Anatomical Composition Research Articles

Competition at the soybean V6 stage affects root morphology and biochemical composition.

The experiment was conducted in the 2016/17 crop season in a greenhouse at Passo Fundo University, Brazil. We hypothesised that the morphological characteristics and biochemical and anatomical composition of soybean roots and shoots, when competing with weeds during different growth periods, are negatively affected, so current concepts of competition between plants should also consider changes in plant roots. The soybean cultivar P 95R51 and horseweed (Conyza bonariensis) were used. The treatments consisted of the presence or absence of weeds during different coexistence periods of soybean with horseweed. The periods were V0-V3, V0-V6, V0-R2, V3-R6, V6-R6 and R2-R6, where V0 was the date of soybean sowing and V3, V6, R2 and R6 were phenological stages of the crop. Two fresh roots were used to examine morphological traits. Four roots were used for quantification of dry matter and secondary metabolites. Root length was reduced by 21%, 14% and 20% when competing with a weed in the V0-V3, V0-V6 and R2-R6 coexistence periods, respectively. Total phenol content in the V0-V6 and V0-R2 periods was reduced when plants were in competition with weeds; a similar trend was found for flavonoids in the V0-V6 period. Soybean-horseweed competition from crop emergence to the V6 stage, in general, affects shoot and root morphological traits and the biochemical composition of the soybean roots. The presence of horseweed at the V3, V6 and R2 stages does not negatively alter the traits evaluated. Root anatomical composition is not modified during all coexistence periods with horseweed.

ANATOMY OF TULP’S VALVE

Introduction: Tulp’s valve is also known as ileocaecal valve which is situated at ileocaecal junction. Tulp’s valve is a diverse anatomical valve where the ileum makes an access into the caecum. Earlier researchers have observed that there is occurrence of high densities of neurons in the Tulp’s valve, though meticulous anatomical depiction about constitution of the myenteric plexus in and around the Tulp’s valve has thus far to be obtained in humans. In array to add contribution to this vicinity of explore, the present work was performed to appreciate the anatomical composition of myenteric plexus in and around the Tulp’s valve in human foetuses.
 Materials and Methods: The research was performed on ileocaecal sections obtained from human foetuses (n=17) of various gestational ages after obtaining ethical authorization from the ethical clearance committee of Hind Institute of Medical Sciences, Sitapur. Cresyl Violet staining and NADPH- diaphorase enzyme histochemistry was performed over the obtained ileocaecal sections. Study Group-1(G-1) included foetuses of 9 to 14 week of gestational age group while Group-2(G-2) comprised of foetuses of 15 to 33 week of gestational age group. The Neuronal cell profiles (area, perimeter, ferret diameter) and Neuronal cell density were assessed in and around the Tulp’s valve in human foetuses. 
 Results: In Cresyl violet stained sections, the difference in the neuronal cell profile area between G-1 (50.10±2.26 µm2 )and G-2 (61.25±4.07 µm2 ) was found to be statistically significant (p=0.0028).The perimeter of myenteric neuronal cells in G-1 (26.32±0.51 µm ) was significantly (p=0.0028) lower than G-2 (29.17±0.85 µm). The differences in Feret diameter of neuronal cells between G-1 (9.49±0.27 µm) and G-2 (10.53±0.21 µm) was statistically significant (p=0.0028). The neuronal cell density in Myenteric Ganglia (MG) in G-1 and G-2 was 60.01±9.77 and 52.27±6.54 respectively, which was statistically insignificant (p=0.1367) difference. The difference in the nitrergic neuronal cell area between G-1 (66.35±8.43 µm2) and G-2 (74.93±0.53 µm2) was statistically significant (p=0.0038). The mean perimeter of nitrergic neuronal cells in G-1 (32.01±2.57µm) was insignificantly (p=0.2001) lower than G-2 (33.83±0.73 µm). The mean Feret diameter of G-1 (11.97±1.26) was also insignificantly (p=0.2624) lower than G-2 (12.91±0.75). The nitrergic neuronal cell density in Myenteric Ganglia in G-1 was 22.41±4.13 and in G-2 it was 18.61±2.09, which was statistically insignificant (p=0.0983). acquaintance of the innervations of the Tulp’s valve in human foetuses may help in restoration of it for improved movement of ileum inside into the caecum, as well as to check retrospective run of caecal inside into the ileum.
 Keywords: Tulp’s Valve, Cresyl Violet, NADPH- diaphorase, Nitrergic Neurons

