Synaptic wiring motifs in posterior parietal cortex support decision-making.

The posterior parietal cortex exhibits choice-selective activity during perceptual decision-making tasks1-10. However, it is not known how this selective activity arises from the underlying synaptic connectivity. Here we combined virtual-reality behaviour, two-photon calcium imaging, high-throughput electron microscopy and circuit modelling to analyse how synaptic connectivity between neurons in the posterior parietal cortex relates to their selective activity. We found that excitatory pyramidal neurons preferentially target inhibitory interneurons with the same selectivity. In turn, inhibitory interneurons preferentially target pyramidal neurons with opposite selectivity, forming an opponent inhibition motif. This motif was present even between neurons with activity peaks in different task epochs. We developed neural-circuit models of the computations performed by these motifs, and found that opponent inhibition between neural populations with opposite selectivity amplifies selective inputs, thereby improving the encoding of trial-type information. The models also predict that opponent inhibition between neurons with activity peaks in different task epochs contributes to creating choice-specific sequential activity. These results provide evidence for how synaptic connectivity in cortical circuits supports a learned decision-making task.

Identifying Interpretable Latent Factors with Sparse Component Analysis.

In many neural populations, the computationally relevant signals are posited to be a set of 'latent factors' - signals shared across many individual neurons. Understanding the relationship between neural activity and behavior requires the identification of factors that reflect distinct computational roles. Methods for identifying such factors typically require supervision, which can be suboptimal if one is unsure how (or whether) factors can be grouped into distinct, meaningful sets. Here, we introduce Sparse Component Analysis (SCA), an unsupervised method that identifies interpretable latent factors. SCA seeks factors that are sparse in time and occupy orthogonal dimensions. With these simple constraints, SCA facilitates surprisingly clear parcellations of neural activity across a range of behaviors. We applied SCA to motor cortex activity from reaching and cycling monkeys, single-trial imaging data from C. elegans, and activity from a multitask artificial network. SCA consistently identified sets of factors that were useful in describing network computations.

Representational drift: Emerging theories for continual learning and experimental future directions.

Recent work has revealed that the neural activity patterns correlated with sensation, cognition, and action often are not stable and instead undergo large scale changes over days and weeks-a phenomenon called representational drift. Here, we highlight recent observations of drift, how drift is unlikely to be explained by experimental confounds, and how the brain can likely compensate for drift to allow stable computation. We propose that drift might have important roles in neural computation to allow continual learning, both for separating and relating memories that occur at distinct times. Finally, we present an outlook on future experimental directions that are needed to further characterize drift and to test emerging theories for drift's role in computation.

Participant Outcomes of a Student-Run, Intensive, Short-Term, Task-Specific Rehabilitation Program for Individuals Post-Stroke.

Empathy, when demonstrated by health care providers, results in improved patient compliance and enhanced patient outcomes. Yet, self-reported empathy has been shown to decrease in health care professional students during their course of study. Possible reasons for this decrease in empathy have included the type of curriculum of the professional program, participation in clinical experiences, the movement from idealism to realism, and student distress. This current study using the Jefferson Scale of Empathy-Health Professions Student Version (JSE-HPS) demonstrated that Doctor of Physical Therapy (DPT) students, from two DPT programs, showed an increase in their self-reported levels of empathy over the course of their professional education. These students were surveyed before and after clinical experiences and represented two pedagogically different DPT programs. These data suggest that DPT students may differ from the trends found in other healthcare domains. Instead of developing interventions to improve student empathy, as has been suggested, educational time may be better spent helping these DPT students protect and utilize their current levels of empathy.

Stable task information from an unstable neural population.

Over days and weeks, neural activity representing an animal's position and movement in sensorimotor cortex has been found to continually reconfigure or 'drift' during repeated trials of learned tasks, with no obvious change in behavior. This challenges classical theories, which assume stable engrams underlie stable behavior. However, it is not known whether this drift occurs systematically, allowing downstream circuits to extract consistent information. Analyzing long-term calcium imaging recordings from posterior parietal cortex in mice (Mus musculus), we show that drift is systematically constrained far above chance, facilitating a linear weighted readout of behavioral variables. However, a significant component of drift continually degrades a fixed readout, implying that drift is not confined to a null coding space. We calculate the amount of plasticity required to compensate drift independently of any learning rule, and find that this is within physiologically achievable bounds. We demonstrate that a simple, biologically plausible local learning rule can achieve these bounds, accurately decoding behavior over many days.

