Comparative connectomics of the descending and ascending neurons of the Drosophila nervous system: stereotypy and sexual dimorphism.

In most complex nervous systems there is a clear anatomical separation between the nerve cord, which contains most of the final motor outputs necessary for behaviour, and the brain. In insects, the neck connective is both a physical and information bottleneck connecting the brain and the ventral nerve cord (VNC, spinal cord analogue) and comprises diverse populations of descending (DN), ascending (AN) and sensory ascending neurons, which are crucial for sensorimotor signalling and control. Integrating three separate EM datasets, we now provide a complete connectomic description of the ascending and descending neurons of the female nervous system of Drosophila and compare them with neurons of the male nerve cord. Proofread neuronal reconstructions have been matched across hemispheres, datasets and sexes. Crucially, we have also matched 51% of DN cell types to light level data defining specific driver lines as well as classifying all ascending populations. We use these results to reveal the general architecture, tracts, neuropil innervation and connectivity of neck connective neurons. We observe connected chains of descending and ascending neurons spanning the neck, which may subserve motor sequences. We provide a complete description of sexually dimorphic DN and AN populations, with detailed analysis of circuits implicated in sex-related behaviours, including female ovipositor extrusion (DNp13), male courtship (DNa12/aSP22) and song production (AN hemilineage 08B). Our work represents the first EM-level circuit analyses spanning the entire central nervous system of an adult animal.

Neurotransmitter classification from electron microscopy images at synaptic sites in Drosophila melanogaster.

High-resolution electron microscopy of nervous systems has enabled the reconstruction of synaptic connectomes. However, we do not know the synaptic sign for each connection (i.e., whether a connection is excitatory or inhibitory), which is implied by the released transmitter. We demonstrate that artificial neural networks can predict transmitter types for presynapses from electron micrographs: a network trained to predict six transmitters (acetylcholine, glutamate, GABA, serotonin, dopamine, octopamine) achieves an accuracy of 87% for individual synapses, 94% for neurons, and 91% for known cell types across a D. melanogaster whole brain. We visualize the ultrastructural features used for prediction, discovering subtle but significant differences between transmitter phenotypes. We also analyze transmitter distributions across the brain and find that neurons that develop together largely express only one fast-acting transmitter (acetylcholine, glutamate, or GABA). We hope that our publicly available predictions act as an accelerant for neuroscientific hypothesis generation for the fly.

Rewarding Capacity of Optogenetically Activating a Giant GABAergic Central-Brain Interneuron in Larval Drosophila.

Larvae of the fruit fly Drosophila melanogaster are a powerful study case for understanding the neural circuits underlying behavior. Indeed, the numerical simplicity of the larval brain has permitted the reconstruction of its synaptic connectome, and genetic tools for manipulating single, identified neurons allow neural circuit function to be investigated with relative ease and precision. We focus on one of the most complex neurons in the brain of the larva (of either sex), the GABAergic anterior paired lateral neuron (APL). Using behavioral and connectomic analyses, optogenetics, Ca2+ imaging, and pharmacology, we study how APL affects associative olfactory memory. We first provide a detailed account of the structure, regional polarity, connectivity, and metamorphic development of APL, and further confirm that optogenetic activation of APL has an inhibiting effect on its main targets, the mushroom body Kenyon cells. All these findings are consistent with the previously identified function of APL in the sparsening of sensory representations. To our surprise, however, we found that optogenetically activating APL can also have a strong rewarding effect. Specifically, APL activation together with odor presentation establishes an odor-specific, appetitive, associative short-term memory, whereas naive olfactory behavior remains unaffected. An acute, systemic inhibition of dopamine synthesis as well as an ablation of the dopaminergic pPAM neurons impair reward learning through APL activation. Our findings provide a study case of complex circuit function in a numerically simple brain, and suggest a previously unrecognized capacity of central-brain GABAergic neurons to engage in dopaminergic reinforcement.SIGNIFICANCE STATEMENT The single, identified giant anterior paired lateral (APL) neuron is one of the most complex neurons in the insect brain. It is GABAergic and contributes to the sparsening of neuronal activity in the mushroom body, the memory center of insects. We provide the most detailed account yet of the structure of APL in larval Drosophila as a neurogenetically accessible study case. We further reveal that, contrary to expectations, the experimental activation of APL can exert a rewarding effect, likely via dopaminergic reward pathways. The present study both provides an example of unexpected circuit complexity in a numerically simple brain, and reports an unexpected effect of activity in central-brain GABAergic circuits.

A Case Study on Reviewing Specialist Services Commissioning in Wales: TAVI for Severe Aortic Stenosis.

