Severe behavior problems in SYNGAP1-related disorder: A summary of 11 consecutive patients in a tertiary care specialty clinic

SYNGAP1-related disorder (SYNGAP1-RD) is a neurodevelopmental disorder that is commonly associated with epilepsy, autism spectrum disorder (ASD), and disruptive behaviors. In this study, behavior problems in 11 consecutive patients with SYNGAP1-RD are described and quantified based on a behavioral screening conducted within the context of a multi-disciplinary tertiary care specialty clinic visit. The behavioral phenotype was then compared to published samples of behavior problems in ASD and other genetic cause of epilepsy occurring in the context of neurodevelopmental disorders using results from the Aberrant Behavior Checklist-Community (ABC-C), an empirically derived outcome measure. We report common antecedent and consequent events surrounding problem behavior across individuals. Additionally, we report on the management approach of caregivers and the impact of problem behaviors on the family. Our results suggest a number of commonalities between behavioral profiles in SYNGAP1-RD with ASD and other genetic causes of developmental and epileptic encephalopathies, and also highlight severe behavior problems as a specific behavioral phenotype of SYNGAP1-RD.

Experimental arena size alters larval zebrafish photolocomotor behaviors and influences bioactivity responses to a model neurostimulant

Zebrafish behavior is increasingly common in biomedical and environmental studies of chemical bioactivity. Multiple experimental arena sizes have been used to measure photolocomotion in zebrafish depending on age, endpoints observed, and instrumentation, among other factors. However, the extent to which methodological parameters may influence naïve behavioral performance and detection of behavioral changes is poorly understood. Here we measured photolocomotion and behavioral profiles of naïve larval zebrafish across arena sizes. We then performed concentration response studies with the model neurostimulant caffeine, again across various arena dimensions. We found total swimming distance of unexposed fish to increase logarithmically with arena size, which as related to circumference, area, and volume. Photomotor response during light/dark transitions also increased with arena size. Following caffeine exposure, total distance travelled was significantly (p < 0.001) affected by well size, caffeine treatment (p < 0.001), and the interaction of these two experimental factors (p < 0.001). In addition, behavioral response profiles showed differences between 96 well plates and larger well sizes. Biphasic response, with stimulation at lower concentrations and refraction at the highest concentration, was observed in dark conditions for the 96 well size only, though almost no effects were identified in the light. However, swimming behavior was significantly (p < 0.1) altered in the highest studied caffeine treatment level in larger well sizes during both light and dark periods. Our results indicate zebrafish swim more in larger arenas and arena size influences behavioral response profiles to caffeine, though differences were mostly observed between very small and large arenas. Further, careful consideration should be given when choosing arena size, because small wells may lead to restriction, while larger wells may differentially reflect biologically relevant effects. These findings can improve comparability among experimental designs and demonstrates the importance of understanding confounding methodological variables.

Developmental environment has lasting effects on amphibian post-metamorphic behavior and thermal physiology

Environmental challenges early in development can result in complex phenotypic trade-offs and long-term effects on individual physiology, performance, and behavior, with implications for disease and predation risk. We examined the effects of simulated pond-drying and elevated water temperatures on development, growth, thermal physiology, and behavior in a North American amphibian, Rana sphenocephala. Tadpoles were raised in outdoor mesocosms under warming and drying regimes based on projected climatic conditions in 2070. We predicted that amphibians experiencing the rapid pond drying and elevated pond temperatures associated with climate change would accelerate development, be smaller at metamorphosis and demonstrate long-term differences in physiology and exploratory behavior post-metamorphosis. While both drying and warming accelerated development and reduced survival to metamorphosis, only drying resulted in smaller animals at metamorphosis. Around one-month post-metamorphosis, animals from the control treatment jumped relatively farther at high temperatures in jumping trials. In addition, across all treatments, frogs with shorter larval periods had lower critical thermal minima and maxima. We also found that developing under warming and drying resulted in a less exploratory behavioral phenotype, and that drying resulted in higher selected temperatures in a thermal gradient. Furthermore, behavior predicted thermal preference, with less exploratory animals selecting higher temperatures. Our results underscore the multi-faceted effects of early developmental environments on behavioral and physiological phenotypes later in life. Thermal preference can influence disease risk through behavioral thermoregulation, and exploratory behavior may increase risk of predation or pathogen encounter. Thus, climatic stressors during development may mediate amphibian exposure and susceptibility to predators and pathogens into later life stages.

