Search

BACKGROUND Outcome of infants with tracheostomy have not been well described in the literature. Our objective was to describe the respiratory, growth, and survival outcomes of infants with tracheostomy. METHODS A retrospective study was conducted on 204 infants born between 2005 and 2015 with tracheostomy at

Rationale: Neuroendocrine cell hyperplasia of infancy (NEHI) is an important form of children’s interstitial and diffuse lung disease for which the diagnostic strategy has evolved. The prevalence of comorbidities in NEHI that may influence treatment has not been previously assessed. Objectives: To evaluate a previously unpublished NEHI clinical score for assistance in diagnosis of NEHI and to assess comorbidities in NEHI. Methods: We performed a retrospective chart review of 199 deidentified patients with NEHI from 11 centers. Data were collected in a centralized Research Electronic Data Capture registry and we performed descriptive statistics. Results: The majority of patients with NEHI were male (66%). The sensitivity of the NEHI Clinical Score was 87% (95% confidence interval [CI], 0.82–0.91) for all patients from included centers and 93% (95% CI, 0.86–0.97) for those with complete scores (e.g., no missing data). Findings were similar when we limited the population to the 75 patients diagnosed by lung biopsy (87%; 95% CI, 0.77–0.93). Of those patients evaluated for comorbidities, 51% had gastroesophageal reflux, 35% had aspiration or were at risk for aspiration, and 17% had evidence of immune system abnormalities. Conclusions: The NEHI Clinical Score is a sensitive tool for clinically evaluating NEHI; however, its specificity has not yet been addressed. Clinicians should consider evaluating patients with NEHI for comorbidities, including gastroesophageal reflux, aspiration, and immune system abnormalities, because these can contribute to the child’s clinical picture and may influence clinical course and treatment.

Decades of research have shown that the NAc is a critical region influencing addiction, mood, and food consumption through its effects on reinforcement learning, motivation, and hedonic experience. Pharmacological studies have demonstrated that inhibition of the NAc shell induces voracious feeding, leading to the hypothesis that the inhibitory projections that emerge from the NAc normally act to restrict feeding. While much of this work has focused on projections to the lateral hypothalamus, the role of NAc projections to the VTA in the control food intake has been largely unexplored. Using a retrograde viral labeling technique and real-time monitoring of neural activity with fiber photometry, we find that medial NAc shell projections to the VTA (mNAc→VTA) are inhibited during food-seeking and food consumption in male mice. We also demonstrate that this circuit bidirectionally controls feeding: optogenetic activation of NAc projections to the VTA inhibits food-seeking and food intake (in both sexes), while optogenetic inhibition of this circuit potentiates food-seeking behavior. Additionally, we show that activity of the NAc to VTA pathway is necessary for adaptive inhibition of food intake in response to external cues. These data provide new insight into NAc control over feeding in mice, and contribute to an emerging literature elucidating the role of inhibitory midbrain feedback within the mesolimbic circuit. SIGNIFICANCE STATEMENT The medial NAc has long been known to control consummatory behavior, with particular focus on accumbens projections to the lateral hypothalamus. Conversely, NAc projections to the VTA have mainly been studied in the context of drug reward. We show that NAc projections to the VTA bidirectionally control food intake, consistent with a permissive role in feeding. Additionally, we show that this circuit is normally inactivated during consumption and food-seeking. Together, these findings elucidate how mesolimbic circuits control food consumption.

Objective: Nonadherence to inhaled corticosteroids contributes to poor asthma control. This study evaluated two different theory-based intervention approaches to address nonadherence in adults with asthma using a person-based, qualitative approach to investigate comprehensibility, coherence and acceptability.Methods: The two intervention approaches addressed treatment beliefs and misconceptions in asthma, aiming to provide a common-sense rationale for medication adherence. Approach one reframed asthma using a concept of balance, the second approach was more traditional presenting medical consequences of nonadherence. We ran three focus group interviews involving 19 adults with asthma to investigate patient acceptability of the intervention approaches and their influence on perceptions of asthma and medication.Results: Approach one was perceived as novel compared to current practice, logical and easily understandable. Its use of non-medical jargon was perceived as representing information more positively, moving away from stigmatizing people with asthma. Approach two was perceived as not sufficiently novel, not applicable to everyone's illness experience and triggering fear.Conclusions: Patient feedback allowed us to refine our intervention strategy prior to running costly feasibility trials. Patient-based approaches for intervention planning may facilitate implementation and acceptability of interventions in practice.

N-methyl-D-aspartate receptor (NMDAR) modulators have recently received increased attention as potential therapeutics for posttraumatic stress disorder (PTSD). Here, we tested a novel NMDAR-positive modulator, NYX-783, in the following two rodent models of PTSD: an auditory fear-conditioning model and a single-prolonged stress (SPS) model. We examined the ability of NYX-783 to reduce subsequent fear-based behaviors by measuring enhanced fear extinction and reduced spontaneous recovery (spontaneous return of fear) in male mice. NYX-783 administration significantly reduced spontaneous recovery in both PTSD models and enhanced fear extinction in the SPS model. Furthermore, NYX-783 increased the NMDA-induced inward currents of excitatory and inhibitory neurons in the infralimbic medial prefrontal cortex (IL mPFC) and that the GluN2B subunit of NMDARs on pyramidal neurons in the IL mPFC is required for its effect on spontaneous recovery. The downstream expression of brain-derived neurotrophic factor was required for NYX-783 to achieve its behavioral effect. These results elucidate the cellular targets of NYX-783 and the molecular mechanisms underlying the inhibition of spontaneous recovery. These preclinical findings support the hypothesis that NYX-783 may have therapeutic potential for PTSD treatment and may be particularly useful for inhibiting spontaneous recovery.

Background Metabotropic glutamate receptor 5 (mGlu5) plays an important role in excessive alcohol use and the mGlu5/Homer2/Erk2 signaling pathway has been implicated in binge drinking. The mGlu5 negative allosteric modulator (NAM) 2-methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP) has been shown to reduce binge drinking in male mice, but less is known about its effect on female mice. Here, we sought to determine whether sex differences exists in the effects of MPEP on binge drinking and whether they relate to changes in the MPEP mGlu5/Homer2/Erk2 signaling. Methods We measured the dose-response effect of MPEP on alcohol consumption in male and female mice using the Drinking in the Dark (DID) paradigm to assess potential sex differences. To rule out possible confounds of MPEP on locomotion, we measured the effects of MPEP on locomotor activity and drinking simultaneously during DID. Lastly, to test whether MPEP-induced changes in alcohol consumption were related to changes in Homer2 or Erk2 expression, we performed qPCR using brain tissue acquired from mice that had undergone 7 days of DID. Results 30 mg/kg MPEP reduced binge alcohol consumption across female and male mice, with no sex differences in the dose-response relationship. Locomotor activity did not mediate the effects of MPEP on alcohol intake, but activity correlated with alcohol intake independent of MPEP. MPEP did not change the expression of Homer2 and Erk2 mRNA in the bed nucleus of the stria terminalis (BNST) or nucleus accumbens in mice whose drinking was reduced by MPEP, relative to saline. There was a positive relationship between alcohol intake and Homer2 expression in the BNST. Conclusions MPEP reduced alcohol consumption during DID in male and female C57BL/6 mice but did not change Homer2/Erk2 expression. Locomotor activity did not mediate the effects of MPEP on alcohol intake, though it correlated with alcohol intake. Alcohol intake during DID predicted BNST Homer2 expression. These data provide support for the regulation of alcohol consumption by mGlu5 across sexes.

The compulsive, habitual behaviors that have been observed in individuals diagnosed with substance use disorders may be due to disruptions in the neural circuits that mediate goal-directed actions. The endocannabinoid system has been shown to play a critical role in habit learning, but the role of this neuromodulatory system in habit expression is unclear. Here, we investigated the role of the endocannabinoid system in established habitual actions using contingency degradation in male C57BL/6 mice. We found that administration of the endocannabinoid transport inhibitor AM404 reduced habitual responding for food and that antagonism of cannabinoid receptor type 1 (CB1), but not transient receptor potential cation subfamily V (TRPV1), receptors produced a similar reduction in habitual responding. Moreover, pharmacological stimulation of CB1 receptors increased habitual responding for food. Co-administration of an enzyme inhibitor that selectively increases the endocannabinoid 2-arachidonoyl glycerol (2-AG) with AM404 partially restored habitual responding for food. Together, these findings demonstrate an important role for the endocannabinoid system in the expression of habits and provide novel insights into potential pharmacological strategies for reducing habitual behaviors in mental disorders.

