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Many animals use visual information to navigate 1-4 , but how such information is encoded and integrated by the navigation system remains incompletely understood. In Drosophila melanogaster, EPG neurons in the central complex compute the heading direction 5 by integrating visual input from ER neurons 6-12 , which are part of the anterior visual pathway (AVP) 10,13-16 . Here we densely reconstruct all neurons in the AVP using electron-microscopy data 17 . The AVP comprises four neuropils, sequentially linked by three major classes of neurons: MeTu neurons 10,14,15 , which connect the medulla in the optic lobe to the small unit of the anterior optic tubercle (AOTUsu) in the central brain; TuBu neurons 9,16 , which connect the AOTUsu to the bulb neuropil; and ER neurons 6-12 , which connect the bulb to the EPG neurons. On the basis of morphologies, connectivity between neural classes and the locations of synapses, we identify distinct information channels that originate from four types of MeTu neurons, and we further divide these into ten subtypes according to the presynaptic connections in the medulla and the postsynaptic connections in the AOTUsu. Using the connectivity of the entire AVP and the dendritic fields of the MeTu neurons in the optic lobes, we infer potential visual features and the visual area from which any ER neuron receives input. We confirm some of these predictions physiologically. These results provide a strong foundation for understanding how distinct sensory features can be extracted and transformed across multiple processing stages to construct higher-order cognitive representations., (© 2024. The Author(s).)

A catalogue of neuronal cell types has often been called a 'parts list' of the brain 1 , and regarded as a prerequisite for understanding brain function 2,3 . In the optic lobe of Drosophila, rules of connectivity between cell types have already proven to be essential for understanding fly vision 4,5 . Here we analyse the fly connectome to complete the list of cell types intrinsic to the optic lobe, as well as the rules governing their connectivity. Most new cell types contain 10 to 100 cells, and integrate information over medium distances in the visual field. Some existing type families (Tm, Li, and LPi) 6-10 at least double in number of types. A new serpentine medulla (Sm) interneuron family contains more types than any other. Three families of cross-neuropil types are revealed. The consistency of types is demonstrated by analysing the distances in high-dimensional feature space, and is further validated by algorithms that select small subsets of discriminative features. We use connectivity to hypothesize about the functional roles of cell types in motion, object and colour vision. Connectivity with 'boundary types' that straddle the optic lobe and central brain is also quantified. We showcase the advantages of connectomic cell typing: complete and unbiased sampling, a rich array of features based on connectivity and reduction of the connectome to a substantially simpler wiring diagram of cell types, with immediate relevance for brain function and development., (© 2024. The Author(s).)

Many animals, including humans, navigate their surroundings by visual input, yet we understand little about how visual information is transformed and integrated by the navigation system. In Drosophila melanogaster , compass neurons in the donut-shaped ellipsoid body of the central complex generate a sense of direction by integrating visual input from ring neurons, a part of the anterior visual pathway (AVP). Here, we densely reconstruct all neurons in the AVP using FlyWire, an AI-assisted tool for analyzing electron-microscopy data. The AVP comprises four neuropils, sequentially linked by three major classes of neurons: MeTu neurons, which connect the medulla in the optic lobe to the small unit of anterior optic tubercle (AOTUsu) in the central brain; TuBu neurons, which connect the anterior optic tubercle to the bulb neuropil; and ring neurons, which connect the bulb to the ellipsoid body. Based on neuronal morphologies, connectivity between different neural classes, and the locations of synapses, we identified non-overlapping channels originating from four types of MeTu neurons, which we further divided into ten subtypes based on the presynaptic connections in medulla and postsynaptic connections in AOTUsu. To gain an objective measure of the natural variation within the pathway, we quantified the differences between anterior visual pathways from both hemispheres and between two electron-microscopy datasets. Furthermore, we infer potential visual features and the visual area from which any given ring neuron receives input by combining the connectivity of the entire AVP, the MeTu neurons' dendritic fields, and presynaptic connectivity in the optic lobes. These results provide a strong foundation for understanding how distinct visual features are extracted and transformed across multiple processing stages to provide critical information for computing the fly's sense of direction., Competing Interests: Competing interests The authors declare no competing interests.

