Projection Patterns Research Articles

Characterization of the IDENTIFYTM surface scanning system for radiation therapy setup on a closed-bore linac.

In radiation therapy, surface guidance can be used for patient setup and intra-fraction motion monitoring. The surface guided radiation therapy (SGRT) system from Varian Medical systems, IDENTIFYTM, consists of three pods, including cameras and a random pattern projector, mounted on the ceiling. The information captured by the cameras is used to make a reconstruction of the surface. The aim of the study was to assess the technical performance of this SGRT system on a closed-bore linac. Phantom measurements were performed to assess the accuracy, precision, reproducibility and temporal stability of the system, both in align and in load position. Translations of the phantoms in lateral, longitudinal, and vertical direction, and rotations around three axes (pitch, roll and yaw) were performed with an accurate, in-house built, positioning stage. Different phantom geometries and different surface colors were used, and various ambient light intensities were tested. The accuracy of the IDENTIFYTM system at the closed-bore linac was 0.07mm and 0.07 degrees at load position, and 0.06mm and 0.01 degrees at align position for the white head phantom. The precision was 0.02mm and 0.02 degrees in load position, and 0.01mm and 0.02 degrees in align position. The accuracy for the Penta-Guide phantom was comparable to the white head phantom, with 0.06mm and 0.01 degrees in align position. The system was slightly less accurate for translations of the CIRS lung phantom in align position (0.20mm, 0.05 degrees). Reproducibility measurements showed a variation of 0.02mm in load position. Regarding the temporal stability, the maximum drift over 30min was 0.33mm and 0.02 degrees in load position. No effect of ambient light level on the accuracy of the IDENTIFYTM system was observed. Regarding different surface colors, the accuracy of the system for a black phantom was slightly worse compared to a white surface, but not clinical relevant. The IDENTIFYTM system can adequately be used for motion monitoring on a closed-bore linac with submillimeter accuracy. The results of the performed measurements meet the clinical requirements described in the guidelines of the AAPM and the ESTRO.

Calibration-free structured-light-based 3D scanning system in laparoscope for robotic surgery.

Accurate 3D shape measurement is crucial for surgical support and alignment in robotic surgery systems. Stereo cameras in laparoscopes offer a potential solution; however, their accuracy in stereo image matching diminishes when the target image has few textures. Although stereo matching with deep learning has gained significant attention, supervised learning requires a large dataset of images with depth annotations, which are scarce for laparoscopes. Thus, there is a strong demand to explore alternative methods for depth reconstruction or annotation for laparoscopes. Active stereo techniques are a promising approach for achieving 3D reconstruction without textures. In this study, a 3D shape reconstruction method is proposed using an ultra-small patterned projector attached to a laparoscopic arm to address these issues. The pattern projector emits a structured light with a grid-like pattern that features node-wise modulation for positional encoding. To scan the target object, multiple images are taken while the projector is in motion, and the relative poses of the projector and a camera are auto-calibrated using a differential rendering technique. In the experiment, the proposed method is evaluated by performing 3D reconstruction using images obtained from a surgical robot and comparing the results with a ground-truth shape obtained from X-rayCT.

Visual afferents from an eye in the terrestrial slug Limax valentianus.

Terrestrial gastropods have a lens-bearing eye on the tip of their tentacles. There are two morphologically distinct photoreceptors, called Type-I and Type-II photoreceptors, in the retina. Type-I photoreceptors are equipped with highly developed photoreceptive microvilli in their outer rhabdomeric segment, whereas Type-II photoreceptors have short and fewer microvilli. Although both types of photoreceptors send afferent projections directly to the brain, their destinations in the brain, called optic neuropiles, have not been sufficiently investigated. Our recent studies revealed that there are commissural fibers in the cerebral ganglia that transmit photic information acquired by bilateral eyes. Moreover, some of the retinal photoreceptors are connected by gap junctions to the photosensitive brain neurons, suggesting the functional interaction of the photic information between the eye and brain photoreceptors, as well as between bilateral eyes. However, it has not been clarified which type of retinal photoreceptors send commissural projections to the contralateral hemiganglion nor interact with the brain photoreceptors. In the present study, we demonstrated by molecular histological analyses and tracer injections that (1) Type-I and Type-II photoreceptors send glutamatergic afferent projections to the medial and lateral lobes of the ipsilateral optic neuropile, respectively, (2) direct synaptic interaction between bilateral optic nerves occurs in the medial lobe of the optic neuropile, and (3) brain photosensory neurons form gap junctions with the medial lobe of the contralateral optic neuropile. These results reveal an ordered pattern of afferent projections from the retina and provide insight into the different functional roles of retinal photoreceptors.

