Florey Department of Neuroscience and Mental Health - Research Publications
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ItemConsidering equity and cost-effectiveness in assessing a parenting intervention to promote early childhood development in rural Vietnam(OXFORD UNIV PRESS, 2023-09-18)Considering equity in early childhood development (ECD) is important to ensure healthy development for every child. Equity-informative cost-effectiveness analysis can further guide decision makers to maximize outcomes with limited resources while promoting equity. This cost-effectiveness study aimed to examine the equity impacts of a multicomponent ECD intervention in rural Vietnam. We estimated the cost-effectiveness of the intervention with a 30-month time horizon from the service provider and household perspectives with equity considerations. Data were from a cluster-randomized controlled trial comparing the intervention with the local standard of care. The incremental cost-effectiveness ratios (ICERs) per child cognitive development score gained were estimated by household wealth quintile and maternal education level, adjusted for cluster effects and baseline characteristics such as maternal parity and age. A 3% discount rate was applied to costs, and non-parametric cluster bootstrapping was used to examine uncertainty around ICERs. Children in the intervention had higher cognitive development scores than those in the control arm across all subgroups. Based on intervention recurrent cost, the ICER per cognitive development score gained was lower in children from the poorest quintile (-US$6) compared to those from the richest quintile (US$16). Similarly, the ICER per cognitive development score gained was lower in children whose mothers had the lowest education level (-US$0.02) than those with mothers who had the highest education level (US$7). Even though our findings should be interpreted with caution due to the insufficient study power, the findings suggest that the intervention could promote equity while improving child cognitive development with greater cost-effectiveness in disadvantaged groups.
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ItemPromoting early childhood development in Viet Nam: cost-effectiveness analysis alongside a cluster-randomised trial.(Elsevier BV, 2023-08)BACKGROUND: Economic evaluations are critical to ensure effective resource use to implement and scale up child development interventions. This study aimed to estimate the cost-effectiveness of a multicomponent early childhood development intervention in rural Viet Nam. METHODS: We did a cost-effectiveness study alongside a cluster-randomised trial with a 30-month time horizon. The study included 669 mothers from 42 communes in the intervention group, and 576 mothers from 42 communes in the control group. Mothers in the intervention group attended Learning Clubs sessions from mid-pregnancy to 12 months after delivery. The primary outcomes were child cognitive, language, motor, and social-emotional development at age 2 years. In this analysis, we estimated the incremental cost-effectiveness ratios (ICERs) of the intervention compared with the usual standard of care from the service provider and household perspectives. We used non-parametric bootstrapping to examine uncertainty, and applied a 3% discount rate. FINDINGS: The total intervention cost was US$169 898 (start-up cost $133 692 and recurrent cost $36 206). The recurrent cost per child was $58 (1 341 741 Vietnamese dong). Considering the recurrent cost alone, the base-case ICER was $14 and mean ICER of 1000 bootstrap samples was $14 (95% CI -0·48 to 30) per cognitive development score gained with a 3% discount rate to costs. The ICER per language and motor development score gained was $22 and $20, respectively, with a 3% discount rate to costs. INTERPRETATION: The intervention was cost-effective: the ICER per child cognitive development score gained was 0·5% of Viet Nam's gross domestic product per capita, alongside other benefits in language and motor development. This finding supports the scaling up of this intervention in similar socioeconomic settings. FUNDING: Australian National Health and Medical Research Council and Grand Challenges Canada. TRANSLATION: For the Vietnamese translation of the abstract see Supplementary Materials section.
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ItemAssessment of conditioned fear extinction in male and female adolescent rats(PERGAMON-ELSEVIER SCIENCE LTD, 2020-06-01)Pavlovian fear conditioning and extinction have been widely studied across many species to understand emotional learning and memory. Importantly, it is becoming clear that these processes are affected by sex and age. In adult rodents and humans, sex differences are evident in extinction, with estradiol playing a significant role. In adolescence, an extinction deficit has been reported in rodents and humans. However, the influence of sex on extinction during adolescence is unknown. This is surprising, since adolescence coincides with the onset of hormone cycling, and therefore it might be expected that hormones fluctuations exert a more profound effect at this time. Therefore, we examined Pavlovian fear conditioning and extinction in adolescent male and female rats. In experiment 1, 35-day-old male and female rats were exposed to 6 pairings of a conditioned stimulus (CS, a tone) with an aversive unconditioned stimulus (US, a footshock). The next day they were extinguished in a contextually distinct chamber, via 60 presentations of the CS without the US. Extinction recall was tested 24 hours later in the extinction context. Estrous phase was monitored by cytology on vaginal smears taken 1 hour after each behavioral session. In experiment 2, male and female rats were given sham surgery or gonadectomy at 21 days of age. They were then trained and tested as for experiment 1. We observed that females in proestrus or met/diestrus during extinction showed delayed extinction and impaired extinction recall the next day compared to males. Ovariectomy enhanced extinction for female rats, but orchidectomy delayed extinction for males. Plasma analyses showed that met/di/proestrus phases were associated with high estradiol levels. These findings suggest that high plasma estradiol levels impair extinction for adolescent females. These results contradict what is reported in adult animals, suggesting that hormonal influences on extinction are dependent on age. Given that impaired extinction is widely used as a model to understand resistance to exposure-based therapies, our findings have important implications for understanding mental health treatments in adolescents.
