Recovery kinetics of dual AAV-mediated human otoferlin expression.

Deafness-causing deficiencies in otoferlin (OTOF) have been addressed preclinically using dual adeno-associated virus (AAV)-based approaches. However, timing of transduction, recombination of mRNA, and protein expression with dual hybrid AAV methods methods have not previously been characterized. Here, we have established an ex vivo assay to determine the kinetics of dual-AAV mediated expression of OTOF in hair cells of the mouse utricle. We utilized two different recombinant vectors that comprise DB-OTO, one containing the 5' portion of OTOF under the control of the hair cell-specific Myo15 promoter, and the other the 3' portion of OTOF. We explored specificity of the Myo15 promoter in hair cells of the mouse utricle, established dose response characteristics of DB-OTO ex vivo in an OTOF-deficient mouse model, and demonstrated tolerability of AAV1 in utricular hair cells. Furthermore, we established deviations from a one-to-one ratio of 5' to 3' vectors with little impact on recombined OTOF. Finally, we established a plateau in quantity of recombined OTOF mRNA and protein expression by 14 to 21 days ex vivo with comparable recovery timing to that in vivo model. These findings demonstrate the utility of an ex vivo model system for exploring expression kinetics and establish in vivo and ex vivo recovery timing of dual AAV-mediated OTOF expression.

Observation of oxygenated intermediates in functional mimics of aminophenol dioxygenase.

Aminophenol dioxygenases (APDO) are mononuclear nonheme iron enzymes that utilize dioxygen (O2) to catalyze the conversion of o-aminophenols to 2-picolinic acid derivatives in metabolic pathways. This study describes the synthesis and O2 reactivity of two synthetic models of substrate-bound APDO: [FeII(TpMe2)(tBu2APH)] (1) and [FeII(TpMe2)(tBuAPH)] (2), where TpMe2 = hydrotris(3,5-dimethylpyrazole-1-yl)borate, tBu2APH = 4,6-di-tert-butyl-2-aminophenolate, and tBuAPH2 = 4-tert-butyl-2-aminophenolate. Both Fe(II) complexes behave as functional APDO mimics, as exposure to O2 results in oxidative CC bond cleavage of the o-aminophenolate ligand. The ring-cleaved products undergo spontaneous cyclization to give substituted 2-picolinic acids, as verified by 1H NMR spectroscopy, mass spectrometry, and X-ray crystallography. Reaction of the APDO models with O2 at low temperature reveals multiple intermediates, which were probed with UV-vis absorption, electron paramagnetic resonance (EPR), Mössbauer (MB), and resonance Raman (rRaman) spectroscopies. The most stable intermediate at -70 °C in THF exhibits multiple isotopically-sensitive features in rRaman samples prepared with 16O2 and 18O2, confirming incorporation of O2-derived atom(s) into its molecular structure. Insights into the geometric structures, electronic properties, and spectroscopic features of the observed intermediates were obtained from density functional theory (DFT) calculations. Although functional APDO models have been previously reported, this is the first time that an oxygenated ligand-based radical has been detected and spectroscopically characterized in the ring-cleaving mechanism of a relevant synthetic system.

Identifying patients at risk of anaphylaxis.

Anaphylaxis is an acute, potentially fatal, systemic hypersensitivity reaction that warrants prompt diagnosis and management. It continues to be challenging to anticipate who may be at risk of a severe, life-threatening allergic reaction. Anaphylaxis can be caused by a range of allergens, such as certain foods, medications, latex, insect stings, etc. Cofactors that augment the severity of clinical symptoms and increase the risk of poor outcomes include exercise, stress, infectious diseases, underlying mast cell disease, active allergic disease such as asthma, advanced age, intake of certain medications, history of previous anaphylaxis, and delayed or missed administration of adrenaline. According to the European Anaphylaxis Registry, food is the major elicitor of anaphylaxis, especially eggs, cow milk, and nuts, in children and adolescents. Reaction to insect venom has also been noted in young adulthood. Early recognition of signs and symptoms and prompt treatment are crucial in anaphylaxis management to avoid serious and even fatal outcomes. It is crucial for both individuals and clinicians to identify the cause of anaphylaxis. Biomarkers of anaphylaxis, such as histamine, tryptase, platelet activation factor (PAF), chymase, carboxypeptidase A3, dipeptidyl peptidase I (DPPI), basogranulin, CCL-2, hsa-miR-451a, may be useful in diagnosis and management. The purpose of this review article is to present a comprehensive overview of current evidence and expert opinions regarding the risk factors that predispose individuals to anaphylaxis. Additionally, it provides insights into potential biomarkers and genetic markers for accurate diagnosis and management. This review underscores the significance of expert guidance in enhancing patient outcomes and enabling self-management of anaphylactic episodes.