Hormones do not maketh the mole-rat: No steroid hormone signatures of subordinate behavioral phenotypes

In some cooperatively breeding groups, individuals have distinct behavioral characteristics that are often stable and predictable across time. However, in others, as in the eusocial naked mole-rat, evidence for behavioral phenotypes is ambiguous. Here, we study whether the naked mole-rat can be divided into discrete phenotypes and if circulating hormone concentrations underpin these differences. Naked mole-rat colonies consist of a single breeding female and large numbers of non-reproductive subordinates that in some cases can exceed several hundred in a colony. The subordinates can potentially be divided into soldiers, who defend the colony; workers, who maintain it; and dispersers, who want to leave it. We established six colonies de novo, tracked them over three years, and assessed the behavior and hormone concentrations of the subordinates. We found that soldiers tended to be from earlier litters and were higher ranked compared to workers, whereas dispersers were distributed throughout litters and rankings. There was no difference in estradiol, testosterone, or dehydroepiandrosterone (DHEA) concentrations among phenotypes. Progesterone concentrations were higher in soldiers, but this difference appeared to be driven by a few individuals. Principal component analysis demonstrated that soldiers separated into a discrete category relative to workers/dispersers, with the highest ranked loadings being age, body mass, and testosterone concentrations. However, the higher testosterone in soldiers was correlated with large body size instead of strictly behavioral phenotype. Workers and dispersers have more overlap with each other and no hormonal differences. Thus the behavioral variation in subordinate naked mole-rats is likely not driven by circulating steroid hormone concentrations, but rather it may stem from alternative neural and/or neuroendocrine mechanisms.

Benzoresorcinol induces developmental neurotoxicity and injures exploratory, learning and memorizing abilities in zebrafish

Benzophenones (BPs) are a class of UV absorber commonly used in skin care products like sunscreens. With its wide range of application, its environmental and human hazards have received much attention in recent days. Previous studies on the toxicity of BPs mainly focused on its endocrine-disrupting effects, but there are limited studies on its neurodevelopment and neurotoxicity. Herein, using the zebrafish model we studied the neurodevelopmental- and neuro-toxicity of benzophenone 1 (BP1) (0.8, 1.0, 1.2, 1.6, and 2.4 μg/mL). As a result, BP1 led to an increase of embryo mortality, a decrease in hatching rate, and an increase in the rate of developmental abnormalities in a concentration-dependent manner. BP1 also caused developmental defects in the central nervous system (CNS) and dopaminergic (DA) neurons. Accordingly, BP1 injured larval zebrafish general locomotion and response to stimuli in light/dark challenge. In adult zebrafish, BP1 exposure (1, 10, 100, 1000 μg/L) caused inhibition of learning and memory abilities in the T-maze tests, and inhibited exploratory behavior and activity in the novel tank diving tests. Further, transcription levels of genes related to neurotoxicity, neurodevelopment, and anxiety revealed that BP1 may affect the development and function of the myelin sheath, inducing structural and functional defects of CNS, manifested as abnormal behaviors such as anxiety. Hence, the current study revealed the neurodevelopmental toxicity and neurotoxicity of BP1, expanded our knowledge about the toxic effects of BP1 on organisms, posing a possible threat to the environment and human health.

Challenges of a small world analysis for the continuous monitoring of behavior in mice

Documenting a mouse's "real world" behavior in the "small world" of a laboratory cage with continuous video recordings offers insights into phenotypical expression of mouse genotypes, development and aging, and neurological disease. Nevertheless, there are challenges in the design of a small world, the behavior selected for analysis, and the form of the analysis used. Here we offer insights into small world analyses by describing how acute behavioral procedures can guide continuous behavioral methodology. We show how algorithms can identify behavioral acts including walking and rearing, circadian patterns of action including sleep duration and waking activity, and the organization of patterns of movement into home base activity and excursions, and how they are altered with aging. We additionally describe how specific tests can be incorporated within a mouse's living arrangement. We emphasize how machine learning can condense and organize continuous activity that extends over extended periods of time.