The most dynamic period of postnatal brain development occurs during adolescence, the period between childhood and adulthood. Neuroimaging studies have observed morphologic and functional changes during adolescence, and it is believed that these changes serve to improve the functions of circuits that underlie decision-making. Direct evidence in support of this hypothesis, however, has been limited because most preclinical decision-making paradigms are not readily translated to humans. Here, we developed a reversal-learning protocol for the rapid assessment of adaptive choice behavior in dynamic environments in rats as young as postnatal day 30. A computational framework was used to elucidate the reinforcement-learning mechanisms that change in adolescence and into adulthood. Using a cross-sectional and longitudinal design, we provide the first evidence that value-based choice behavior in a reversal-learning task improves during adolescence in male and female Long–Evans rats and demonstrate that the increase in reversal performance is due to alterations in value updating for positive outcomes. Furthermore, we report that reversal-learning trajectories in adolescence reliably predicted reversal performance in adulthood. This novel behavioral protocol provides a unique platform for conducting biological and systems-level analyses of the neurodevelopmental mechanisms of decision-making. SIGNIFICANCE STATEMENT The neurodevelopmental adaptations that occur during adolescence are hypothesized to underlie age-related improvements in decision-making, but evidence to support this hypothesis has been limited. Here, we describe a novel behavioral protocol for rapidly assessing adaptive choice behavior in adolescent rats with a reversal-learning paradigm. Using a computational approach, we demonstrate that age-related changes in reversal-learning performance in male and female Long–Evans rats are linked to specific reinforcement-learning mechanisms and are predictive of reversal-learning performance in adulthood. Our behavioral protocol provides a unique platform for elucidating key components of adolescent brain function.

Flexible decision-making in dynamic environments requires both retrospective appraisal of reinforced actions and prospective reasoning about the consequences of actions. These complementary reinforcement-learning systems can be characterized computationally with model-free and model-based algorithms, but how these processes interact at a neurobehavioral level in normal and pathological states is unknown. Here, we developed a translationally analogous multistage decision-making (MSDM) task to independently quantify model-free and model-based behavioral mechanisms in rats. We provide the first direct evidence that male rats, similar to humans, use both model-free and model-based learning when making value-based choices in the MSDM task and provide novel analytic approaches for independently quantifying these reinforcement-learning strategies. Furthermore, we report thatex vivodopamine tone in the ventral striatum and orbitofrontal cortex correlate with model-based, but not model-free, strategies, indicating that the biological mechanisms mediating decision-making in the multistage task are conserved in rats and humans. This new multistage task provides a unique behavioral platform for conducting systems-level analyses of decision-making in normal and pathological states.SIGNIFICANCE STATEMENTDecision-making is influenced by both a retrospective “model-free” system and a prospective “model-based” system in humans, but the biobehavioral mechanisms mediating these learning systems in normal and disease states are unknown. Here, we describe a translationally analogous multistage decision-making task to provide a behavioral platform for conducting neuroscience studies of decision-making in rats. We provide the first evidence that choice behavior in rats is influenced by model-free and model-based systems and demonstrate that model-based, but not model-free, learning is associated with corticostriatal dopamine tone. This novel behavioral paradigm has the potential to yield critical insights into the mechanisms mediating decision-making alterations in mental disorders.

Background Interneuronal pathology is implicated in many neuropsychiatric disorders, including autism spectrum disorder (ASD) and Tourette syndrome (TS). Interneurons of the striatum, including the parvalbumin-expressing fast-spiking interneurons (FSIs) and the large cholinergic interneurons (CINs), are affected in patients with TS and in preclinical models of both ASD and TS. Methods To test the causal importance of these neuronal abnormalities, we recapitulated them in vivo in developmentally normal mice using a combination transgenic–viral strategy for targeted toxin-mediated ablation. Results We found that conjoint ~50% depletion of FSIs and CINs in the dorsal striatum of male mice produces spontaneous stereotypy and marked deficits in social interaction. Strikingly, these behavioral effects are not seen in female mice; because ASD and TS have a marked male predominance, this observation reinforces the potential relevance of the finding to human disease. Neither of these effects is seen when only one or the other interneuronal population is depleted; ablation of both is required. Depletion of FSIs, but not of CINs, also produces anxiety-like behavior, as has been described previously. Behavioral pathology in male mice after conjoint FSI and CIN depletion is accompanied by increases in activity-dependent signaling in the dorsal striatum; these alterations were not observed after disruption of only one interneuron type or in doubly depleted female mice. Conclusions These data indicate that disruption of CIN and FSI interneurons in the dorsal striatum is sufficient to produce network and behavioral changes of potential relevance to ASD, in a sexually dimorphic manner.

To identify factors leading to readmission for tracheostomized, ventilator-dependent infants2 years of age.Retrospective cohort study of 117 tracheostomized, ventilator-dependent infants followed through 2 years of age.Home ventilator use (at hospital discharge, 6 and 12 months of age), inhaled steroid use (at 12 and 24 months of age), oxygen dependence (at 6 and 12 months of age) and tracheostomy (at discharge, 6 and 12 months of age) were increased risks for rehospitalization. Equipment malfunction throughout the first 2 years also contributed to readmissions. Viral infection, with rhinovirus/enterovirus the most commonly identified pathogen, was the most common etiology for rehospitalization. Diuretic use and initial comorbid diagnoses were not associated with increased risk of rehospitalization.The risk for rehospitalization for infants requiring tracheostomy and ventilator support was affected by prolonged oxygen use, prolonged ventilator dependence, inhaled steroid use and equipment malfunction, and was equally distributed throughout the first 2 years of life.

Impaired fear extinction contributes to the persistence of post-traumatic stress disorder (PTSD), and can be utilized for the study of novel therapeutic agents. Glutamate plays an important role in the formation of traumatic memories, and in the pathophysiology and treatment of PTSD, highlighting several possible drug targets. Recent clinical studies demonstrate that infusion of ketamine, a glutamate NMDA receptor antagonist, rapidly and significantly reduces symptom severity in PTSD patients. In the present study, we examine the mechanisms underlying the actions of ketamine in a rodent model of fear conditioning, extinction, and renewal. Rats received ketamine or saline 24 h after fear conditioning and were then subjected to extinction-training on each of the following three days. Ketamine administration enhanced extinction on the second day of training (i.e., reduced freezing behavior to cue) and produced a long-lasting reduction in freezing on exposure to cue plus context 8 days later. Additionally, ketamine and extinction exposure increased levels of mTORC1 in the medial prefrontal cortex (mPFC), a region involved in the acquisition and retrieval of extinction, and infusion of the selective mTORC1 inhibitor rapamycin into the mPFC blocked the effects of ketamine on extinction. Ketamine plus extinction also increased cFos in the mPFC and administration of a glutamate-AMPA receptor antagonist blocked the effects of ketamine. These results support the hypothesis that ketamine produces long-lasting mTORC1/protein synthesis and activity dependent effects on neuronal circuits that enhance the expression of extinction and could represent a novel approach for the treatment of PTSD.

Background Schizophrenia is a debilitating neuropsychiatric disorder typically diagnosed from late adolescence to adulthood. Subthreshold behavioral symptoms (e.g., cognitive deficits and substance abuse) often precede the clinical diagnosis of schizophrenia. However, these prodromal symptoms have not been consistently associated with structural and functional brain biomarkers, limiting the chance of early diagnosis of schizophrenia. Methods Using an extensively multimodal range of magnetic resonance methods (for anatomy, metabolism, and function), we screened early biomarkers in a methylazoxymethanol acetate (MAM) rat model of schizophrenia and saline-treated control (SHAM) rats, in conjunction with immunohistochemistry, myelin staining, and a novel three-choice, reversal-learning task to identify early behavioral markers corresponding the subthreshold symptoms. Results MAM (vs. SHAM) rats had lower/higher structural connectivity in anterior/posterior corpus callosum. The orbitofrontal cortex of MAM rats showed lower resting-state functional magnetic resonance imaging functional connectivity in conjunction with lower neuronal density, lower glucose oxidation, and attenuated neurotransmission (hypofrontality). In contrast, these measures were all higher in visual cortex of MAM rats (posterior hyperactivity), which might parallel perceptual problems in schizophrenia. In behavioral studies, MAM (vs. SHAM) rats displayed abnormal orbitofrontal cortex–mediated decision-making processes, resulting in a novel reward-sensitive hyperflexible phenotype, which might reflect vulnerability of prodromal patients to substance abuse. Conclusions We identified two novel biomarkers of early schizophrenia in a preclinical rat model: hypofrontality associated with the hyperflexible phenotype, and posterior hyperactivity. Because each of these magnetic resonance methods is clinically translatable, these markers could contribute to early diagnosis and the development of novel therapies of schizophrenia.

Summary Adaptive decision making in dynamic environments requires multiple reinforcement-learning steps that may be implemented by dissociable neural circuits. Here, we used a novel directionally specific viral ablation approach to investigate the function of several anatomically defined orbitofrontal cortex (OFC) circuits during adaptive, flexible decision making in rats trained on a probabilistic reversal learning task. Ablation of OFC neurons projecting to the nucleus accumbens selectively disrupted performance following a reversal, by disrupting the use of negative outcomes to guide subsequent choices. Ablation of amygdala neurons projecting to the OFC also impaired reversal performance, but due to disruptions in the use of positive outcomes to guide subsequent choices. Ablation of OFC neurons projecting to the amygdala, by contrast, enhanced reversal performance by destabilizing action values. Our data are inconsistent with a unitary function of the OFC in decision making. Rather, distinct OFC-amygdala-striatal circuits mediate distinct components of the action-value updating and maintenance necessary for decision making.