Spinal Cord Stimulator Inequities Within the US Military Health System.

OBJECTIVES: Although studies have described inequities in spinal cord stimulation (SCS) receipt, there is a lack of information to inform system-level changes to support health care equity. This study evaluated whether Black patients exhaust more treatment options than do White patients, before receiving SCS. MATERIALS AND METHODS: This retrospective cohort study included claims data of Black and non-Latinx White patients who were active-duty service members or military retirees who received a persistent spinal pain syndrome (PSPS) diagnosis associated with back surgery within the US Military Health System, January 2017 to January 2020 (N = 8753). A generalized linear model examined predictors of SCS receipt within two years of diagnosis, including the interaction between race and number of pain-treatment types received. RESULTS: In the generalized linear model, Black patients (10.3% [8.7%, 12.0%]) were less likely to receive SCS than were White patients (13.6% [12.7%, 14.6%]) The interaction term was significant; White patients who received zero to three different types of treatments were more likely to receive SCS than were Black patients who received zero to three treatments, whereas Black and White patients who received >three treatments had similar likelihoods of receiving a SCS. CONCLUSIONS: In a health care system with intended universal access, White patients diagnosed with PSPS tried fewer treatment types before receiving SCS, whereas the number of treatment types tried was not significantly related to SCS receipt in Black patients. Overall, Black patients received SCS less often than did White patients. Findings indicate the need for structured referral pathways, provider evaluation on equity metrics, and top-down support.

Development of NR0B2 as a therapeutic target for the re-education of tumor associated myeloid cells.

Immune checkpoint blockade (ICB) has had limited utility in several solid tumors such as breast cancer, a major cause of cancer-related mortality in women. Therefore, there is considerable interest in alternate strategies to promote an anti-cancer immune response. A paper co-published in this issue describes how NR0B2, a protein involved in cholesterol homeostasis, functions within myeloid immune cells to modulate the inflammasome and reduce the expansion of immune-suppressive regulatory T cells (Treg). Here, we develop NR0B2 as a potential therapeutic target. NR0B2 in tumors is associated with improved survival for several cancer types including breast. Importantly, NR0B2 expression is also prognostic of ICB success. Within breast tumors, NR0B2 expression is inversely associated with FOXP3, a marker of Tregs. While a described agonist (DSHN) had some efficacy, it required high doses and long treatment times. Therefore, we designed and screened several derivatives. A methyl ester derivative (DSHN-OMe) emerged as superior in terms of (1) cellular uptake, (2) ability to regulate expected expression of genes, (3) suppression of Treg expansion using in vitro co-culture systems, and (4) efficacy against the growth of primary and metastatic tumors. This work identifies NR0B2 as a target to re-educate myeloid immune cells and a novel ligand with significant anti-tumor efficacy in preclinical models.

TERT activation targets DNA methylation and multiple aging hallmarks.