Color and polarization provide complementary information about the world and are detected by specialized photoreceptors. However, the downstream neural circuits that process these distinct modalities are incompletely understood in any animal. Using electron microscopy, we have systematically reconstructed the synaptic targets of the photoreceptors specialized to detect color and skylight polarization in Drosophila , and we have used light microscopy to confirm many of our findings. We identified known and novel downstream targets that are selective for different wavelengths or polarized light, and followed their projections to other areas in the optic lobes and the central brain. Our results revealed many synapses along the photoreceptor axons between brain regions, new pathways in the optic lobes, and spatially segregated projections to central brain regions. Strikingly, photoreceptors in the polarization-sensitive dorsal rim area target fewer cell types, and lack strong connections to the lobula, a neuropil involved in color processing. Our reconstruction identifies shared wiring and modality-specific specializations for color and polarization vision, and provides a comprehensive view of the first steps of the pathways processing color and polarized light inputs., Competing Interests: EK, KL, AN, AZ, GS, MF, CL, BG, HL, AT, TO, PA, HD, DB, GR, MR, MW No competing interests declared, (© 2021, Kind et al.)

Colour vision involves colour-opponent cells, which are excited and inhibited by different wavelengths. Synaptic interconnections between Drosophila Dm8 cells are required for forming spatio-chromatic receptive fields with a center and surround of opposing polarity which can invert, depending on the stimulus., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Specialized ommatidia harboring polarization-sensitive photoreceptors exist in the 'dorsal rim area' (DRA) of virtually all insects. Although downstream elements have been described both anatomically and physiologically throughout the optic lobes and the central brain of different species, little is known about their cellular and synaptic adaptations and how these shape their functional role in polarization vision. We have previously shown that in the DRA of Drosophila melanogaster, two distinct types of modality-specific 'distal medulla' cell types (Dm-DRA1 and Dm-DRA2) are post-synaptic to long visual fiber photoreceptors R7 and R8, respectively. Here we describe additional neuronal elements in the medulla neuropil that manifest modality-specific differences in the DRA region, including DRA-specific neuronal morphology, as well as differences in the structure of pre- or post-synaptic membranes. Furthermore, we show that certain cell types (medulla tangential cells and octopaminergic neuromodulatory cells) specifically avoid contacts with polarization-sensitive photoreceptors. Finally, while certain transmedullary cells are specifically absent from DRA medulla columns, other subtypes show specific wiring differences while still connecting the DRA to the lobula complex, as has previously been described in larger insects. This hints towards a complex circuit architecture with more than one pathway connecting polarization-sensitive DRA photoreceptors with the central brain.

