ABSTRACT
PURPOSE: The MORPHEUS platform was designed to identify early efficacy signals and evaluate the safety of novel immunotherapy combinations across cancer types. The phase Ib/II MORPHEUS-UC trial (NCT03869190) is evaluating atezolizumab plus magrolimab, niraparib, or tocilizumab in platinum-refractory locally advanced or metastatic urothelial carcinoma (mUC). Additional treatment combinations were evaluated and will be reported separately. PATIENTS AND METHODS: Patients had locally advanced or mUC that progressed during or following treatment with a platinum-containing regimen. The primary efficacy endpoint was investigator-assessed objective response rate (ORR). Key secondary endpoints included investigator-assessed progression-free survival (PFS) and overall survival (OS). Safety and exploratory biomarker analyses were also conducted. RESULTS: Seventy-six patients were randomized to receive either atezolizumab plus magrolimab (n = 16), atezolizumab plus niraparib (n = 15), atezolizumab plus tocilizumab (n = 15), or atezolizumab monotherapy (control; n = 30). No additive benefit in ORR, PFS, or OS was seen in the treatment arms versus the control. The best confirmed ORR was 26.7% with atezolizumab plus magrolimab, 6.7% with atezolizumab plus niraparib, 20.0% with atezolizumab plus tocilizumab, and 27.6% with atezolizumab monotherapy. Overall, the treatment combinations were tolerable, and adverse events were consistent with each agent's known safety profile. Trends were observed for shrinkage of programmed death-ligand 1-positive tumors (atezolizumab, atezolizumab plus magrolimab, atezolizumab plus tocilizumab), inflamed tumors, or tumors with high mutational burden (atezolizumab), and immune excluded tumors (atezolizumab plus magrolimab). CONCLUSIONS: The evaluated regimens in MORPHEUS-UC were tolerable. However, response rates for the combinations did not meet the criteria for further development in platinum-experienced locally advanced or mUC.
Subject(s)
Carcinoma, Transitional Cell , Urinary Bladder Neoplasms , Urologic Neoplasms , Humans , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Carcinoma, Transitional Cell/pathology , Platinum/therapeutic use , Urologic Neoplasms/pathologyABSTRACT
The central amygdala (CeA) orchestrates adaptive responses to emotional events. While CeA substrates for defensive behaviors have been studied extensively, CeA circuits for appetitive behaviors and their relationship to threat-responsive circuits remain poorly defined. Here, we demonstrate that the CeA sends robust inhibitory projections to the lateral substantia nigra (SNL) that contribute to appetitive and aversive learning in mice. CeAâSNL neural responses to appetitive and aversive stimuli were modulated by expectation and magnitude consistent with a population-level salience signal, which was required for Pavlovian conditioned reward-seeking and defensive behaviors. CeAâSNL terminal activation elicited reinforcement when linked to voluntary actions but failed to support Pavlovian associations that rely on incentive value signals. Consistent with a disinhibitory mechanism, CeA inputs preferentially target SNL GABA neurons, and CeAâSNL and SNL dopamine neurons respond similarly to salient stimuli. Collectively, our results suggest that amygdala-nigra interactions represent a previously unappreciated mechanism for influencing emotional behaviors.
Subject(s)
Appetitive Behavior/physiology , Avoidance Learning/physiology , Central Amygdaloid Nucleus/physiology , Dopaminergic Neurons/physiology , GABAergic Neurons/physiology , Substantia Nigra/physiology , Animals , Conditioning, Classical/physiology , Emotions , Mice , Neural Pathways , Reinforcement, Psychology , Reward , Substantia Nigra/cytologyABSTRACT
Children who undergo heart transplantation are at risk for long-term neurodevelopmental sequelae secondary to heart disease and its treatment. Detailed neuropsychological profiles in clinical sample status post-pediatric heart transplantation are sparse in the literature, and there is little information regarding predictors of neuropsychological functioning or how it relates to medication adherence in this population. The present study examined these questions in a retrospective analysis of 27 pediatric heart transplantation recipients referred for clinical neuropsychological evaluation. The sample demonstrated mild-to-moderate decrements across domains of neuropsychological functioning. Children with premorbid congenital heart disease performed more poorly in working memory, word reading, and parent-rated conceptual adaptive skills compared to children with premorbid cardiomyopathy. Additionally, a higher number of rejection episodes were related to poorer verbal memory. Children with parent-reported attention problems had better adherence to immunosuppressant medication, which may have represented greater caregiver involvement in medication management. Taken together, clinically referred children with history of heart transplantation showed broad-based difficulties across neuropsychological domains according to formal testing and parent rating scales. This population requires routine neuropsychological monitoring and intervention.