Insufficient telomerase activity, stemming from low telomerase reverse transcriptase (TERT) gene transcription, contributes to telomere dysfunction and aging pathologies. Besides its traditional function in telomere synthesis, TERT acts as a transcriptional co-regulator of genes pivotal in aging and age-associated diseases. Here, we report the identification of a TERT activator compound (TAC) that upregulates TERT transcription via the MEK/ERK/AP-1 cascade. In primary human cells and naturally aged mice, TAC-induced elevation of TERT levels promotes telomere synthesis, blunts tissue aging hallmarks with reduced cellular senescence and inflammatory cytokines, and silences p16INK4a expression via upregulation of DNMT3B-mediated promoter hypermethylation. In the brain, TAC alleviates neuroinflammation, increases neurotrophic factors, stimulates adult neurogenesis, and preserves cognitive function without evident toxicity, including cancer risk. Together, these findings underscore TERT's critical role in aging processes and provide preclinical proof of concept for physiological TERT activation as a strategy to mitigate multiple aging hallmarks and associated pathologies.

NR0B2 re-educates myeloid immune cells to reduce regulatory T cell expansion and progression of breast and other solid tumors.

Although survival from breast cancer has dramatically increased, many will develop recurrent, metastatic disease. Unfortunately, survival for this stage of disease remains very low. Activating the immune system has incredible promise since it has the potential to be curative. However, immune checkpoint blockade (ICB) which works through T cells has been largely disappointing for metastatic breast cancer. One reason for this is a suppressive myeloid immune compartment that is unaffected by ICB. Cholesterol metabolism and proteins involved in cholesterol homeostasis play important regulatory roles in myeloid cells. Here, we demonstrate that NR0B2, a nuclear receptor involved in negative feedback of cholesterol metabolism, works in several myeloid cell types to impair subsequent expansion of regulatory T cells (Tregs); Tregs being a subset known to be highly immune suppressive and associated with poor therapeutic response. Within myeloid cells, NR0B2 serves to decrease many aspects of the inflammasome, ultimately resulting in decreased IL1ß; IL1ß driving Treg expansion. Importantly, mice lacking NR0B2 exhibit accelerated tumor growth. Thus, NR0B2 represents an important node in myeloid cells dictating ensuing Treg expansion and tumor growth, thereby representing a novel therapeutic target to re-educate these cells, having impact across different solid tumor types. Indeed, a paper co-published in this issue demonstrates the therapeutic utility of targeting NR0B2.

Social Determinants and Consequences of Pain: Toward Multilevel, Intersectional, and Life Course Perspectives.

Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain remain rarely addressed in the context of pain prevention and management. In this review, we aim to 1) examine the broad scope of social determinants and consequences of pain and their interactions across multiple levels of organization, and 2) provide a framework synthesizing existing concepts and potential areas for future work on social aspects of pain, drawing upon socioecological, intersectional, and life course approaches. Integrating interdisciplinary theory and evidence, we outline pathways through which multilevel social factors and pain may affect each other over time. We also provide a brief summary of intrapersonal aspects of pain, which are thought to operate at the interface between individuals and the social context. Progressing from micro- to macrolevel factors, we illustrate how social determinants of pain can directly or indirectly contribute to pain experiences, expression, risk, prognosis, and impact across populations. We consider 1) at the interpersonal level, the roles of social comparison, social relatedness, social support, social exclusion, empathy, and interpersonal conflict; 2) at the group or community level, the roles of intimacy groups, task groups, social categories, and loose associations; and 3) at the societal level, the roles of political, economic, and cultural systems, as well as their policies and practices. We present examples of multilevel consequences of pain across these levels and discuss opportunities to reduce the burden and inequities of pain by expanding multilevel social approaches in pain research and practice. PERSPECTIVE: Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain are often unclearly defined, hindering their use in pain prevention, management, and research. We summarize the scope of social aspects of pain and provide a framework synthesizing existing concepts and potential areas for future work.

Neighborhood Deprivation is Associated With Hospital Length of Stay, Discharge Disposition, and Readmission Rates for Patients Who Survive Hospitalization With Traumatic Brain Injury.