Insufficient sleep is associated with increased risk of chronic diseases, substance use, and unintentional injuries. Little is known about the disparities in short sleep among sexual minority youth.A nationally representative sample of U.S. students in grades 9-12 (n = 14,703) from the 2015 Youth Risk Behavior Survey was analyzed to examine the prevalence and risk factors of short sleep. Self-reported sleep duration (very short: ≤5 h, short: 6-7 h, normal: ≥8 h per day) were compared by sex group (male vs. female) and sexual orientation (heterosexual, gay, lesbian, bisexual, and unsure).Of all respondents, 88.8% were heterosexual/straight, 2.0% were lesbian or gay, 6.0% were bisexual, and 3.2% were unsure about their sexual identity. Bisexual and unsure girls (36.2%, 95% CI [31.3-41.0] and 33.7%, CI [25.6-41.8], respectively) had a higher prevalence of very short sleep duration than straight girls (19.8%, CI [18.3-21.4]). Gay and unsure boys (38.5%, CI [25.6-51.5] and 33.3%, CI [23.5-32.1], respectively) had a higher prevalence of very short sleep duration than straight boys (16.5%, CI [15.1-17.9]). The effects of sexual minority status on very short sleep duration attenuated when incrementally adjusting for influencing factors, and further analysis identified that feeling sad/hopeless had the largest standardized mediation effect.Sexual minority adolescents had a higher prevalence of reporting very short sleep duration as compared to their straight peers, and the effects were mediated by influencing variables including demographic factors, substance use, excessive media use, and experiences of victimization/mental health problems.

Manipulations of memory reconsolidation can interfere with the ability of a drug-paired cue to drive drug-seeking behavior. However, the typical reconsolidation paradigm that reactivates the memory through the presentation of the cue (conditioned stimulus (CS)) only interferes with the memory of the reactivated CS while leaving other drug-paired CSs intact and able to continue driving drug-seeking behavior. Here, we used a novel unconditioned-stimulus (US) reactivation paradigm to interfere with the ability of multiple cues to drive drug-seeking behavior after just one reactivation and treatment session. Rats were trained to self-administer cocaine, during which time each active lever press resulted in an i.v. cocaine infusion paired with one of two cues that alternated within each session. The drug memory was later reactivated with either i.v. or i.p. cocaine presentation in the absence of any cue. The histone acetyltransferase (HAT) inhibitor garcinol or vehicle was injected following US reactivation to impair reconsolidation. Rats were later tested on cue-induced reinstatement to both cues. Garcinol administered after either i.v. or i.p. cocaine reactivation significantly decreased cue-induced reinstatement to both cues, indicative of reconsolidation impairment. In addition, garcinol administered in the absence of reconsolidation or at a 6 h delay when the memory should be restabilized had no effect on reinstatement, further suggesting that garcinol’s effects on reinstatement are through reconsolidation-based mechanisms. Our results demonstrate that a US-reactivation paradigm may be preferable to traditional CS-reactivation paradigms for treating disorders that involve multiple CS–US associations and support investigations of garcinol as a therapeutic pharmacological agent.

Previously consolidated memories have the potential to enter a state of lability upon memory recall, during which time the memory can be altered before undergoing an additional consolidation-like process and being stored again as a long-term memory. Blocking reconsolidation of aberrant memories has been proposed as a potential treatment for psychiatric disorders including addiction. Here we investigated of the effect of systemically administering the protein synthesis inhibitor cycloheximide or the β-adrenergic antagonist propranolol on reconsolidation. Rats were trained to self-administer cocaine, during which each lever press resulted in the presentation of a cue paired with an intravenous infusion of cocaine. After undergoing lever press extinction to reduce operant responding, the cue memory was reactivated and rats were administered systemic injections of propranolol, cycloheximide, or vehicle. Post-reactivation cycloheximide, but not propranolol, resulted in a reactivation-dependent decrease in cue-induced reinstatement, indicative of reconsolidation blockade by protein synthesis inhibition. The present data indicate that systemically targeting protein synthesis as opposed to the β-adrenergic system may more effectively attenuate the reconsolidation of a drug-related memory and decrease drug-seeking behavior.

Sustained abstinence from cocaine use is frequently compromised by exposure to environmental stimuli that have previously been strongly associated with drug taking. Such cues trigger memories of the effects of the drug, leading to craving and potential relapse. Our work has demonstrated that manipulating cocaine-cue memories by destabilizing them through interfering with the reconsolidation process is one potential therapeutic tool by which to prolong abstinence. Here, we examine the use of the naturally occurring amnestic agent garcinol to manipulate an established cocaine-cue memory. Rats underwent 12 days of cocaine self-administration training during which time active lever presses resulted in an i.v. infusion of cocaine that was paired with a light/tone cue. Next rats underwent lever extinction for 8 days followed by light/tone reactivation and a test of cue-induced cocaine-seeking behavior. Systemic injection of garcinol 30 min after reactivation significantly impaired the reconsolidation of the cocaine-associated cue memory. Further testing revealed that garcinol had no effect on drug-induced cocaine-seeking, but was capable of blocking the initial conditioned reinforcing properties of the cue and prevents the acquisition of a new response. Additional experiments showed that the effects of garcinol are specific to reactivated memories only, temporally constrained, cue-specific, long-lasting, and persist following extended cocaine access. These data provide strong evidence that the naturally occurring compound, garcinol, may be a potentially useful tool to sustain abstinence from drug abuse.

RATIONALE: Environmental stimuli, or cues, associated with the use of drugs such as cocaine are one of the primary drivers of relapse. Thus, identifying mechanisms to reduce the motivational properties of drug cues is an important research goal. OBJECTIVES: The purpose of this study was to identify cellular signaling events in the nucleus accumbens (NAc) that are induced when a cocaine cue memory is either extinguished through repeated cue presentation in the absence of drug, or when the memory is reactivated and reconsolidated by a brief cue re-exposure. Signaling events specific to extinction or reconsolidation represent potential targets for pharmacotherapeutics that may enhance extinction or disrupt reconsolidation to reduce the likelihood of relapse. METHODS: Male Sprague-Dawley rats were trained to self-administer cocaine paired with an audiovisual cue. Following a period of self-administration, the memory for the cocaine-associated cue was either extinguished, reactivated, or not manipulated (control) 15 min before sacrifice. Tissue from the NAc was subsequently analyzed using mass spectrometry based phosphoproteomics to identify cellular signaling events induced by each condition. RESULTS: Extinction and reconsolidation of the cocaine cue memory produced both common and distinct changes in protein phosphorylation. Notably, there were no significant changes in protein phosphorylation that were modulated in the opposite direction by the two behavioral conditions. Comparison of NAc phosphoproteomic changes to previously identified changes in the basolateral amygdala (BLA) revealed that cue extinction increases phosphorylation at serine (S) 883 of the GABA(B) receptor subunit 2 and on S14 of syntaxin 1a in both regions, while no common regional signaling events were identified in the reconsolidation group. CONCLUSIONS: Phosphoproteomics is a useful tool for identifying signaling cascades involved in different memory processes and revealed novel potential targets for selectively targeting extinction versus reconsolidation of a cocaine cue memory. Furthermore, cross region analysis suggests that cue extinction may produce unique signaling events associated with increased inhibitory signaling.

Objective This article aimed to identify readmission risk factors through 2 years of life for infants with severe bronchopulmonary dysplasia (BPD) who do not require tracheostomy and ventilatory support after neonatal intensive care unit (NICU) discharge. It also aimed to identify if clinical differences exist between the subcategories of severe BPD. Study Design A retrospective chart review was performed on 182 infants with severe BPD born between 2010 and 2015. A total of 130 infants met the inclusion criteria and were stratified into three groups based on their respiratory status at 36 weeks of gestational age: group A—oxygen (O2), group B—assisted ventilation (AV), group C—both O2 and AV. NICU clinical risk factors for readmission were assessed at set time points (6/12/18/24 months). Reasons for readmission were assessed for the entire cohort and severe BPD subgroups. Conclusion An NICU diagnosis of neurologic abnormality, necrotizing enterocolitis, invasive NICU infection, dysphagia, and O2 at NICU discharge differed between the three subgroups of severe BPD. The most common cause of readmission was viral respiratory tract infection. Inhaled steroid use remained stable over time, while oxygen use and diuretic use declined over time. Risk factors for readmission in the entire cohort included g-tube, O2 use, and diuretic use at 12 months. There was no significant difference in readmission rates between the three BPD subgroups.