Subject(s)
Heart Diseases/surgery , Heart Transplantation/psychology , Medication Adherence/psychology , Neurodevelopmental Disorders/etiology , Postoperative Complications/etiology , Adolescent , Child , Child, Preschool , Cross-Sectional Studies , Female , Graft Rejection/prevention & control , Heart Diseases/complications , Heart Diseases/psychology , Humans , Immunosuppressive Agents/therapeutic use , Male , Medication Adherence/statistics & numerical data , Neurodevelopmental Disorders/diagnosis , Neurodevelopmental Disorders/epidemiology , Neurodevelopmental Disorders/psychology , Neuropsychological Tests , Postoperative Complications/diagnosis , Postoperative Complications/epidemiology , Postoperative Complications/psychology , Referral and Consultation , Retrospective Studies , Risk FactorsABSTRACT
The extensively abused recreational drug (±)3,4-methylenedioxymethamphetamine (MDMA) has shown promise as an adjunct to psychotherapy for treatment-resistant psychiatric disease. It is unknown, however, whether the mechanisms underlying its prosocial therapeutic effects and abuse potential are distinct. We modeled both the prosocial and nonsocial drug reward of MDMA in mice and investigated the mechanism of these processes using brain region-specific pharmacology, transgenic manipulations, electrophysiology, and in vivo calcium imaging. We demonstrate in mice that MDMA acting at the serotonin transporter within the nucleus accumbens is necessary and sufficient for MDMA's prosocial effect. MDMA's acute rewarding properties, in contrast, require dopaminergic signaling. MDMA's prosocial effect requires 5-HT1b receptor activation and is mimicked by d-fenfluramine, a selective serotonin-releasing compound. By dissociating the mechanisms of MDMA's prosocial effects from its addictive properties, we provide evidence for a conserved neuronal pathway, which can be leveraged to develop novel therapeutics with limited abuse liability.
Subject(s)
Brain/physiology , N-Methyl-3,4-methylenedioxyamphetamine/pharmacology , Reward , Social Behavior , Animals , Dopamine/metabolism , Dopamine Plasma Membrane Transport Proteins/metabolism , Female , Male , Mice, Inbred C57BL , Nucleus Accumbens/drug effects , Nucleus Accumbens/physiology , Receptors, Oxytocin/metabolism , Receptors, Serotonin/metabolism , Serotonin Plasma Membrane Transport Proteins/metabolismABSTRACT
Introduction: To improve access to care and engage adolescent transplant recipients for adherence-promoting interventions, innovative solutions utilizing technology are needed. Materials and Methods: This study describes the implementation of a five-session group intervention targeting medication adherence in adolescent transplant recipients through home-based telemedicine. Results: Seven videoconferencing groups were conducted with a total of 33 participants living a median of 57 miles away from their transplant medical center. The median coefficient of variation (CV) of tacrolimus (immunosuppression medication) decreased from 32.2% to 23.5% from the pregroup to postgroup phase. Analyses indicated that the group was acceptable and engaging for participants, as highlighted by one participant reporting, "I liked how me and the group members came together it felt like a little family." Overall satisfaction with the group and with the technology was endorsed by 86%. The group intervention was generally feasible; however, there were technological difficulties reported by participants and the facilitator, particularly given the diversity of the home-based connections and equipment. Other adaptations helped improve recruitment, attendance, and participation. Discussion: Implementing a telehealth group can pose unique challenges, especially with a group of adolescent participants. Although nonsignificant, we observed a decrease in the median CV of tacrolimus, indicating that medication adherence generally improved after group intervention. Our experience facilitating these groups provides insights into strategies to optimize feasibility and the participant experience. Distance of participants from the hospital is an important consideration and provides a strong rationale for the need for telemedicine-enabled approaches. We explore and discuss the challenges to implementing a home-based group, suggest practical strategies and developmentally sensitive adjustments when working with adolescents, and propose strategies to prepare clinicians for obstacles that may present when implementing a telehealth group with youth.