BACKGROUND AND OBJECTIVES: Traumatic brain injury (TBI) is a leading cause of disability in the United States. Limited research exists on the influence of area-level socioeconomic status and outcomes after TBI. This study investigated the correlation between the Area Deprivation Index (ADI) and (1) 90-day hospital readmission rates, (2) facility discharge, and (3) prolonged (≥5 days) hospital length of stay (LOS). METHODS: Single-center retrospective review of adult (18 years or older) patients who were admitted for TBI during 2018 was performed. Patients were excluded if they were admitted for management of a chronic or subacute hematoma. We extracted relevant clinical and demographic data including sex, comorbidities, age, body mass index, smoking status, TBI mechanism, and national ADI. We categorized national ADI rankings into quartiles for analysis. Univariate, multivariate, and area under the receiver operating characteristic curve (AUROC) analyses were performed to assess the relationship between ADI and 90-day readmission, hospital LOS, and discharge disposition. RESULTS: A total of 523 patients were included in final analysis. Patients from neighborhoods in the fourth ADI quartile were more likely to be Black (P = .007), have a body mass index ≥30 kg/m2 (P = .03), have a Charlson Comorbidity Index ≥5 (P = .004), and have sustained a penetrating TBI (P = .01). After controlling for confounders in multivariate analyses, being from a neighborhood in the fourth ADI quartile was independently predictive of 90-day hospital readmission (odds ratio [OR]: 1.35 [1.12-1.91], P = .011) (model AUROC: 0.82), discharge to a facility (OR: 1.46 [1.09-1.78], P = .03) (model AUROC: 0.79), and prolonged hospital LOS (OR: 1.95 [1.29-2.43], P = .015) (model AUROC: 0.85). CONCLUSION: After adjusting for confounders, including comorbidities, TBI mechanism/severity, and age, higher ADI was independently predictive of longer hospital LOS, increased risk of 90-day readmission, and nonhome discharge. These results may help establish targeted interventions to identify at-risk patients after TBI.

Treatment of common femoral artery steno-occlusive disease: a comprehensive review of anatomical and hemodynamic considerations.

Open surgical repair, often in the form of endarterectomy, is still the gold standard for steno-occlusive disease in the common femoral artery, despite the success of lower-risk endovascular alternatives in other peripheral arterial regions. Stenting in the common femoral artery is not widely adopted due to the proximity of the artery to the mobile hip joint, and the perceived risk this has on the stent structure due to kinking. The purpose of this review was to assess how hip movement contributes to the anatomical and biomechanical challenges proposed in the common femoral artery, and how these challenges impact the hemodynamics with both open surgical and endovascular stent treatments. The findings demonstrated that the common femoral artery is a fixed arterial segment which does not bend or twist as previously perceived. However, high degrees of bending and twisting are evident in the vessels directly proximal and distal to the common femoral artery. Mechanical testing suggests that the latest generation braided Nitinol stents could be well-suited to these challenges. Both endarterectomy and stenting provide good hemodynamic results regarding limb perfusion. However, other hemodynamic parameters, such as wall shear stress, may not be optimized with either modality, increasing the risk of chronic restenosis. As a high proportion of common femoral artery disease extends into the adjacent arterial segments, further research is warranted to ascertain the optimum hemodynamic stent configuration, as a lower-risk alternative to open surgery.

The continuous flow synthesis of azos.

Azo compounds find use in many areas of science, displaying crucial properties for important applications as photoconductive organic pigments, fluorescent quenchers, paints, cosmetics, inks, and in the large and valuable dye industry. Due to the unstable intermediates, and the exothermic and fast reactions used in their synthesis, high value azo compounds are excellent candidates for continuous flow manufacturing. This comprehensive review covers the progress made to date on developing continuous flow systems for azo synthesis and reflects on the main challenges still to be addressed, including scale up, conversion, product purity, and environmental impact. The further development of integrated continuous flow processes has the potential to help tackle these challenges and deliver improved methods for azo compound generation.

Cerebral Venous Sinus Thrombosis Following Lumbar Puncture.