High-resolution single-pixel imaging based on a probe of single-mode fiber and hybrid multimode fiber

In single-pixel imaging, the combination of random speckles generated by the multimode fiber (MMF) as projection patterns and the compressed sensing theory is beneficial for improving imaging performance and expanding application scenarios. However, the image reconstruction quality using the MMF is usually unsatisfactory, which is helpless for retrieving objects with detailed information or multi-resolution objects. The reason lies in the limited number and compromised spatial resolution of low-correlated speckle patterns provided by the MMF in practical circumstances like long operating time or bending disturbances. Here, we propose a novel concept of hybrid multimode fibers (HMMF) for single-pixel imaging resolution enhancement. Based on the bending insensitivity property of single-mode fiber (SMF) and the compatibility property of small bending radius and high mode density of HMMF, the wavelength-modulated SMF-HMMF probe is designed to significantly improve the number and spatial resolution of speckle patterns while ensuring the robustness of the imaging system. The experimental results demonstrate that the spatial resolution of the speckle patterns has been improved by approximately 3 times (from 20.35 pixels to 7.24 pixels) compared to the non-HMMF probe. The correlation of the speckle patterns holds as low as about 0.1, even when the tuning wavelength interval is reduced to 5 pm. The maximum deviation of the repeatability of the speckle pattern was 0.044 for the 120-min interval tested, and the consistent output of the speckle pattern under various bending configurations demonstrates the strong robustness of the imaging system. High-quality imaging of multi-resolution target objects has been achieved even at a remarkably low sampling rate (SR) of 5 %. This study has the potential to expand the application of single-pixel imaging systems in flexible and long-distance detection imaging scenarios.

High-throughput mapping of single-neuron projection and molecular features by retrograde barcoded labeling.

Deciphering patterns of connectivity between neurons in the brain is a critical step toward understanding brain function. Imaging-based neuroanatomical tracing identifies area-to-area or sparse neuron-to-neuron connectivity patterns, but with limited throughput. Barcode-based connectomics maps large numbers of single-neuron projections, but remains a challenge for jointly analyzing single-cell transcriptomics. Here, we established a rAAV2-retro barcode-based multiplexed tracing method that simultaneously characterizes the projectome and transcriptome at the single neuron level. We uncovered dedicated and collateral projection patterns of ventromedial prefrontal cortex (vmPFC) neurons to five downstream targets and found that projection-defined vmPFC neurons are molecularly heterogeneous. We identified transcriptional signatures of projection-specific vmPFC neurons, and verified Pou3f1 as a marker gene enriched in neurons projecting to the lateral hypothalamus, denoting a distinct subset with collateral projections to both dorsomedial striatum and lateral hypothalamus. In summary, we have developed a new multiplexed technique whose paired connectome and gene expression data can help reveal organizational principles that form neural circuits and process information.