Subject(s)
Health Services Accessibility/organization & administration , Medication Adherence/statistics & numerical data , Telemedicine/organization & administration , Transplant Recipients , Videoconferencing/organization & administration , Adolescent , Female , Health Behavior , Humans , Immunosuppressive Agents/therapeutic use , Male , Patient Satisfaction , Tacrolimus/therapeutic useABSTRACT
Most decisions share a common goal: maximize reward and minimize punishment. Achieving this goal requires learning which choices are likely to lead to favorable outcomes. Dopamine is essential for this process, enabling learning by signaling the difference between what we expect to get and what we actually get. Although all animals appear to use this dopamine prediction error circuit, some do so more than others, and this neural heterogeneity correlates with individual variability in behavior. In this issue of PLOS Biology, Lee and colleagues show that manipulating a simple task parameter can bias the animals' behavioral strategy and modulate dopamine release, implying that how we learn is just as flexible as what we learn.
Subject(s)
Dopamine , Reward , Animals , Choice Behavior , Learning , MotivationABSTRACT
Non-adherence remains a significant problem among pediatric (and adult) renal transplant recipients. Non-adherence among solid organ transplant recipients results in US$15-100 million annual costs. Estimates of non-adherence range from 30 to 70% among pediatric patients. Research demonstrates that a 10% decrement in adherence is associated with 8% higher hazard of graft failure and mortality. Focus has begun to shift from patient factors that impact adherence to the contributing healthcare and systems factors. The purpose of this review is to describe problems within the systems implicated in non-adherence and potential solutions that may be related to positive adherence outcomes. Systems issues include insurance and legal regulations, provider and care team barriers to optimal care, and difficulties with transitioning to adult care. Potential solutions include recognition of how systems can work together to improve patient outcomes through improvements in insurance programs, a multi-disciplinary care team approach, evidence-based medical management, pharmacy-based applications and interventions to simplify medication regimens, improved transition protocols, and telehealth/technology-based multi-component interventions. However, there remains a significant lack of reliability in the application of these potential solutions to systems issues that impact patient adherence. Future efforts should accordingly focus on these efforts, likely by leveraging quality improvement and related principles, and on the investigation of the efficacy of these interventions to improve adherence and graft outcomes.
Subject(s)
Delivery of Health Care/statistics & numerical data , Kidney Transplantation/adverse effects , Patient Compliance/statistics & numerical data , Transplant Recipients/statistics & numerical data , Adolescent , Child , Humans , Immunosuppressive Agents/administration & dosage , Immunosuppressive Agents/economics , Risk Factors , Young AdultABSTRACT
The aim of this study was to assess healthcare provider perspectives on barriers to medication adherence and to discover recommendations for interventions among providers of pediatric solid-organ transplant patients. An anonymous online survey was administered to a multidisciplinary pool of pediatric transplant providers from February 2015 to March 2016. It consisted of 15 questions regarding transplant providers' attitudes, clinical practice, and beliefs pertaining to medication adherence among teenage solid-organ transplant recipients. Data were analyzed using descriptive statistics. Responses to open-ended questions were coded and categorized into themes. One hundred ten surveys were completed by providers specializing in pediatric heart, kidney, liver, lung, and/or intestinal transplantation. Commonly cited reasons for poor adherence were forgetting/poor planning (94%), the desire to be normal (86%), lack of support (86%), and poor parental monitoring (79%). Suggestions to improve adherence included increasing peer and family support, providing education, and incorporating technology into adherence regimens. Barriers to adherence in transplant patients are recognized by providers and are both similar to and disparate from patient and family identified barriers published in the literature. Providers recognize the importance of education, social support, and technologically driven interventions on improving outcomes in the transplant population.
