Acoustic communication between insects serves as an excellent model system for analyzing the neuronal mechanisms underlying auditory information processing. The detailed organization of auditory neural circuits in the brain has not yet been described. To understand the central auditory pathways, we used the brain of the fruit fly Drosophila melanogaster as a model and performed a large-scale analysis of the interneurons associated with the primary auditory center. By screening expression driver strains and performing single-cell labeling of these strains, we identified 44 types of interneurons innervating the primary auditory center. Five types were local interneurons whereas the other 39 types were projection interneurons connecting the primary auditory center with other brain regions. The projection neurons comprised three frequency-selective pathways and two frequency-embracive pathways. Mapping of their connection targets revealed that five neuropils in the brain-the wedge (WED), anterior ventrolateral protocerebrum, posterior ventrolateral protocerebrum (PVLP), saddle (SAD), and gnathal ganglia (GNG)-were intensively connected with the primary auditory center. In addition, several other neuropils, including visual and olfactory centers in the brain, were directly connected to the primary auditory center. The distribution patterns of the spines and boutons of the identified neurons suggest that auditory information is sent mainly from the primary auditory center to the PVLP, WED, SAD, GNG, and thoracico-abdominal ganglia. Based on these findings, we established the first comprehensive map of secondary auditory interneurons, which indicates the downstream information flow to parallel ascending pathways, multimodal pathways, and descending pathways.

Compared with connections between the retinae and primary visual centers, relatively less is known in both mammals and insects about the functional segregation of neural pathways connecting primary and higher centers of the visual processing cascade. Here, using the Drosophila visual system as a model, we demonstrate two levels of parallel computation in the pathways that connect primary visual centers of the optic lobe to computational circuits embedded within deeper centers in the central brain. We show that a seemingly simple achromatic behavior, namely phototaxis, is under the control of several independent pathways, each of which is responsible for navigation towards unique wavelengths. Silencing just one pathway is enough to disturb phototaxis towards one characteristic monochromatic source, whereas phototactic behavior towards white light is not affected. The response spectrum of each demonstrable pathway is different from that of individual photoreceptors, suggesting subtractive computations. A choice assay between two colors showed that these pathways are responsible for navigation towards, but not for the detection itself of, the monochromatic light. The present study provides novel insights about how visual information is separated and processed in parallel to achieve robust control of an innate behavior.

The long history of neuroscience has accumulated information about numerous types of neurons in the brain of various organisms. Because such neurons have been reported in diverse publications without controlled format, it is not easy to keep track of all the known neurons in a particular nervous system. To address this issue we constructed an online database called Flybrain Neuron Database (Flybrain NDB), which serves as a platform to collect and provide information about all the types of neurons published so far in the brain of Drosophila melanogaster. Projection patterns of the identified neurons in diverse areas of the brain were recorded in a unified format, with text-based descriptions as well as images and movies wherever possible. In some cases projection sites and the distribution of the post- and presynaptic sites were determined with greater detail than described in the original publication. Information about the labeling patterns of various antibodies and expression driver strains to visualize identified neurons are provided as a separate sub-database. We also implemented a novel visualization tool with which users can interactively examine three-dimensional reconstruction of the confocal serial section images with desired viewing angles and cross sections. Comprehensive collection and versatile search function of the anatomical information reported in diverse publications make it possible to analyze possible connectivity between different brain regions. We analyzed the preferential connectivity among optic lobe layers and the plausible olfactory sensory map in the lateral horn to show the usefulness of such a database.

Many feeding behaviours are the result of stereotyped, organized sequences of motor patterns. These patterns have been the subject of neuroethological studies, such as electrophysiological characterization of neurons governing prey capture in toads. However, technical limitations have prevented detailed study of the functional role of these neurons, a common problem for vertebrate organisms. Complexities involved in studies of whole-animal behaviour can be resolved in Drosophila, in which remote activation of brain cells by genetic means enables us to examine the nervous system in freely moving animals to identify neurons that govern a specific behaviour, and then to repeatedly target and manipulate these neurons to characterize their function. Here we show neurons that generate the feeding motor program in Drosophila. We carried out an unbiased screen using remote neuronal activation and identified a critical pair of brain cells that induces the entire feeding sequence when activated. These 'feeding neurons' (here abbreviated to Fdg neurons for brevity) are also essential for normal feeding as their suppression or ablation eliminates sugar-induced feeding behaviour. Activation of a single Fdg neuron induces asymmetric feeding behaviour and ablation of a single Fdg neuron distorts the sugar-induced feeding behaviour to become asymmetric, indicating the direct role of these neurons in shaping motor-program execution. Furthermore, recording neuronal activity and calcium imaging simultaneously during feeding behaviour reveals that the Fdg neurons respond to food presentation, but only in starved flies. Our results demonstrate that Fdg neurons operate firmly within the sensorimotor watershed, downstream of sensory and metabolic cues and at the top of the feeding motor hierarchy, to execute the decision to feed.

