Nucleus accumbens neurons dynamically respond to appetitive and aversive associative learning.

To survive, individuals must learn to associate cues in the environment with emotionally relevant outcomes. This association is partially mediated by the nucleus accumbens (NAc), a key brain region of the reward circuit that is mainly composed by GABAergic medium spiny neurons (MSNs), that express either dopamine receptor D1 or D2. Recent studies showed that both populations can drive reward and aversion, however, the activity of these neurons during appetitive and aversive Pavlovian conditioning remains to be determined. Here, we investigated the relevance of D1- and D2-neurons in associative learning, by measuring calcium transients with fiber photometry during appetitive and aversive Pavlovian tasks in mice. Sucrose was used as a positive valence unconditioned stimulus (US) and foot shock was used as a negative valence US. We show that during appetitive Pavlovian conditioning, D1- and D2-neurons exhibit a general increase in activity in response to the conditioned stimuli (CS). Interestingly, D1- and D2-neurons present distinct changes in activity after sucrose consumption that dynamically evolve throughout learning. During the aversive Pavlovian conditioning, D1- and D2-neurons present an increase in the activity in response to the CS and to the US (shock). Our data support a model in which D1- and D2-neurons are concurrently activated during appetitive and aversive conditioning.

Online learning in Health Professions Education. Part 1: Teaching and learning in online environments: AMEE Guide No. 161.

Online learning in Health Professions Education (HPE) has been evolving over decades, but COVID-19 changed its use abruptly. Technology allowed necessary HPE during COVID-19, but also demonstrated that many HP educators and learners had little knowledge and experience of these complex sociotechnical environments. Due to the educational benefits and flexibility that technology can afford, many higher education experts agree that online learning will continue and evolve long after COVID-19. As HP educators stand at the crossroads of technology integration, it is important that we examine the evidence, theories, advantages/disadvantages, and pedagogically informed design of online learning. This Guide will provide foundational concepts and practical strategies to support HPE educators and institutions toward advancing pedagogically informed use of online HPE. This Guide consists of two parts. The first part will provide an overview of evidence, theories, formats, and educational design in online learning, including contemporary issues and considerations such as learner engagement, faculty development, inclusivity, accessibility, copyright, and privacy. The second part (to be published as a separate Guide) focuses on specific technology tool types with practical examples for implementation and integration of the concepts discussed in Guide 1, and will include digital scholarship, learning analytics, and emerging technologies. In sum, both guides should be read together, as Guide 1 provides the foundation required for the practical application of technology showcased in Guide 2.Please refer to the video abstract for Part 1 of this Guide at https://bit.ly/AMEEGuideOnlineLearning.

Online learning in health professions education. Part 2: Tools and practical application: AMEE Guide No. 163.

Part 1 of the AMEE Guide Online learning in health professions education focused on foundational concepts such as theory, methods, and instructional design in online learning. Part 2 builds upon Part 1, introducing technology tools and applications of these foundational concepts by exploring the various levels (from beginner to advanced) of utilisation, while describing how their usage can transform Health Professions Education. This Part covers Learning Management Systems, infographics, podcasting, videos, websites, social media, online discussion forums, simulation, virtual patients, extended and virtual reality. Intertwined are other topics, such as online small group teaching, game-based learning, FOAM, online social and collaboration learning, and virtual care teaching. We end by discussing digital scholarship and emerging technologies. Combined with Part 1, the overall aim of Part 2 is to produce a comprehensive overview to help guide effective use online learning in Health Professions Education.

Involvement of nucleus accumbens D2-medium spiny neurons projecting to the ventral pallidum in anxiety-like behaviour.

