Valence-dependent dopaminergic modulation during reversal learning in Parkinson's disease: A neurocomputational approach.

Reinforcement learning, crucial for behavior in dynamic environments, is driven by rewards and punishments, modulated by dopamine (DA) changes. This study explores the dopaminergic system's influence on learning, particularly in Parkinson's disease (PD), where medication leads to impaired adaptability. Highlighting the role of tonic DA in signaling the valence of actions, this research investigates how DA affects response vigor and decision-making in PD.

Effects of 2 months of methylphenidate on energy expenditure in individuals with obesity: A randomized, double-blind, placebo-controlled pilot study.

Methylphenidate (MPH) has been previously shown to increase resting energy expenditure (REE) in individuals of normal weight; however, the effects on individuals living with obesity are currently unknown. Ten individuals living with obesity were randomly assigned to undergo 60 days of MPH administration with a daily dose of 0.5 mg/kg body weight or a placebo control.

Barriers and facilitators to implementing a Canadian shared-care ADHD program in pediatric settings in Shanghai: a consolidated framework for implementation research approach.

Objectives: The vast majority of children with Attention-Deficit Hyperactivity Disorder (ADHD) do not have access to proper diagnosis and treatment in China. The goal of this project is to identify the challenges and facilitators in implementing a Canadian ADHD Shared Care Pathways program in pediatric settings in Shanghai region.

Methods: Purposive semi-structured focus groups were conducted on a total of 13 healthcare practitioners from the Shanghai Xinuha, Ninghai and Chongming hospitals.

Cumulative Dosage of Intrathecal Chemotherapy Agents Predicts White Matter Integrity in Long-Term Survivors of Acute Lymphoblastic Leukemia: A PETALE Study.

Acute lymphoblastic leukemia (ALL) stands as the most prevalent form of pediatric cancer in North America, with a current five-year survival rate of 85%. While more children achieved ALL remission and transition into adulthood, the prevalence of long-term treatment-related effects, especially neurocognitive sequelae, remains significant. This study pursues two objectives.

Contributing factors to well-being in a sample of long-term survivors of childhood acute lymphoblastic leukemia: the role of social support in emotional regulation.

To understand why some long-term childhood cancer survivors experience positive adjustment in the long run,[Q1] this study aimed to (1) explore associations between well-being, health status, social support, and emotion regulation (ER) strategies in a cohort of long-term childhood lymphoblastic leukemia (cALL) survivors, (2) identify the individual contribution of each ER strategy to well-being (3) and their interaction with social support. We used data from 92 participants from the PETALE cohort (51% female, aged 24 ± 7 years). Measures included well-being (WHO-5), health status (15D), social support (SSQ-6), cognitive reappraisal and expressive suppression (ERQ), and emotional processing and expression (EAC).

Mediators and moderators of the effects of the COVID-19 crisis on parent-child conflict in children in tertiary mental health care.

This study focused on children treated for mental health problems during the pandemic. The present study examined how parent's difficulties in managing COVID-19 restrictions increased children's behavioral problems (internalizing and externalizing) and parent-child conflict through parental mental health and parental stress. Family functioning, particularly problem-solving ability, was tested as a resilience factor.

Contribution of Fatigue to Cognitive Dysfunction in Childhood Acute Lymphoblastic Leukemia Survivors.

Late effects such as neurocognitive issues and fatigue have been reported in childhood acute lymphoblastic leukemia (cALL) survivors. Yet, their association is often poorly understood. In this study, we wished to (1) describe neurocognitive difficulties and fatigue in a well-characterized cohort of long-term cALL survivors and (2) explore the risk of having neurocognitive deficits as a function of fatigue.

Safety and Tolerability of tDCS across Different Ages, Sexes, Diagnoses, and Amperages: A Randomized Double-Blind Controlled Study.

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with substantial evidence for its safety and tolerability in adults. However, less than 5% of published tDCS research is in pediatrics. Our primary objective was to investigate tDCS safety, tolerability, and acceptability in a sample of children and adults.