Behavioral responses to odorants require neurons of the higher olfactory centers to integrate signals detected by different chemosensory neurons. Recent studies revealed stereotypic arborizations of second-order olfactory neurons from the primary olfactory center to the secondary centers, but how third-order neurons read this odor map remained unknown.

Encoding of olfactory information in insects occurs in the antennal lobe where the olfactory receptor neurons interact with projection neurons and local interneurons in a complex sensory processing circuitry. While several studies have addressed the developmental mechanisms involved in specification and connectivity of olfactory receptor neurons and projection neurons in Drosophila, the local interneurons are far less well understood.

Different types of Drosophila dopaminergic neurons (DANs) reinforce memories of unique valence and provide state-dependent motivational control [1]. Prior studies suggest that the compartment architecture of the mushroom body (MB) is the relevant resolution for distinct DAN functions [2, 3]. Here we used a recent electron microscope volume of the fly brain [4] to reconstruct the fine anatomy of individual DANs within three MB compartments. We find the 20 DANs of the γ5 compartment, at least some of which provide reward teaching signals, can be clustered into 5 anatomical subtypes that innervate different regions within γ5. Reconstructing 821 upstream neurons reveals input selectivity, supporting the functional relevance of DAN sub-classification. Only one PAM-γ5 DAN subtype γ5(fb) receives direct recurrent feedback from γ5β'2a mushroom body output neurons (MBONs) and behavioral experiments distinguish a role for these DANs in memory revaluation from those reinforcing sugar memory. Other DAN subtypes receive major, and potentially reinforcing, inputs from putative gustatory interneurons or lateral horn neurons, which can also relay indirect feedback from MBONs. We similarly reconstructed the single aversively reinforcing PPL1-γ1pedc DAN. The γ1pedc DAN inputs mostly differ from those of γ5 DANs and they cluster onto distinct dendritic branches, presumably separating its established roles in aversive reinforcement and appetitive motivation [5, 6]. Tracing also identified neurons that provide broad input to γ5, β'2a, and γ1pedc DANs, suggesting that distributed DAN populations can be coordinately regulated. These connectomic and behavioral analyses therefore reveal further complexity of dopaminergic reinforcement circuits between and within MB compartments.

Wiring a complex brain requires many neurons with intricate cell specificity, generated by a limited number of neural stem cells. Drosophila central brain lineages are a predetermined series of neurons, born in a specific order. To understand how lineage identity translates to neuron morphology, we mapped 18 Drosophila central brain lineages. While we found large aggregate differences between lineages, we also discovered shared patterns of morphological diversification. Lineage identity plus Notch-mediated sister fate govern primary neuron trajectories, whereas temporal fate diversifies terminal elaborations. Further, morphological neuron types may arise repeatedly, interspersed with other types. Despite the complexity, related lineages produce similar neuron types in comparable temporal patterns. Different stem cells even yield two identical series of dopaminergic neuron types, but with unrelated sister neurons. Together, these phenomena suggest that straightforward rules drive incredible neuronal complexity, and that large changes in morphology can result from relatively simple fating mechanisms.

To perform most behaviors, animals must send commands from higher-order processing centers in the brain to premotor circuits that reside in ganglia distinct from the brain, such as the mammalian spinal cord or insect ventral nerve cord. How these circuits are functionally organized to generate the great diversity of animal behavior remains unclear. An important first step in unraveling the organization of premotor circuits is to identify their constituent cell types and create tools to monitor and manipulate these with high specificity to assess their function. This is possible in the tractable ventral nerve cord of the fly. To generate such a toolkit, we used a combinatorial genetic technique (split-GAL4) to create 195 sparse driver lines targeting 198 individual cell types in the ventral nerve cord. These included wing and haltere motoneurons, modulatory neurons, and interneurons. Using a combination of behavioral, developmental, and anatomical analyses, we systematically characterized the cell types targeted in our collection. Taken together, the resources and results presented here form a powerful toolkit for future investigations of neural circuits and connectivity of premotor circuits while linking them to behavioral outputs.

Digital brain atlas is a kind of image database that specifically provide information about neurons and glial cells in the brain. It has various advantages that are unmatched by conventional paper-based atlases. Such advantages, however, may become disadvantages if appropriate cares are not taken. Because digital atlases can provide unlimited amount of data, they should be designed to minimize redundancy and keep consistency of the records that may be added incrementally by different staffs. The fact that digital atlases can easily be revised necessitates a system to assure that users can access previous versions that might have been cited in papers at a particular period. To inherit our knowledge to our descendants, such databases should be maintained for a very long period, well over 100 years, like printed books and papers. Technical and organizational measures to enable long-term archive should be considered seriously. Compared to the initial development of the database, subsequent efforts to increase the quality and quantity of its contents are not regarded highly, because such tasks do not materialize in the form of publications. This fact strongly discourages continuous expansion of, and external contributions to, the digital atlases after its initial launch. To solve these problems, the role of the biocurators is vital. Appreciation of the scientific achievements of the people who do not write papers, and establishment of the secure academic career path for them, are indispensable for recruiting talents for this very important job.