Offerings, feasting, and psychopomps in the north-east of the Iberian Peninsula: the role of animals in the Bòbila Madurell (Sant Quirze del Vallès, Barcelona) funerary ritual (late fifth millennium–early fourth millennium cal BC)

This study focuses on the role of faunal remains in funerary rituals in the Middle Neolithic necropolis of Bobila Madurell (Sant Quirze del Valles, Barcelona) (“Madurell Sur” and “Madurell Ferrocarril” sectors). Faunal remains recovered in these burials a priori inform about the different uses of animals in funerary rituals. Complete and partial anatomical connections, isolated elements, and/or bone fragments were recovered. These may appear directly associated with human remains or scattered among the structures’ fill. Animal remains were analyzed using zooarchaeological and taphonomic methods: anatomical and taxonomical composition, age of death, and human modifications. The data obtained were linked to burial type and human remains’ sex and age. Results show that the economic importance of domestic animals for Middle Neolithic groups would also cover their symbolic and funerary world. In Bobila Madurell, animals could be offerings and play a part in feasts. In addition, faunal data confirm the ritual diversity and the possible social differentiation of these groups previously proposed by other studies.

The vertebrate tail: a gene playground for evolution.

The tail of all vertebrates, regardless of size and anatomical detail, derive from a post-anal extension of the embryo known as the tail bud. Formation, growth and differentiation of this structure are closely associated with the activity of a group of cells that derive from the axial progenitors that build the spinal cord and the muscle-skeletal case of the trunk. Gdf11 activity switches the development of these progenitors from a trunk to a tail bud mode by changing the regulatory network that controls their growth and differentiation potential. Recent work in the mouse indicates that the tail bud regulatory network relies on the interconnected activities of the Lin28/let-7 axis and the Hox13 genes. As this network is likely to be conserved in other mammals, it is possible that the final length and anatomical composition of the adult tail result from the balance between the progenitor-promoting and -repressing activities provided by those genes. This balance might also determine the functional characteristics of the adult tail. Particularly relevant is its regeneration potential, intimately linked to the spinal cord. In mammals, known for their complete inability to regenerate the tail, the spinal cord is removed from the embryonic tail at late stages of development through a Hox13-dependent mechanism. In contrast, the tail of salamanders and lizards keep a functional spinal cord that actively guides the tail's regeneration process. I will argue that the distinct molecular networks controlling tail bud development provided a collection of readily accessible gene networks that were co-opted and combined during evolution either to end the active life of those progenitors or to make them generate the wide diversity of tail shapes and sizes observed among vertebrates.

The Most Common Tools to Measure Trauma Severity: A review Study

Introduction: Due to the increasing mortality rate from trauma, determining the severity of injury has a very important role in the prognosis of the injured person. On the other hand, the quality of medical care provided to the casualties is evaluated using the Trauma Scoring System. Various scales were used to determine the trauma severity of injured. In this study, the most commonly used tools are investigated. Methods: This review was conducted by searching throughout the Persian data bases of Magiran, Barakat, SID and English databases of Scopus, Web of sciences, PubMed, and Google scholar. To conduct the search, the following keywords were used: "Severity of Trauma", "Trauma scoring", and "Trauma Scoring System" without considering any time intervals. Our early search resulted in 2125 articles. Finally, 17 articles were analyzed and different functions of traumatic assessment tools were compared and studied. Results: Traumatic assessment methods vary based on the anatomical and physiological parameters and composition of these two methods. In this study, the Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), and New Injury Severity Score (NISS) were considered as anatomical parameters; Revised Trauma Score (RTS) as physiological parameters; Trauma Score Injury Severity Score (TRISS) and A Severity Characterization of Trauma (ASCOST) were mentioned as a hybrid ranking system. Conclusion: Application of accurate scientific evaluations in trauma severity assessment methods and application of each method in its appropriate position would result in appropriate improvements in the development of trauma care. In addition, these systems can play an important role in providing care to patients with traumatic injuries in the present and future.