BACKGROUND: The nucleus accumbens (NAcc) is a crucial brain region for emotionally relevant behaviours. The NAcc is mainly composed of medium spiny neurons (MSNs) expressing either dopamine receptor D1 (D1-MSNs) or D2 (D2-MSNs). The D1-MSNs project to the ventral tegmental area (VTA) and the ventral pallidum (VP), whereas the D2-MSNs project only to the VP. The D1- and D2-MSNs have been associated with depression-like behaviours, but their contribution to anxiety remains to be determined. METHODS: We used optogenetic tools to selectively manipulate D1-MSN projections from the NAcc core to the VP or VTA and D2-MSN projections to the VP during validated anxiety-producing behavioural procedures in naive mice. In addition, we assessed the effects of optical stimulation on neuronal activity using in vivo electrophysiologic recordings in anesthetized animals. RESULTS: Optogenetic activation of D1-MSN projections to the VTA or VP did not trigger anxiety-like behaviour. However, optical activation of D2-MSN projections to the VP significantly increased anxiety-like behaviour. This phenotype was associated with a decrease in the neuronal activity of putative GABAergic neurons in the VP. Importantly, pretreating D2-MSN-VP animals with the γ-aminobutyric acid modulator diazepam prevented the optically triggered anxiety-like behaviour. LIMITATIONS: The exclusive use of males in the behavioural tests limits broader interpretation of the findings. Although we used optogenetic conditions that trigger quasi-physiologic changes, there are caveats associated with the artificial manipulation of neuronal activity. CONCLUSION: The D2-MSN-VP projections contributed to the development of anxiety-like behaviour, through modulation of GABAergic activity in the VP.

Laterodorsal tegmentum-ventral tegmental area projections encode positive reinforcement signals.

The laterodorsal tegmentum (LDT) is a brainstem nucleus classically involved in REM sleep and attention, and that has recently been associated with reward-related behaviors, as it controls the activity of ventral tegmental area (VTA) dopaminergic neurons, modulating dopamine release in the nucleus accumbens. To further understand the role of LDT-VTA inputs in reinforcement, we optogenetically manipulated these inputs during different behavioral paradigms in male rats. We found that in a two-choice instrumental task, optical activation of LDT-VTA projections shifts and amplifies preference to the laser-paired reward in comparison to an otherwise equal reward; the opposite was observed with inhibition experiments. In a progressive ratio task, LDT-VTA activation boosts motivation, that is, enhances the willingness to work to get the reward associated with LDT-VTA stimulation; and the reverse occurs when inhibiting these inputs. Animals abolished preference if the reward was omitted, suggesting that LDT-VTA stimulation adds/decreases value to the stimulation-paired reward. In addition, we show that LDT-VTA optical activation induces robust preference in the conditioned and real-time place preference tests, while optical inhibition induces aversion. The behavioral findings are supported by electrophysiological recordings and c-fos immunofluorescence correlates in downstream target regions. In LDT-VTA ChR2 animals, we observed an increase in the recruitment of lateral VTA dopamine neurons and D1 neurons from nucleus accumbens core and shell; whereas in LDT-VTA NpHR animals, D2 neurons appear to be preferentially recruited. Collectively, these data show that the LDT-VTA inputs encode positive reinforcement signals and are important for different dimensions of reward-related behaviors.

What effect does delirium have on family and nurses of older adult patients?

OBJECTIVES: This study aims to analyse the level of distress caused by delirium in patients' family and their nurses, and to identify factors associated with psychological distress in families of older adult inpatients in Intermediate Care Units/IMCUs regarding their global experience during hospitalization. METHOD: A prospective pilot study was carried out with families and nurses of older adult patients (≥65 y.o.) consecutively recruited from two IMCUs in Intensive Care Medicine Service in a University Hospital. Patients with Glasgow Coma Scale ≤11, brain injury, blindness/deafness and inability to communicate were excluded. Delirium was daily assessed with Confusion Assessment Method/CAM. The distress level regarding this episode in family and nurses was measured with Delirium Experience Questionnaire/DEQ. Family psychological distress of all recruited patients was assessed with Kessler Psychological Distress Scale/K10. RESULTS: This study included 42 inpatients (mean age/MA = 78 y.o., 50% women), 32 families (68.8% sons/daughters, MA = 50.6 y.o., 81.3% women) and 12 nurses caring for delirium patients (MA = 33 y.o., all women). A total of 12 (28.6%) patients had delirium. Distress related to this episode were higher for families than for nurses (M = 3 vs. M = 2), but differences did not reach statistical significance (Z = -1.535, p = 0.125). The hierarchical regression model explained 44.3% of variability in family psychological distress. Higher levels of psychological distress were associated with living with the patient (p = 0.029), presence of previous cognitive decline (p = 0.048) and development of delirium (p = 0.010). CONCLUSION: These preliminary results show that family psychological distress is higher, when older adult patients developed delirium during hospitalization. Particular attention to these family carers should be given in future development of psychological support and psychoeducational interventions.