Objective To report on the population of infants receiving a tracheostomy, identify acute post-tracheostomy clinical decompensations, and seek predictive markers associated with acute complications following the placement of a tracheostomy. Study Design Retrospective deidentified clinical data was provided by the Infant Pulmonary Data Repository at Children's Mercy Hospital, Kansas City. Data from infants undergoing tracheostomy from January 1, 2008 through September 30, 2016 were divided into one of two study groups based on clinical correlations: (1) no acute decompensations within 72 hours post-tracheostomy or (2) acute clinical decompensation defined as sustained escalation of respiratory care within the 72 hours following tracheostomy. Results Thirty-four percent of infants undergoing tracheostomy during this period developed acute post-tracheostomy clinical decompensations. Elevated pre-tracheostomy positive end expiratory pressure, mean airway pressure, and echocardiogram findings suggestive of pulmonary hypertension (PH) or ventricular dysfunction were associated with acute post-tracheostomy clinical decompensations. Additionally acute post-tracheostomy clinical decompensation was associated with higher rate of death prior to discharge. Conclusion Infants requiring higher respiratory support and infants with PH or ventricular dysfunction are at risk of acute post-tracheostomy clinical decompensation, thus identifying these patients may lead to better pre-tracheostomy counseling and potentially targeted treatments to decrease this risk.

Critical periods are temporary windows of heightened neural plasticity early in development. For example, fear memories in juvenile rodents are subject to erasure following extinction training, while after closure of this critical period, extinction training only temporarily and weakly suppresses fear memories. Persistence of fear memories is important for survival, but the inability to effectively adapt to the trauma is a characteristic of post-traumatic stress disorder. We examined whether Nogo Receptor 1 (NgR1) regulates the plasticity associated with fear extinction. Loss of NgR1 function in adulthood eliminates spontaneous fear recovery and fear renewal, with a restoration of fear reacquisition rate to equal that of naïve mice; thus mimicking the phenotype observed in juvenile rodents. Regional gene disruption demonstrates that NgR1 expression is required in both the basolateral amygdala (BLA) and infralimbic (IL) cortex to prevent fear erasure. NgR1 expression by parvalbumin expressing interneurons is essential for limiting extinction-dependent plasticity. NgR1 gene deletion enhances anatomical changes of inhibitory synapse markers after extinction training. Thus, NgR1 robustly inhibits elimination of fear expression in the adult brain and could serve as a therapeutic target for anxiety disorders, such as post-traumatic stress disorder (PTSD).

Although several studies have examined the subcortical circuitry underlying Pavlovian-to-instrumental transfer (PIT), the role of medial prefrontal cortex in this behavior is largely unknown. Elucidating the cortical contributions to PIT will be key for understanding how reward-paired cues control behavior in both adaptive and maladaptive context (i.e., addiction). Here we use bilateral lesions in a rat model to show that infralimbic prefrontal cortex (ilPFC) is necessary for appropriate expression of PIT. Further, we show that ilPFC mediates this effect via functional connectivity with nucleus accumbens shell (NAcS). Together, these data provide the first demonstration that a specific cortico-striatal circuit is necessary for cue-invigorated reward seeking during specific PIT.

Background Sub-anesthetic doses of the NMDA antagonist ketamine have been shown to model the formation and stability of delusion in human subjects. The latter has been predicted to be due to aberrant prediction error resulting in enhanced destabilization of beliefs. To extend the scope of this model, we investigated the effect of administration of low dose systemic ketamine on memory in a rodent model of memory reconsolidation. Methods Systemic ketamine was administered either prior to or immediately following auditory fear memory reactivation in rats. Memory strength was assessed by measuring freezing behavior 24 h later. Follow up experiments were designed to investigate an effect of pre-reactivation ketamine on short-term memory (STM), closely related memories, and basolateral amygdala (BLA) specific destabilization mechanisms. Results Rats given pre-reactivation, but not post-reactivation, ketamine showed larger freezing responses 24 h later compared to vehicle. This enhancement was not observed 3 h after the memory reactivation, nor was it seen in a closely related contextual memory. Prior inhibition of a known destabilization mechanism in the BLA blocked the effect of pre-reactivation ketamine. Conclusions Pre- but not post-reactivation ketamine enhances fear memory. These data together with recent data in human subjects supports a model of delusion fixity that proposes that aberrant prediction errors result in enhanced destabilization and strengthening of delusional belief.

Despite considerable evidence of higher rates of alcohol use disorders (AUDs) in men than in women, there is a dearth of research into the underlying causes of this disparity. As the gap in high risk drinking between men and women closes, it is critical to disentangle the biological factors that may place men and women at different risk for the development of AUDs as well as AUD-associated health problems. While sex differences in alcohol drinking have been reported in animal models and in human alcoholics, it increasingly seems that consummatory behavior may be dissociated from propensity toward inflexible and cue-elicited drug seeking and taking that characterize alcohol use disorders. While much of this work was initially performed in males a growing, yet limited, body of literature suggests that there are sex differences in both cue reactivity, and further, the relationship between cue reactivity and the maintenance of addictive behavior, indicating that males may be at greater risk for the development of a subset of addiction-related behaviors independent of alcohol consumption. Here, we will review the current literature on sex effects on the relationship between incentive motivation and addictive behavior and discuss unanswered questions that we expect will inform the development of individualized and sex-specific treatment and prevention strategies for AUDs. We believe that a greater understanding of how sex interacts with in cue reactivity to independently mediate the drug taking and risk for the development of uncontrolled drug or alcohol-seeking and -taking will inform the development of individualized treatment and prevention strategies for addiction.

The persistent use of psychostimulant drugs, despite the detrimental outcomes associated with continued drug use, may be because of disruptions in reinforcement-learning processes that enable behavior to remain flexible and goal directed in dynamic environments. To identify the reinforcement-learning processes that are affected by chronic exposure to the psychostimulant methamphetamine (MA), the current study sought to use computational and biochemical analyses to characterize decision-making processes, assessed by probabilistic reversal learning, in rats before and after they were exposed to an escalating dose regimen of MA (or saline control). The ability of rats to use flexible and adaptive decision-making strategies following changes in stimulus-reward contingencies was significantly impaired following exposure to MA. Computational analyses of parameters that track choice and outcome behavior indicated that exposure to MA significantly impaired the ability of rats to use negative outcomes effectively. These MA-induced changes in decision making were similar to those observed in rats following administration of a dopamine D2/3 receptor antagonist. These data use computational models to provide insight into drug-induced maladaptive decision making that may ultimately identify novel targets for the treatment of psychostimulant addiction. We suggest that the disruption in utilization of negative outcomes to adaptively guide dynamic decision making is a new behavioral mechanism by which MA rigidly biases choice behavior.

ObjectivesThe National Health Service (NHS) in England recently introduced general practice pharmacists (GPPs) to provide medication-focused support to both patients and the general practice team. This healthcare model may benefit people with asthma, who currently receive suboptimal care and demonstrate low medication adherence. This study aimed to explore the perspectives of adults with asthma on the potential for pharmacist-led adherence support delivered in general practice, with a focus on how these perspectives are formed.Design and settingThe study was conducted in the United Kingdom (UK) utilising a qualitative interview methodology. Participants were invited to partake in a telephone-based semistructured interview, followed by an online questionnaire for demographic details and asthma history. Qualitative data were analysed using thematic analysis.ParticipantsParticipants (n=17) were adults with asthma in the UK with a prescription for an inhaled corticosteroid. Participants did not have previous experience with GPPs and were asked to provide their views on a proposed GPP-led service.ResultsParticipant perspectives of GPPs were determined by trust in pharmacists, perceived gaps in asthma care and the perceived strain on the NHS. Trust was based on pharmacists’ perceived clinical competency, established over time, and gauged through a ‘benchmarking’ process. GPP’s fit in current asthma care was assessed based on potential role overlap with other healthcare professionals, continuity of care and medication-related support needs. Participants navigated the NHS based on a perceived hierarchy of healthcare professionals (general practitioners on top, nurses, then pharmacists), and this influenced their perspectives of GPPs.ConclusionWhile the GPP scheme shows promise based on the perspectives of people with asthma, the identified barriers to optimal patient engagement and service implementation will need to be addressed for the service to be effective.

Objective: Assess the impact of intercurrent respiratory infections in infants

To assess pulmonary outcomes of infants

The orbitofrontal cortex (oPFC) sends substantial projections to the ventrolateral striatum and aspects of the nucleus accumbens that are, functionally, poorly understood. This is despite probable cortico-striatal involvement in multiple diseases such as addiction and obsessive-compulsive disorder. Here we surgically disconnected the oPFC from the ventrolateral striatum using unilateral asymmetric lesions in mice and classified instrumental decision-making strategies. Mice with symmetric lesions that spared one oPFC-striatal network served as controls. As a complementary approach, we selectively knocked down Brain-derived neurotrophic factor (Bdnf) bilaterally in the oPFC and ascertained behavioral and neurobiological consequences within the downstream striatum. oPFC-striatal disconnection and oPFC Bdnf knockdown blocked sensitivity to outcome-predictive relationships in both food-reinforced and cocaine-associated settings. Bdnf knockdown simultaneously regulated striatal BDNF expression, and striatal c-Fos predicted sensitivity to action-outcome associative contingencies. Previous evidence strongly implicates the dorsolateral striatum in stimulus-response habit formation. Our findings thus provide novel evidence for functional compartmentalisation within the lateral striatum, with the dorsal compartment subserving classical stimulus-response habit systems and a ventral compartment coordinating outcome-based decision-making via oPFC interactions. This compartmentalisation may apply to both 'natural', as in the case of food-reinforced behavior, and 'pathological', as in the case of cocaine-seeking, contexts.