Gustatory information is essential for animals to select edible foods and avoid poisons. Whereas mammals detect tastants with their taste receptor cells, which convey gustatory signals to the brain indirectly via the taste sensory neurons, insect gustatory receptor neurons (GRNs) send their axons directly to the primary gustatory center in the suboesophageal ganglion (SOG). In spite of this relatively simple architecture, the precise structure of the insect primary gustatory center has not been revealed in enough detail. To obtain comprehensive anatomical knowledge about this brain area, we screened the Drosophila melanogaster GAL4 enhancer-trap strains that visualize specific subsets of the gustatory neurons as well as putative mechanosensory neurons associated with the taste pegs. Terminals of these neurons form three branches in the SOG. To map the positions of their arborization areas precisely, we screened newly established LexA::VP16 enhancer-trap strains and obtained a driver line that labels a large subset of peripheral sensory neurons. By double-labeling specific and landmark neurons with GAL4 and LexA strains, we were able to distinguish 11 zones in the primary gustatory center, among which 5 zones were identified newly in this study. Arborization areas of various known GRNs on the labellum, oesophagus, and legs were also mapped in this framework. The putative mechanosensory neurons terminate exclusively in three zones of these areas, supporting the notion of segregated primary centers that are specialized for chemosensory and mechanosensory signals associated with gustatory sensation.

Sensory systems provide input to motor networks on the state of the body and environment. One such sensory system in insects is the campaniform sensilla (CS), which detect deformations of the exoskeleton arising from resisted movements or external perturbations. When physical strain is applied to the cuticle, CS external structures are compressed, leading to transduction in an internal sensory neuron. In Drosophila melanogaster, the distribution of CS on the exoskeleton has not been comprehensively described. To investigate CS number, location, spatial arrangement, and potential differences between individuals, we compared the front, middle, and hind legs of multiple flies using scanning electron microscopy. Additionally, we imaged the entire body surface to confirm known CS locations. On the legs, the number and relative arrangement of CS varied between individuals, and single CS of corresponding segments showed characteristic differences between legs. This knowledge is fundamental for studying the relevance of cuticular strain information within the complex neuromuscular networks controlling posture and movement. This comprehensive account of all D. melanogaster CS helps set the stage for experimental investigations into their responsivity, sensitivity, and roles in sensory acquisition and motor control in a light-weight model organism.

The importance of low-density lipoprotein cholesterol (LDL-C) in the primary prevention of cardiovascular disease has recently been reported in the population aged ≥75 years with hypercholesterolemia. Therefore, the current status of LDL-C management for primary prevention of coronary artery disease in patients aged ≥75 years with type 2 diabetes mellitus was investigated.

Stereotactic body radiotherapy (SBRT) is a promising approach in treating painful bone metastases. However, the superiority of SBRT over conventional external beam radiotherapy (cEBRT) remains controversial. Therefore, this systematic review and meta-analysis of randomised controlled trials was conducted to compare SBRT and cEBRT for the treatment of bone metastases.

The primary olfactory centers of both vertebrates and insects are characterized by glomerular structure. Each glomerulus receives sensory input from a specific type of olfactory sensory neurons, creating a topographic map of the odor quality. The primary olfactory center is also innervated by various types of neurons such as local neurons, output projection neurons (PNs), and centrifugal neurons from higher brain regions. Although recent studies have revealed how olfactory sensory input is conveyed to each glomerulus, it still remains unclear how the information is integrated and conveyed to other brain areas. By using the GAL4 enhancer-trap system, we conducted a systematic mapping of the neurons associated with the primary olfactory center of Drosophila, the antennal lobe (AL). We identified in total 29 types of neurons, among which 13 are newly identified in the present study. Analyses of arborizations of these neurons in the AL revealed how glomeruli are linked with each other, how different PNs link these glomeruli with multiple secondary sites, and how these secondary sites are organized by the projections of the AL-associated neurons.