Ln3Q9 as a molecular framework for ion-size-driven assembly of heterolanthanide (Nd, Er, Yb) multiple near-infrared emitters.

A unique example of discrete molecular entity Nd(y)Er(x)Yb(3-(x+y))Q9 (1) (Q = quinolinolato) containing three different lanthanides simultaneously emitting in three different spectral regions in the NIR, ranging from 900 to 1600 nm, has been synthesized and fully chararacterized. A simple molecular strategy based on tuning metal composition in the Ln3Q9 framework, which contains inequivalent central and terminal coordination sites, has allowed a satisfactory ion-size-driven control of molecular speciation close to 90%. In 1 the central position of the larger Nd ion is well distinguished from the terminal ones of the smaller Yb(3+) and Er(3+), which are almost "vicariants" as found in the heterobimetallic Er(x)Yb(3-x)Q9 (2). The Ln3Q9 molecular architecture, which allows communication between the ions, has proved to afford multiple NIR emission in 1 and 2, and is promising to develop a variety of multifunctional materials through the variation of the Ln composition.

Aggregation/disaggregation of chlorophyll a in model phospholipid-detergent vesicles and micelles.

The photosynthetic pigments of higher plants exist in complex oligomeric states, which are difficult to study in vivo. To investigate aggregation processes of chlorophyll a (Chl a), we used an in vitro reconstitution procedure, with this pigment incorporated into liposomes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), micelles and pre-micelle media of the detergent n-dodecyltrimethylammonium chloride (DTAC), and mixed, spontaneous, DMPC-DTAC vesicles and micelles. Chl a oligomers were characterized by UV-visible absorption, steady-state and time-resolved fluorescence, and fluorescence lifetime imaging microscopy. Equivalent diameters of the colloidal structures were obtained by fluorescence correlation spectroscopy. In DMPC liposomes and DMPC-DTAC vesicles and micelles, three fluorescence lifetimes indicated the coexistence of Chl a monomers (≈5 ns) and oligomers (≈1-2 to ≈0.1 ns). The increase in DTAC amount, in the mixed system, induces a progressive solubilization of DMPC liposomes (from vesicles to micelles) and simultaneous disruption of Chl a aggregates; in pure DTAC micelles, mostly monomers were found. The present work aims for a better understanding of chlorophyll-chlorophyll (Chl-Chl), Chl-lipid, and Chl-detergent interactions in spontaneous colloidal micro- and nanostructures.

ACTH-producing adrenocortical carcinoma: an exceedingly rare diagnosis.

BACKGROUND: Adrenocortical carcinoma is a very rare endocrinopathy that has a poor prognosis and is frequently associated with ACTH-independent Cushing's syndrome. Despite having an adrenocortical carcinoma, our patient surprisingly had an ACTH-dependent Cushing's syndrome. CASE REPORT: A 26-year-old female presented with Cushing's syndrome and an abdominal mass. Imaging studies revealed an adrenal mass consistent with a high-grade malignancy. Laboratory workup showed hypercortisolism, hyperandrogenism, and hypokalemia with normal levels of metanephrines. Unexpectedly, her ACTH levels were remarkably elevated. The pathological analysis of a tumor sample was conclusive for adrenocortical carcinoma with immunopositivity for ACTH. CONCLUSIONS: Our patient suffered from an adrenocortical carcinoma that was ectopically producing ACTH. This case emphasizes that physicians should have a broad-minded approach when evaluating cases of rare endocrine malignancies.