Generalising XTRACT tractography protocols across common macaque brain templates

Non-human primates are extensively used in neuroscience research as models of the human brain, with the rhesus macaque being a prominent example. We have previously introduced a set of tractography protocols (XTRACT) for reconstructing 42 corresponding white matter (WM) bundles in the human and the macaque brain and have shown cross-species comparisons using such bundles as WM landmarks. Our original XTRACT protocols were developed using the F99 macaque brain template. However, additional macaque template brains are becoming increasingly common. Here, we generalise the XTRACT tractography protocol definitions across five macaque brain templates, including the F99, D99, INIA, Yerkes and NMT. We demonstrate equivalence of such protocols in two ways: (a) Firstly by comparing the bodies of the tracts derived using protocols defined across the different templates considered, (b) Secondly by comparing the projection patterns of the reconstructed tracts across the different templates in two cross-species (human–macaque) comparison tasks. The results confirm similarity of all predictions regardless of the macaque brain template used, providing direct evidence for the generalisability of these tractography protocols across the five considered templates.

Clozapine Induces Neuronal Activation in the Medial Prefrontal Cortex in a Projection Target-Biased Manner.

The medial prefrontal cortex (mPFC) is associated with various behavioral controls via diverse projections to cortical and subcortical areas of the brain. Dysfunctions and modulations of this circuitry are related to the pathophysiology of schizophrenia and its pharmacotherapy, respectively. Clozapine is an atypical antipsychotic drug used for treatment-resistant schizophrenia and is known to modulate neuronal activity in the mPFC. However, it remains unclear which prefrontal cortical projections are activated by clozapine among the various projection targets. To identify the anatomical characteristics of neurons activated by clozapine at the mesoscale level, we investigated the brain-wide projection patterns of neurons with clozapine-induced c-Fos expression in the mPFC. Using a whole-brain imaging and virus-mediated genetic tagging of activated neurons, we found that clozapine-responsive neurons in the mPFC had a wide range of projections to the mesolimbic, amygdala and thalamic areas, especially the mediodorsal thalamus. These results may provide key insights into the neuronal basis of the therapeutic action of clozapine.

Molecular diversity and functional dynamics in the central amygdala.

The central amygdala (CeA) is crucial in integrating sensory and associative information to mediate adaptive responses to emotional stimuli. Recent advances in genetic techniques like optogenetics and chemogenetics have deepened our understanding of distinct neuronal populations within the CeA, particularly those involved in fear learning and memory consolidation. However, challenges remain due to overlapping genetic markers complicating neuron identification. Furthermore, a comprehensive understanding of molecularly defined cell types and their projection patterns, which are essential for elucidating functional roles, is still developing. Recent advancements in transcriptomics are starting to bridge these gaps, offering new insights into the functional dynamics of CeA neurons. In this review, we provide an overview of the expanding genetic markers for amygdala research, encompassing recent developments and current trends. We also discuss how novel transcriptomic approaches are redefining cell types in the CeA and setting the stage for comprehensive functional studies.

Parallel computational ghost imaging with modulation patterns multiplexing and permutation inspired by compound eyes

Real-time computational ghost imaging (CGI) has received significant attention in recent years to overcome the trade-off between long acquisition time and high reconstructed image quality of CGI. Inspired by compound eyes, we propose a parallel computational ghost imaging with modulation patterns multiplexing and permutation to achieve a faster and high-resolution CGI. With modulation patterns multiplexing and permutation, several small overlapping fields-of-view can be obtained; meanwhile, the difficulty in alignment of illumination light field and multiple detectors can be well resolved. The method combining compound eyes with multi-detectors to capture light intensity can resolve the issue of a gap between detector units in the array detector. Parallel computation facilitates significantly reduced acquisition time, while maintaining reconstructed quality without compromising the sampling ratio. Experiments indicate that using m × m detectors reduce modulation pattern count, projector storage, and projection time to around 1/m2 of typical CGI methods, while increasing image resolution to m2 times. This work greatly promotes the practicability of parallel computational ghost imaging and provides optional solution for real-time computational ghost imaging.

Whole-brain spatial organization of hippocampal single-neuron projectomes.