Subject(s)
Medication Adherence/psychology , Transplant Recipients/psychology , Adolescent , Attitude of Health Personnel , Canada , Health Knowledge, Attitudes, Practice , Humans , Patient Participation , Professional-Patient Relations , Qualitative Research , Social Support , Surveys and Questionnaires , United StatesABSTRACT
We introduce the EPOCH Measure of Adolescent Well-Being, which assesses 5 positive psychological characteristics (Engagement, Perseverance, Optimism, Connectedness, and Happiness) that might foster well-being, physical health, and other positive outcomes in adulthood. To create the measure, a pool of 60 items was compiled, and a series of 10 studies with 4,480 adolescents (age 10-18) from the United States and Australia were used to develop and test the measure, including the factor structure, internal and test-retest reliability, and convergent, discriminant, and predictive validity. The final 20-item measure demonstrated adequate psychometric properties, although additional studies are needed to further validate the measure, extend to other population groups, and examine the extent to which it predicts long-term outcomes. As a brief multidimensional measure, the EPOCH measure contributes to the empirical testing and application of well-being theory, and offers a valuable addition to batteries designed to assess adolescent positive psychological functioning. (PsycINFO Database Record
Subject(s)
Personal Satisfaction , Psychometrics/instrumentation , Surveys and Questionnaires/standards , Adolescent , Australia , Female , Humans , Male , Reproducibility of Results , United StatesABSTRACT
OBJECTIVE: To compare the results of categorically based versus dimensionally based scoring algorithms for a Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV)-referenced teacher rating scale for assessing ADHD and commonly co-occurring conditions and to determine their relative agreement with ratings of symptom-induced impairment. METHOD: Teachers completed Child and Adolescent Symptom Inventory-4R (CASI-4R) ratings for 1,092 youth (ages 6-18 years) referred to a child and adolescent psychiatry outpatient service. Caseness was determined according to DSM-IV symptom count (categorical model) and T-score (dimensional model) criteria. RESULTS: Agreement between symptom count and T-score cutoffs was generally good (kappa ≥ 0.61) for ADHD-Inattentive, ADHD-Hyperactive-Impulsive, ADHD-Combined (except adolescent females), Oppositional Defiant Disorder, and Conduct Disorder, but this was not the case for anxiety and depressive disorders where only 15% of kappas were good. Agreement of impairment cutoff with T-score and symptom count cutoffs ranged from poor to good. CONCLUSION: In general, although in many cases CASI-4R categorical and dimensional scoring algorithms generated similar results, there was considerable variability across disorders, age groups, scoring method, and in some cases, gender. Moreover, symptom counts and T-scores are not a proxy for assessing impairment suggesting that each scoring strategy likely provides unique information for clinical decision-making.
Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnosis , Adolescent , Algorithms , Attention Deficit Disorder with Hyperactivity/complications , Attention Deficit and Disruptive Behavior Disorders/complications , Attention Deficit and Disruptive Behavior Disorders/diagnosis , Child , Conduct Disorder/complications , Conduct Disorder/diagnosis , Diagnosis, Differential , Diagnostic and Statistical Manual of Mental Disorders , Dysthymic Disorder/complications , Dysthymic Disorder/diagnosis , Female , Humans , Hyperkinesis/complications , Hyperkinesis/diagnosis , Male , Retrospective StudiesABSTRACT
The structure-guided design of chloride-conducting channelrhodopsins has illuminated mechanisms underlying ion selectivity of this remarkable family of light-activated ion channels. The first generation of chloride-conducting channelrhodopsins, guided in part by development of a structure-informed electrostatic model for pore selectivity, included both the introduction of amino acids with positively charged side chains into the ion conduction pathway and the removal of residues hypothesized to support negatively charged binding sites for cations. Engineered channels indeed became chloride selective, reversing near -65 mV and enabling a new kind of optogenetic inhibition; however, these first-generation chloride-conducting channels displayed small photocurrents and were not tested for optogenetic inhibition of behavior. Here we report the validation and further development of the channelrhodopsin pore model via crystal structure-guided engineering of next-generation light-activated chloride channels (iC++) and a bistable variant (SwiChR++) with net photocurrents increased more than 15-fold under physiological conditions, reversal potential further decreased by another â¼ 15 mV, inhibition of spiking faithfully tracking chloride gradients and intrinsic cell properties, strong expression in vivo, and the initial microbial opsin channel-inhibitor-based control of freely moving behavior. We further show that inhibition by light-gated chloride channels is mediated mainly by shunting effects, which exert optogenetic control much more efficiently than the hyperpolarization induced by light-activated chloride pumps. The design and functional features of these next-generation chloride-conducting channelrhodopsins provide both chronic and acute timescale tools for reversible optogenetic inhibition, confirm fundamental predictions of the ion selectivity model, and further elucidate electrostatic and steric structure-function relationships of the light-gated pore.
