Comparison of short-term outcomes following robotic ventral hernia repair in patients with obesity: a review of 9742 patients from the Abdominal Core Health Quality Collaborative database.

Despite the paucity of evidence on robotic ventral hernia repair (RVHR) in patients with obesity, the robotic platform is being used more frequently in hernia surgery. The impact of obesity on RVHR outcomes has not been thoroughly studied. Obesity is considered a major risk factor for the development of recurrent ventral hernias and postoperative complications; however, we hypothesize that patients undergoing robotic repairs will have similar complication profiles despite their body mass index (BMI). We performed a retrospective analysis of patients aged 18-90 years who underwent RVHR between 2013 and 2023 using data from the Abdominal Core Health Quality Collaborative registry. Preoperative, intraoperative, and postoperative characteristics were compared in non-obese and obese groups, determined using a univariate and logistic regression analysis to compare short-term outcomes. The registry identified 9742 patients; 3666 were non-obese; 6076 were classified as obese (BMI > 30 kg/m2). There was an increased odds of surgical site occurrence in patients with obesity, mostly seroma formation; however, obesity was not a significant factor for a complication requiring a procedural intervention after RVHR. In contrast, the hernia-specific quality-of-life scores significantly improved following surgery for all patients, with those with obesity having more substantial improvement from baseline. Obesity does increase the risk of certain complications following RVHR in a BMI-dependent fashion; however, the odds of requiring a procedural intervention are not significantly increased by BMI. Patients with obesity have a significant improvement in their quality of life, and RVHR should be carefully considered in this population.

Working memory constraints for visuomotor retrieval strategies.

Recent work has shown the fundamental role that cognitive strategies play in visuomotor adaptation. While algorithmic strategies, such as mental rotation, are flexible and generalizable, they are computationally demanding. To avoid this computational cost, people can instead rely on memory retrieval of previously successful visuomotor solutions. However, such a strategy is likely subject to strict stimulus-response associations and rely heavily on working memory. In a series of five experiments, we sought to estimate the constraints in terms of capacity and precision of working memory retrieval for visuomotor adaptation. This was accomplished by leveraging different variations of visuomotor item-recognition and visuomotor rotation tasks where we associated unique rotations with specific targets in the workspace and manipulated the set size (i.e., number of rotation-target associations). Notably, from Experiment 1 to 4, we found key signatures of working memory retrieval and not mental rotation. In particular, participants were less accurate and slower for larger set sizes and less recent items. Using a Bayesian latent-mixture model, we found that such decrease in performance was the result of increasing guessing behavior and less precise memories. In addition we estimated that participants' working memory capacity was limited to 2-5 items, after which guessing increasingly dominated performance. Finally, in Experiment 5, we showed how the constraints observed across Experiments 1 to 4 can be overcome when relying on long-term memory retrieval. Our results point to the opportunity of studying other sources of memories where visuomotor solutions can be stored (e.g., episodic memories) to achieve successful adaptation.

Examining the Gateway Hypothesis and Mapping Substance Use Pathways on Social Media: Machine Learning Approach.

