brain and behavior. The present study aims to examine the long-term effects of the enriched environment (EE), which was imposed during the adolescence period of life, on their passive avoidance and recognition memories as well as anxiety-like behaviors and hippocampal brain-derived neurotrophic factor (BDNF) levels, in sleep-deprived male rats. In the present study, the male pups were separated from their mothers in postnatal day 21 (PND21) and were housed in the standard or EE for 40 days. In PND 61, the rats were allocated in four groups: control, SD (sleep deprivation), EE, and EE+SD groups. Sleep deprivation was induced in rats by a modified multiple platform model for 24 hours. Open field, novel object recognition memory, and passive avoidance memory tests were used to examine behavior and cognitive ability. The expression of hippocampal BDNF levels was determined by PCR. The results revealed that SD increased anxiety-like behaviors and impaired cognitive ability, while adolescent EE housing alleviated these changes. In addition, EE reversed SD-induced changes in hippocampal BDNF level. We also demonstrated that EE not only has beneficial effects on the cognitive functions of normal rats but also declined memory deficits induced by sleep deprivation. In conclusion, our results suggest that housing in EE during the adolescence period of life reduces cognitive impairment induced by SD. The increase of the BDNF level in the hippocampus is a possible mechanism to alleviate cognitive performance in sleep-deprived rats.

Motor Vehicle Collisions during Adolescence: The Role of Alexithymic Traits and Defense Strategies

International literature has shown that adolescents represent the population most at risk of fatal and nonfatal motor vehicle collisions (MVCs). Adolescents’ alexithymic traits and significant use of immature defense strategies have been seen to play a key role. This study aimed to investigate the possible mediation role played by defense strategies use in the relationship between alexithymia and MVCs. Our sample consisted of 297 adolescents divided into four subgroups, based on the number of visits to the emergency department due to an MVC. We assessed adolescents’ alexithymic traits and defense strategies use through self-report instruments. Results showed that males reported a higher rate of MVCs than females. Higher rates of MVCs are associated with more alexithymic traits and maladaptive defense strategies use. Adolescents’ Acting Out and Omnipotence use significantly mediated the relationship between alexithymia and MVCs. Our findings suggest the recidivism of MVCs as an attempt to cope with emotional difficulties, with important clinical implications.

Alcohol trajectories and subsequent risk for opioid misuse in a cohort of urban adolescents

Background: The opioid epidemic is a public health emergency in the US. Alcohol is the most widely used addictive substance among all age groups; however, the contribution of different alcohol use trajectories throughout adolescence and young adulthood to the development of opioid misuse in young adulthood among urban minority youth has not been investigated. Methods: Data are from a study of 580 youth (85% African American, 67% low SES) residing in Baltimore City followed from ages 6-26. Alcohol trajectories were identified between ages 14 and 26 using group-based trajectory modeling. Opioid misuse was defined as using opioid painkillers without a prescription or using heroin between ages 19 and 26. Opioid misuse outcomes were also investigated separately. Logistic regression examined associations of alcohol trajectories with opioid misuse in young adulthood adjusting for socio-demographics, early use of tobacco and cannabis, neighborhood, and peer factors. Results: Six alcohol use trajectories were identified: Young adult increasing (21.4%), adult increasing (19.1%), abstaining (19.1%), experimenting (15.3%), adolescent increasing (14.8%), and adolescent limited (10.2%). In models fully adjusted for covariates, relative to the abstaining trajectory, the adolescent increasing trajectory was associated with an elevated risk of opioid misuse (aOR = 3.3, 95%CI = 1.4, 7.8) and prescription opioid misuse (aOR = 3.9, 95%CI = 1.4, 10.8) in young adulthood. Conclusions: Escalating alcohol use in adolescence and young adulthood is associated with an elevated risk of opioid misuse in young adulthood in a cohort of predominantly African American and socio-economically disadvantaged young people. Tailored interventions should target high levels of alcohol use during these developmental periods to reduce risk for opioid misuse among disadvantaged youth.

Measuring resilience in children: a review of recent literature and recommendations for future research

PURPOSE OF REVIEW

Understanding variability in developmental outcomes following exposure to early life adversity (ELA) has been an area of increasing interest in psychiatry, as resilient outcomes are just as prevalent as negative ones. However, resilient individuals are understudied in most cohorts and even when studied, resilience is typically defined as an absence of psychopathology. This review examines current approaches to resilience and proposes more comprehensive and objective ways of defining resilience.

RECENT FINDINGS

Of the 36 studies reviewed, the most commonly used measure was the Strengths and Difficulties Questionnaire (n = 6), followed by the Child Behavior Checklist (n = 5), the Resilience Scale for Chinese Adolescents (n = 5), the Rosenberg Self-Esteem Scale (n = 4), and the Child and Youth Resilience Scale (n = 3).

SUMMARY

This review reveals that studies tend to rely on self-report methods to capture resilience which poses some challenges. We propose a complementary measure of child resilience that relies on more proactive behavioral and observational indicators; some of our preliminary findings are presented. Additionally, concerns about the way ELA is characterized as well as the influence of genetics on resilient outcomes prompts further considerations about how to proceed with resiliency research.