The ability to inhibit drinking is a significant challenge for recovering alcoholics, especially in the presence of alcohol-associated cues. Previous studies have demonstrated that the regulation of cue-guided alcohol seeking is mediated by the basolateral amygdala (BLA), nucleus accumbens (NAc), and medial prefrontal cortex (mPFC). However, given the high interconnectivity between these structures, it is unclear how mPFC projections to each subcortical structure, as well as projections between BLA and NAc, mediate alcohol-seeking behaviors. Here, we evaluate how cortico-striatal, cortico-amygdalar, and amygdalo-striatal projections control extinction and relapse in a rat model of alcohol seeking. Specifically, we used a combinatorial viral technique to express diphtheria toxin receptors in specific neuron populations based on their projection targets. We then used this strategy to create directionally selective ablations of three distinct pathways after acquisition of ethanol self-administration but before extinction and reinstatement. We demonstrate that ablation of mPFC neurons projecting to NAc, but not BLA, blocks cue-induced reinstatement of alcohol seeking and neither pathway is necessary for extinction of responding. Further, we show that ablating BLA neurons that project to NAc disrupts extinction of alcohol approach behaviors and attenuates reinstatement. Together, these data provide evidence that the mPFC→NAc pathway is necessary for cue-induced reinstatement of alcohol seeking, expand our understanding of how the BLA→NAc pathway regulates alcohol behavior, and introduce a new methodology for the manipulation of target-specific neural projections.SIGNIFICANCE STATEMENTThe vast majority of recovering alcoholics will relapse at least once and understanding how the brain regulates relapse will be key to developing more effective behavior and pharmacological therapies for alcoholism. Given the high interconnectivity of cortical, striatal, and limbic structures that regulate alcohol intake, it has been difficult to disentangle how separate projections between them may control different aspects of these complex behaviors. Here, we demonstrate a new approach for noninvasively ablating each of these pathways and testing their necessity for both extinction and relapse. We show that inputs to the nucleus accumbens from medial prefrontal cortex and amygdala regulate alcohol-seeking behaviors differentially, adding to our understanding of the neural control of alcoholism.

Dopamine D2/3 receptor signaling is critical for flexible adaptive behavior; however, it is unclear whether D2, D3, or both receptor subtypes modulate precise signals of feedback and reward history that underlie optimal decision making. Here, PET with the radioligand [11C]-(+)-PHNO was used to quantify individual differences in putative D3 receptor availability in rodents trained on a novel three-choice spatial acquisition and reversal-learning task with probabilistic reinforcement. Binding of [11C]-(+)-PHNO in the midbrain was negatively related to the ability of rats to adapt to changes in rewarded locations, but not to the initial learning. Computational modeling of choice behavior in the reversal phase indicated that [11C]-(+)-PHNO binding in the midbrain was related to the learning rate and sensitivity to positive, but not negative, feedback. Administration of a D3-preferring agonist likewise impaired reversal performance by reducing the learning rate and sensitivity to positive feedback. These results demonstrate a previously unrecognized role for D3 receptors in select aspects of reinforcement learning and suggest that individual variation in midbrain D3 receptors influences flexible behavior. Our combined neuroimaging, behavioral, pharmacological, and computational approach implicates the dopamine D3 receptor in decision-making processes that are altered in psychiatric disorders. SIGNIFICANCE STATEMENT Flexible decision-making behavior is dependent upon dopamine D2/3 signaling in corticostriatal brain regions. However, the role of D3 receptors in adaptive, goal-directed behavior has not been thoroughly investigated. By combining PET imaging with the D3-preferring radioligand [11C]-(+)-PHNO, pharmacology, a novel three-choice probabilistic discrimination and reversal task and computational modeling of behavior in rats, we report that naturally occurring variation in [11C]-(+)-PHNO receptor availability relates to specific aspects of flexible decision making. We confirm these relationships using a D3-preferring agonist, thus identifying a unique role of midbrain D3 receptors in decision-making processes.

GLYX-13 is a putative NMDA receptor modulator with glycine-site partial agonist properties that produces rapid antidepressant effects, but without the psychotomimetic side effects of ketamine. Studies were conducted to examine the molecular, cellular, and behavioral actions of GLYX-13 to further characterize the mechanisms underlying the antidepressant actions of this agent. The results demonstrate that a single dose of GLYX-13 rapidly activates the mTORC1 pathway in the prefrontal cortex (PFC), and that infusion of the selective mTORC1 inhibitor rapamycin into the medial PFC (mPFC) blocks the antidepressant behavioral actions of GLYX-13, indicating a requirement for mTORC1 similar to ketamine. The results also demonstrate that GLYX-13 rapidly increases the number and function of spine synapses in the apical dendritic tuft of layer V pyramidal neurons in the mPFC. Notably, GLYX-13 significantly increased the synaptic responses to hypocretin, a measure of thalamocortical synapses, compared with its effects on 5-HT responses, a measure of cortical-cortical responses mediated by the 5-HT2A receptor. Behavioral studies further demonstrate that GLYX-13 does not influence 5-HT2 receptor induced head twitch response or impulsivity in a serial reaction time task (SRTT), whereas ketamine increased responses in both tests. In contrast, both GLYX-13 and ketamine increased attention in the SRTT task, which is linked to hypocretin–thalamocortical responses. The differences in the 5-HT2 receptor synaptic and behavioral responses may be related to the lack of psychotomimetic side effects of GLYX-13 compared with ketamine, whereas regulation of the hypocretin responses may contribute to the therapeutic benefits of both rapid acting antidepressants.

An essential component of goal-directed decision-making is the ability to maintain flexible responding based on the value of a given reward, or “reinforcer.” The medial orbitofrontal cortex (mOFC), a subregion of the ventromedial prefrontal cortex, is uniquely positioned to regulate this process. We trained mice to nose poke for food reinforcers and then stimulated this region using CaMKII-driven Gs-coupled designer receptors exclusively activated by designer drugs (DREADDs). In other mice, we silenced the neuroplasticity-associated neurotrophin brain-derived neurotrophic factor (BDNF). Activation of Gs-DREADDs increased behavioral sensitivity to reinforcer devaluation, whereasBdnfknockdown blocked sensitivity. These changes were accompanied by modifications in breakpoint ratios in a progressive ratio task, and they were recapitulated inBdnf+/−mice. Replacement of BDNF selectively in the mOFC inBdnf+/−mice rescued behavioral deficiencies, as well as phosphorylation of extracellular-signal regulated kinase 1/2 (ERK1/2). Thus, BDNF expression in the mOFC is both necessary and sufficient for the expression of typical effort allocation relative to an anticipated reinforcer. Additional experiments indicated that expression of the immediate-early gene c-foswas aberrantly elevated in theBdnf+/−dorsal striatum, and BDNF replacement in the mOFC normalized expression. Also, systemic administration of an MAP kinase kinase inhibitor increased breakpoint ratios, whereas the addition of discrete cues bridging the response–outcome contingency rescued breakpoints inBdnf+/−mice. We argue that BDNF–ERK1/2 in the mOFC is a key regulator of “online” goal-directed action selection.SIGNIFICANCE STATEMENTGoal-directed response selection often involves predicting the consequences of one's actions and the value of potential payoffs. Lesions or chemogenetic inactivation of the medial orbitofrontal cortex (mOFC) in rats induces failures in retrieving outcome identity memories (Bradfield et al., 2015), suggesting that the healthy mOFC serves to access outcome value information when it is not immediately observable and thereby guide goal-directed decision-making. Our findings suggest that the mOFC also bidirectionally regulates effort allocation for a given reward and that expression of the neurotrophin BDNF in the mOFC is both necessary and sufficient for mice to sustain stable representations of reinforcer value.

Successful addiction treatment depends on maintaining long-term abstinence, making relapse prevention an essential therapeutic goal. However, exposure to environmental cues associated with drug use often thwarts abstinence efforts by triggering drug using memories that drive craving and relapse. We sought to develop a dual approach for weakening cocaine memories through phosphoproteomic identification of targets regulated in opposite directions by memory extinction compared with reconsolidation in male Sprague-Dawley rats that had been trained to self-administer cocaine paired with an audiovisual cue. We discovered a novel, inversely regulated, memory-dependent phosphorylation event on calcium-calmodulin-dependent kinase II α (CaMKIIα) at serine (S)331. Correspondingly, extinction-associated S331 phosphorylation inhibited CaMKIIα activity. Intra-basolateral amygdala inhibition of CaMKII promoted memory extinction and disrupted reconsolidation, leading to a reduction in subsequent cue-induced reinstatement. CaMKII inhibition had no effect if the memory was neither retrieved nor extinguished. Therefore, inhibition of CaMKII represents a novel mechanism for memory-based addiction treatment that leverages both extinction enhancement and reconsolidation disruption to reduce relapse-like behavior. SIGNIFICANCE STATEMENT Preventing relapse to drug use is an important goal for the successful treatment of addictive disorders. Relapse-prevention therapies attempt to interfere with drug-associated memories, but are often hindered by unintentional memory strengthening. In this study, we identify phosphorylation events that are bidirectionally regulated by the reconsolidation versus extinction of a cocaine-associated memory, including a novel site on CaMKIIα. Additionally, using a rodent model of addiction, we show that CaMKII inhibition in the amygdala can reduce relapse-like behavior. Together, our data supports the existence of mechanisms that can be used to enhance current strategies for addiction treatment.