BACKGROUND: Substance misuse presents significant global public health challenges. Understanding transitions between substance types and the timing of shifts to polysubstance use is vital to developing effective prevention and recovery strategies. The gateway hypothesis suggests that high-risk substance use is preceded by lower-risk substance use. However, the source of this correlation is hotly contested. While some claim that low-risk substance use causes subsequent, riskier substance use, most people using low-risk substances also do not escalate to higher-risk substances. Social media data hold the potential to shed light on the factors contributing to substance use transitions. OBJECTIVE: By leveraging social media data, our study aimed to gain a better understanding of substance use pathways. By identifying and analyzing the transitions of individuals between different risk levels of substance use, our goal was to find specific linguistic cues in individuals' social media posts that could indicate escalating or de-escalating patterns in substance use. METHODS: We conducted a large-scale analysis using data from Reddit, collected between 2015 and 2019, consisting of over 2.29 million posts and approximately 29.37 million comments by around 1.4 million users from subreddits. These data, derived from substance use subreddits, facilitated the creation of a risk transition data set reflecting the substance use behaviors of over 1.4 million users. We deployed deep learning and machine learning techniques to predict the escalation or de-escalation transitions in risk levels, based on initial transition phases documented in posts and comments. We conducted a linguistic analysis to analyze the language patterns associated with transitions in substance use, emphasizing the role of n-gram features in predicting future risk trajectories. RESULTS: Our results showed promise in predicting the escalation or de-escalation transition in risk levels, based on the historical data of Reddit users created on initial transition phases among drug-related subreddits, with an accuracy of 78.48% and an F1-score of 79.20%. We highlighted the vital predictive features, such as specific substance names and tools indicative of future risk escalations. Our linguistic analysis showed that terms linked with harm reduction strategies were instrumental in signaling de-escalation, whereas descriptors of frequent substance use were characteristic of escalating transitions. CONCLUSIONS: This study sheds light on the complexities surrounding the gateway hypothesis of substance use through an examination of web-based behavior on Reddit. While certain findings validate the hypothesis, indicating a progression from lower-risk substances such as marijuana to higher-risk ones, a significant number of individuals did not show this transition. The research underscores the potential of using machine learning with social media analysis to predict substance use transitions. Our results point toward future directions for leveraging social media data in substance use research, underlining the importance of continued exploration before suggesting direct implications for interventions.

Direct Admission Program Implementation: A Qualitative Analysis of Variation Across Health Systems.

OBJECTIVES: Direct admission (DA) to the hospital has the potential to improve family satisfaction and timeliness of care by bypassing the emergency department. Using the RE-AIM implementation framework, we sought to characterize variation across health systems in the reach, effectiveness, adoption, and implementation of a DA program from the perspectives of parents and multidisciplinary clinicians. METHODS: As part of a stepped-wedge cluster randomized trial to compare the effectiveness of DA to admission through the emergency department, we evaluated DA rates across 69 clinics and 3 health systems and conducted semi-structured interviews with parents and clinicians. We used thematic analysis to identify themes related to the reach, effectiveness, adoption, and implementation of the DA program and applied axial coding to characterize thematic differences across sites. RESULTS: Of 2599 hospitalizations, 171 (6.6%) occurred via DA, with DA rates varying 10-fold across health systems from 0.9% to 9.3%. Through the analysis of 137 interviews, including 84 with clinicians and 53 with parents, we identified similarities across health systems in themes related to perceived program effectiveness and patient and family engagement. Thematic differences across sites in the domains of program implementation and clinician adoption included variation in transfer center efficiency, trust between referring and accepting clinicians, and the culture of change within the health system. CONCLUSIONS: The DA program was adopted variably, highlighting unique challenges and opportunities for implementation in different hospital systems. These findings can inform future quality improvement efforts to improve transitions to the hospital.

Reactive high-spin iron(IV)-oxo sites through dioxygen activation in a metal-organic framework.

In nature, nonheme iron enzymes use dioxygen to generate high-spin iron(IV)=O species for a variety of oxygenation reactions. Although synthetic chemists have long sought to mimic this reactivity, the enzyme-like activation of O2 to form high-spin iron(IV) = O species remains an unrealized goal. Here, we report a metal-organic framework featuring iron(II) sites with a local structure similar to that in α-ketoglutarate-dependent dioxygenases. The framework reacts with O2 at low temperatures to form high-spin iron(IV) = O species that are characterized using in situ diffuse reflectance infrared Fourier transform, in situ and variable-field Mössbauer, Fe Kß x-ray emission, and nuclear resonance vibrational spectroscopies. In the presence of O2, the framework is competent for catalytic oxygenation of cyclohexane and the stoichiometric conversion of ethane to ethanol.

Exploring the role of task success in implicit motor adaptation.