O PADRÃO POSTURAL ENTRE OS ALUNOS ATIVOS E SEDENTÁRIOS NO ENSINO FUNDAMENTAL

The postural pattern of kids must be essentially preserved, because it is in this phase that they develop the most, and at the same time, their bodies are in structural accommodations. Nowadays, due to technological advance, majority of children have become sedentary, which affects their anatomical composition, impairing their health. Therefore, the goal of this study was to identify the postural of active kids and sedentary kids in elementary school. Were used is students at Professora Hilda RomaziniMeloSchool, União da Vitória – PR, in the year 2018. The sample was composed of kids of both sexes, between the ages of 8 to 10 years old. The data collection instrument used was Pate’s formulary, published by Mota, 2012. In order to do the postural assessment, it was used a simetograph. At the end of the study, it was observed that more than 70 percent of the students had any kind of postural deviation; as the amount of physical activity increased among the students, it was possible to notice that the development of their postural patterns became better. All of the alterations that were found are predisposed to correction by a muscular strengthening and stretching program properly accompanied and oriented by a Physical Education professional.

Bamboo particle reinforced polypropylene composites made from different fractions of bamboo culm: Fiber characterization and analysis of composite properties

AbstractDifferences in anatomical structure and chemical composition of bamboo fractions have an obvious influence on the properties of bamboo thermoplastic composites (BPCs). Six fractions of bamboo particles including bamboo culm (BC), bamboo green (BG), bamboo timber (BT), bamboo yellow (BY), bamboo node (BN), and bamboo processing residue (BR) were prepared and compounded with polypropylene (PP) to fabricate BPCs using extrusion. The anatomical structure, chemical composition, crystallinity, and morphology of the bamboo particles were characterized. The processability, mechanical properties, creep‐recovery, and dynamic viscoelasticity of the BPCs were evaluated. The results show that the anatomical structure and composition of the bamboo fractions influenced the crystallinity, morphology, and aspect ratio (L/D) of the bamboo particles, as well as the performance of the resulting composites. BG had the largest crystallinity, length, and L/D, followed by BC and BT. BY was the shortest with the smallest L/D. The BC/PP composites exhibited the best processability and optimal mechanical properties. The BG/PP composites had the highest modulus and creep resistance. The BY/PP composites had the poorest processability and mechanical performance. These results indicate that BG from processing residues can be recycled into high‐value composites and provide a scientific basis for further research on BPCs made from bamboo processing residues.

New site-specific anatomical defects discovered within the female urogenital tract

ObjectivesTesting whether the site-specific anatomical defect(s) can occur within the urethral stabilizing mechanism; determining the anatomical structure compositions of the urethral stabilizing mechanism. Study designIn an international setting, fifteen human fresh female cadavers subjected to urogenital tract stratum-by-stratum macro- and micro-dissection and a case series study type utilized in this scientific research. The primary outcome measured occurrences of anatomical site-specific defects within the urethral stabilizing mechanism and the secondary outcome measured the anatomical structures of the urethral stabilizing mechanism. ResultsSite-specific defects occurred within the urethral stabilizing mechanism in four out of fifteen subjects (26.6%); defects most commonly identified within suburethral-paraurethral-periurethral areas. The ventral perineal membrane and distal condensations of the arcus tendineus levatoris ani defects were also present. The urethral stabilizing mechanism consists of multiple anatomical structures located in different anatomical regions. ConclusionsSite-specific defects occur within the urethral stabilizing mechanism in women. The urethral stabilizing mechanism consists of multiple anatomical structures located in different anatomical regions, and they fuse with the urethral wall.