Stressor exposure biases decision-making strategies from those based on the relationship between actions and their consequences to others restricted by stimulus-response associations. Chronic stressor exposure also desensitizes glucocorticoid receptors (GR) and diminishes motivation to acquire food reinforcement, although causal relationships are largely not established. We show that a history of chronic exposure to the GR ligand corticosterone or acute posttraining GR blockade with RU38486 makes rodents less able to perform actions based on their consequences. Thus, optimal GR binding is necessary for the consolidation of new response-outcome learning. In contrast, medial prefrontal (but not striatal) BDNF can account for stress-related amotivation, in that selective medial prefrontal cortical Bdnf knockdown decreases break-point ratios in a progressive-ratio task. Knockdown also increases vulnerability to RU38486. Despite the role of BDNF in dendritic spine reorganization, deep-layer spine remodeling does not obviously parallel progressive-ratio response patterns, but treatment with the Na + -channel inhibitor riluzole reverses corticosteroid-induced motivational deficits and restores prefrontal BDNF expression after corticosterone. We argue that when prefrontal neurotrophin systems are compromised, and GR-mediated hypothalamic-pituitary-adrenal axis feedback is desensitized (as in the case of chronic stress hormone exposure), amotivation and inflexible maladaptive response strategies that contribute to stress-related mood disorders result.

The serotonergic system in the brain plays important roles in alcohol consumption and abuse. Serotonergic neurotransmission is mainly mediated by serotonin receptors. Among the 7 known serotonin (5-HT) receptor subfamilies (5-HT1–7), only the 5-HT3 receptor directly gates an ion channel. Ethanol (EtOH) has been shown to directly interact with the 5-HT3 receptor and potentiate the action of 5-HT at the 5-HT3 receptor in a dose-dependent manner (Zhou et al., 1998). This effect can be blocked by administration of the specific 5-HT3 receptor antagonist troposetron (Lovinger and Zhou, 1998). Ondansetron, another 5-HT3 receptor antagonist, has been reported to be efficacious in reducing heavy drinking and increasing abstinence in alcoholics (Johnson et al., 2000, 2011). The 5-HT3 receptor is composed of 2 major subunits: 5-HT3A and 5-HT3B. 5-HT3A is the obligatory subunit; only 5-HT3A can form receptors independently, and it is required for the formation of functional receptors (Maricq et al., 1991). Importantly, the 5-HT3 receptor is expressed throughout the mesolimbic system, including the nucleus accumbens and the ventral tegmental area (VTA) that are known to be important for the formation of addictive behaviors (Mylecharane, 1996). Based on these data, it appears that abnormal transcription of the serotonin receptor 3A gene (HTR3A), resulting either from genetic polymorphisms or promoter DNA methylation alterations, could influence an individual’s vulnerability to alcohol dependence. There is a growing body of evidence demonstrates that epigenetic modifications (such as DNA methylation and histone modification that alter DNA accessibility and chromatin structure) are associated with alcohol dependence. Promoter DNA hypermethylation has been identified in a number of genes in peripheral blood of human alcoholics. These genes include the α-synuclein gene (SNCA) (Bonsch et al., 2005), the monoamine oxidase A gene (MAOA) (Philibert et al., 2008a), the serotonin transporter gene (SLC6A4) (Philibert et al., 2008b), the N-methyl-d-aspartate receptor subunit 2B gene (NR2B or GRIN2B) (Biermann et al., 2009), and the proopiomelanocortin gene (POMC) (Muschler et al., 2010). Our recent study also demonstrated increased DNA methylation in the promoter region of HTR3A in peripheral blood of human alcoholics (Zhang et al., in press). There is also evidence that epigenetic processes, including DNA methylation, could influence gene expression at the level of transcription (Gibney and Nolan, 2010). Therefore, altered methylation and subsequent expression of HTR3A may significantly influence vulnerability to AD by impacting serotonin signaling at the 5-HT3 receptor. Although the above-mentioned human studies are instrumental in examining the role of DNA methylation in alcohol dependence, the investigation of epigenetic changes in peripheral blood of human alcoholics has 2 major limitations. First, these experiments do not enable us to assess whether alcohol dependence-associated DNA methylation changes directly resulted from chronic alcohol consumption or whether these differences reflect preexisting changes that predispose individuals to alcoholism. It is already known that environmental factors such as early-life stress and malnutrition (that may be abnormal in alcoholic subjects) can also alter DNA methylation patterns (Alegria-Torres et al., 2011). Moreover, DNA methylation changes in alcoholic subjects may be caused by co-occurring drug use or comorbid psychiatric illness. Second, the above-cited studies used genomic DNA extracted from peripheral blood (or lymphoblastoid cell lines derived from peripheral blood lymphocytes) for determination of DNA methylation. It is as yet unclear whether DNA methylation patterns in peripheral blood are representative of brain DNA methylation and/or whether any effects of alcohol use impact peripheral blood and brain DNA methylation patterns in a homogeneous manner. Because these questions are not readily answerable using human studies, alternative models for addressing these issues are needed. To explore the causal role of EtOH exposure in DNA methylation and to assess whether EtOH-induced DNA methylation changes are consistent in peripheral blood and in the brain, we used a mouse model of subacute EtOH drinking. Specifically, we used a mouse drinking-in-the-dark (DID) paradigm (Rhodes et al., 2007), which has been shown to produce high levels of EtOH consumption while minimizing environmental stress to the animals, to investigate whether EtOH drinking directly produced hypermethylation of HTR3A promoter region, as recently seen in the peripheral blood of human alcoholics (Zhang et al., in press). DNA methylation was assessed in 9 different brain regions (dorsomedial prefrontal cortex [DMPFC], ventromedial prefrontal cortex [VMPFC], VTA, dorsolateral striatum [DLSTR], dorsomedial striatum [DMSTR], ventral striatum [VSTR], amygdala [AMY], hippocampus [HIPPO], and cerebellum [CBL]) that were selected based on their role in the reward pathway and their role in supporting the behavioral changes that are thought to underlie alcoholism (Everitt and Robbins, 2005; Oscar-Berman and Marinkovic, 2007). Additionally, expression levels of mouse Htr3a in specific brain regions were compared between alcohol- and water-drinking mice. This study made it possible to investigate (i) whether EtOH consumption led to altered DNA methylation in the promoter region of mouse Htr3a, (ii) whether EtOH drinking induced differential DNA methylation in mouse blood and different brain regions, and (iii) whether Htr3a promoter methylation changes are related to gene expression levels.

Chronic stress during adolescence is associated with an increased risk for alcoholism and addictive disorders. Addiction is also associated with increased impulsivity, and stress during adolescence could alter cortical circuits responsible for response inhibition. Therefore, the present study determined the effect of chronic exposure to the stress hormone corticosterone (CORT) during adolescence on tests of impulsivity in adulthood and examined possible biochemical mechanisms. Male Sprague-Dawley rats were exposed to CORT by their drinking water during adolescence (post-natal day 30–50). The rats were then tested in adulthood to assess behavior on the 5-choice serial reaction time task (5CSRTT), stop-signal reaction time task (SSRTT), and the delay-discounting task, which differentially assess attention, impulsive action, and impulsive choice. Yohimbine-induced impulsivity on the 5CSRTT and biochemical analysis of the lateral orbital frontal cortex (lOFC) was also assessed owing to the ability of yohimbine to activate the hypothalamic-pituitary-adrenal axis and influence impulsivity. Adolescent CORT-treated rats were found to behave largely like controls on the 5CSRTT, but did show reduced premature responses when the intertrial interval was increased. Nevertheless, the CORT-treated rats tended to have more yohimbine-induced impulsive responses at low doses on this task, which was not found to be due to increased pCREB in the lOFC, but could be related to a higher expression/activity of the AMPA receptor subunit GluR1. Adolescent CORT-treated rats performed more accurately on the SSRTT, but showed greater impulsivity on the delay-discounting task, as indicated by steeper discounting functions. Therefore, adolescent CORT exposure reduced impulsive action but increased impulsive choice, indicating that chronic stress hormone exposure in adolescence can have long-term consequences on behavior.