The Welsh Health Specialised Services Committee (WHSSC) is responsible for planning, commissioning and funding specialised healthcare in Wales. Investment in new technologies or services is based on clinical and economic evidence, using a consistent and transparent process. This is accomplished in three stages. The first stage is the preparation of a rapid evidence review. This then informs the development or update of the relevant Commissioning Policy. The final stage is to prioritise the Commissioning Policy recommendations against all other new services and interventions, to inform WHSSC's annual commissioning intentions. In 2017, a review was conducted of the WHSSC Commissioning Policy for transcatheter aortic valve implantation for severe aortic stenosis. Prior to this only high-risk patients were eligible for transcatheter aortic valve implantation. The rapid evidence review identified three randomised controlled trials and two economic analyses relevant to the decision problem. Transcatheter aortic valve implantation was generally found to be more expensive and more effective than medical management or surgical aortic valve replacement, with incremental cost-effectiveness ratios around £10,500-£36,000 for inoperable groups and £17,000-£24,000 in high-risk groups. The rapid evidence review, expert advice and stakeholder feedback informed the revision process of the Commissioning Policy for transcatheter aortic valve implantation. This recommended the addition of patients unsuitable for surgical aortic valve replacement and the removal of explicit risk scoring. This recommendation was subject to the prioritisation process (carried out annually). The updated transcatheter aortic valve implantation recommendation was ranked second out of 23 technologies and services competing for additional WHSSC funding. The WHSSC Integrated Commissioning Plan for specialised services in Wales (2019) therefore included funding to support the new criteria for transcatheter aortic valve implantation treatment.

In Wales, specialised health services are selected and funded at a national level by the Welsh Health Specialised Services Committee. Specialised services are provided for small numbers of patients, requiring highly specialised professionals or technologies. When the aortic heart valve becomes narrowed with disease it can be replaced with an artificial valve. This normally requires open surgery, which is risky for some patients, particularly those who are frail. Since 2012, the Welsh Health Specialised Services Committee have funded a less invasive procedure called TAVI (transcatheter aortic valve implantation) for patients who could have open surgery but at a high risk. In 2017, this policy needed updating, thus a new evidence review was conducted. This showed that patients at high risk from open surgery were more likely to survive if they underwent TAVI. Others, for whom open surgery was too risky, were also more likely to survive if they underwent TAVI instead of medication. However, TAVI tended to produce more vascular problems, such as blockages or damage to blood vessels. Transcatheter aortic valve implantation is generally more effective and more expensive than either drugs or open surgery in these patient groups, but is within cost-effectiveness limits often used in the UK National Health Service. As a result of the review, experts recommended that TAVI should be available to more patients, which would require greater levels of funding. Transcatheter aortic valve implantation was ranked as second out of 23 new or updated treatments competing for funding allocations. The Welsh Health Specialised Services Committee therefore published a new Commissioning Plan for TAVI in 2019 that now included patients who are considered too risky to undergo open surgery.

Managing access to advanced therapy medicinal products: Challenges for NHS Wales.

Advanced Therapy Medicinal Products (ATMPs), which include gene, somatic cell therapies and tissue-engineered medicines, have the potential to transform current care pathways by offering durable and potentially curative outcomes. However, they are exceptionally expensive, with prices exceeding £1m per patient in some cases. With an expectation that a large number of ATMPs will soon gain marketing authorisation (global market is estimated to reach £9bn to £14bn by 2025), healthcare payers and providers face a number of challenges to facilitate patient access to this new category of medicines. This viewpoint reflects on the experience of introducing ATMPs into the National Health Service in Wales where £1 in every £200 spent on medicines (2019/2020) is expected to be on ATMPs for just 20 patients. Evidence to date makes it apparent that decisions regarding clinical and cost-effectiveness and the scale of the budget impact of implementing ATMPs create both financial and health service risks. Consequently, there are significant policy implications. A critical examination is made of the approaches taken for the health technology assessment and appraisal of ATMPs, the methods of payment and service impacts of these medicines, and the approach taken to horizon scanning and subsequent modelling of the financial impact over the next 10 years.

Dietary intervention for people with mental illness in South Australia.

BACKGROUND: People with serious mental illness (SMI) have a 25-30 year lower life expectancy than the general population due largely to cardiovascular disease (CVD). Mediterranean diet can reduce CVD risk and repeat events by 30-70%. We conducted a pilot feasibility study (HELFIMED) with people who have SMI residing within a Community Rehabilitation Centre in South Australia, aimed at improving participants' diets according to Mediterranean diet principles. METHODS: During a 3-month intervention, participants were provided with nutrition education, food hampers, and twice-weekly cooking workshops and guided shopping trips. This report presents the results of a mixed method evaluation of the programme using thorough in-depth interviews with participants and support staff (n = 20), contextualized by changes in dietary biomarkers and CVD risk factors. RESULTS: The framework thematic analysis revealed evidence of improvements in participants' knowledge of and intake of the key elements of a Mediterranean-style diet (fruit and vegetables, olive oil, fish, legumes), reduction in poor nutrition habits (soft drinks, energy drinks, take away meals) and development of independent living skills-culinary skills such as food preparation and cooking based on simple recipes, food shopping and budgeting, healthy meal planning and social interaction. These changes were supported by dietary biomarkers, and were associated with reduced CVD risk factors. CONCLUSIONS: A Mediterranean diet-based pilot study achieved positive change in dietary behaviours associated with CVD risk for participants with SMI. This supports a need to include dietary education and cooking skills into rehabilitation programmes for people with SMI.