Subject(s)
Avoidance Learning/physiology , Chlorides/metabolism , Ion Channel Gating/physiology , Optogenetics , Rhodopsin/chemistry , Action Potentials , Amino Acid Sequence , Animals , Arginine/chemistry , Avoidance Learning/radiation effects , Basolateral Nuclear Complex/physiology , Basolateral Nuclear Complex/radiation effects , Cells, Cultured , Dependovirus/genetics , Electroshock , Fear , Fiber Optic Technology , Genetic Vectors/administration & dosage , Genetic Vectors/genetics , HEK293 Cells , Hippocampus/cytology , Histidine/chemistry , Humans , Hydrogen-Ion Concentration , Ion Channel Gating/radiation effects , Male , Memory/physiology , Memory/radiation effects , Mice , Mice, Inbred C57BL , Models, Molecular , Molecular Sequence Data , Mutagenesis, Site-Directed , Neurons/physiology , Protein Conformation , Rats , Rats, Sprague-Dawley , Rhodopsin/metabolism , Rhodopsin/radiation effects , Sequence Alignment , Ventral Tegmental Area/physiologyABSTRACT
Dopamine (DA) neurons in the midbrain ventral tegmental area (VTA) integrate complex inputs to encode multiple signals that influence motivated behaviors via diverse projections. Here, we combine axon-initiated viral transduction with rabies-mediated trans-synaptic tracing and Cre-based cell-type-specific targeting to systematically map input-output relationships of VTA-DA neurons. We found that VTA-DA (and VTA-GABA) neurons receive excitatory, inhibitory, and modulatory input from diverse sources. VTA-DA neurons projecting to different forebrain regions exhibit specific biases in their input selection. VTA-DA neurons projecting to lateral and medial nucleus accumbens innervate largely non-overlapping striatal targets, with the latter also sending extensive extra-striatal axon collaterals. Using electrophysiology and behavior, we validated new circuits identified in our tracing studies, including a previously unappreciated top-down reinforcing circuit from anterior cortex to lateral nucleus accumbens via VTA-DA neurons. This study highlights the utility of our viral-genetic tracing strategies to elucidate the complex neural substrates that underlie motivated behaviors.
Subject(s)
Neural Pathways , Neurons/metabolism , Ventral Tegmental Area/cytology , Ventral Tegmental Area/metabolism , Animals , Brain Mapping , Dopamine/metabolism , Mice , Mice, Inbred C57BL , Nucleus Accumbens/metabolism , Rabies virus , gamma-Aminobutyric Acid/metabolismABSTRACT
Research investigating attention-deficit/hyperactivity disorder (ADHD) and co-occurring disorders such as oppositional defiant disorder, conduct disorder, anxiety, and depression has surged in popularity; however, the developmental relations between ADHD and these comorbid conditions remain poorly understood. The current paper uses a developmental psychopathology perspective to examine conditions commonly comorbid with ADHD during late childhood through adolescence. First, we present evidence for ADHD and comorbid disorders. Next, we discuss emotion regulation and its associations with ADHD. The role of parenting behaviors in the development and maintenance of emotion regulation difficulties and comorbid disorders among children with ADHD is explored. An illustrative example of emotion regulation and parenting over the course of development is provided to demonstrate bidirectional relations among these constructs. We then present an integrated conceptual model of emotion regulation as a shared risk process that may lead to different comorbid conditions among children with ADHD. Implications and directions for future research are presented.
Subject(s)
Anxiety Disorders/psychology , Attention Deficit Disorder with Hyperactivity/psychology , Attention Deficit and Disruptive Behavior Disorders/psychology , Conduct Disorder/psychology , Depressive Disorder/psychology , Emotions/physiology , Adolescent , Anxiety Disorders/complications , Attention Deficit Disorder with Hyperactivity/complications , Attention Deficit and Disruptive Behavior Disorders/complications , Child , Conduct Disorder/complications , Depressive Disorder/complications , Humans , ParentingABSTRACT
Ventral tegmental area (VTA) dopamine (DA) neurons have been implicated in reward, aversion, salience, cognition, and several neuropsychiatric disorders. Optogenetic approaches involving transgenic Cre-driver mouse lines provide powerful tools for dissecting DA-specific functions. However, the emerging complexity of VTA circuits requires Cre-driver mouse lines that restrict transgene expression to a precisely defined cell population. Because of recent work reporting that VTA DA neurons projecting to the lateral habenula release GABA, but not DA, we performed an extensive anatomical, molecular, and functional characterization of prominent DA transgenic mouse driver lines. We find that transgenes under control of the tyrosine hydroxylase, but not the dopamine transporter, promoter exhibit dramatic non-DA cell-specific expression patterns within and around VTA nuclei. Our results demonstrate how Cre expression in unintentionally targeted cells in transgenic mouse lines can confound the interpretation of supposedly cell-type-specific experiments. This Matters Arising paper is in response to Stamatakis et al. (2013), published in Neuron. See also the Matters Arising Response paper by Stuber et al. (2015), published concurrently with this Matters Arising in Neuron.