Assessments of prolonged effects of desflurane and sevoflurane on motor learning deficits in aged AppNL-G-F/NL-G-F mice

As the proportion of elderly in society increases, so do the number of older patients undergoing surgical procedures. This is concerning as exposure to anesthesia has been identified as a risk factor for Alzheimer's disease (AD). However, the causal relationship between clinical AD development and anesthesia remains conjectural. Preclinical studies have demonstrated that anesthesia, such as halothane, isoflurane, and sevoflurane, induces AD-like pathophysiological changes and cognitive impairments in transgenic mouse models of AD. Desflurane does not have these effects and is expected to have more potential for use in elderly patients, yet little is known about its effects, especially on non-cognitive functions, such as motor and emotional functions. Thus, we examined the postanesthetic effects of desflurane and sevoflurane on motor and emotional function in aged App^{NL-G-F/NL-G-F} (App-KI) mice. This is a recently developed transgenic mouse model of AD exhibiting amyloid β peptide (Aβ) amyloidosis and a neuroinflammatory response in an age-dependent manner without non-physiological amyloid precursor protein (APP) overexpression. Mice were subjected to a short behavioral test battery consisting of an elevated plus maze, a balance beam test, and a tail suspension test seven days after exposure to 8.0% desflurane for 6 h or 2.8% sevoflurane for 2 h. App-KI mice showed significant increments in the percentage of entry and time spent in open arms in the elevated plus maze, increments in the number of slips and latency to traverse for the balance beam test, increments in the limb clasping score, increments in immobile duration, and decrements in latency to first immobile episode for the tail suspension test compared to age-matched wild type (WT) controls. Desflurane- and sevoflurane-exposed App-KI mice showed a delayed decrement in the number of slips for each trial in the balance beam test, while air-treated App-KI mice rapidly improved their performance, and increased their clasping behavior in the tail suspension test. Furthermore, App-KI inhibited the change in membrane GluA3 following exposure to anesthetics in the cerebellum. These results suggest high validity of App-KI mice as an animal model of AD.

Effects of mother's imitation on speech sounds in infants with Down syndrome

BACKGROUND

The Down syndrome behavioral phenotype includes delays in making speech sounds, production of more non-speech sounds than speech sounds, and contrasting strengths in social development. Within a behavior analytic framework, we conceptualize characteristics of the Down syndrome behavioral phenotype as creating a context for impairments in speech sound development that suggest interventions caregivers can use to improve speech sounds.

AIM AND METHOD

We examined one intervention, the effects of mother's contingent vocal imitation, on rate of speech and non-speech sound production in infants with Down syndrome using an ABAB design.

RESULTS

Mothers responded favorably to learning to imitate their infants' vocalizations and their contingent vocal imitation was associated with increases in infant speech sounds.

CONCLUSIONS

The increases in infant speech sound suggest the promise of this approach and future research examining variations in contingent vocal imitation and additional outcomes.

The adaptive functioning profile of Pitt-Hopkins syndrome

BACKGROUND

There are few cohort studies describing the adaptive functioning profile for Pitt-Hopkins syndrome (PTHS). In this study we examine the adaptive functioning profile for PTHS and compare it to Angelman syndrome (AS).

METHOD

Caregivers of 14 individuals with PTHS, 33 with deletion AS and 23 with non-deletion AS, completed the Vineland Adaptive Behavior Scales-II.

RESULTS

The profile of adaptive functioning in PTHS was characterised by strengths in socialisation, followed by motor skills, communication then daily living skills. The PTHS group scored significantly lower than the non-deletion AS group on all domains except socialisation and significantly lower than the deletion AS group, for motor skills only.

CONCLUSIONS

An uneven adaptive behavior profile for individuals with PTHS mirrors that of AS, with implications for assessment and intervention.

Post-acquisition effects of viruses on vector behavior are important components of manipulation strategies

A growing number of studies suggest that plant viruses manipulate host plant phenotypes to increase transmission-conducive behaviors by vectors. Studies on this phenomenon frequently omit examination of interactions that occur after vectors acquire virions, which provides an incomplete understanding of the ecology of plant virus manipulation. Here, by taking a full factorial approach that considered both the infection status of the host (Montia perfoliata) and viruliferous status of the aphid (Myzus persicae), we explored the effects of a circulative, non-propagative virus (Turnip yellows virus [TuYV]) on a suite of behavior and performance metrics that are relevant for virus transmission. Our results demonstrate that viruliferous aphids exhibited an increased velocity of movement and increased activity levels in locomotor and dispersal-retention assays. They also had increased fecundity and showed a capacity to more efficiently exploit resources by taking less time to reach the phloem and ingesting more sap, regardless of plant infection status. In contrast, non-viruliferous aphids only exhibited enhanced fecundity and biomass on TuYV-infected hosts, and had overall reduced dispersal and locomotor activity relative to viruliferous aphids. In this pathosystem, post-acquisition effects were stronger and more conducive to virus transmission than the purely pre-acquisition effects mediated by virus effects on the host plant. Our study provides additional support for the hypothesis that virus manipulation of vector behavior includes both pre- and post-acquisition effects and demonstrates the importance of considering both components when studying putative virus manipulation strategies.