Despite the importance of the insect nervous system for functional and developmental neuroscience, descriptions of insect brains have suffered from a lack of uniform nomenclature. Ambiguous definitions of brain regions and fiber bundles have contributed to the variation of names used to describe the same structure. The lack of clearly determined neuropil boundaries has made it difficult to document precise locations of neuronal projections for connectomics study. To address such issues, a consortium of neurobiologists studying arthropod brains, the Insect Brain Name Working Group, has established the present hierarchical nomenclature system, using the brain of Drosophila melanogaster as the reference framework, while taking the brains of other taxa into careful consideration for maximum consistency and expandability. The following summarizes the consortium's nomenclature system and highlights examples of existing ambiguities and remedies for them. This nomenclature is intended to serve as a standard of reference for the study of the brain of Drosophila and other insects.

BigNeuron is an open community bench-testing platform with the goal of setting open standards for accurate and fast automatic neuron tracing. We gathered a diverse set of image volumes across several species that is representative of the data obtained in many neuroscience laboratories interested in neuron tracing. Here, we report generated gold standard manual annotations for a subset of the available imaging datasets and quantified tracing quality for 35 automatic tracing algorithms. The goal of generating such a hand-curated diverse dataset is to advance the development of tracing algorithms and enable generalizable benchmarking. Together with image quality features, we pooled the data in an interactive web application that enables users and developers to perform principal component analysis, t-distributed stochastic neighbor embedding, correlation and clustering, visualization of imaging and tracing data, and benchmarking of automatic tracing algorithms in user-defined data subsets. The image quality metrics explain most of the variance in the data, followed by neuromorphological features related to neuron size. We observed that diverse algorithms can provide complementary information to obtain accurate results and developed a method to iteratively combine methods and generate consensus reconstructions. The consensus trees obtained provide estimates of the neuron structure ground truth that typically outperform single algorithms in noisy datasets. However, specific algorithms may outperform the consensus tree strategy in specific imaging conditions. Finally, to aid users in predicting the most accurate automatic tracing results without manual annotations for comparison, we used support vector machine regression to predict reconstruction quality given an image volume and a set of automatic tracings.

We aimed to investigate (1) promising clinical findings for the recognition of focal type autoimmune pancreatitis (FAIP) and (2) the impact of endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) on the diagnosis of FAIP.

Metabolic syndrome (Mets) is the major contributor to the onset of metabolic complications, such as hypertension, type 2 diabetes mellitus (DM), dyslipidemia, and non-alcoholic fatty liver disease, resulting in cardiovascular diseases. C57BL/6 mice on a high-fat and high-sucrose diet (HFHSD) are a well-established model of Mets but have minor endothelial dysfunction in isolated aortas without perivascular adipose tissue (PVAT). The purpose of this study was to evaluate the effects of additional factors such as DM, dyslipidemia, and steatohepatitis on endothelial dysfunction in aortas without PVAT. Here, we employed eight-week-old male C57BL/6 mice fed with a normal diet (ND), HFHSD, steatohepatitis choline-deficient HFHSD (HFHSD-SH), and HFHSD containing 1% cholesterol and 0.1% deoxycholic acid (HFHSD-Chol) for 16 weeks. At week 20, some HFHSD-fed mice were treated with streptozocin to develop diabetes (HFHSD-DM). In PVAT-free aortas, the endothelial-dependent relaxation (EDR) did not differ between ND and HFHSD (p = 0.25), but in aortas with PVAT, the EDR of HFHSD-fed mice was impaired compared with ND-fed mice (p = 0.005). HFHSD-DM, HFHSD-SH, and HFHSD-Chol impaired the EDR in aortas without PVAT (p < 0.001, p = 0.019, and p = 0.009 vs. ND, respectively). Furthermore, tempol rescued the EDR in those models. In the Mets model, the EDR is compromised by PVAT, but with the addition of DM, dyslipidemia, and SH, the vessels themselves may result in impaired EDR.

The first and secondary olfactory centers in the olfactory pathway in Drosophila are organized into neuropil structures called glomeruli. The antennal lobe (AL), the first olfactory center in larval Drosophila, is organized in 21 glomeruli. Each AL glomerulus receives innervation from a specific olfactory sensory neuron (OSN), and is therefore identifiable anatomically by the position of the OSN terminal. Olfactory projection neurons (PNs) send a dendrite to a single AL glomerulus and an axon that usually terminates in a single glomerulus in the mushroom body (MB) calyx, a secondary olfactory center, and in the lateral horn. By random labeling of single PNs that express GH146-GAL4, it was previously shown that PNs stereotypically innervate specific AL and calyx glomeruli, and most of these connections have been mapped. Here we report the pattern of innervation of GAL4 lines that drive expression of reporter genes in single or a few PNs, including PNs not identified by the widely used GH146-GAL4 driver. We have mapped the AL and calyx glomeruli innervated by these labeled PNs. This study provides a collection of GAL4 lines to molecularly mark the connections between specific AL and calyx glomeruli. It thus confirms and extends the previous map of AL-calyx connectivity that was based only on randomly labeled single PNs, and provides tools for targeted manipulation of specific PNs for developmental and functional studies.