Although implicit motor adaptation is driven by sensory-prediction errors (SPEs), recent work has shown that task success modulates this process. Task success has typically been defined as hitting a target, which signifies the goal of the movement. Visuomotor adaptation tasks are uniquely situated to experimentally manipulate task success independently from SPE by changing the target size or the location of the target. These two, distinct manipulations may influence implicit motor adaptation in different ways, so, over four experiments, we sought to probe the efficacy of each manipulation. We found that changes in target size, which caused the target to fully envelop the cursor, only affected implicit adaptation for a narrow range of SPE sizes, while jumping the target to overlap with the cursor more reliably and robustly affected implicit adaptation. Taken together, our data indicate that, while task success exerts a small effect on implicit adaptation, these effects are susceptible to methodological variations. Future investigations of the effect of task success on implicit adaptation could benefit from employing target jump manipulations instead of target size manipulations.NEW & NOTEWORTHY Recent work has suggested that task success, namely, hitting a target, influences implicit motor adaptation. Here, we observed that implicit adaptation is modulated by target jump manipulations, where the target abruptly "jumps" to meet the cursor; however, implicit adaptation was only weakly modulated by target size manipulations, where a static target either envelops or excludes the cursor. We discuss how these manipulations may exert their effects through different mechanisms.

Using Social Media to Examine Themes Surrounding Fentanyl Misuse and Risk Indicators.

Background: Opioid misuse is a crisis in the United States, and synthetic opioids such as fentanyl pose risks for overdose and mortality. Individuals who misuse substances commonly seek information and support online due to stigma and legal concerns, and this online networking may provide insight for substance misuse prevention and treatment. We aimed to characterize topics in substance-misuse related discourse among members of an online fentanyl community. Method: We investigated posts on a fentanyl-specific forum on the platform Reddit to identify emergent substance misuse-related themes potentially indicative of heightened risk for overdose and other adverse health outcomes. We analyzed 27 posts and 338 comments with a qualitative codebook established using a subset of user posts via inductive and deductive methods. Posts and comments were independently reviewed by two coders with a third coder resolving discrepancies. The top 200 subreddits with the most activity by r/fentanyl members were also inductively analyzed to understand interests of r/fentanyl users. Results: Functional/quality of life impairments due to substance misuse (29%) was the most commonly occurring theme, followed by polysubstance use (27%) and tolerance/dependence/withdrawal (20%). Additional themes included drug identification with photos, substances cut with other drugs, injection drugs, and past overdoses. Media-focused subreddits and other drug focused communities were among the communities most often followed by r/fentanyl users. Conclusion: Themes closely align with DSM-V substance use disorder symptoms for fentanyl and other substances. High involvement in media-focused subreddits and other substance-misuse-related communities suggests digital platforms as acceptable for overdose prevention and recovery support interventions.

Effects of neonatal fentanyl on late adolescent opioid-mediated behavior.

Introduction: Because of the steady increase in the use of synthetic opioids in women of childbearing age, a large number of children are at risk of exposure to these drugs prenatally or postnatally through breast milk. While there is older literature looking at the effects of morphine and heroin, there are relatively few studies looking at the long-term effects of high-potency synthetic opioid compounds like fentanyl. Thus, in the present study, we assessed whether brief exposure to fentanyl in male and female rat pups during a period roughly equivalent to the third trimester of CNS development altered adolescent oral fentanyl self-administration and opioid-mediated thermal antinociception. Methods: We treated the rats with fentanyl (0, 10, or 100 µg/kg sc) from postnatal day (PD) 4 to PD 9. The fentanyl was administered daily in two injections given 6 h apart. After the last injection on PD 9, the rat pups were left alone until either PD 40 where they began fentanyl self-administration training or PD 60 where they were tested for morphine- (0, 1.25, 2.5, 5, or 10 mg/kg) or U50,488- (0, 2.5, 5, 10, or 20 mg/kg) induced thermal antinociception. Results: In the self-administration study, we found that female rats had more active nose pokes than male rats when receiving a fentanyl reward but not sucrose alone solution. Early neonatal fentanyl exposure did not significantly alter fentanyl intake or nose-poke response. In contrast, early fentanyl exposure did alter thermal antinociception in both male and female rats. Specifically, fentanyl (10 µg/kg) pre-treatment increased baseline paw-lick latencies, and the higher dose of fentanyl (100 µg/kg) reduced morphine-induced paw-lick latencies. Fentanyl pre-treatment did not alter U50,488-mediated thermal antinociception. Conclusions: Although our exposure model is not reflective of typical human fentanyl use during pregnancy, our study does illustrate that even brief exposure to fentanyl during early development can have long-lasting effects on mu-opioid-mediated behavior. Moreover, our data suggest that females may be more susceptible to fentanyl abuse than males.