Trajectories of Change in the Behavioral and Health Phenotype of Adolescents and Adults with Fragile X Syndrome and Intellectual Disability: Longitudinal Trends Over a Decade

This study examined trajectories of daily living skills, behavior problems, body mass index (BMI), and health conditions spanning nearly a decade in adolescents and adults with fragile X syndrome (N = 134; age range at study end = 19-49 years), examining influences of sex and autism spectrum disorder (ASD) symptoms. Hierarchical linear modeling revealed early increases in daily living skills, with decreases at older ages. Behavior problems became less severe over time, with some increases at older ages. Individuals gained weight and had increasing health problems over time. Fewer ASD symptoms were associated with greater daily living skills and fewer behavior problems at study start. This study offers some of the first prospective quantitative analyses of behavioral and health life course trajectories in FXS.

Behavioral and neurochemical characterization of the spontaneous mutation tremor, a new mouse model of audiogenic seizures

The tremor mutant phenotype results from an autosomal recessive spontaneous mutation arisen in a Swiss-Webster mouse colony. The mutant mice displayed normal development until three weeks of age when they began to present motor impairment comprised by whole body tremor, ataxia, and decreased exploratory behavior. These features increased in severity with aging suggesting a neurodegenerative profile. In parallel, they showed audiogenic generalized clonic seizures. Results from genetic mapping identified the mutation tremor on chromosome 14, in an interval of 5 cM between D14Mit37 (33.21 cM) and D14Mit115 (38.21 cM), making Early Growth Response 3 (Egr3) the main candidate gene. Comparing with wild type (WT) mice, the tremor mice showed higher hippocampal gene expression of Egr3 and Gabra1 and increased concentrations of noradrenalin (NOR; p = .0012), serotonin (5HT; p = .0083), 5-hydroxyindoleacetic acid (5-HIAA; p = .0032), γ-amino butyric acid (GABA; p = .0123), glutamate (p = .0217) and aspartate (p = .0124). In opposition, the content of glycine (p = .0168) and the vanillylmandelic acid (VMA)/NOR ratio (p = .032) were decreased. Regarding to dopaminergic system, neither dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) contents nor the turnover rate of DA showed statistically significant differences between WT and mutant mice. Data demonstrated that audiogenic seizures of tremor mice are associated with progressive motor impairment as well as to hippocampal alterations of the Egr3 and Gabra1 gene expression and amino acid and monoamine content. In addition, the tremor mice could be useful for study of neurotransmission pathways as modulators of epilepsy and the pathogenesis of epilepsies occurring with generalized clonic seizures.

Profile repeatability: A new method for evaluating repeatability of individual hormone response profiles

There is broad interest in determining repeatability of individual responses. Current methods calculate repeatability of individual points (initial and/or peak), time to peak value, or a single measure of the integrated total response (area under the curve), rather than the shape of the response profile. Repeatability estimates of response profiles using linear mixed models (LMM) generate an average repeatability for an aggregate of individuals, rather than an estimate of individual repeatability. Here we use a novel ad hoc method to calculate repeatability of individual response profiles and demonstrate the need for a more rigorous assessment protocol. Response profile repeatability has not been defined at the individual level. We do this using a new metric, Profile Repeatability (PR), which incorporates components of variance and the degree to which response profiles cross each other in a time series. Values range from 0 (no repeatability) to 1 (complete repeatability). We created synthetic data to represent a range of apparent time series repeatability, and 20 independent observers visually ranked those data sets by degree of repeatability. We also applied the method to real data on stress responses of European starlings Sturnus vulgaris. We then computed PR scores for the synthetic data and for real data from European starling corticosterone responses over time, and contrast the results to those from LMM. Finally, we assessed the sensitivity of PR to reductions in the number of time points in the corticosterone response, as well as reductions in the number of replicates per individual. We found the average PR scores for a group of individuals to be somewhat robust to reductions in points in the time series; however, the ranks of individuals (PR values relative to one another) could change substantially with reduction in the number of values in a time series. PR showed threshold sensitivity to losing replicate time series between 6 and 4 replicates. Surprisingly, human observers fell into two disparate groups when ranking repeatability of the synthetic data, and the PR score indicated that human observers may underestimate repeatability of data where replicates cross each other. In contrast to the average profile repeatability estimated using LMMs, our approach calculates individual repeatability. From our perspective, LMM does not provide a definitive idea of repeatability at the individual level; in essence, it concludes that suites of time series with low within-individual variance has high repeatability, regardless of replicate trajectories. LMM and PR have non-linear relationships between 0 and 1, but PR has greater discrimination for mid-values of repeatability. Consistent average group repeatability can be associated with substantial differences in individual ranks suggests that estimating individual repeatability is critical. The PR score should be useful in comparing repeatability of any type of nonlinear, including non-monotonic, response profiles over time, which are common in both physiology and behavior, and it demonstrates the specific needs for future improvements of a profile repeatability metric.