Dental Pain: Dentine Sensitivity, Hypersensitivity and Cracked Tooth Syndrome.

Dentine hypersensitivity is a frequently encountered patient complaint that can present with a number of associated factors including erosion and abrasion. the hydrodynamic mechanism responsible for dentine hypersensitivity is intimately related to the anatomical and physiological composition of teeth. Alterations to the integrity of the enamel and dentine through processes of trauma, decay and toothwear can increase dentine permeability. This gives rise to symptoms of sensitivity as dentinal fluid movement in response to thermal, chemical and mechanical cues stimulate the pulpal Aδ fibres. Restorative procedures can also rapidly change the architecture of the protective enamel and dentine layers leading to pulpal inflammation and increased thermal sensitivity of the tooth.<br/> Patient-reported symptoms of dentine hypersensitivity can be attributed to a number of possible causes and a definitive diagnosis can therefore be difficult. A full history including social and medical factors such as occupation, diet and/or medication is likely to provide significant information to aid a diagnosis. Consideration of occlusal factors should not be overlooked as these may contribute to symptoms arising from a cracked tooth.<br/> Management strategies are linked to the diagnosis - from topically applied desensitising pastes and resin bonding agents to direct restorations and possibly more advanced restorative procedures such as root canal treatment. Management should, however, be staged to enable more conservative strategies to prevail prior to considering irreversible dental interventions.

Palma forrageira na alimentação de ruminantes

The different species and varieties of spineless cactus constitute a food resource used in the several arid and semi-arid regions of the world. The nutritive value of this forage plant oscillates due to a series of adaptive factors attributed to aridity, and phenotypic differences between the species, varieties or clones of the plant, fertilization and cropping practices, age, cladodes and time of storage can be highlighted. cutting, among other aspects, that together will have different implications in animal nutrition. Spineless cactus has a high acceptability for ruminants and large quantities can be voluntarily consumed, as all species of palm have high digestibility of dry matter, however due to several factors that lead to differences in chemical and anatomical composition, there may be variation to feed intake, digestibility and utilization of its nutrients. Thus, the objective of this work was to discuss the use of spineless cactus genotypes in the feeding of ruminant animals.

The anatomy of resting energy expenditure: body composition mechanisms.

Body mass in humans and animals is strongly associated with the rate of heat production as defined by resting energy expenditure (REE). Beginning with the ancient Greeks up to the present time, philosophers and scientists have endeavored to understand the nature and sources of bodily heat. Today we recognize that body mass consists of organs and tissues, each of which produces a specified amount of heat at rest. An individual organ's REE can now be estimated in vivo as the product of its assumed mass-specific metabolic rate and its imaging-derived mass; whole-body REE reflects the sum of organ and tissue metabolic rates. The sizes of organs and total body mass in adults are governed by two main factors, a person's stature or height, and their level of adiposity. With greater body size, as represented by adult height independent of adiposity, organs remain stable or increase in mass according to distinct "scaling" patterns. Similarly, with greater relative adiposity organs adaptively accommodate to the increase in imposed mechanical and metabolic loading conditions. Through a detailed analysis of these stature and adiposity effects, we show how classical statistical REE prediction models can be mechanistically understood at the anatomic body composition level.

Microorganisms that attack forest species in the north of the state of Mato Grosso

Sawnwood presents one of the main forest products commercialized in the northern region of southern Amazonia, but due to its anatomical, chemical and physical composition, it becomes a target of deterioration of xylophagous organisms in general, due to the presence of parenchyma tissue in its constitution , The arrangement of the elements gives greater or less resistance to the proliferation of fungi in the cell wall, since wood that has high volumes of extractives, become more resistant and gives the wood a lower degree of susceptibility to the development of organisms in the cellular wall of the wood, works which identify xylophagous organisms in wood, are still in the initial phase, with few scientific studies on species of commercial interest. Thus, the general objective of the work is to identify the microorganisms that attack the wood of native species of southern Amazonia, as well as to classify the types of fungi attack in the woods, for the development of the study, such as the following species: cedrinho (E risma uncinatum ); white cedar (E risma bicolor ); cupiuba (G oupia glabra ); Rosinha (V ochysia maxima ). Six genera of fungi under the wood solution were identified during the evaluation period: Trichorderma sp; P aecilomyces variotii; G raphium arrosporium; R hizoctonia solani; L asioplodia theobromae and F usarium sp . are that they are classified in relation to the damage of the wood as stains and emboloradores. T richorderma and P aecilomyces variotii are categorized as wood shapers, due to an increase in quality, a quality of the wood, thus reducing its technological properties.