Nonviral gene delivery to neural stem cells with minicircles by microporation.

The main purpose of this work was to evaluate the transfection of novel DNA vectors, minicircles (mC), on embryonic stem cell-derived neural stem cells (NSC). We demonstrated that by combining microporation with mC, 75% of NSC expressing a transgene is achieved without compromising cell survival, morphology, and differentiation potential. When comparing mC with their plasmid DNA (pDNA) counterparts, both gave rise to similar transfection levels but cells harboring mC showed 10% higher cell viability, maintaining 90% of survival at least for 10 days. Long-term analysis showed that NSC harbor a higher number of mC copies and consequently exhibit higher transgene expression when compared to their pDNA counterpart. Taken together, our results offer the first insights on the use of mC as a novel and safe strategy to genetically engineer NSC envisaging their use as biopharmaceuticals in clinical settings for the treatment of neurodegenerative or neurological diseases.

Mercury methylation in mesocosms with and without the aquatic macrophyte Eichhornia crassipes (mart.) Solms.

Mercury is a toxic pollutant and spreads to several compartments in the environment. Previous in-vitro studies showed that roots of aquatic macrophytes are sites of methylmercury formation, performed mainly by sulfate-reducing bacteria (SRB). The objective of this study was to observe MMHg formation and distribution among filtered water (0.2µm), suspended and settled particles and macrophyte roots during seventeen days, in (203)Hg- spiked mesocosms with and without live Eichhornia crassipes whole plants and a SRB inhibitor. Root samples were also incubated in-vitro for comparison of MM(203)Hg formation under in-vitro and in-vivo conditions. To evaluate the effect of SRB inhibition by sodium molybdate on total heterotrophic activity, the latter was measured by (3)H-leucine uptake. Inhibition of Hg methylation by sodium molybdate decreased with time in mesocosms. MMHg averaged 10, 12.4 and 0.23 percent of total (203)Hg present in filtered water, suspended particles and roots respectively. In vitro MMHg formation in roots averaged 5.54 percent of total added (203)Hg, with a clearer SRB inhibition effect than in mesocosms. Though significant, MMHg formation in roots from in-vivo mesocosms was one order of magnitude lower than previously found in in-vitro incubations of roots alone.

Maternal diabetes affects rat offspring retinal structure and function: Sex-specific vulnerabilities at infancy.

AIMS: Maternal diabetes negatively impacts the offspring's brain, but little is known about its effects on the retina, which is also part of the central nervous system. We hypothesized that maternal diabetes adversely influences offspring retina development leading to structural and functional deficits. MAIN METHODS: Retinal structure and function were evaluated at infancy, by optical coherence tomography and electroretinography, in male and female offspring of control, diabetic and diabetic-treated with insulin Wistar rats. KEY FINDINGS: Maternal diabetes induced a delay in male and female offspring eye-opening, while insulin treatment expedited it. Structural analysis showed that maternal diabetes decreased the thickness of the inner and outer segment layer of photoreceptors in male offspring. Electroretinography also revealed that maternal diabetes decreased the amplitude of scotopic b-wave and flicker response in males, suggesting bipolar cells and cone photoreceptor dysfunction, an effect not observed in females. Conversely, maternal diabetes decreased cone arrestin protein levels in female retinas, while not affecting cone photoreceptor number. Dam insulin therapy was efficient in preventing the offspring photoreceptor changes. SIGNIFICANCE: Our results suggest that photoreceptors are affected by maternal diabetes, which may account for visual impairments at infancy. Notably, both male and female offspring presented specific vulnerabilities to hyperglycemia in this sensitive period of development.

Occurrence and predictors of delirium in critically ill older patients: a prospective cohort study.