Joint attention in Down syndrome: A meta-analysis

BACKGROUND

Some studies have indicated that joint attention may be a relative strength in Down syndrome (DS), but other studies have not.

AIM

To conduct a meta-analysis of joint attention in DS to more conclusively determine if this is a relative strength or weakness when compared to children with typical development (TD), developmental disabilities (DD), and autism spectrum disorder (ASD).

METHODS AND PROCEDURES

Journal articles published before September 13, 2016, were identified by using the search terms "Down syndrome" and "joint attention" or "coordinating attention". Identified studies were reviewed and coded for inclusion criteria, descriptive information, and outcome variables.

OUTCOMES AND RESULTS

Eleven studies (553 participants) met inclusion criteria. Children with DS showed similar joint attention as TD children and higher joint attention than children with DD and ASD. Meta-regression revealed a significant association between age and joint attention effect sizes in the DS vs. TD contrast.

CONCLUSIONS AND IMPLICATIONS

Joint attention appears to not be a weakness for children with DS, but may be commensurate with developmental level. Joint attention may be a relative strength in comparison to other skills associated with the DS behavioral phenotype. Early interventions for children with DS may benefit from leveraging joint attention skills.

Early social communication in infants with fragile X syndrome and infant siblings of children with autism spectrum disorder

BACKGROUND

Little research in fragile X syndrome (FXS) has prospectively examined early social communication.

AIMS

To compare early social communication in infants with FXS, infant siblings of children with autism spectrum disorder (ASIBs), and typically developing (TD) infants.

METHODS AND PROCEDURES

Participants were 18 infants with FXS, 21 ASIBs, and 22 TD infants between 7.5-14.5 months. Social communication was coded using the Communication Complexity Scale during the administration of Autism Observation Scale for Infants.

OUTCOMES AND RESULTS

Descriptively different patterns were seen across the three groups. Overall infants with FXS had lower social communication than ASIBs or TD infants when controlling for nonverbal cognitive abilities. However, infants with FXS had similar levels of social communication as ASIBs or TD infants during peek-a-boo. No differences were observed between ASIBs and TD infants. For all infants, higher social communication was related to lower ASD risk.

CONCLUSIONS AND IMPLICATIONS

Findings provide insight into the developmental course of social communication in FXS. The dynamic nature of social games may help to stimulate communication in infants with FXS. Language interventions with a strong social component may be particularly effective for promoting language development in FXS.

Mice Behavioral Phenotype Changes after Administration of Anani (Symphonia globulifera, Clusiaceae), an Alternative Latin American and African Medicine

Background:

Anani, (Symphonia globulifera, Clusiaceae), known as chewstick, is a traditional plant occurring in Africa and in Central and South Americas that is used against parasites and microorganisms. Although its use is popular in some of these countries, there is a lack of information related to its influence over behavioral phenotype (BP).

Objective:

The objective of this study is to evaluate the influence of the administration of the extract obtained from the aerial organs of Anani (EB1257) to male Balb-c mice over BP.

Materials and Methods:

Open cage observation, open field, and elevated-plus maze apparatuses were used. Evaluations were done 15, 30, 60, 120, and 180 min after intraperitoneal administration of Anani extract.

Results:

Impairment of general behavior activity, response to touch, tail squeeze, defecation, locomotion and rearing frequency were observed although no signs of hemorrhage or macroscopical alterations of internal organs. Anani is harmful, but not toxic if used in the appropriate doses, yet to be determined to male mice. Impairment of locomotion and defecation was observed, indicating some degree of influence over locomotion, but no alterations in anxiety levels were assessed. Three compounds were previously found in the plant-lupeol (1), β-amyrin (2) and 3-β-hydroxyglutin-5-ene (3), and one is being described for the first time to occur in the species: oleanolic acid (4).