Cerebral venous sinus thrombosis (CVST) is a rare and potentially fatal condition. It is believed to be one of the rare complications of lumbar puncture (LP), however other causes and risk factors should be considered and ruled out. Diagnosis can be challenging after an LP as it can mimic low pressure or post dural puncture. We present a 23-year-old patient diagnosed with CVST following a diagnostic lumbar puncture, in the absence of other risk factors. The patient presented with a persistent headache that was initially attributed to low CSF pressure, as well as a transient episode of right hemi-body paresthesia. Neuroimaging including contrasted MRI with venography confirmed the diagnosis. The patient had negative hypercoagulable evaluation and was placed on anticoagulation on discharge. Our report highlights the importance of considering CVST in refractory headaches after LP and the value of neuroimaging when indicated.

Thrombectomy Outcomes in Acute Basilar Artery Occlusions Due to Intracranial Atherosclerotic Disease.

BACKGROUND AND OBJECTIVES: Intracranial atherosclerotic disease (ICAD) large vessel occlusion (LVO) is responsible for up to 30% of LVO. In this study, we aimed to determine the likelihood of favorable functional outcomes (modified Rankin Scale 0-3) in acute ICAD-LVO basilar occlusion compared with embolic basilar occlusion. METHODS: This is an analysis of the Posterior Circulation Ischemic Stroke Evaluation: Analyzing Radiographic and Intraprocedural Predictors for Mechanical Thrombectomy Registry in which patients with acute basilar artery occlusions from 8 comprehensive stroke centers were included from 2015 to 2021. Patients were dichotomized into with (ICAD-LVO) or without underlying ICAD (embolic). Descriptive statistics for each group and multivariate logistic analysis were performed on the primary outcome. RESULTS: Three hundred forty-six patients were included. There were 215 patients with embolic (62%) and 131 patients with ICAD-LVO (38%). Baseline demographics were equivalent between the 2 groups except for sex (male 47% vs 67%; P < .001), history of stroke (12% vs 25%; P = .002), and atrial fibrillation (31% vs 17%; P = .003). At 90 days, patients in the ICAD-LVO cohort were less likely to achieve favorable functional outcomes (odds ratio [OR] 0.41, 95% CI 0.22-0.72; P = .003) after adjusting for potentially confounding factors. In addition, ICAD-LVO strokes were less likely to achieve thrombolysis in cerebral infarction ≥2b (OR 0.29, 95% CI 0.14-0.57; P < .001). ICAD-LVO lesions were more likely to require stent placement (OR 14.94, 95% CI 4.91-45.49; P < .001). Subgroup analysis demonstrated favorable functional outcomes in patients who underwent stenting and angioplasty compared with failed recanalization cohort (OR 4.96, 95% CI 1.68-14.64; P < .004). CONCLUSION: Patients with acute basilar ICAD-LVO have higher morbidity and mortality compared with patients with embolic source. Lower rates of successful recanalization in the ICAD-LVO cohort support this finding. Our subgroup analysis demonstrates that stenting should be considered in patients with recanalization failure. Rates of symptomatic intracranial hemorrhage were similar between the ICAD-LVO and embolic cohorts.

Natural language processing pipeline to extract prostate cancer-related information from clinical notes.

OBJECTIVES: To develop an automated pipeline for extracting prostate cancer-related information from clinical notes. MATERIALS AND METHODS: This retrospective study included 23,225 patients who underwent prostate MRI between 2017 and 2022. Cancer risk factors (family history of cancer and digital rectal exam findings), pre-MRI prostate pathology, and treatment history of prostate cancer were extracted from free-text clinical notes in English as binary or multi-class classification tasks. Any sentence containing pre-defined keywords was extracted from clinical notes within one year before the MRI. After manually creating sentence-level datasets with ground truth, Bidirectional Encoder Representations from Transformers (BERT)-based sentence-level models were fine-tuned using the extracted sentence as input and the category as output. The patient-level output was determined by compilation of multiple sentence-level outputs using tree-based models. Sentence-level classification performance was evaluated using the area under the receiver operating characteristic curve (AUC) on 15% of the sentence-level dataset (sentence-level test set). The patient-level classification performance was evaluated on the patient-level test set created by radiologists by reviewing the clinical notes of 603 patients. Accuracy and sensitivity were compared between the pipeline and radiologists. RESULTS: Sentence-level AUCs were ≥ 0.94. The pipeline showed higher patient-level sensitivity for extracting cancer risk factors (e.g., family history of prostate cancer, 96.5% vs. 77.9%, p < 0.001), but lower accuracy in classifying pre-MRI prostate pathology (92.5% vs. 95.9%, p = 0.002) and treatment history of prostate cancer (95.5% vs. 97.7%, p = 0.03) than radiologists, respectively. CONCLUSION: The proposed pipeline showed promising performance, especially for extracting cancer risk factors from patient's clinical notes. CLINICAL RELEVANCE STATEMENT: The natural language processing pipeline showed a higher sensitivity for extracting prostate cancer risk factors than radiologists and may help efficiently gather relevant text information when interpreting prostate MRI. KEY POINTS: When interpreting prostate MRI, it is necessary to extract prostate cancer-related information from clinical notes. This pipeline extracted the presence of prostate cancer risk factors with higher sensitivity than radiologists. Natural language processing may help radiologists efficiently gather relevant prostate cancer-related text information.