Taphonomy of a novel small carnivore: experimental analysis of honey badger (Mellivora capensis) modifications on leporid prey

The honey badger is a widespread, but understudied African carnivore, with high potential as a bone accumulator in cave and fossil deposits. This study serves as the first investigation into the taphonomic modifications of this species when feeding on small to medium-sized prey. Domestic rabbit (Oryctolagus cunniculus) carcasses where fed experimentally to a breeding pair of captive honey badgers housed at the Johannesburg Zoo. Bones from the feeding refuse and the carnivore scats were analysed for anatomical composition, fragmentation patterns, tooth marks and digestion. The results were compared with feeding studies with various small carnivores on leporid prey. Honey badgers preferentially opened their prey at the belly and focussed their feeding on nutritionally high-yield soft parts, often discarding low-yield parts like distal appendages, crania and the skins. Bones from the refuse assemblage were often complete and unmodified but stripped of flesh. Bones from the scat assemblage displayed very high fragmentation, light digestive modification and high numbers of tooth marked bones. This latter character was particularly diagnostic for the honey badger. This study investigates a carnivore that has received little interest and shows the high potential of this carnivore to act as a bone accumulator. Further taphonomic research into this species will greatly enhance our understanding of this species and its activity in the fossil record.

Contrasting physiological responses to Mediterranean climate variability are revealed by intra-annual density fluctuations in tree rings of Quercus ilex L. and Pinus pinea L.

Mixed forests of Quercus ilex L. and Pinus pinea L. are widely found throughout the Mediterranean Basin, being representative of two co-existing functional types: evergreen-sclerophyllous drought-resistant species and Mediterranean-adapted drought-avoidant conifers. Their contrasting physiological strategies to cope with water deficit influence all the processes regulating their growth such as wood formation, leading to peculiar tree-ring anatomical features such as intra-annual density fluctuations (IADFs). Intra-annual density fluctuations are abrupt changes in wood anatomical traits within a tree ring, appearing as latewood-like cells within earlywood or earlywood-like cells within latewood, and are frequently found in Mediterranean species as a response to seasonal climate changes. In this study, we characterized the anatomical traits and composition of carbon and oxygen stable isotopes in IADFs occurring in tree rings of Q. ilex and P. pinea trees co-existing at a same site in Southern Italy, in order to link their xylem hydraulic properties with the related physiological mechanisms. The relationships between IADF occurrence and seasonal mean temperature and total precipitation were investigated, with the aim of assessing whether they can be used as indicators of species-specific responses to intra-annual climate fluctuations. Results show that IADF period of formation is during autumn months for both species. The influence of climate on IADF occurrence was found to be an indicator of species-specific response to climate: an increased stomatal conductance associated to the formation of a wood safer against embolism was found in Q. ilex, while a tighter stomatal control associated to a more efficient wood with regard to hydraulic conductivity occurred in P. pinea. Moreover, the assessment of the influence of climate on IADF occurrence indicates that, with rising temperatures, Q. ilex would form fewer IADFs compared with P. pinea. Other study cases are desirable to assess the suggested forecasts and to link the plasticity of the species to form IADFs with their effective adaptive capability to compete for resources, and to explain how it may influence future population development.

The anatomical components of the cardiac outflow tract of chondrichthyans and actinopterygians.