Conclusions:

The present work contributes in the support of the rational use of Anani, an important Latin American and African alternative medicine, presenting findings that are being reported for the first time.

SUMMARY

Symphonia globulifera impairs locomotion and defecatin in behavior analyses

No alterations in anxiety was observed

Oleanolic acid occurs in the species.

Abbreviations used: BP: Behavioral phenotype; OF: Open field, EPM: Elevated-plus maze, MMA/ICMBio/SISBIO: Ministério do Meio Ambiente/Instituto Chico Mendes de Conservação da Biodiversidade/Sistema de Autorização e Informação em Biodiversidade, IBAMA/MMA/CGen: Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis/Ministério do Meio Ambiente/Conselho de Gestão do Patrimônio Genético, AM: Amazonas State, UNIP: Universidade Paulista, mg: milligram, kg: kilogram, I.P: Intraperitoneal, CEUA/ICS/UNIP: Comissão de Ética no Uso de Animais/Instituto de Ciências da Saúde/Universidade Paulista, LD: Lethal dose, NLD: Nonlethal dose, GBA: General behavior activity, FCHCL₃: Fraction chloroform, FBuOH: Fraction buthanol, FH₂O: Fraction water, FrHEX: Fraction hexane, FrDCM: Fraction dichloromethane, FrMeOH: Fraction methanol, ¹³C NMR: Carbon nuclear magnetic resonance, EPA: United States Environmental Protection Agency.

Prader-Willi syndrome mental health research strategy workshop proceedings: the state of the science and future directions

Abstract

This paper reports on the ‘Prader-Willi Syndrome (PWS) Mental Health Research Strategy Workshop’ that took place in March 2015. PWS is characterized by a complex phenotype affecting multiple systems with a high prevalence of maladaptive behaviours, and neuropsychiatric illness. Prader Willi syndrome results from the absence of paternally derived alleles located at the imprinted chromosomal locus, 15q11–13. The goal of the workshop was to highlight the state of the science of the mental health of people with this rare neurodevelopmental disorder. Mental ill health and maladaptive behaviors significantly impact quality of life for persons with PWS and their caregivers. Effective treatments and further research into this area are critically needed.

Methods

A multidisciplinary group of scientists and health care professionals were brought together to discuss the mental health and behavioral needs of people with PWS. The workshop strategy was to integrate established work on PWS with other relevant areas of study. The meeting also focused on two neurobiological systems that research had suggested were relevant to understanding the broader mental health aspects of PWS: the autonomic nervous system and oxytocin/vasopressin pathways. Other relevant topics were considered and recommendations made.

Results

The workshop presentations and working group discussions revealed that no one approach was sufficient to fully conceptualize the mental health challenges in PWS. Workshop discussions pointed to the need for theoretically informed studies focused on clinical characterization, measurement, and the probing of specific neurobiological systems through pharmaceutical or other interventions. Future studies in this area should explore the use of advanced neuroimaging protocols, as well as molecular studies using iPS cells in order to create more informed theories.

Conclusions

Within this framework, workshop participants identified and prioritized key research questions, and highlighted current opportunities. Recommendations were made with respect to the development of specific resources and tools for furthering mental health research such as The Global PWS Registry, the development of effective endpoints, the use of animal models and iPS cells to aid understanding of the neurobiological underpinnings. Additionally, collaborative opportunities across disciplines and syndromes were highlighted and targeted research initiatives focused on psychological/behavioral interventions modified for use in PWS were recommended.

Role of mitochondrial uncoupling protein-2 (UCP2) in higher brain functions, neuronal plasticity and network oscillation

Background/Purpose

Major psychiatric illnesses, affecting 36% of the world's population, are profound disorders of thought, mood and behavior associated with underlying impairments in synaptic plasticity and cellular resilience. Mitochondria support energy demanding processes like neural transmission and synaptogenesis and are thus points of broadening interest in the energetics underlying the neurobiology of mental illness. These experiments interrogated the importance of mitochondrial flexibility in behavior, synaptic and cortical activity in a mouse model.

Methods

We studied mice with ablated uncoupling protein-2 expression (UCP2 KO) and analyzed cellular, circuit and behavioral attributes of higher brain regions.

Results

We found that mitochondrial impairment induced by UCP2 ablation produces an anxiety prone, cognitively impaired behavioral phenotype. Further, NMDA receptor blockade in the UCP2 KO mouse model resulted in changes in synaptic plasticity, brain oscillatory and sensory gating activities.