Subject(s)
Action Potentials/physiology , Dopamine Plasma Membrane Transport Proteins/genetics , Dopamine/metabolism , Dopaminergic Neurons/metabolism , GABAergic Neurons/metabolism , Habenula/metabolism , Mice, Transgenic/genetics , Ventral Tegmental Area/metabolism , gamma-Aminobutyric Acid/metabolism , Animals , Dopamine Plasma Membrane Transport Proteins/metabolism , Gene Expression , Mesencephalon/metabolism , Mice , Mice, Transgenic/metabolism , Models, Animal , Promoter Regions, Genetic , Transcriptional ActivationABSTRACT
The brain's remarkable capacity to generate cognition and behavior is mediated by an extraordinarily complex set of neural interactions that remain largely mysterious. This complexity poses a significant challenge in developing therapeutic interventions to ameliorate psychiatric disease. Accordingly, few new classes of drugs have been made available for patients with mental illness since the 1950s. Optogenetics offers the ability to selectively manipulate individual neural circuit elements that underlie disease-relevant behaviors and is currently accelerating the pace of preclinical research into neurobiological mechanisms of disease. In this review, we highlight recent findings from studies that employ optogenetic approaches to gain insight into normal and aberrant brain function relevant to mental illness. Emerging data from these efforts offers an exquisitely detailed picture of disease-relevant neural circuits in action, and hints at the potential of optogenetics to open up entirely new avenues in the treatment of psychiatric disorders.
Subject(s)
Brain/pathology , Mental Disorders/pathology , Nerve Net/pathology , Neural Pathways/pathology , Optogenetics , Brain/metabolism , Humans , Photic StimulationABSTRACT
The neural basis of positive reinforcement is often studied in the laboratory using intracranial self-stimulation (ICSS), a simple behavioral model in which subjects perform an action in order to obtain exogenous stimulation of a specific brain area. Recently we showed that activation of ventral tegmental area (VTA) dopamine neurons supports ICSS behavior, consistent with proposed roles of this neural population in reinforcement learning. However, VTA dopamine neurons make connections with diverse brain regions, and the specific efferent target(s) that mediate the ability of dopamine neuron activation to support ICSS have not been definitively demonstrated. Here, we examine in transgenic rats whether dopamine neuron-specific ICSS relies on the connection between the VTA and the nucleus accumbens (NAc), a brain region also implicated in positive reinforcement. We find that optogenetic activation of dopaminergic terminals innervating the NAc is sufficient to drive ICSS, and that ICSS driven by optical activation of dopamine neuron somata in the VTA is significantly attenuated by intra-NAc injections of D1 or D2 receptor antagonists. These data demonstrate that the NAc is a critical efferent target sustaining dopamine neuron-specific ICSS, identify receptor subtypes through which dopamine acts to promote this behavior, and ultimately help to refine our understanding of the neural circuitry mediating positive reinforcement.
Subject(s)
Dopamine/metabolism , Dopaminergic Neurons/metabolism , Mesencephalon/cytology , Nucleus Accumbens/metabolism , Receptors, Dopamine D1/metabolism , Receptors, Dopamine D2/metabolism , Reinforcement, Psychology , Animals , Bacterial Proteins/metabolism , Behavior, Animal , Luminescent Proteins/metabolism , Male , Rats , Rats, Long-Evans , Rats, Transgenic , Reward , Time FactorsABSTRACT
Individuals with ASD have significant impairments in adaptive skills, particularly adaptive socialization skills. The present study examined the extent to which 20 items from the Vineland Adaptive Behavior Scales-Socialization Domain differentiated between ASD and developmentally delayed (DD) groups. Participants included 108 toddlers with ASD or DD under the age of 3 years. Nine of the 20 items significantly distinguished the groups. The ASD group demonstrated significantly weaker socialization skills, including deficits in basic social behaviors. The results support the notion that (a) socialization deficits in ASD impact foundational social skills typically emerging in the first year of life, (b) examination of specific social adaptive behaviors contribute to differential diagnosis, and (c) foundational social behaviors should be targeted for intervention.