Glenoid Fracture Fixation Using an Acu-Loc Distal Radius Plate.

Displaced fractures of the glenoid require surgical fixation. This poses multiple problems, including a difficult approach and achieving adequate reduction with current implants. We provide a surgical technical tip for fixing scapula neck and glenoid rim fractures with an Acu-Loc distal radius plate (Acumed, Weyhill, UK), illustrated with two recent case reports. Here, we present two cases of a 58-year-old female and a 51-year-old male presenting to a hospital following a fall, both sustaining an isolated right glenoid intra-articular fracture evident on plain radiographs. CT scans revealed a displaced and fragmented glenoid surface. A reverse Judet posterior approach facilitated exposure to enable the reduction of the glenoid, an uncommon approach. Current plate designs provide surgeons with limited options to fix complex fractures of the scapula and were not suitable here. The lateral scapula border and inferior glenoid have a similar anatomical shape to the distal radius. An Acu-Loc locking distal radius plate with a radial styloid plate was trialled and provided a good reduction to the fragmented glenoid. A distal radius plate can be a useful option to consider in complex scapula neck and glenoid rim fractures. A better understanding of glenoid shape will facilitate the further development of orthopaedic implants. Familiarity with various surgical approaches is needed to operate on these complex fractures.

Paradoxical gender effects in meat consumption across cultures.

Men tend to eat more meat than women, but it is not clear why. We tested three hypotheses in a cross-cultural design (20,802 individuals in 23 countries across four continents): that gender differences are (a) universal, (b) related to gender roles and thus weaker in countries with higher gender equality and human development, or (c) related to opportunities to express gender roles and thus stronger in countries with higher gender equality and human development. Across all countries, men tended to consume more meat than women. However, this difference increased significantly in countries with greater human development and gender equality. The paradoxical gender gap in meat consumption aligns with previous research that suggests greater differences in behavior across genders in contexts that are more developed and gender equal. We discuss implications for theories of culture and gender as well as practical implications for global meat reduction.

Proceedings of the dengue endgame summit: Imagining a world with dengue control.

The first dengue "endgame" summit was held in Syracuse, NY over August 9 and 10, 2023. Organized and hosted by the Institute for Global Health and Translational Sciences at SUNY Upstate Medical University, the gathering brought together researchers, clinicians, drug and vaccine developers, government officials, and other key stakeholders in the dengue field for a highly collaborative and discussion-oriented event. The objective of the gathering was to discuss the current state of dengue around the world, what dengue "control" might look like, and what a potential roadmap might look like to achieve functional dengue control. Over the course of 7 sessions, speakers with a diverse array of expertise highlighted both current and historic challenges associated with dengue control, the state of dengue countermeasure development and deployment, as well as fundamental virologic, immunologic, and medical barriers to achieving dengue control. While sustained eradication of dengue was considered challenging, attendees were optimistic that significant reduction in the burden of dengue can be achieved by integration of vector control with effective application of therapeutics and vaccines.