Conclusions

We conclude that disruptions in mitochondrial function may play a critical role in pathophysiology of mental illness. Specifically, we have shown that NMDA driven behavioral, synaptic, and brain oscillatory functions are impaired in UCP2 knockout mice.

•

Impairment of mitochondrial functions by removal of UCP2 has multiple behavioral and circuit impairments of animals.

Toward an integrative science of the developing human mind and brain: Focus on the developing cortex

Based on the Huttenlocher lecture, this article describes the need for a more integrative scientific paradigm for addressing important questions raised by key observations made over 2 decades ago. Among these are the early descriptions by Huttenlocher of variability in synaptic density in cortex of postmortem brains of children of different ages and the almost simultaneous reports of cortical volume reductions on MR imaging in children and adolescents. In spite of much progress in developmental neurobiology, developmental cognitive neuroscience, and behavioral and imaging genetics, we still do not know how these early observations relate to each other. It is argued that large scale, collaborative research programs are needed to establish the associations between behavioral differences among children and imaging biomarkers, and to link the latter to cellular changes in the developing brain. Examples of progress and challenges remaining are illustrated with data from the Pediatric Imaging, Neurocognition, and Genetics Project (PING).

Differentiation of rodent behavioral phenotypes and methylphenidate action in sustained and flexible attention tasks

Methyphenidate (MPH) is the primary drug treatment of choice for ADHD. It is also frequently used off-label as a cognitive enhancer by otherwise healthy individuals from all age groups and walks of life. Military personnel, students, and health professionals use MPH illicitly to increase attention and improve workplace performance over extended periods of work activity. Despite the frequency of its use, the efficacy of MPH to enhance cognitive function across individuals and in a variety of circumstances is not well characterized. We sought to better understand MPH׳s cognitive enhancing properties in two different rodent models of attention. We found that MPH could enhance performance in a sustained attention task, but that its effects in this test were subject dependent. More specifically, MPH increased attention in low baseline performing rats but had little to no effect on high performing rats. MPH exerted a similar subject specific effect in a test of flexible attention, i.e. the attention set shifting task. In this test MPH increased behavioral flexibility in animals with poor flexibility but impaired performance in more flexible animals. Overall, our results indicate that the effects of MPH are subject-specific and depend on the baseline level of performance. Furthermore, good performance in in the sustained attention task was correlated with good performance in the flexible attention task; i.e. animals with better vigilance exhibited greater behavioral flexibility. The findings are discussed in terms of potential neurobiological substrates, in particular noradrenergic mechanisms, that might underlie subject specific performance and subject specific responses to MPH. This article is part of a Special Issue entitled SI: Noradrenergic System.

Behavioral characterization of CD36 knockout mice with SHIRPA primary screen

CD36 is a member of the class B scavenger receptor family of cell surface proteins, which plays a major role in fatty acid, glucose and lipid metabolism. Besides, CD36 functions as a microglial surface receptor for amyloid beta peptide. Regarding this, we suggest CD36 might also contribute to neuropsychiatric disease. The aim of this study was to achieve a behavioral phenotype of CD36 knockout (CD36(-/-)) mice. We characterized the behavior of CD36(-/-) mice and C57BL/6J mice by subjecting them to a series of tests, which include SHIRPA primary behavioral screen test, 1% sucrose preference test, elevated plus-maze test, open-field test and forced swimming test. The results showed that CD36(-/-) mice traversed more squares, emitted more defecation, exhibited higher tail elevation and had more aggressive behaviors than C57BL/6J mice. The CD36(-/-) mice spent more time and traveled longer distance in periphery zone in the open-field test. Meanwhile, the numbers that CD36(-/-) mice entered in the open arms of elevated plus-maze were reduced. These findings suggest that CD36(-/-) mice present an anxious phenotype and might be involved in neuropsychiatric disorders.

Behavioral characterization of striatal-enriched protein tyrosine phosphatase (STEP) knockout mice

Striatal-enriched protein tyrosine phosphatase (STEP) has been described as a regulator of multiple kinases and glutamate receptor subunits critical for synaptic plasticity. Published behavioral and biochemical characterization from the founder line of STEP knockout (KO) mice revealed superior cognitive performance, with enhanced phosphorylation of substrates such as ERK, Fyn and GluN2B; suggesting that inhibitors of STEP may have potential as therapeutic agents for the treatment of neuropsychiatric disorders. The objectives of this work aimed to replicate and extend the previously reported behavioral consequences of STEP knockout. Consistent with previous reported data, STEP KO mice demonstrated exploratory activity levels and similar motor coordination relative to WT littermate controls as well as intact memory in a Y-maze spatial novelty test. Interestingly, KO mice demonstrated deficits in pre-pulse inhibition as well as reduced seizure threshold relative to WT controls. Immunohistochemical staining of brains revealed the expected gene-dependent reduction in STEP protein confirming knockout in the mice. The present data confirm expression and localization of STEP and the absence in KO mice, and describe functional downstream implications of reducing STEP levels in vivo.