Fecal Keratin 8 Is a Noninvasive and Specific Marker for Intestinal Injury in Necrotizing Enterocolitis.

Specific biomarkers of intestinal injury associated with necrotizing enterocolitis (NEC) are needed to diagnose and monitor intestinal mucosal injury and recovery. This study aims to develop and test a modified enzyme-linked immunosorbent assay (ELISA) protocol to detect the total keratin 8 (K8) in the stool of newborns with NEC and investigate the clinical value of fecal K8 as a marker of intestinal injury specifically associated with NEC. We collected fecal samples from five newborns with NEC and five gestational age-matched premature neonates without NEC at the Lucile Packard Children's Hospital Stanford and Washington University School of Medicine, respectively. Fecal K8 levels were measured using a modified ELISA protocol and Western blot, and fecal calprotectin was measured using a commercial ELISA kit. Clinical data, including gestational age, birth weight, Bell stage for NEC, feeding strategies, total white blood cell (WBC) count, and other pertinent clinical variables, were collected and analyzed. Fecal K8 levels were significantly higher in the pre-NEC group (1-2 days before diagnosis of NEC) and NEC group than those in the non-NEC group (p = 0.013, p = 0.041). Moreover, fecal K8 was relatively higher at the onset of NEC and declined after the resolution of the disease (p = 0.019). Results with similar trends to fecal K8 were also seen in fecal calprotectin (p = 0.046), but not seen in total WBC count (p = 0.182). In conclusion, a modified ELISA protocol for the total K8 protein was successfully developed for the detection of fecal K8 in the clinical setting of premature newborns with NEC. Fecal K8 is noted to be significantly increased in premature newborns with NEC and may, therefore, serve as a noninvasive and specific marker for intestinal epithelial injury associated with NEC.

Exploring the role of task success in implicit motor adaptation.

We learn to improve our motor skills using different forms of feedback: sensory-prediction error, task success, and reward/punishment. While implicit motor adaptation is driven by sensory-prediction errors, recent work has shown that task success modulates this process. Task success is often confounded with reward, so we sought to determine if the effects of these two signals on adaptation can be dissociated. To address this question, we conducted five experiments that isolated implicit learning using error-clamp visuomotor reach adaptation paradigms. Task success was manipulated by changing the size and position of the target relative to the cursor providing visual feedback, and reward expectation was established using monetary cues and auditory feedback. We found that neither monetary cues nor auditory feedback affected implicit adaptation, suggesting that task success influences implicit adaptation via mechanisms distinct from conventional reward-related processes. Additionally, we found that changes in target size, which caused the target to either exclude or fully envelop the cursor, only affected implicit adaptation for a narrow range of error sizes, while jumping the target to overlap with the cursor more reliably and robustly affected implicit adaptation. Taken together, our data indicate that, while task success exerts a small effect on implicit adaptation, these effects are susceptible to methodological variations and unlikely to be mediated by reward.

IFITM proteins: Understanding their diverse roles in viral infection, cancer, and immunity.

Interferon-induced transmembrane proteins (IFITMs) are broad spectrum antiviral factors that inhibit the entry of a wide range of clinically important pathogens including influenza A virus, HIV-1, and Dengue virus. IFITMs are thought to act primarily by antagonizing virus-cell membrane fusion in this regard. However, recent work on these proteins has uncovered novel post-entry viral restriction mechanisms. IFITMs are also increasingly thought to have a role regulating immune responses, including innate antiviral and inflammatory responses as well as adaptive T-cell and B-cell responses. Further, IFITMs may have pathological activities in cancer, wherein IFITM expression can be a marker of therapeutically resistant and aggressive disease courses. In this review, we summarize the respective literatures concerning these apparently diverse functions with a view to identifying common themes and potentially yielding a more unified understanding of IFITM biology.