An exploratory analysis of the performance of methylphenidate regimens based on a PKPD model of dopamine and norepinephrine transporter occupancy.

Methylphenidate (MPH) is a psychostimulant which inhibits the uptake of dopamine and norepinephrine transporters, DAT and NET, and is mostly used to treat Attention Deficit/Hyperactivity Disorder. The current dose optimization is done through titration, a cumbersome approach for patients. To assess the therapeutic performance of MPH regimens, we introduce an in silico framework composed of (i) a population pharmacokinetic model of MPH, (ii) a pharmacodynamic (PD) model of DAT and NET occupancy, (iii) a therapeutic box delimited by time and DAT occupancy, and (iv) a performance score computation.

A mechanistic model of ADHD as resulting from dopamine phasic/tonic imbalance during reinforcement learning.

Attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children. Although the involvement of dopamine in this disorder seems to be established, the nature of dopaminergic dysfunction remains controversial. The purpose of this study was to test whether the key response characteristics of ADHD could be simulated by a mechanistic model that combines a decrease in tonic dopaminergic activity with an increase in phasic responses in cortical-striatal loops during learning reinforcement.

Implementing a Canadian shared-care ADHD program in Beijing: Barriers and facilitators to consider prior to start-up.

Background: The shared care pathway for ADHD is a program developed in Canada with two main strategies: (a) implement a shared care pathway between general practitioners (GPs) and specialists, and (b) step up or down care so that the patient is treated at the most appropriate level of care, depending on the complexity or outcome of their illness. The current study aims to identify the challenges and facilitators of implementing this program in a Chinese mental health service setting.

Methods: Two focus groups were conducted using semi-structured interviews with a total of 7 health care providers in Beijing.

Magnetoencephalography resting-state correlates of executive and language components of verbal fluency.

Verbal fluency (VF) is a heterogeneous cognitive function that requires executive as well as language abilities. The purpose of this study was to elucidate the specificity of the resting state MEG correlates of the executive and language components. To this end, we administered a VF test, another verbal test (Vocabulary), and another executive test (Trail Making Test), and we recorded 5-min eyes-open resting-state MEG data in 28 healthy participants.

Two-month administration of methylphenidate improves olfactory sensitivity and suppresses appetite in individuals with obesity.

Olfaction contributes to feeding behaviour and is modulated by changes in dopamine levels. Methylphenidate (MPH) increases brain dopamine levels and has been shown to reduce appetite and promote weight loss in patients with attention deficit hyperactivity disorder. The objectives of this study were to test the effect of MPH on olfaction, appetite, energy intake, and body weight (BW) on individuals with obesity.

Screening for distress in pediatric cancer survivors: A systematic comparison of one-step and two-step strategies to minimize detection errors.

Background: Childhood cancer survivors should be routinely screened for psychological distress. However, existing screening tools promoted by cancer care institutions, such as the Distress Thermometer (DT) generate high rates of errors. The aim of this study is to help refining strategies of screening psychological distress in this population by exploring two-step methods combining the DT on step #1 with one question on step #2.

Differential stress response to psychological and physical stressors in children using spatial versus response-dependent navigation strategies.

Previous work from our lab has shown that basal cortisol levels are different between healthy young adults who spontaneously use caudate nucleus-dependent response strategies compared to young adults who use hippocampus-dependent spatial navigation strategies. Young adults who use caudate nucleus dependent strategies display lower basal cortisol levels compared to those who use hippocampus-dependent strategies. In the current study, we assessed navigation strategies in children using a virtual navigation task and measured cortisol at baseline as well as cortisol reactivity to both a psychological and to a physical stressor.

Systematic Review on the Safety and Tolerability of Transcranial Direct Current Stimulation in Children and Adolescents.

Background: Transcranial direct current stimulation (tDCS) is a safe, tolerable, and acceptable technique in adults. However, there is limited evidence for its safety in youth. Although limited, there are a handful of important empirical articles that have evaluated safety and tolerability outcomes in youth.