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ItemEarly life stress alters pituitary growth during adolescence-A longitudinal study(PERGAMON-ELSEVIER SCIENCE LTD, 2015-03-01)The pituitary gland is integral in mediating the stress-response via its role in hypothalamic-pituitary-adrenal (HPA) axis function. Pituitary gland volume (PGV) is altered in stress-related psychopathology, and one study to date has shown stress to be associated with age-related PGV change during adolescence. The current study investigated the effects of a number of different types of early life (i.e., childhood and adolescent) stress (including childhood maltreatment, stressful life events, and maternal affective behavior) on PGV development from mid- to late adolescence using a longitudinal design. The influence of PGV development on depressive and anxiety symptoms was also investigated. Ninety one (49 male) adolescents took part in mother-child dyadic interaction tasks when they were approximately 12 years old, reported on childhood maltreatment and stressful life events when they were approximately 15 years old, and underwent two waves of structural magnetic resonance imaging (MRI) scans, when they were approximately 16 and 19 years old. Results revealed that childhood maltreatment predicted accelerated PGV development in females, and maternal dysphoric behavior predicted accelerated PGV development in the whole sample. PGV development was not associated with depressive or anxiety symptoms. These results suggest an effect of early life stress on altered HPA axis function across mid- to late adolescence. Further research is required to assess functional implications and whether these changes might be associated with risk for subsequent psychopathology.
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ItemExtinction of a cocaine-taking context that protects against drug-primed reinstatement is dependent on the metabotropic glutamate 5 receptor(WILEY, 2015-05-01)We investigated the effects of extinguishing action-reward versus context-reward associations on drug-primed reinstatement, and the potential role of the metabotropic glutamate 5 receptor (mGlu5) in these different types of extinction in rats that self-administer cocaine. We observed that daily context extinction (non-reinforced exposures to the cocaine-taking context with retracted levers) was just as effective as daily lever extinction in reducing cocaine-primed reinstatement compared with passive abstinence. Additionally, systemic injections of the mGlu5 negative allosteric modulator MTEP (3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine) following each extinction session significantly impaired the ability of context extinction to reduce cocaine-primed reinstatement, without affecting reinstatement after lever extinction or passive abstinence.
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ItemPostnatal development of neurotransmitter systems and their relevance to extinction of conditioned fear(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2017-02-01)Remembering and forgetting are fundamental features of an organism. Extinction is a type of forgetting where there is a decrease in the significance and/or the meaning of an associative memory when elements of that memory no longer predict one another. The neural mechanisms underlying extinction of fear memories have been extensively studied in the laboratory because extinction processes are clinically relevant to exposure therapies that treat anxiety disorders. However, only in the last decade have we begun to unveil the similarities and differences in plasticity underlying extinction across development. So far it is clear that extinction is a developmentally dissociated process in behavior and in pharmacology, however there are many large gaps in the literature in understanding how the developmental trajectory of different neurotransmitters contribute to changes in the nature of extinction across development. We attempt to address these gaps in the present review. Major neurotransmitter systems including the glutamatergic and GABAergic systems, the monoamines, the endogenous opioid and cannabinoid systems, acetylcholines, and neuropeptides such as oxytocin have all been identified to play some role in extinction of fear memories and have been covered in this review. We hope to facilitate more research into mechanisms of extinction at different stages of life, especially noting that mental disorders are increasingly classified as neurodevelopmental disorders.