Anticoagulation and Antiplatelet Agents in Peripheral Arterial Interventions.

Effective revascularization of peripheral artery disease relies on periprocedural pharmacological regulation of the clotting cascade. Patient-specific factors such as cardiovascular risk factors, contraindications, and individual psychosocial factors must be considered when initiating post revascularization management. Management with anticoagulant and antiplatelet agents is discussed to guide the interventionalist on which therapy may be appropriate for their patient. While exact treatment may be institution and provider dependent, the interventionist must be familiar with the available classes of medications and how they can be prescribed in the postprocedural setting to improve cardiovascular outcomes.

Contextual effects in sensorimotor adaptation adhere to associative learning rules.

Traditional associative learning tasks focus on the formation of associations between salient events and arbitrary stimuli that predict those events. This is exemplified in cerebellar-dependent delay eyeblink conditioning, where arbitrary cues such as a tone or light act as conditioned stimuli (CSs) that predict aversive sensations at the cornea (unconditioned stimulus [US]). Here, we ask if a similar framework could be applied to another type of cerebellar-dependent sensorimotor learning - sensorimotor adaptation. Models of sensorimotor adaptation posit that the introduction of an environmental perturbation results in an error signal that is used to update an internal model of a sensorimotor map for motor planning. Here, we take a step toward an integrative account of these two forms of cerebellar-dependent learning, examining the relevance of core concepts from associative learning for sensorimotor adaptation. Using a visuomotor adaptation reaching task, we paired movement-related feedback (US) with neutral auditory or visual contextual cues that served as CSs. Trial-by-trial changes in feedforward movement kinematics exhibited three key signatures of associative learning: differential conditioning, sensitivity to the CS-US interval, and compound conditioning. Moreover, after compound conditioning, a robust negative correlation was observed between responses to the two elemental CSs of the compound (i.e. overshadowing), consistent with the additivity principle posited by theories of associative learning. The existence of associative learning effects in sensorimotor adaptation provides a proof-of-concept for linking cerebellar-dependent learning paradigms within a common theoretical framework.

Continuous manipulation of mental representations is compromised in cerebellar degeneration.

We introduce a novel perspective on how the cerebellum might contribute to cognition, hypothesizing that this structure supports dynamic transformations of mental representations. In support of this hypothesis, we report a series of neuropsychological experiments comparing the performance of individuals with degenerative cerebellar disorders on tasks that either entail continuous, movement-like mental operations or more discrete mental operations. In the domain of visual cognition, the cerebellar disorders group exhibited an impaired rate of mental rotation, an operation hypothesized to require the continuous manipulation of a visual representation. In contrast, the cerebellar disorders group showed a normal processing rate when scanning items in visual working memory, an operation hypothesized to require the maintenance and retrieval of remembered items. In the domain of mathematical cognition, the cerebellar disorders group was impaired at single-digit addition, an operation hypothesized to primarily require iterative manipulations along a mental number-line; this group was not impaired on arithmetic tasks linked to memory retrieval (e.g. single-digit multiplication). These results, obtained in tasks from two disparate domains, point to a potential constraint on the contribution of the cerebellum to cognitive tasks. Paralleling its role in motor control, the cerebellum may be essential for coordinating dynamic, movement-like transformations in a mental workspace.

Distinct Neural Signatures of Outcome Monitoring After Selection and Execution Errors.