The outflow tract of the fish heart is the segment interposed between the ventricle and the ventral aorta. It holds the valves that prevent blood backflow from the gill vasculature to the ventricle. The anatomical composition, histological structure and evolutionary changes in the fish cardiac outflow tract have been under discussion for nearly two centuries and are still subject to debate. This paper offers a brief historical review of the main conceptions about the cardiac outflow tract components of chondrichthyans (cartilaginous fish) and actinopterygians (ray-finned fish) which have been put forward since the beginning of the nineteenth century up to the current day. We focus on the evolutionary origin of the outflow tract components and the changes to which they have been subject in the major extant groups of chondrichthyans and actinopterygians. In addition, an attempt is made to infer the primitive anatomical design of the heart of the gnathostomes (jawed vertebrates). Finally, several areas of further investigation are suggested. Recent work on fish heart morphology has shown that the cardiac outflow tract of chondrichthyans does not consist exclusively of the myocardial conus arteriosus as classically thought. A conus arteriosus and a bulbus arteriosus, devoid of myocardium and mainly composed of elastin and smooth muscle, are usually present in cartilaginous and ray-finned fish. This is consistent with the suggestion that both components coexisted from the onset of the gnathostome radiation. There is evidence that the conus arteriosus appeared in the agnathans. By contrast, the evolutionary origin of the bulbus is still unclear. It is almost certain that in all fish, both the conus and bulbus develop from the embryonic second heart field. We suggest herein that the primitive anatomical heart of the jawed vertebrates consisted of a sinus venosus containing the pacemaker tissue, an atrium possessing trabeculated myocardium, an atrioventricular region with compact myocardium which supported the atrioventricular valves, a ventricle composed of mixed myocardium, and an outflow tract consisting of a conus arteriosus, with compact myocardium in its wall and valves at its luminal side, and a non-myocardial bulbus arteriosus that connected the conus with the ventral aorta. Chondrichthyans have retained this basic anatomical design of the heart. In actinopterygians, the heart has been subject to notable changes during evolution. Among them, the following two should be highlighted: (i) a decrease in size of the conus in combination with a remarkable development of the bulbus, especially in teleosts; and (ii) loss of the myocardial compact layer of the ventricle in many teleost species.

Wood anatomy of five species from Mozambique and its potential application

SUMMARY: Wood trade is strongly dependent on global economic conditions. In Africa, the market for tropical wood also has dynamic changes. In Mozambique, the international demand for wood comes mainly from emerging economies such as China and India. Almost 70 % of the country is still covered by forests and other woody vegetation. There are many species with favorable properties for wood commerce, although, at present, this is restricted to a few species. We analyzed the wood anatomy of Acacia nigrescens, Combretum imberbe, Icuria dunensis, Pericopsis angolensis and Sterculia appendiculata and comment about properties and potential use based on their anatomical composition. In general, the species presented wood diffuse pores, simple perforation plates, alternate intervessel pits, deposits in vessels; abundant axial parenchyma; multiseriate rays, very thick-walled fibers and mineral inclusions. Based on anatomical characteristics, the studied species have great potential for use in panels industry, furniture, floor, structures and craftwork.

Anatomía foliar comparada de &lt;i&gt;Gaiadendron punctatum&lt;/i&gt; y &lt;i&gt;Tripodanthus belmirensis&lt;/i&gt; (Loranthacea)

Se describe la anatomía foliar de las especies Gaiadendron punctatum y Tripodanthus belmirensis, al objeto de estudiar posibles caracteres que permitan una identificación precisa de estos dos géneros de la familia Loranthaceae, de hábito arbustivo o arbóreo. Las muestras se procesaron y sometieron a tinción con técnicas clásicas para su observación al microscopio óptico. Ambas especies presentaron similitudes como una epidermis monoestratificada y estomas de tipo rubiáceo. Sin embargo, se observó una composición anatómica claramente diferenciada en aspectos como el mesófilo, forma y ubicación de las células epidérmicas y la presencia de acumulaciones de súber en G. punctatum o idioblastos abundantes en T. belmirensis. Se construyó una clave dicotómica para la determinación de especies con base en caracteres anatómicos de la hoja entre las especies del género Tripodanthus y G. punctatum, además se discute brevemente el uso de caracteres anatómicos en la determinación y soporte de entidades taxonómicas diferenciables dentro de la familia Loranthaceae.