Objectives: This study aims to analyze the occurrence of delirium in critically ill older patients and to identify predictors of delirium. Methods: This prospective study included critically ill older patients admitted into level II units of Intensive Care Medicine Department of a University Hospital. Patients with Glasgow Coma Scale score ≤11, traumatic brain injury, terminal disease, history of psychosis, blindness/deafness, or inability to understanding/speaking Portuguese were excluded. The Confusion Assessment Method-Short Form (CAM-4) was used to assess the presence of delirium. Results: The final sample (n = 105) had a median age of 80 years, most being female (56.2%), widowed (49.5%), and with complete primary education (53%). Through CAM-4, 36.2% of the patients had delirium. The delirium group was more likely to have previous cognitive decline (48.6% vs 19.6%, P = .04) and severe dependency in instrumental activities of daily living (34.3% vs 14.8%, P = .032), comparing with patients without delirium. The final multiple logistic regression model explained that patients with previous cognitive decline presented a higher risk for delirium (odds ratio: 4.663, 95% confidence Interval: 1.055-20.599, P = .042). Conclusions: These findings corroborate previous studies, showing that cognitive decline is an independent predictor for delirium in older patients. This study is an important contribution for the knowledge regarding the predictors of delirium. The recognition of these factors will help to identify patients who are at high risk for this syndrome and implement early screening and prevention strategies. However, further studies with larger samples, recruited from other clinical settings as well as analyzing other potential factors for delirium, will be needed.

Dementia in multiple sclerosis: report of a case with cortical gray matter involvement and frontotemporal-like clinical features.

Multiple sclerosis (MS) is primarily a white matter disease, but may also involve the gray matter, a feature not often demonstrated in vivo. This report presents the case of a patient with MS and clinical features mimicking frontotemporal dementia due to clear-cut cortical gray matter involvement in the left frontal lobe.

Mercury methylation and the microbial consortium in periphyton of tropical macrophytes: effect of different inhibitors.

Macrophyte-associated periphyton is known as a site of Hg accumulation and methylation in tropical environments. Sulfate-reducing bacteria (SRB) is found in periphyton and its role in Hg methylation is acknowledged. However, the contribution of other microorganisms to this process is largely unknown. We tested the effect of inhibitors for different microorganisms on methylmercury (MMHg) formation on distinct macrophyte species from lakes of the Bolivian Amazon basin and in Brazil. We also tested the effect of inhibitors on bacterial secondary activity at two lakes in Brazil. Samples were incubated on-site with (203)Hg and Me(203)Hg was extracted and measured by liquid scintillation. MMHg formation on macrophytes varied among species ranging from 0.2% to 36%. Treatments with specific inhibitors resulted in reduction of MMHg production on most sites and inhibitors. The most successful treatment was the co-inhibition of SRB and methanogens. The inhibitions of algae and fungi activity showed fewer effects on methylation rates at all sites analyzed. Bacterial secondary activity was slightly affected by algae and fungi inhibition, and largely influenced by prokaryotic, SRB and methanogens inhibition. The data suggest that MMHg formation may not be directly performed by all microorganisms in periphyton but depends on complex interactions among them.

Prenatal dexamethasone exposure alters effort decision making and triggers nucleus accumbens and anterior cingulate cortex functional changes in male rats.

Daily, individuals select actions based on cost-benefit to allocate resources into goal-directed actions. Different brain regions coordinate this complex decision, including the nucleus accumbens (NAc), anterior cingulate cortex (ACC), and ventral tegmental area (VTA). In utero exposure to synthetic glucocorticoids (iuGC), such as dexamethasone, triggers prominent motivation deficits but the impact of this exposure in the ACC-NAc and/or ACC-VTA circuits is unknown. Here, we show that iuGC exposure causes decreased motivation for natural rewards (food) and impaired effort-based decision-making. Importantly, reduced neuronal activation (number of c-fos+ neurons) was observed in the NAc core and ACC of iuGC rats in comparison to CTR rats after performing the effort-based decision-making task. In addition, iuGC treatment led to increased NAc and ACC basal neuronal activity. Electrophysiological recordings during optogenetic modulation of ACC terminals in the NAc revealed that the ACC-NAc circuit is dysfunctional in iuGC animals. These data suggest that iuGC animals present motivational and effort-based decision-making deficits that can be associated with the observed ACC-NAc dysfunction.