Molecular, physiological and behavioral characterization of the heterozygous Df[h15q13]/+ mouse model associated with the human 15q13.3 microdeletion syndrome

The human 15q13.3 microdeletion syndrome (DS) is caused by a heterozygous microdeletion (MD) affecting six genes: FAN1; MTMR10; TRPM1; KLF13; OTUD7A; and CHRNA7. Carriers are at risk for intellectual disability, epilepsy, autism spectrum disorder, and schizophrenia. Here we used the Df[h15q13]/+ mouse model with an orthologous deletion to further characterize molecular, neurophysiological, and behavioral parameters that are relevant to the 15q13.3 DS. First, we verified the expression and distribution of the α7 nicotinic acetylcholine receptor (nAChR), a gene product of the CHRNA7, in cortical and subcortical areas. Results revealed similar mRNA distribution pattern in wildtype (WT) and heterozygous (Het) mice, with about half the number of α7 nAChR binding sites in mutants. Hippocampal recordings showed similar input/output responses of field excitatory post-synaptic potentials and theta-burst induced long-term potentiation in WT and Het mice. Het males exhibited impaired spatial learning acquisition in the Barnes Maze. Indicative of increased seizure susceptibility, Het mice developed secondary seizures after 6-Hz corneal stimulation, and had significantly increased sensitivity to the chemoconvulsant pentylenetetrazol resulting in increased spiking in hippocampal EEG recordings. Basal mRNA expression of brain derived neurotrophic factor and activity regulated immediate early genes (c-fos, Arc, Erg-1 and Npas4) during adolescence, a critical period of brain maturation, was unaffected by genotype. Thus, the MD did not show gross neuroanatomical, molecular, and neurophysiological abnormalities despite deficits in spatial learning and increased susceptibility to seizures. Altogether, our results verify the phenotypic profile of the heterozygous Df[h15q13]/+ mouse model and underscore its translational relevance for human 15q13.3 DS.

Adversity in childhood is linked to mental and physical health throughout life

The prevalence of “toxic stress” and huge downstream consequences in disease, suffering, and financial costs make prevention and early intervention crucial, say Charles A Nelson and colleagues

Social Cognitive Interventions for Adolescents with Autism Spectrum Disorders: A Systematic Review

INTRODUCTION

Autism spectrum disorder (ASD), a heterogeneous neurodevelopmental disorder, impacts social experience and functioning throughout the lifespan. Although the postnatal phase of neuroplasticity has been a focus for early interventions in ASD, a second critical period in adolescence has emerged as a promising target for experience-dependent remediation. Interventions addressing the multidimensional construct of social cognition have also shown potential as a therapeutic approach. Yet, to date, evidence-based social cognitive interventions (SCIs) designed for adolescents with ASD are still lacking. In this review, we aim to survey and synthesize the extant literature on SCIs for adolescents with ASD in order to inform next steps for treatment research.

METHODS

Using the PRISMA guidelines, we limited our queries to peer-reviewed, English-language journal articles describing SCI trials for adolescents with ASD using a randomized controlled design.

RESULTS

Eighteen articles in total met our inclusion/exclusion criteria. We present and discuss these trials using the non-exclusive categories of group-based social skills interventions, experiential-based interventions, and computer-assisted interventions.

LIMITATIONS

To ensure a focus on adolescence, we excluded trials with teen-age participants if mean subject age was not between 12-18 years. Also, given the variability across studies in outcome measures, study designs, samples, and effect sizes, findings were incommensurable.

CONCLUSIONS

Several reviewed SCIs reported post-treatment improvements in varied domains but findings were inconsistent. Further investigations of existing and novel interventions are warranted; attention to assessing and improving long-term skill transfer is essential. Technology-assisted augmentations may improve treatment efficacy and ecological validity of therapeutic gains.

Sex-dependent effects of postweaning exposure to an enriched environment on novel objective recognition memory and anxiety-like behaviors: The role of hippocampal BDNF level

Exposure to enriched environment (EE) has been indicated to enhance cognitive functions, hippocampal neural plasticity, neurogenesis, long-term potentiation, and levels of the brain-derived neurotrophic factor (BDNF) in laboratory animals. Also, studies on the sex-dependent effects of exposure to EE during adolescence on adult cognitive functions are less. This is important because the beneficial effects of EE may be predominant in the adolescence stage. Therefore, the present study was designed to compare the effects of EE during adolescence (PND21-PND60) on novel objective recognition memory (NORM), anxiety-like behaviors, and hippocampal BDNF mRNA level in the adult male and female rats. Assessment of NORM and anxiety-like behaviors has been done by novel objective recognition task, open field (OF), and elevated plus maze (EPM), respectively. The expression of BDNF mRNA level was also evaluated by quantitative RT-PCR. Our findings demonstrated that housing in the EE during adolescence improves NORM in adult male rats. Also, exposure to EE during adolescence had a different effect on anxiety-like behaviors in both sexes. Additionally, our results indicated an augmented BDNF level in the hippocampus of male and female rats. In conclusion, adolescent exposure to EE has sex-dependent effects on cognitive functions and anxiety-like behaviors and increases BDNF mRNA expression in the hippocampus of both male and female rats; thus, BDNF is an important factor that can mediate the beneficial effects of EE and running exercise on cognitive functions and psychiatric traits.