A microfluidic approach to study variations in Chlamydomonas reinhardtii alkaline phosphatase activity in response to phosphate availability.

Algal growth depends strongly on phosphorus (P) as a key nutrient, underscoring the significance of monitoring P levels. Algal species display a sensitive response to fluctuations in P availability, notably through the expression of alkaline phosphatase (AP) when challenged with P-depletion. As such, alkaline phosphatase activity (APA) serves as a valuable metric for P availability, offering insights into how algae utilize and fix available P resources. However, current APA quantification methods lack single cell resolution, while also being time- and reagent consuming. Microfluidics offers a promising cost-effective solution to these limitations, providing a platform for precise single-cell analysis. In this study, a trap-based microfluidic device was integrated with a commercially available AP live stain to study the single cell APA response of a model algae strain, Chlamydomonas reinhardtii, when exposed to different exogenous P levels. A three-step culture-starve-spike process was used to induce APA in cells cultured under two different basal P levels (1 and 21 mM). When challenged with different spiked P levels (ranging from 0.1-41 mM), C. reinhardtii cells demonstrated a highly heterogeneous APA response. Two-way ANOVA confirmed that this response is influenced by both spiked and basal P levels. Utilizing an unsupervised machine learning approach (HDBSCAN), distinct subpopulations of C. reinhardtii cells were identified exhibiting varying levels of APA at the single-cell level. These subpopulations encompass significant groups of individual cells with either notably high or low APA, contributing to the overall behavior of the cohorts. Considerable intrapopulation differences in APA were observed across cohorts with similar average behavior. For instance, while some cohorts exhibited a concentrated distribution around the overall average APA, others displayed subpopulations dispersed across a wider range of APA levels. This underscores the potential bias introduced by analyzing a small number of cells in bulk, which may skew results by overrepresenting extreme behavioral subpopulations. The findings if this study highlight the need for analytical approaches that account for single cell heterogeneity in APA and demonstrate the utility of microfluidics as a well-suited means for such investigations. This study illuminates the complexities of APA regulation at the single cell level, providing crucial insights that advance our understanding of algal phosphorus metabolism and environmental responses.

Distinct action signals by subregions in nucleus accumbens during STOP-change performance.

Nucleus accumbens (NAc) is thought to contribute to motivated behavior by signaling the value of reward-predicting cues and the delivery of anticipated reward. NAc is subdivided into core and shell, with each region containing different populations of neurons that increase or decrease firing to rewarding events. While there are various and numerous theories of functions pertaining to these subregions and cell types, most are in the context of reward processing, with fewer considering that NAc might serve functions related to action selection more generally. We recorded from single neurons in NAc as rats of both sexes performed a STOP-change task that is commonly used to study motor control and impulsivity. In this task, rats respond quickly to a spatial cue on 80% of trials (GO) and must stop and redirect planned movement on 20% of trials (STOP). We found that the activity of reward-excited neurons signaled accurate response direction on GO, but not STOP trials, and that these neurons exhibited higher pre-cue firing after correct trials resulting in stronger firing during correct GO trials and errant STOP trials, while reward-inhibited neurons significantly represented response direction on STOP trials at the time of the instrumental response. Finally, the proportion of reward-excited to reward-inhibited neurons and the strength of pre-cue firing decreased as the electrode traversed NAc. We conclude that reward-excited cells (more common in core) promote proactive action selection, while reward-inhibited cells (more common in shell) contribute to accurate responding on STOP trials that require reactive suppression and redirection of behavior.Significant Statement The ability to appropriately adapt behavior is an important part of human cognition, and one that is disrupted by many neuropsychiatric disorders. Here we recorded from neurons in the nucleus accumbens (NAc) as rats performed a cognitive control task and found cell type- and subregion-specific firing patterns. Core and reward-excited cells track trial outcome history, proactively driving behavior to the first cue-a strategy that is appropriate for most trials. Conversely, shell and reward-inhibited neurons signal accurate response direction on trials requiring redirection of behavior. Together, these data suggest that NAc neuronal populations differentially contribute to action selection.