Losing a point in tennis could result from poor shot selection or faulty stroke execution. To explore how the brain responds to these different types of errors, we examined feedback-locked EEG activity while participants completed a modified version of a standard three-armed bandit probabilistic reward task. Our task framed unrewarded outcomes as the result of either errors of selection or errors of execution. We examined whether amplitude of a medial frontal negativity (the feedback-related negativity [FRN]) was sensitive to the different forms of error attribution. Consistent with previous reports, selection errors elicited a large FRN relative to rewards, and amplitude of this signal correlated with behavioral adjustment after these errors. A different pattern was observed in response to execution errors. These outcomes produced a larger FRN, a frontocentral attenuation in activity preceding this component, and a subsequent enhanced error positivity in parietal sites. Notably, the only correlations with behavioral adjustment were with the early frontocentral attenuation and amplitude of the parietal signal; FRN differences between execution errors and rewarded trials did not correlate with subsequent changes in behavior. Our findings highlight distinct neural correlates of selection and execution error processing, providing insight into how the brain responds to the different classes of error that determine future action.

Ultrasound Verification of Laparoscopic-Assisted Transversus Abdominis Plane Blocks in Children Undergoing Laparoscopic Procedures.

Purpose: Ultrasound-guided transversus abdominis plane (TAP) blocks have been demonstrated to decrease postoperative pain; however, laparoscopic-assisted TAP (L-TAP) blocks have not been well studied in children. Our study utilized intraoperative ultrasound to verify whether surgeon-administered blocks using only laparoscopic visualization were reliably delivered into the correct plane. Materials and Methods: Patients undergoing laparoscopic procedures were enrolled to receive L-TAP blocks. Preblock and postblock ultrasounds were performed to document the plane of local anesthetic delivery. Ultrasound images were reviewed by two blinded anesthesiologists to determine whether the L-TAP block was administered into the desired plane. Results: Fifty-one patients were enrolled. The average age was 5.9 years (range: 2 days to 17 years) and the mean weight was 25.4 kg (range: 2.64-118.8 kg). The most common procedures were inguinal hernia repair (n = 19), appendectomy (n = 10), and gastrostomy-tube placements (n = 13). Nine surgeons performed 93 L-TAP blocks (average: 10.3 blocks/surgeon). Ultrasound confirmed distribution in the correct plane in 53.5/93 blocks (57.5%; 58.0% for attending surgeons), with 77.4% concurrence between the anesthesiologist reviewers. Conclusion: L-TAP achieves delivery of local anesthetic into the correct tissue plane in over half the cases with minimal training. Further studies are needed to examine the effect of L-TAP blocks on reducing postoperative pain in pediatric patients.

Distraction enterogenesis in the murine colon.

BACKGROUND/PURPOSE: Distraction enterogenesis with intraluminal spring technology has been successfully used to lengthen segments of murine small intestine. We hypothesized that biocompatible springs could also be used to lengthen murine large intestine. METHODS: Age and weight matched C57BL/6 mice underwent surgical insertion of nitinol spring-loaded capsules into the cecum. Segment lengths were measured at initial spring placement and at euthanasia after 7 and 14 days. Histologic adaptations were evaluated at scarification. RESULTS: Cecal segments loaded with compressed springs lengthened an average of 150%, which was significantly longer than control segments loaded with either empty capsules or uncompressed springs. Muscularis layers tended to be thicker in the compressed spring groups compared to control groups. CONCLUSIONS: Insertion of a compressed nitinol spring into the cecum results in significant colonic lengthening in a mouse model. The ability to increase cecum length serves as proof of concept that distraction enterogenesis technology may be feasibly applied to large intestinal models. The use of distraction enterogenesis technology shows promise for application to clinical models in the treatment of pediatric intestinal disease.

Effects of repeated treatment with the 5-HT1A and 5-HT1B agonists (R)-( +)-8-hydroxy-DPAT and CP-94253 on the locomotor activity and axillary temperatures of preweanling rats: evidence of tolerance and behavioral sensitization.