An integrative model of Parkinson's disease treatment including levodopa pharmacokinetics, dopamine kinetics, basal ganglia neurotransmission and motor action throughout disease progression.

Levodopa is considered the gold standard treatment of Parkinson's disease. Although very effective in alleviating symptoms at their onset, its chronic use with the progressive neuronal denervation in the basal ganglia leads to a decrease in levodopa's effect duration and to the appearance of motor complications. This evolution challenges the establishment of optimal regimens to manage the symptoms as the disease progresses.

Nonlinear pharmacodynamics of levodopa through Parkinson's disease progression.

The effect of levodopa in alleviating the symptoms of Parkinson's disease is altered in a highly nonlinear manner as the disease progresses. This can be attributed to different compensation mechanisms taking place in the basal ganglia where the dopaminergic neurons are progressively lost. This alteration in the effect of levodopa complicates the optimization of a drug regimen.

Contributing Factors of Unmet Needs Among Young Adult Survivors of Childhood Acute Lymphoblastic Leukemia with Comorbidities.

This study aimed to: (1) describe the domains and levels of unmet needs of young adult survivors of childhood acute lymphoblastic leukemia (cALL) with comorbidities, and (2) to explore the factors associated with higher levels of unmet needs. Unmet need was considered as supportive care needs not met. The most vulnerable cALL survivors from the PETALE study cohort completed the Short-Form Survivor Unmet Needs Survey, the Brief Pain Inventory and the 15D instrument of health-related quality of life.

What Do We Know about Transcranial Direct Current Stimulation for Major Depression?

The interest in using non-invasive brain stimulation (NIBS) for the treatment of major depression (MD), including treatment resistant depression, is growing rapidly. The paper by Bennabi and Haffen ( , ) was an important step towards the formal acceptance of transcranial direct current stimulation (tDCS) as a possible form of therapy. Their review demonstrated favourable support for the beneficial effects of tDCS for MD, coupled with necessary practical considerations, such as its relatively low cost, portability/ease of use in clinical settings, non-invasiveness, and good tolerability.

Acceptability of transcranial direct current stimulation in children and adolescents with ADHD: The point of view of parents.

Transcranial direct current stimulation (tDCS) is a novel treatment option for attention deficit hyperactivity disorder. To facilitate translation into clinical practice, we interviewed parents of children who have experienced experimental tDCS. A grounded theory approach using open, axial, and selective coding provided seven emergent themes for acceptability: tDCS provides hope for parents, safety tolerability and side effects of tDCS versus medication, burden of treatment, education and trust with care providers, cost and coverage, unestablished tDCS efficacy versus established medication effectiveness, perceived compliance of tDCS versus medication.

The effect of cardiorespiratory fitness and physical activity levels on cognitive functions in survivors of childhood acute lymphoblastic leukemia.

Most childhood acute lymphoblastic leukemia (ALL) survivors develop chronic treatment-related adverse effects several years after the end of the treatment. Regular physical activity and a good cardiorespiratory fitness can decrease the risks of neurological disturbances and increase cognitive function scores. The aim of this study was to examine the effect of good cardiorespiratory fitness and physical activity levels on cognitive functions.

What Is the Link Between Attention-Deficit/Hyperactivity Disorder and Sleep Disturbance? A Multimodal Examination of Longitudinal Relationships and Brain Structure Using Large-Scale Population-Based Cohorts.

Background: Attention-deficit/hyperactivity disorder (ADHD) comorbid with sleep disturbances can produce profound disruption in daily life and negatively impact quality of life of both the child and the family. However, the temporal relationship between ADHD and sleep impairment is unclear, as are underlying common brain mechanisms.

Methods: This study used data from the Quebec Longitudinal Study of Child Development (n = 1601, 52% female) and the Adolescent Brain Cognitive Development Study (n = 3515, 48% female).