Publisher Correction: Recycling lithium-ion batteries from electric vehicles.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A Quantitative Measurement of Physical Therapists' Empathy and Exploration of the Relationship With Practice Setting and Work Engagement.

Clinical empathy has been studied in a number of health-care disciplines suggesting that higher practitioner empathy leads to improved patient health and wellness and improved patient outcomes. While some aspects of the physical therapist-patient relationship have been described, evidence of quantitative assessment of clinical empathy in physical therapists is scarce. To investigate the level of self-reported clinical empathy in physical therapists and its relationship to practice environment and workplace engagement, the Jefferson Scale of Empathy-Health Provider version (JSE-HP) and the Oldenburg Burnout Inventory (OLBI) were used. Study participants were 123 physical therapists working full time at either an acute care setting, a rehabilitation hospital, or an outpatient clinic. These physical therapists demonstrated a mean JSE-HP score of 118.5 (9.1) and a mean OLBI score of 15.63 (3.5). This mean empathy score was found to be higher than reported empathy level of some health disciplines such as nursing and pharmacy yet lower than others such as mental health workers, psychiatrists, and pediatricians. Practice setting was not found to be a significant factor regarding empathy levels in physical therapists. As reported in previous studies, there was a positive correlation between being female and having higher empathy levels. A positive correlation was found between age and work disengagement. Finally, our hypothesis regarding a negative correlation between empathy and work disengagement was confirmed, suggesting that workplace disengagement may diminish a physical therapist's empathy, which may then negatively affect patient clinical outcomes.

Recycling lithium-ion batteries from electric vehicles.

Rapid growth in the market for electric vehicles is imperative, to meet global targets for reducing greenhouse gas emissions, to improve air quality in urban centres and to meet the needs of consumers, with whom electric vehicles are increasingly popular. However, growing numbers of electric vehicles present a serious waste-management challenge for recyclers at end-of-life. Nevertheless, spent batteries may also present an opportunity as manufacturers require access to strategic elements and critical materials for key components in electric-vehicle manufacture: recycled lithium-ion batteries from electric vehicles could provide a valuable secondary source of materials. Here we outline and evaluate the current range of approaches to electric-vehicle lithium-ion battery recycling and re-use, and highlight areas for future progress.

A Cross-Sectional Study of Empathy Among Students at Two Doctor of Physical Therapy Programs in Boston.

BACKGROUND: A decline in empathy has been demonstrated in college students over a 30-year period. While higher empathy levels have been measured in healthcare students vs non-healthcare students, reports show a disheartening decrease in student empathy scores over the course of professional healthcare education. OBJECTIVE: The purpose of this study was to assess self-reported empathy in students at two Doctor of Physical Therapy (DPT) programs, one of which used problem-based learning pedagogy while the other used a more traditional didactic teaching method. METHODS: This was a cross-sectional study of cohorts of students enrolled at two DPT programs between June 2016 and January 2017. Empathy levels were measured using the Jefferson Scale of Empathy-Health Professions Student version (JSE-HPS) at the start of each year in their DPT education. Demographic factors of gender and age were also examined. RESULTS: The majority of respondents were female (243/304) with an even distribution of respondents per year of educational experience. There was no significant difference in levels of empathy when comparing the cohorts of students from the two pedagogically different DPT programs. Females demonstrated higher levels of empathy than males. There was a greater level of empathy in third-year students than first-year students in both programs. CONCLUSION: No differences were found in empathy levels between students from two pedagogically different institutions. As empathy is correlated with improved patient outcomes and patient satisfaction, endeavors to understand, document, and increase students' empathy levels should be investigated.

Hemilabile bonding of 1-oxa-4,7-dithiacyclononane in cyclometallated palladium(ii) complexes.