The TD6.3 faunal assemblage of the Gran Dolina site (Atapuerca, Spain): a late Early Pleistocene hyena den

Ethological studies have shown that besides human groups, large-medium carnivores have bone-collecting habits. The research developed since the last half of the twentieth century has attempted to characterise the carnivore’s accumulations and to identify them in the archaeo-paleontological record. At present, we have diagnostic criteria that define the accumulations produced by hyenids (mainly, Crocuta crocuta), thereby allowing us to differentiate them from the other accumulating agents. The faunal assemblage recovered at the Early Pleistocene TD6.3 layer of the Gran Dolina site is characterised by the presence of typical elements described in hyena dens: presence of small carnivores remains, high bone breakage, low epiphysis survival and a high frequency (>30%) of specimens with carnivore induced modifications, including large amounts of digested bones. However, attritional mortality profiles, hyena’s cubs remains, mid-shaft bone cylinders or differential anatomical composition among different weight-sizes, have not been observed or are ambiguous. In addition, anthropic evidences are scarce and concentrated in the uppermost section of the layer. TD6.3 is the result of an accumulation produced by hyenas using the cave as a den, in alternation with sporadic occupations by hominin groups. TD6.3 shows that hyena fossil accumulations may present great anatomical and taxonomic variability.

Gaze-Stabilizing Central Vestibular Neurons Project Asymmetrically to Extraocular Motoneuron Pools.

Within reflex circuits, specific anatomical projections allow central neurons to relay sensations to effectors that generate movements. A major challenge is to relate anatomical features of central neural populations, such as asymmetric connectivity, to the computations the populations perform. To address this problem, we mapped the anatomy, modeled the function, and discovered a new behavioral role for a genetically defined population of central vestibular neurons in rhombomeres 5–7 of larval zebrafish. First, we found that neurons within this central population project preferentially to motoneurons that move the eyes downward. Concordantly, when the entire population of asymmetrically projecting neurons was stimulated collectively, only downward eye rotations were observed, demonstrating a functional correlate of the anatomical bias. When these neurons are ablated, fish failed to rotate their eyes following either nose-up or nose-down body tilts. This asymmetrically projecting central population thus participates in both upward and downward gaze stabilization. In addition to projecting to motoneurons, central vestibular neurons also receive direct sensory input from peripheral afferents. To infer whether asymmetric projections can facilitate sensory encoding or motor output, we modeled differentially projecting sets of central vestibular neurons. Whereas motor command strength was independent of projection allocation, asymmetric projections enabled more accurate representation of nose-up stimuli. The model shows how asymmetric connectivity could enhance the representation of imbalance during nose-up postures while preserving gaze stabilization performance. Finally, we found that central vestibular neurons were necessary for a vital behavior requiring maintenance of a nose-up posture: swim bladder inflation. These observations suggest that asymmetric connectivity in the vestibular system facilitates representation of ethologically relevant stimuli without compromising reflexive behavior.SIGNIFICANCE STATEMENT Interneuron populations use specific anatomical projections to transform sensations into reflexive actions. Here we examined how the anatomical composition of a genetically defined population of balance interneurons in the larval zebrafish relates to the computations it performs. First, we found that the population of interneurons that stabilize gaze preferentially project to motoneurons that move the eyes downward. Next, we discovered through modeling that such projection patterns can enhance the encoding of nose-up sensations without compromising gaze stabilization. Finally, we found that loss of these interneurons impairs a vital behavior, swim bladder inflation, that relies on maintaining a nose-up posture. These observations suggest that anatomical specialization permits neural circuits to represent relevant features of the environment without compromising behavior.

Correlation, consequence, and functionality in microbiome-immune interplay.

Correlation, consequence, and functionality in microbiome-immune interplay.