Recall of delirium and related distress in elderly hospitalized patients: A prospective study.

Background: Delirium is a very common neuropsychiatric disorder in the elderly, with a significant physical and psychological burden. Much is still unknown about its psychological effects. This study aims to identify the proportion of patients who recall delirium and to analyze the distress caused by it. In addition, this study aims to analyze the association between delirium recall and related distress and global psychological distress regarding hospitalization. Methods: This is a prospective study with elderly hospitalized patients in level-2 units of intensive care medicine department of a university hospital. Exclusion criteria were a Glasgow Coma Scale total ≤11, brain injury, blindness, deafness, or inability to communicate. Delirium was daily assessed with the Confusion Assessment Method. Delirium recall and related distress in patients were measured using the Delirium Experience Questionnaire. Global psychological distress was assessed with the Kessler Psychological Distress Scale. Results: From 105 patients, 38 (36.2%) developed delirium. Most patients did not remember the delirium episode (64.7%). Among those who remembered (35.3%), most described delirium as a distressing experience (75%). Delirium recall was associated with high global psychological distress (P = .029). Conclusions: Distress related to delirium is high, namely in patients who recall the episode. Global psychological distress during hospitalization is associated with delirium recall. This study highlights the need to assess the experience of delirium in these patients, as well as the importance of providing support and psychological interventions to minimize the associated distress.

Distinct role of nucleus accumbens D2-MSN projections to ventral pallidum in different phases of motivated behavior.

The nucleus accumbens (NAc) is a key region in motivated behaviors. NAc medium spiny neurons (MSNs) are divided into those expressing dopamine receptor D1 or D2. Classically, D1- and D2-MSNs have been described as having opposing roles in reinforcement, but recent evidence suggests a more complex role for D2-MSNs. Here, we show that optogenetic modulation of D2-MSN to ventral pallidum (VP) projections during different stages of motivated behavior has contrasting effects in motivation. Activation of D2-MSN-VP projections during a reward-predicting cue results in increased motivational drive, whereas activation at reward delivery decreases motivation; optical inhibition triggers the opposite behavioral effect. In addition, in a free-choice instrumental task, animals prefer the lever that originates one pellet in opposition to pellet plus D2-MSN-VP optogenetic activation and vice versa for optogenetic inhibition. In summary, D2-MSN-VP projections play different, and even opposing, roles in distinct phases of motivated behavior.

Interaction between Lactobacillus reuteri and periodontopathogenic bacteria using in vitro and in vivo (G. mellonella) approaches.

Periodontitis is a multifactorial inflammatory disease, and the major cause of tooth loss in adults. New therapies have been proposed for its treatment, including the use of probiotics such as Lactobacillus reuteri. The objective of this study was to evaluate the antimicrobial effects of L. reuteri: live, heat-killed and culture filtrate (cell-free supernatant), on periodontopathogenic bacteria (Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans) in vitro, as well as the in vivo survival curve, hemocyte density and microbial recovery using Galleria mellonella. For in vitro assays, all preparations reduced colony forming units of F. nucleatum, while only live L. reuteri reduced the growth of A. actinomycetemcomitans. All treatments reduced periodontopathogenic bacteria growth in vivo. The treatment with the supernatant increased the survival of larvae infected with F. nucleatum more than the treatment with live L. reuteri, and none of the treatments altered the survival of A. actinomycetemcomitans-infected larvae. In addition, the treatment with L. reuteri preparations did not alter the hemocyte count of F. nucleatum- and A. actinomycetemcomitans-infected larvae. This study demonstrated that L. reuteri preparations exerted antimicrobial effects and increased the survival of G. mellonella infected by F. nucleatum, although only live L. reuteri was able to reduce the growth of A. actinomycetemcomitans in vitro.