Subject(s)
Adaptation, Psychological , Child Development Disorders, Pervasive/physiopathology , Social Behavior , Child Development Disorders, Pervasive/diagnosis , Child, Preschool , Developmental Disabilities/diagnosis , Developmental Disabilities/physiopathology , Diagnosis, Differential , Female , Humans , Infant , MaleABSTRACT
Situations in which rewards are unexpectedly obtained or withheld represent opportunities for new learning. Often, this learning includes identifying cues that predict reward availability. Unexpected rewards strongly activate midbrain dopamine neurons. This phasic signal is proposed to support learning about antecedent cues by signaling discrepancies between actual and expected outcomes, termed a reward prediction error. However, it is unknown whether dopamine neuron prediction error signaling and cue-reward learning are causally linked. To test this hypothesis, we manipulated dopamine neuron activity in rats in two behavioral procedures, associative blocking and extinction, that illustrate the essential function of prediction errors in learning. We observed that optogenetic activation of dopamine neurons concurrent with reward delivery, mimicking a prediction error, was sufficient to cause long-lasting increases in cue-elicited reward-seeking behavior. Our findings establish a causal role for temporally precise dopamine neuron signaling in cue-reward learning, bridging a critical gap between experimental evidence and influential theoretical frameworks.
Subject(s)
Association Learning/physiology , Conditioning, Operant/physiology , Dopaminergic Neurons/physiology , Ventral Tegmental Area/cytology , Acoustic Stimulation , Animals , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Channelrhodopsins , Cues , Electric Stimulation , Estrous Cycle/genetics , Extinction, Psychological/physiology , Female , Food Preferences/physiology , Functional Laterality/genetics , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Optogenetics , Predictive Value of Tests , Rats , Rats, Long-Evans , Rats, Transgenic , Reward , Tyrosine 3-Monooxygenase/genetics , Tyrosine 3-Monooxygenase/metabolismABSTRACT
Dopamine (DA) is known to play essential roles in neural function and behavior. Accordingly, DA neurons have been the focus of intense experimental investigation that has led to many important advances in our understanding of how DA influences these processes. However, it is becoming increasingly appreciated that delineating the precise contributions of DA neurons to cellular, circuit, and systems-level phenomena will require more sophisticated control over their patterns of activity than conventional techniques can provide. Specifically, the roles played by DA neurons are likely to depend on their afferent and efferent connectivity, the timing and length of their neural activation, and the nature of the behavior under investigation. Recently developed optogenetic tools hold great promise for disentangling these complex issues. Here we discuss the use of light-sensitive microbial opsins in the context of outstanding questions in DA research. A major technical advance offered by these proteins is the ability to bidirectionally modulate DA neuron activity in in vitro and in vivo preparations on a time scale that more closely approximates those of neural, perceptual and behavioral events. In addition, continued advances in rodent genetics and viral-mediated gene delivery have contributed to the ability to selectively target DA neurons or their individual afferent and efferent connections. Further, these tools are suitable for use in experimental subjects engaged in complex behaviors. After reviewing the strengths and limitations of optogenetic methodologies, we conclude by describing early efforts in the application of this valuable new approach that demonstrate its potential to improve our understanding of the neural and behavioral functions of DA. This article is part of a Special Issue entitled Optogenetics (7th BRES).
Subject(s)
Behavior , Causality , Dopaminergic Neurons/physiology , Optogenetics , Action Potentials/genetics , Action Potentials/physiology , Animals , Brain/cytology , Dopamine/genetics , Dopamine/metabolism , Photic StimulationABSTRACT
Currently there is no general approach for achieving specific optogenetic control of genetically defined cell types in rats, which provide a powerful experimental system for numerous established neurophysiological and behavioral paradigms. To overcome this challenge we have generated genetically restricted recombinase-driver rat lines suitable for driving gene expression in specific cell types, expressing Cre recombinase under the control of large genomic regulatory regions (200-300 kb). Multiple tyrosine hydroxylase (Th)::Cre and choline acetyltransferase (Chat)::Cre lines were produced that exhibited specific opsin expression in targeted cell types. We additionally developed methods for utilizing optogenetic tools in freely moving rats and leveraged these technologies to clarify the causal relationship between dopamine (DA) neuron firing and positive reinforcement, observing that optical stimulation of DA neurons in the ventral tegmental area (VTA) of Th::Cre rats is sufficient to support vigorous intracranial self-stimulation (ICSS). These studies complement existing targeting approaches by extending the generalizability of optogenetics to traditionally non-genetically-tractable but vital animal models.