Background Food restriction is known to enhance learning and motivation. The neural mechanisms underlying these responses likely involve alterations in gene expression in brain regions mediating the motivation to feed. Methods Analysis of gene expression profiles in male C57BL/6J mice using whole-genome microarrays was completed in the medial prefrontal cortex, nucleus accumbens, ventral tegmental area, and the hypothalamus following a 5-day food restriction. Quantitative polymerase chain reaction was used to validate these findings and determine the time course of expression changes. Plasma levels of the stress hormone corticosterone (CORT) were measured by enzyme-linked immunosorbent assay. Expression changes were measured in adrenalectomized animals that underwent food restriction, as well as in animals receiving daily injections of CORT. Progressive ratio responding for food, a measure of motivated behavior, was assessed after CORT treatment in restricted and fed animals. Results Brief food restriction results in an upregulation of peripheral stress responsive genes in the mammalian brain. Time-course analysis demonstrated rapid and persistent expression changes in all four brain regions under study. Administration of CORT to nonrestricted animals was sufficient to induce a subset of the genes, and alterations in gene expression after food restriction were dependent on intact adrenal glands. CORT can increase the motivation to work for food only in the restricted state. Conclusions These data demonstrate a central role for CORT in mediating both molecular and behavioral responses to food restriction. The stress hormone-induced alterations in gene expression described here may be relevant for both adaptive and pathological responses to stress.

We recently demonstrated that blocking specific nicotinic acetylcholine receptors (nAChRs) abolishes the conditioned reinforcing properties of ethanol-associated cues in rat, suggesting nAChRs as promising pharmacological targets for prevention of cue-induced relapse.The present study investigated the involvement of nAChR subtypes in the conditioned reinforcing properties of stimuli associated with a natural reward (sucrose).Water-deprived rats were trained to associate a tone + light stimulus (CS) with the presentation of a 0.1 M sucrose solution for 10 consecutive days. On the subsequent day, the animals were tested on the stringent acquisition of a new instrumental response with conditioned reinforcement, following a systemic injection of the nonselective nAChR antagonist mecamylamine (MEC) or the selective α7 and α6/α3β2β3* nAChR antagonist methyllycaconitine (MLA). At testing, the rats were presented with two novel levers. Responding on the lever assigned as active (CR lever) resulted in a presentation of the CS alone, while pressing the inactive lever (NCR lever) had no programmed consequences.Control animals pressed the CR lever significantly more than the NCR lever, demonstrating that the CR had acquired conditioned reinforcing properties. Systemic MEC as well as MLA reduced the CR lever responses to the same level as for the NCR lever.These results demonstrate a role for the α7 and/or α6/α3β2β3* nAChRs in conditioned reinforcement to a natural reward and suggest neuronal nAChRs as common mediators of the impact of cues on incentive processes.

Differences between men and women in alcohol abuse prevalence have long been attributed to social and hormonal factors. It is, however, becoming apparent that sex differences in substance dependence are also influenced by genetic factors. Using a four core genotype mouse model that enables dissociation of chromosomal and gonadal sex, we show that habitual responding for alcohol reinforcement is mediated by sex chromosome complement independent of gonadal phenotype. After moderate instrumental training, chromosomal male (XY) mice became insensitive to outcome devaluation, indicating habitual responding. Chromosomal female (XX) mice remained sensitive to outcome devaluation, signifying goal-directed behavior. There was no effect of gonadal phenotype on habitual responding. Conversely, alcohol drinking was predicted by gonadal phenotype independent of sex chromosome complement. These results indicate that different alcoholism-related behaviors are determined independently by gonadal and chromosomal sex.

Anatomically selective medial prefrontal cortical projections regulate the extinction of stimulus–reinforcement associations, but the mechanisms underlying extinction of an instrumental response for reward are less well-defined and may involve structures that regulate goal-directed action. We show brain-derived neurotrophic factor (bdnf) knock-down in the prelimbic, but not orbitofrontal, cortex accelerates the initial extinction of instrumental responding for food and reduces striatal BDNF protein. When knock-down mice were provided with alternative response options to readily obtain reinforcement, extinction of the previously reinforced response was unaffected, consistent with the hypothesis that the prelimbic cortex promotes instrumental action, particularly when reinforcement is uncertain or unavailable.

Cocaine administration in rats increases locomotor activity as a result of underlying changes in neurotransmitter dynamics and intracellular signaling. The serine/ threonine phosphatase, calcineurin, is known to modulate several signaling proteins that can influence behavioral responses to cocaine.This study aimed to determine whether calcineurin plays a role in locomotor responses associated with acute and repeated cocaine exposure. Second, we examined cocaine-mediated changes in intracellular signaling to identify potential mechanism underlying the ability of calcineurin to influence cocaine-mediated behavior.Locomotor activity was assessed over 17 days in male Sprague-Dawley rats (n = 48) that received daily administration of cocaine (15 mg/kg, s.c.) or saline in the presence or absence of the calcineurin inhibitor, cyclosporine (15 mg/kg, i.p.). Non-cocaine-treated animals from this initial experiment (n = 24) also received an acute cocaine challenge on day 18 of testing.Daily cyclosporine administration potentiated the locomotor response to repeated cocaine 5 min after cocaine injection and attenuated the sustained locomotor response 15 to 40 min after cocaine. Furthermore, cyclosporine pretreatment for 17 days augmented the acute locomotor response to acute cocaine 5 to 30 min after cocaine injection. Finally, repeated exposure to either cocaine or cyclosporine for 22 days increased synapsin I phosphorylation at the calcineurin-sensitive Ser 62/67 site, demonstrating a common downstream target for both calcineurin and cocaine.Our results suggest that calcineurin inhibition augments locomotor responses to cocaine and mimics cocaine-mediated phosphorylation of synapsin I.

Alterations in gene expression in the dorsal striatum caused by chronic cocaine exposure have been implicated in the long-term behavioral changes associated with cocaine addiction. To gain further insight into the molecular alterations that occur as a result of cocaine self-administration, we conducted a microarray analysis of gene expression followed by bioinformatic gene network analysis that allowed us to identify adaptations at the level of gene expression as well as into interconnected networks. Changes in gene expression were examined in the dorsal striatum of rats 1 day after they had self-administered cocaine for 7 days under a 24-hr access, discrete trial paradigm (averaging 98 mg/kg/day). Here we report the regulation of the circadian genes Clock, Bmal1, Cryptochrome1, Period2, as well as several genes that are regulated by/associated with the circadian system (i.e., early growth response 1, dynorphin). We also observed regulation of other relevant genes (i.e., Nur77, beta catenin). These changes were then linked to curated pathways and formulated networks which identified circadian rhythm processes as affected by cocaine self-administration. These data strongly suggest involvement of circadian-associated genes in the brain’s response to cocaine and may contribute to an understanding of addictive behavior including disruptions in sleep and circadian rhythmicity.

The aim of this retrospective, cross-sectional study was to assess the frequency of dietary advice provision by dental hygiene students.Data was obtained from clinical records of third-year Bachelor of Oral Health students at the University of Newcastle. Frequency of dietary advice was recorded by students over a 12-month period. The study investigated associations between demographics, treatment provided and frequency of dietary advice.The results indicated dietary advice was provided infrequently by dental hygiene students, with only 6.48% of all patients seen during the 12-month period receiving dietary advice. A statistically significant correlation was observed between dietary advice and age, with children under the age of 18 being 2.5 times more likely than adults to receive dietary advice. Additionally, patients who received oral hygiene instruction were 2.5 times as likely to receive dietary advice. Strong correlations were also observed between topical and concentrated fluoride application and dietary advice.The findings indicate dietary advice is provided infrequently by dental hygiene students. Further research is required to strengthen the findings and to investigate barriers to dietary advice provision, as well as perceptions of dental practitioners regarding dietary advice.

Cyclin-dependent kinase 5 (Cdk5) regulates dopamine neurotransmission and has been suggested to serve as a homeostatic target of chronic psychostimulant exposure. To study the role of Cdk5 in the modulation of the cellular and behavioral effects of psychoactive drugs of abuse, we developed Cre/loxPconditional knock-out systems that allow temporal and spatial control of Cdk5 expression in the adult brain. Here, we report the generation of Cdk5 conditional knock-out (cKO) mice using the αCaMKII promoter-driven Cre transgenic line (CaMKII-Cre). In this model system, loss of Cdk5 in the adult forebrain increased the psychomotor-activating effects of cocaine. Additionally, these CaMKII-Cre Cdk5 cKO mice show enhanced incentive motivation for food as assessed by instrumental responding on a progressive ratio schedule of reinforcement. Behavioral changes were accompanied by increased excitability of medium spiny neurons in the nucleus accumbens (NAc) in Cdk5 cKO mice. To study NAc-specific effects of Cdk5, another model system was used in which recombinant adeno-associated viruses expressing Cre recombinase caused restricted loss of Cdk5 in NAc neurons. Targeted knock-out of Cdk5 in the NAc facilitated cocaine-induced locomotor sensitization and conditioned place preference for cocaine. These results suggest that Cdk5 acts as a negative regulator of neuronal excitability in the NAc and that Cdk5 may govern the behavioral effects of cocaine and motivation for reinforcement.