The synthesis and characterization of a series of cyclometallated complexes of Pd(ii) incorporating the mixed donor ligand 1-oxa-4,7-dithiacyclononane ([9]aneS2O) are presented in this study. Complexes of the form [Pd(C^N)([9]aneS2O)](PF6) (C^N = 2-phenylpyridine (ppy) 1b, 4-(2-pyridyl)benzaldehyde (ppyCHO) 2b, 7,8-benzoquinoline (bzq) 3b, 2-benzothienylpyridine (btp) 4b, 2-phenylbenzothiazole (pbt) 5b), were obtained in high-yield from a simple two-step synthetic scheme. All of these complexes were fully characterized by NMR, ESI-MS, IR, combustion analyses, and most (1b, 2b, 4b, 5b) by X-ray crystallography. Solution 1H and 13C NMR studies of [Pd(C^N)([9]aneS2O)](PF6) complexes demonstrate complicated [9]aneS2O behavior at room temperature. Variable temperature NMR reveals dynamic bonding of the [9]aneS2O ligand consistent with the presence of both endodentate and exodentate bonding modes. This is in stark contrast to the related [9]aneS3 (1,4,7-trithiacyclononane) cogeners that demonstrate fluxional endodentate bonding only in solution. X-ray structures reveal only exodenate [9]aneS2O bonding in this series, unlike the related [9]aneS3 complexes that show endodenate bonding with an axial PdS interaction. DFT calculations performed on endo and exo [9]aneS2O bonding forms of 4b, as well as a transition state calculation for interconversion, suggest reasonable access to both bonding forms based on the energy barrier. Natural bond order calculations provide further evidence for a weak axial PdO interaction in the endo form of 4b.

Computation through Cortical Dynamics.

Population dynamics is emerging as a language for understanding high-dimensional neural recordings. Remington et al. (2018) explore how inputs to frontal cortex modulate neural dynamics in order to implement a computation of interest.

Studying the old masters of nursing: A critical student experience for developing nursing identity.

In the past professional identity in nursing was inculcated in students alongside institutional pride. A strong sense of professional identity is key to staff retention and recruitment and key to the delivery of quality nursing care. With the wholesale transfer of pre-registration nursing education to the third level sector, however, the reality is that students now divide their affiliations between university and healthcare institutions and professional identity development may be stymied. For this reason, there is need to explore alternative means of developing professional identity. Exposure to nursing history may counteract this tendency. Based on adult nursing students' reflections of a visit to the Florence Nightingale Museum, we discuss the potential of this activity in aiding development of critical professional identity.

Dynamic Reorganization of Neuronal Activity Patterns in Parietal Cortex.

Neuronal representations change as associations are learned between sensory stimuli and behavioral actions. However, it is poorly understood whether representations for learned associations stabilize in cortical association areas or continue to change following learning. We tracked the activity of posterior parietal cortex neurons for a month as mice stably performed a virtual-navigation task. The relationship between cells' activity and task features was mostly stable on single days but underwent major reorganization over weeks. The neurons informative about task features (trial type and maze locations) changed across days. Despite changes in individual cells, the population activity had statistically similar properties each day and stable information for over a week. As mice learned additional associations, new activity patterns emerged in the neurons used for existing representations without greatly affecting the rate of change of these representations. We propose that dynamic neuronal activity patterns could balance plasticity for learning and stability for memory.

Efficacy of rodenticide baits for the control of three invasive rodent species in Hawaii.

We tested the efficacy and palatability of nine commercial rodenticide bait formulations on Polynesian rats (Rattus exulans), roof rats (R. rattus), and house mice (Mus musculus). Efficacy varied by rodenticide tested and rodent species. Generally, rodenticides were more effective against mice than for either of the rat species, and mice tended to consume more rodenticide bait than the laboratory chow alternative food. Efficacy was generally highest for the second-generation anticoagulants tested; however, this varied across products and one-first-generation rodenticide had similar effectiveness. Bait acceptance (palatability) also varied both by rodenticide and by rodent species. Acceptance was the lowest for the acute rodenticides. Bait acceptance appeared to substantially affect the efficacy of rodenticides; materials that were not well accepted produced lower mortality rates. Rodenticide products currently registered for use in Hawaii performed less effectively in this study than other available products not yet registered. Although markets for rodent control products for use on islands are limited, there are advantages to having additional products registered for island use in agriculture, conservation, and public health.

Antibody-antigen exchange equilibria in a field of an external force: design of reagentless biosensors.

This correspondence presents a new strategy for detecting biological molecules that relies on competitive exchange interactions of an analyte with two-component molecular tethers attaching superparamagnetic microspheres (4 microm in diameter) to a sensor surface. The individual tethers consist of an antibody-antigen complex and are designed to selectively detect antigenic proteins in a sensitive reagentless fashion. In order to impart a driving force to the otherwise free energy neutral antibody-antigen exchange equilibrium, a small mechanical force of approximately 10 pN was applied to stretch the antibody-antigen tethers using a massively parallel magnetic tweezers device. The experimental work was carried out with human cardiac troponin I. This serum heart attack marker was used as an example of analytes of credible relevance to biomedical diagnostics. The initial results illustrate the functioning of a cardiotroponin sensor and offer a preliminary estimate of its sensitivity of 16 pM.