Mapping single-neuron projections is essential for understanding brain-wide connectivity and diverse functions of the hippocampus (HIP). Here, we reconstructed 10,100 single-neuron projectomes of mouse HIP and classified 43 projectome subtypes with distinct projection patterns. The number of projection targets and axon-tip distribution depended on the soma location along HIP longitudinal and transverse axes. Many projectome subtypes were enriched in specific HIP subdomains defined by spatial transcriptomic profiles. Furthermore, we delineated comprehensive wiring diagrams for HIP neurons projecting exclusively within the HIP formation (HPF) and for those projecting to both intra- and extra-HPF targets. Bihemispheric projecting neurons generally projected to one pair of homologous targets with ipsilateral preference. These organization principles of single-neuron projectomes provide a structural basis for understanding the function of HIP neurons.

Single-neuron projectomes of mouse paraventricular hypothalamic nucleus oxytocin neurons reveal mutually exclusive projection patterns

Oxytocin (OXT) plays important roles in autonomic control and behavioral modulation. However, it is unknown how the projection patterns of OXT neurons align with underlying physiological functions. Here, we present the reconstructed single-neuron, whole-brain projectomes of 264 OXT neurons of the mouse paraventricular hypothalamic nucleus (PVH) at submicron resolution. These neurons hierarchically clustered into two groups, with distinct morphological and transcriptional characteristics and mutually exclusive projection patterns. Cluster 1 (177 neurons) axons terminated exclusively in the median eminence (ME) and have few collaterals terminating within hypothalamic regions. By contrast, cluster 2 (87 neurons) sent wide-spread axons to multiple brain regions, but excluding ME. Dendritic arbors of OXT neurons also extended outside of the PVH, suggesting capability to sense signals and modulate target regions. These single-neuron resolution observations reveal distinct OXT subpopulations, provide comprehensive analysis of their morphology, and lay the structural foundation for better understanding the functional heterogeneity of OXT neurons.

Projections patterns of precipitation concentration under climate change scenarios

Projections patterns of precipitation concentration under climate change scenarios

Adaptive chessboard-like high-frequency projection method for three-dimensional measurement of shiny surfaces

Abstract Shiny surface is challenging for the structured light fringe projection three-dimensional measurement technique, since the image saturation caused by highlight results in incorrect intensities in captured images of fringe patterns, and leads to serious phase errors and measurement errors. To address the issue, an adaptive chessboard-like high-frequency projection intensity adjustment technique is proposed. The proposed method alleviates image saturation by adaptively adjusting the intensity of the high-frequency chessboard-like projection pattern. And the complementary patterns are projected to suppress reflections and enhance the robustness of decoding. The experimental results demonstrate that the proposed method achieve high measurement accuracy for shiny surfaces.

Motion-resistant three-wavelength spatial frequency domain imaging system with ambient light suppression using an 8-tap CMOS image sensor.

We present a motion-resistant three-wavelength spatial frequency domain imaging (SFDI) system with ambient light suppression using an 8-tap complementary metal-oxide semiconductor (CMOS) image sensor (CIS) developed at Shizuoka University. The system addresses limitations in conventional SFDI systems, enabling reliable measurements in challenging imaging scenarios that are closer to real-world conditions. Our study demonstrates a three-wavelength SFDI system based on an 8-tap CIS. We demonstrate and evaluate the system's capability of mitigating motion artifacts and ambient light bias through tissue phantom reflectance experiments and in vivo volar forearm experiments. We incorporated the Hilbert transform to reduce the required number of projected patterns per wavelength from three to two per spatial frequency. The 8-tap image sensor has eight charge storage diodes per pixel; therefore, simultaneous image acquisition of eight images based on multi-exposure is possible. Taking advantage of this feature, the sensor simultaneously acquires images for planar illumination, sinusoidal pattern projection at three wavelengths, and ambient light. The ambient light bias is eliminated by subtracting the ambient light image from the others. Motion artifacts are suppressed by reducing the exposure and projection time for each pattern while maintaining sufficient signal levels by repeating the exposure. The system is compared to a conventional SFDI system in tissue phantom experiments and then in vivo measurements of human volar forearms. The 8-tap image sensor-based SFDI system achieved an acquisition rate of 9.4 frame sets per second, with three repeated exposures during each accumulation period. The diffuse reflectance maps of three different tissue phantoms using the conventional SFDI system and the 8-tap image sensor-based SFDI system showed good agreement except for high scattering phantoms. For the in vivo volar forearm measurements, our system successfully measured total hemoglobin concentration, tissue oxygen saturation, and reduced scattering coefficient maps of the subject during motion (16.5cm/s) and under ambient light (28.9lx), exhibiting fewer motion artifacts compared with the conventional SFDI. We demonstrated the potential for motion-resistant three-wavelength SFDI system with ambient light suppression using an 8-tap CIS.