Does heightened stress sensitivity predispose an individual toward disease? Our Society for Neuroscience mini-symposium examines the link between stress and disease onset, exploring sex differences and whether there is an increased female predisposition. This session specifically addresses the

Neuronal adaptations in striatal dopamine signaling have been implicated in enhanced responses to addictive drugs. Cyclin-dependent kinase 5 (Cdk5) regulates striatal dopamine signaling and is a downstream target gene of the transcription factor ΔFosB, which accumulates in striatal neurons after chronic cocaine exposure. Here we investigated the role of Cdk5 activity in the nucleus accumbens (NAc) on cocaine-induced locomotor sensitization, responding for reward-associated stimuli (conditioned reinforcement), and cocaine self-administration under a progressive ratio schedule. Repeated infusions of the Cdk5 inhibitor roscovitine into the NAc before cocaine injections augmented both the development and expression of cocaine sensitization without having any intrinsic stimulant actions of its own. Additionally, repeated intra-NAc infusions of roscovitine to saline-injected rats enhanced locomotor responses to a subsequent cocaine challenge. Similar effects were found after infusions of another Cdk5 inhibitor, olomoucine, but not its inactive congener, iso-olomoucine. Repeated inhibition of Cdk5 within the NAc also robustly enhanced the incentive-motivational effects of cocaine, similar to the effect of prior repeated cocaine exposure. The enhanced responding with conditioned reinforcement induced by cocaine persisted at least 2 weeks after the final roscovitine infusion. NAc infusions of olomoucine also produced acute and enduring increases in “breakpoints” achieved on a progressive ratio schedule for cocaine reinforcement. These results demonstrate profound and persistent effects of NAc Cdk5 inhibition on locomotor sensitization and incentive-motivational processes and provide direct evidence for a role for striatal Cdk5-induced alterations in the brain's long-term adaptations to cocaine.

Paul K. Hitchcott, Jennifer J. Quinn and Jane R. TaylorDepartment of Psychiatry, Division of Molecular Psychiatry,Yale University School of Medicine, New Haven, CT 06508,USAInstrumental actions are a vital cognitive asset that endows anorganism with sensitivity to the consequences of its behavior.Response--outcome feedback allows responding to be shaped inorder to maximize beneficial, and minimize detrimental, outcomes.Lesionsofthemedialprefrontalcortex(mPFC)resultinbehaviorthatisinsensitivetochangesinoutcomevalueinanimalsandcompulsivebehavior in several human psychopathologies. Such insensitivity tochangesinoutcomevalueisadefiningcharacteristicofinstrumentalhabits: responses that are controlled by antecedent stimuli ratherthan goal expectancy. Little is known regarding the neurochemicalsubstrates mediating this sensitivity. The present experiments usedsensitivity to posttraining outcome devaluation to index the action--habit status of instrumental responding. Infusions of dopamine intothe ventral mPFC (vmPFC), but not dorsal mPFC, restored outcomesensitivity bidirectionally—decreasing responding following out-come devaluation and increasing responding when the outcomewas not devalued. This bidirectionality makes the possibility thatthese infusions nonspecifically dysregulated vmPFC dopaminetransmission unlikely. VmPFC dopamine promoted instrumentalresponding appropriate to outcome value. Reinforcer consumptiondataindicated that thiswasnotaconsequence of alteredsensitivitytothereinforceritself.WesuggestthatvmPFCdopaminereengagesattentional processes underlying goal-directed behavior.Keywords: action, attention, dopamine, habit, instrumental, prefrontalIntroductionAcquiring knowledge about the relationship between behaviorand its consequences is a vital cognitive asset that permitsresponses to be acquired and/or modified in the pursuit ofspecific goals (Balleine and Dickinson 1998). This ‘‘response--outcome association’’ is one of many encoded during instru-mental conditioning (Colwill 1994). Clearly, dysfunction of theneural substrates that encode or process this information mayresult in maladaptive behavior (Toates 1998).Instrumental responses controlled by knowledge of theirspecific consequences are termed ‘‘actions.’’ The goal-directednature of actions is reflected by their sensitivity to posttrainingchanges in outcome value. Thus, the performance of an actionspontaneously tracks changes in the value of its specificoutcome (Dickinson 1985). Continuous monitoring of theresponse--outcomerelationshiprequiresallocationofprefrontalcortex (PFC)-dependent, limited-capacity cognitive processes(Gehring and Knight 2000; Miller and Cohen 2001). This canbecome redundant once responding has been shaped to pro-duce the optimal behavioral outcome. Thus, extended, stableresponse--outcome conditions promote a shift in the control ofinstrumental responding from being goal directed to beingstimulus elicited. Instrumental responses triggered by environ-mental stimuli are termed ‘‘habits.’’ The stimulus--response na-ture of habits is reflected by their insensitivity to posttrainingchanges in outcome value (Dickinson 1985). This action--habitshift allows efficient responding to be maintained while permit-ting the reallocation of cognitive resources to other demands(Gehring and Knight 2000). Conversely, the inability to shiftfrom habit to action leaves an organism unable to readily adaptto changing environmental conditions. This deficit is apparentin various human psychiatric populations in whom generalcognitive functions are intact; yet, they compulsively performmaladaptive behaviors that are primarily stimulus elicited(Lhermitte 1986; Toates 1998; Montague and Berns 2002).Studies in animals indicate that medial PFC (mPFC) integrityis necessary both for the initial acquisition of task-relevantresponses and the suppression of task-irrelevant, especiallyprepotent, responses (Balleine and Dickinson 1998; Coutureauand Killcross 2003; Killcross and Coutureau 2003; Clark et al.2004; Ostlund and Balleine 2005). Whereas these studies helpdelineate the anatomical substrates mediating the balancebetween actions and habits, the neurochemical substrates thatspecifically influence this balance are not well understood.Dopamine is one likely candidate because activation of dopa-mine neurons increases during response acquisition but de-clines following extended training under stable (i.e., habitpromoting) conditions (Ljungberg et al. 1992). The preferentialcortical targets of these dopaminergic neurons are preciselythose areas implicated in outcome sensitivity, namely, theventralmPFC(vmPFC)(VanEdenetal.1987;Smileyetal.1992).Whereas striatal dopamine has been implicated in habitualinstrumental responding (Faure et al. 2005), there have been noinvestigations of mPFC dopamine modulation of actions and/orhabits. Here, we tested the hypothesis that infusions ofdopamine into the vmPFC would promote goal-directed behav-ior by increasing the sensitivity of instrumental responding tothe value of its outcome. Accordingly, we examined whether,following habit formation, vmPFC infusions of dopamine wouldpromote responding appropriate to outcome value, which wemanipulated using a devaluation procedure that we and othershave previously shown to reduce the performance of aninstrumental action (e.g., Dickinson et al. 2002; Miles et al.2003; Hitchcott et al. 2005; Quinn et al. 2006). Because thevmPFC is implicated in the production of adaptive behavior(e.g., Dalley et al. 2004), and dopamine has been suggested toexertapermissiveeffectonthisfunction(Hollermanetal.2000;Sullivan 2004; Fletcher et al. 2005; Floresco et al. 2006), wehypothesized that dopamine infusions would promote adaptivebehavioral adjustments appropriate to current outcome value

ARPP-16 (cAMP-regulated phospho-protein of molecular weight 16 kDa) is one of several small acid-soluble proteins highly expressed in medium spiny neurons of striatum that are phosphorylated in response to dopamine acting via D1 receptor/protein kinase A (PKA) signaling. We show here that ARPP-16 is also phosphorylatedin vitroandin vivoby microtubule-associated serine/threonine kinase 3 (MAST3 kinase), an enzyme of previously unknown function that is enriched in striatum. We find that ARPP-16 interacts directly with the scaffolding A subunit of the serine/threonine protein phosphatase, PP2A, and that phosphorylation of ARPP-16 at Ser46 by MAST3 kinase converts the protein into a selective inhibitor of B55α- and B56δ-containing heterotrimeric forms of PP2A. Ser46 of ARPP-16 is phosphorylated to a high basal stoichiometry in striatum, suggestive of basal inhibition of PP2A in striatal neurons. In support of this hypothesis, conditional knock-out of ARPP-16 in CaMKIIα::cre/floxed ARPP-16/19 mice results in dephosphorylation of a subset of PP2A substrates including phospho-Thr75-DARPP-32, phospho-T308-Akt, and phospho-T202/Y204-ERK. Conditional knock-out of ARPP-16/19 is associated with increased motivation measured on a progressive ratio schedule of food reinforcement, yet an attenuated locomotor response to acute cocaine. Our previous studies have shown that ARPP-16 is phosphorylated at Ser88 by PKA. Activation of PKA in striatal slices leads to phosphorylation of Ser88, and this is accompanied by marked dephosphorylation of Ser46. Together, these studies suggest that phospho-Ser46-ARPP-16 acts to basally control PP2A in striatal medium spiny neurons but that dopamine acting via PKA inactivates ARPP-16 leading to selective potentiation of PP2A signaling.SIGNIFICANCE STATEMENTWe describe a novel mechanism of signal transduction enriched in medium spiny neurons of striatum that likely mediates effects of the neurotransmitter dopamine acting on these cells. We find that the protein ARPP-16, which is highly expressed in striatal medium spiny neurons, acts as a selective inhibitor of certain forms of the serine/threonine protein phosphatase, PP2A, when phosphorylated by the kinase, MAST3. Under basal conditions, ARPP-16 is phosphorylated by MAST3 to a very high stoichiometry. However, the actions of MAST3 are antagonized by dopamine and cAMP-regulated signaling leading to disinhibition of ARPP-16 and increased PP2A action.