RATIONALE: Drugs that stimulate 5-HT1A/1B receptors produce both tolerance and behavioral sensitization in adult rats and mice, yet it is unknown whether the same types of plasticity are evident during earlier ontogenetic periods. OBJECTIVE: The purpose of this study was to determine whether repeated treatment with selective 5-HT1A and/or 5-HT1B agonists cause tolerance and/or sensitization in preweanling rats. METHODS: In Experiments 1 and 2, male and female preweanling rats were given a single pretreatment injection of saline, the 5-HT1A agonist (R)-( +)-8-hydroxy-DPAT (8-OH-DPAT), or the 5-HT1B agonist CP-94253 on PD 20. After 48 h, rats received a challenge injection of 8-OH-DPAT or CP-94253, respectively. In Experiment 3, rats were pretreated with saline or DPAT + CP on PD 20 and challenged with the same drug cocktail on PD 22. In Experiment 4, the tolerance- or sensitization-inducing properties of 8-OH-DPAT, CP-94253, or DPAT + CP were tested after a 4-day pretreatment regimen on PD 17-20. RESULTS: On the first pretreatment day, 8-OH-DPAT, CP-94253, and DPAT + CP increased locomotion and caused hypothermia. Repeated treatment with 8-OH-DPAT (2 or 8 mg/kg) or DPAT + CP caused locomotor sensitization in preweanling rats. In contrast, tolerance to the hypothermic effects of 8-OH-DPAT (8 mg/kg), CP-94253 (5-20 mg/kg), or DPAT + CP was evident after repeated drug treatment. CONCLUSIONS: During the preweanling period, a single injection of a selective 5-HT1A or 5-HT1B agonist is capable of producing drug-induced plasticity. A pretreatment administration of 8-OH-DPAT causes both tolerance (hypothermia) and behavioral sensitization (locomotor activity) in preweanling rats, whereas repeated CP-94253 treatment results in tolerance.

Revisiting the Role of the Medial Temporal Lobe in Motor Learning.

Classic taxonomies of memory distinguish explicit and implicit memory systems, placing motor skills squarely in the latter branch. This assertion is in part a consequence of foundational discoveries showing significant motor learning in amnesics. Those findings suggest that declarative memory processes in the medial temporal lobe (MTL) do not contribute to motor learning. Here, we revisit this issue, testing an individual (L. S. J.) with severe MTL damage on four motor learning tasks and comparing her performance to age-matched controls. Consistent with previous findings in amnesics, we observed that L. S. J. could improve motor performance despite having significantly impaired declarative memory. However, she tended to perform poorly relative to age-matched controls, with deficits apparently related to flexible action selection. Further supporting an action selection deficit, L. S. J. fully failed to learn a task that required the acquisition of arbitrary action-outcome associations. We thus propose a modest revision to the classic taxonomic model: Although MTL-dependent memory processes are not necessary for some motor learning to occur, they play a significant role in the acquisition, implementation, and retrieval of action selection strategies. These findings have implications for our understanding of the neural correlates of motor learning, the psychological mechanisms of skill, and the theory of multiple memory systems.

Detecting risk level in individuals misusing fentanyl utilizing posts from an online community on Reddit.

INTRODUCTION: Opioid misuse is a public health crisis in the US, and misuse of synthetic opioids such as fentanyl have driven the most recent waves of opioid-related deaths. Because those who misuse fentanyl are often a hidden and high-risk group, innovative methods for identifying individuals at risk for fentanyl misuse are needed. Machine learning has been used in the past to investigate discussions surrounding substance use on Reddit, and this study leverages similar techniques to identify risky content from discussions of fentanyl on this platform. METHODS: A codebook was developed by clinical domain experts with 12 categories indicative of fentanyl misuse risk, and this was used to manually label 391 Reddit posts and comments. Using this data, we built machine learning classification models to identify fentanyl risk. RESULTS: Our machine learning risk model was able to detect posts or comments labeled as risky by our clinical experts with 76% accuracy and 76% sensitivity. Furthermore, we provide a vocabulary of community-specific, colloquial words for fentanyl and its analogues. DISCUSSION: This study uses an interdisciplinary approach leveraging machine learning techniques and clinical domain expertise to automatically detect risky discourse, which may elicit and benefit from timely intervention. Moreover, our vocabulary of online terms for fentanyl and its analogues expands our understanding of online "street" nomenclature for opiates. Through an improved understanding of substance misuse risk factors, these findings allow for identification of risk concepts among those misusing fentanyl to inform outreach and intervention strategies tailored to this at-risk group.