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ItemDevelopmental perspectives on methamphetamine abuse: Exploring adolescent vulnerabilities on brain and behavior(PERGAMON-ELSEVIER SCIENCE LTD, 2018-12-20)Most people that experience illicit drugs do so for the first time during adolescence, and methamphetamine (meth) is no exception. Therefore, research into the effects of meth should highlight the adolescent period. Despite this, the vast majority of current literature has mainly focused on meth exposure during adulthood. In this review, we first describe existing literature that compares the behavioral effects of meth where exposure occurs in adolescence compared to adulthood. Given that there are actually very few such studies, we also look at what is known about neural effects of meth in the adult brain, and relate these to normal neural development occurring during the adolescent period to establish how meth may target maturing regions and related neurochemistry. What emerges overall is that adolescents appear to be more vulnerable to the rewarding and reinforcing effects of meth, and that meth indeed has effects on areas that are in flux during adolescence. However, there is some evidence for a paradoxical resistance to the neurotoxic effects during this period. We highlight the need for further age-related research to better understand, treat, and prevent meth use disorders and addiction in general.
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ItemMetabolic regulation to treat bipolar depression: mechanisms and targeting by trimetazidine(SPRINGERNATURE, 2023-06-29)Bipolar disorder's core feature is the pathological disturbances in mood, often accompanied by disrupted thinking and behavior. Its complex and heterogeneous etiology implies that a range of inherited and environmental factors are involved. This heterogeneity and poorly understood neurobiology pose significant challenges to existing drug development paradigms, resulting in scarce treatment options, especially for bipolar depression. Therefore, novel approaches are needed to discover new treatment options. In this review, we first highlight the main molecular mechanisms known to be associated with bipolar depression-mitochondrial dysfunction, inflammation and oxidative stress. We then examine the available literature for the effects of trimetazidine in said alterations. Trimetazidine was identified without a priori hypothesis using a gene-expression signature for the effects of a combination of drugs used to treat bipolar disorder and screening a library of off-patent drugs in cultured human neuronal-like cells. Trimetazidine is used to treat angina pectoris for its cytoprotective and metabolic effects (improved glucose utilization for energy production). The preclinical and clinical literature strongly support trimetazidine's potential to treat bipolar depression, having anti-inflammatory and antioxidant properties while normalizing mitochondrial function only when it is compromised. Further, trimetazidine's demonstrated safety and tolerability provide a strong rationale for clinical trials to test its efficacy to treat bipolar depression that could fast-track its repurposing to address such an unmet need as bipolar depression.
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ItemMGLU5 receptors are necessary for extinction of drug associated cues and contexts(Wiley, 2017-08-01)Drug-associated cues and contexts are strong predictors of relapse. We used complex behavioural preparations to examine whether extinction of such cues reduces their capacity to trigger drug-seeking. We also examined whether the mGlu5 receptor is necessary for extinction learning. In Experiment 1, rats were trained to lever press for cocaine. Once stable responding was established, the context was extinguished by replacing the rats in the chambers, but with no opportunity to respond (levers were retracted). Control group remained in their home cage. An mGlu5 receptor negative allosteric modulator (MTEP) or vehicle was administered immediately after context extinction sessions. During subsequent drug-induced reinstatement, rats responded less if they had received context extinction; however, this effect was attenuated where MTEP had been applied. In Experiment 2, rats were trained to lever press for cocaine, now paired with a cue light. To extinguish the cue, half of the rats were placed in the chambers and given non-reinforced presentations of the cue, but with the levers retracted. Control rats remained in home cage. All rats received either MTEP or vehicle 20 minutes prior. Cue-induced reinstatement was tested the following day by re-pairing the lever with the light. Rats gave fewer drug-seeking responses following cue extinction. This effect was attenuated by MTEP. Experiment 3 followed the same protocol as Experiment 2, except that a positive allosteric modulator CDPPB or vehicle was administered 20 minutes before CS extinction. At reinstatement, cue-elicited cocaine seeking was lower for the animals that had previously been administered CDPPB, regardless of extinction condition. This study highlights the important role cues and contexts play in driving drug-seeking behaviour during reinstatement. It also shows that mGlu 5 signalling is necessary for extinction of drug-cue associations, and that mGlu5 positive allosteric modulators are promising targets for treating cocaine addiction.
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ItemEditorial: Honouring John Hardy - A true pioneer in research(WILEY, 2022-03-03)This Editorial highlights the knighthood recognition of Sir John Hardy, Professor and Chair at the University College London, for his exceptional services to human health and dementia research. We also celebrate his successful trajectory in neurochemistry and neurogenetics, and acknowledge his long-standing contributions to the Journal of Neurochemistry as an author and editor. John Hardy's research identified key mutations linked to prevalent neurodegenerative diseases in humans and contributed to our understanding of the molecular pathogenesis of Alzheimer disease. As John's career has inspired many generations of researchers in neurochemistry, we present a brief Q&A interview with him on the occasion of his most recent recognition.