Mice over-expressing BDNF in forebrain neurons develop an altered behavioral phenotype with age

Evidence from clinical studies suggests that abnormal activity of brain derived neurotrophic factor (BDNF) contributes to the pathogenesis of autism spectrum disorders (ASDs). A genetically modified line of mice over-expressing a BDNF transgene in forebrain neurons was used to investigate if this mutation leads to changes in behavior consistent with ASD. The mice used in these experiments were behaviorally tested past 5 months of age when spontaneous seizures were evident. These seizures were not observed in age-matched wildtype (WT) mice or younger mice from this transgenic line. The BDNF mice in these experiments weighed less than their WT littermates. The BDNF transgenic (BDNF-tg) mice demonstrated similar levels of sociability in the social approach test. Conversely, the BDNF-tg mice demonstrated less obsessive compulsive-like behavior in the marble burying test, less anxiety-like behavior in the elevated plus maze test, and less depressive-like behavior in the forced swim test. Changes in behavior were found in these older mice that have not been observed in younger mice from this transgenic line, which may be due to the development of seizures as the mice age. These mice do not have an ASD phenotype but may be useful to study adult onset epilepsy.

The effect of hemorrhage on the development of the postnatal mouse cerebellum

Recent studies have shown that hemorrhagic injury in the preterm cerebellum leads to long-term neurological sequelae, such as motor, affective, and cognitive dysfunction. How cerebellar hemorrhage (CBH) affects the development and function of the cerebellum is largely unknown. Our study focuses on developing a mouse model of CBH to determine the anatomical, behavioral, and molecular phenotypes resulting from a hemorrhagic insult to the developing cerebellum. To induce CBH in the postnatal mouse cerebellum, we injected bacterial collagenase, which breaks down surrounding blood vessel walls, into the fourth ventricle at postnatal day two. We found a reduction in cerebellar size during postnatal growth, a decrease in granule cells, and persistent neurobehavioural abnormalities similar to abnormalities reported in preterm infants with CBH. We further investigated the molecular pathways that may be perturbed due to postnatal CBH and found a significant upregulation of genes in the inflammatory and sonic hedgehog pathway. These results point to an activation of endogenous mechanisms of injury and neuroprotection in response to postnatal CBH. Our study provides a preclinical model of CBH that may be used to understand the pathophysiology of preterm CBH and for potential development of preventive therapies and treatments.

Incontinence in individuals with Angelman syndrome: a comparative study

Frequency and type of incontinence and variables associated with incontinence were assessed in individuals with Angelman syndrome (AS; n=71) and in a matched control group (n=69) consisting of individuals with non-specific intellectual disability (ID). A Dutch version of the "Parental Questionnaire: Enuresis/Urinary Incontinence" (Beetz, von Gontard, & Lettgen, 1994) was administered and information on primary caretakers' perspectives regarding each individual's incontinence was gathered. Results show that diurnal incontinence and fecal incontinence during the day more frequently occurred in the control group than in the AS group. In both groups, nocturnal enuresis was the most common form of incontinence. More incontinence was seen in individuals with AS who were younger, had a lower level of adaptive functioning and/or had epilepsy. Individuals with AS were able to stay dry for longer periods of time than the controls and often showed both in-toilet urination and urinary accidents during the day, whereas accidents and correct voids during the day were more set apart in the control group. Also, persons with AS had a lower micturition frequency implying possible voiding postponement. Both groups showed high rates of LUTS (lower urinary tract symptoms) possibly indicative of functional bladder disorders such as voiding postponement, dysfunctional voiding, or even an underactive bladder. In general, most primary caretakers reported severe intellectual disability as the main cause for urinary incontinence. Based on these results incontinence does not appear to be part of the behavioral phenotype of Angelman syndrome. Therefore, pediatric or urologic diagnostics and treatment are recommended for all persons with incontinence and intellectual disability. Further implications for practice and research are given.