Whole-brain serial-section electron microscopy in larval zebrafish.

High-resolution serial-section electron microscopy (ssEM) makes it possible to investigate the dense meshwork of axons, dendrites, and synapses that form neuronal circuits. However, the imaging scale required to comprehensively reconstruct these structures is more than ten orders of magnitude smaller than the spatial extents occupied by networks of interconnected neurons, some of which span nearly the entire brain. Difficulties in generating and handling data for large volumes at nanoscale resolution have thus restricted vertebrate studies to fragments of circuits. These efforts were recently transformed by advances in computing, sample handling, and imaging techniques, but high-resolution examination of entire brains remains a challenge. Here, we present ssEM data for the complete brain of a larval zebrafish (Danio rerio) at 5.5 days post-fertilization. Our approach utilizes multiple rounds of targeted imaging at different scales to reduce acquisition time and data management requirements. The resulting dataset can be analysed to reconstruct neuronal processes, permitting us to survey all myelinated axons (the projectome). These reconstructions enable precise investigations of neuronal morphology, which reveal remarkable bilateral symmetry in myelinated reticulospinal and lateral line afferent axons. We further set the stage for whole-brain structure-function comparisons by co-registering functional reference atlases and in vivo two-photon fluorescence microscopy data from the same specimen. All obtained images and reconstructions are provided as an open-access resource.

People with schizophrenia and depression have a low omega-3 index.

Cardiovascular disease (CVD) is higher in people with mental illness and is associated with a 30 year higher mortality rate in this population. Erythrocyte docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA) (omega-3 index)≤4% is a marker for increased mortality risk from CVD while >8% is protective. Omega-3 polyunsaturated fatty acids are also important for brain function and may ameliorate symptoms of mental illness. We investigated the erythrocyte omega-3 index in people with mental illness. One hundred and thirty adults aged 18-65 years (32.6% male) with schizophrenia (n=14) and depression (n=116) provided blood samples and completed physiological assessments and questionnaires. Both populations had risk factors for metabolic syndrome and CVD. The average omega-3 index was 3.95% (SD=1.06), compared to an estimated 5% in the Australian population. These data indicate an unfavourable omega-3 profile in people with mental illness that could contribute to higher CVD risk.

Quantitative neuroanatomy for connectomics in Drosophila.

Neuronal circuit mapping using electron microscopy demands laborious proofreading or reconciliation of multiple independent reconstructions. Here, we describe new methods to apply quantitative arbor and network context to iteratively proofread and reconstruct circuits and create anatomically enriched wiring diagrams. We measured the morphological underpinnings of connectivity in new and existing reconstructions of Drosophila sensorimotor (larva) and visual (adult) systems. Synaptic inputs were preferentially located on numerous small, microtubule-free 'twigs' which branch off a single microtubule-containing 'backbone'. Omission of individual twigs accounted for 96% of errors. However, the synapses of highly connected neurons were distributed across multiple twigs. Thus, the robustness of a strong connection to detailed twig anatomy was associated with robustness to reconstruction error. By comparing iterative reconstruction to the consensus of multiple reconstructions, we show that our method overcomes the need for redundant effort through the discovery and application of relationships between cellular neuroanatomy and synaptic connectivity.

Semantic interpretation of robust imaging features for Fuhrman grading of renal carcinoma.

Pattern recognition in tissue biopsy images can assist in clinical diagnosis and identify relevant image characteristics linked with various biological characteristics. Although previous work suggests several informative imaging features for pattern recognition, there exists a semantic gap between characteristics of these features and pathologists' interpretation of histopathological images. To address this challenge, we develop a clinical decision support system for automated Fuhrman grading of renal carcinoma biopsy images. We extract 1316 color, shape, texture and topology features and develop one vs. all models for four Fuhrman grades. Our models are highly accurate with 90.4% accuracy in a four-class prediction. Predictivity analysis suggests good generalization of the model development methodology through robustness to dataset sampling in cross-validation. We provide a semantic interpretation for the imaging features used in these models by linking features to pathologists' grading criteria. Our study identifies novel imaging features that are semantically linked to Fuhrman grading criteria.