In the fly optic lobe, ∼800 highly stereotypical columnar microcircuits are arranged retinotopically to process visual information. Differences in cellular composition and synaptic connectivity within functionally specialized columns remain largely unknown. Here, we describe the cellular and synaptic architecture in medulla columns located downstream of photoreceptors in the dorsal rim area (DRA), where linearly polarized skylight is detected for guiding orientation responses. We show that only in DRA medulla columns both R7 and R8 photoreceptors target to the bona fide R7 target layer where they form connections with previously uncharacterized, modality-specific Dm neurons: two morphologically distinct DRA-specific cell types (termed Dm-DRA1 and Dm-DRA2) stratify in separate sublayers and exclusively contact polarization-sensitive DRA inputs, while avoiding overlaps with color-sensitive Dm8 cells. Using the activity-dependent GRASP and trans-Tango techniques, we confirm that DRA R7 cells are synaptically connected to Dm-DRA1, whereas DRA R8 form synapses with Dm-DRA2. Finally, using live imaging of ingrowing pupal photoreceptor axons, we show that DRA R7 and R8 termini reach layer M6 sequentially, thus separating the establishment of different synaptic connectivity in time. We propose that a duplication of R7→Dm circuitry in DRA ommatidia serves as an ideal adaptation for detecting linearly polarized skylight using orthogonal e-vector analyzers., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The combination of nitritation and autotrophic denitrification (anammox) in a single sequencing batch reactor (SBR) is an energy efficient process for nitrogen removal from high-strength ammonia wastewaters. So far, the process has been successfully applied to digester supernatant. However, the process could also be suitable to treat source-separated urine, which has very high ammonium and organic substrate concentrations (up to 8,200 gN/m3 and 10,000 gCOD/m3). In this study, reactor performance was tested for digester supernatant and diluted source-separated urine. Ammonium concentrations in both solutions were similar (between 611 and 642 gN/m3), thus reactor performance could be directly compared. Differences were mainly due to higher activity of heterotrophic bacteria in urine. Nitrogen removal was slightly higher for source-separated urine, because heterotrophic bacteria denitrified the nitrate that was produced by anammox bacteria. In spite of higher heterotrophic growth with source-separated urine, calculated sludge concentrations at steady state were higher with digester supernatant due to accumulation of inert particulate organic matter from the influent. Although the sludge concentrations are less problematic for source-separated urine, process instabilities are more likely, because lower pH values are reached and heterotrophic denitrification can cause sudden increases of nitrite concentrations and/or nitric oxide. Both compounds inhibit aerobic ammonium oxidizing bacteria, heterotrophic bacteria and, most importantly, anammox bacteria. Nitrite and nitric oxide production by heterotrophic denitrification must be better understood to optimize nitritation/anammox for source-separated urine., (IWA Publishing 2008.)

More than half of all Somali refugees in the United States live in Minnesota. To obtain information to develop culturally sensitive health education materials, we conducted two focus groups with 14 Somali women who had each given birth to one child in Minnesota. Overall, women thought that their childbirth experience was positive. They also reported racial stereotyping, apprehension of cesarean births, and concern about the competence of medical interpreters. Women wanted more information about events in the delivery room, pain medications, prenatal visits, interpreters, and roles of hospital staff. The most desirable educational formats were a videotape, audiotapes, printed materials, and birth center tours. To increase their attendance at prenatal appointments, participants said they needed reminder telephone calls, transportation, and childcare.

Background: Many people seek medical care for cold symptoms. The cold-related knowledge and beliefs of adults seeking medical care for themselves or their children may not correspond with current medical opinion., Methods: A total of 249 parents of symptomatic children and 257 symptomatic adults who sought medical advice in the spring of 1997 from 1 of 3 primary care clinics in the Minneapolis-St. Paul, Minnesota, area were surveyed by telephone 48 to 96 hours after contact with the medical system., Results: Of the adults seeking care for a child or themselves, 44% believed viruses alone cause the common cold: an additional 42% believed both viruses and bacteria play a role. Most thought rest (97%) and nonprescription medications (63%) were helpful for colds, which was consistent with published reports. Contrary to medical reports, however, most felt vitamin C (67%) and the inhalation of steam (70%) reduced cold symptoms, and 44% believed antibiotics help colds (chi2=19.57; P=.0002). But 85% believed colds could resolve on their own., Conclusions: Those adults seeking medical care for uncomplicated colds are misinformed about the primary cause of the common cold, the use of prescription medications for treating cold symptoms, and the effectiveness of some palliative care techniques. Care providers should address these perceptions rather than enabling overuse of antibiotics.

The DMD gene, which spans more than 2,000 kbp, has been assigned to band Xp21 of the X chromosome. Two subclones (PERT 87-1 and PERT 87-15) of the intragenic locus DXS164 physically are separated by approximately 60 kbp. Linkage studies were done in 49 informative DMD families by using the LINKAGE program. Crossing-over between the loci studied occurred in four families. A recombination rate of 4% (support interval [Zmax-1] 1%-10%), which was 54 (support interval 14-135-fold) times higher than expected, was found with a maximum lod score of 13.50. These data suggest a hot spot for recombination within DXS164.