East Asian and Southern European craniofacial class III phenotype: two sides of the same coin?

The skeletal class III phenotype is a heterogeneous condition in populations of different ethnicities. This study aimed to analyse the joint and ethnicity-specific clustering of morphological features in skeletal class III patients of Asian and European origins. This cross-sectional study involved South Korean and Spanish participants who fulfilled the cephalometric, clinical, and ethnic-related selection criteria. Radiographic records were standardised, calibrated, and measured. A total of 54 skeletal variables were selected for varimax factorial analysis (VFA). Subsequently, a cluster analysis (CA) was performed (mixed method: k-means and hierarchical clustering). Method error and precision were assessed using ICC, Student's t-test, and the Dahlberg formula. A total of 285 Korean and Spanish participants with skeletal class III malocclusions were analysed. After performing VFA and CA, the joint sample revealed three global clusters, and ethnicity-specific analysis revealed four Korean and five Spanish clusters. Cluster_1_global was predominantly Spanish (79.2%) and male (83.01%) and was characterised by a predominantly mesobrachycephalic pattern and a larger cranial base, maxilla, and mandible. Cluster_2_global and Cluster_3_global were mainly South Korean (73.9% and 75.6%, respectively) and depicted opposite phenotypes of mandibular projection and craniofacial pattern. A distinct distribution of Spanish and South Korean participants was observed in the global analysis. Interethnic and interethnic differences were observed, primarily in the cranial base and maxilla size, mandible projection, and craniofacial pattern. Accurate phenotyping, reflecting the complexity of skeletal class III phenotype across diverse populations, is critical for improving diagnostic predictability and future personalised treatment protocols.

Structural and Functional Organization of Visual Responses in the Inferior Olive of Larval Zebrafish.

The olivo-cerebellar system plays an important role in vertebrate sensorimotor control. Here, we investigate sensory representations in the inferior olive (IO) of larval zebrafish and their spatial organization. Using single-cell labeling of genetically identified IO neurons, we find that they can be divided into at least two distinct groups based on their spatial location, dendritic morphology, and axonal projection patterns. In the same genetically targeted population, we recorded calcium activity in response to a set of visual stimuli using two-photon imaging. We found that most IO neurons showed direction-selective and binocular responses to visual stimuli and that the functional properties were spatially organized within the IO. Light-sheet functional imaging that allowed for simultaneous activity recordings at the soma and axonal level revealed tight coupling between functional properties, soma location, and axonal projection patterns of IO neurons. Taken together, our results suggest that anatomically defined classes of IO neurons correspond to distinct functional types, and that topographic connections between IO and cerebellum contribute to organization of the cerebellum into distinct functional zones.

Food Demand Projection and Consumption Patterns of Urban Households in Nigeria’s Kano State

Changes in population and income are essential components for altering the pattern of food demand. In light of the importance of food demand analysis, this study set out to ascertain urban household consumption trends in Nigeria’s Kano State in order to forecast future demand levels for certain food items. This research contributes to becoming a basis for policymakers to increase food productivity. A household’s cross-sectional survey data elicited through a well-structured questionnaire complemented with an interview schedule from a total of 144 households chosen via a multi-stage sampling procedure was used for the study. The collected data were analyzed using both Linear Approximate/ Almost Ideal Demand System (LA/AIDS) and factor analysis models. Based on empirical evidence, households’ poor purchasing power is owed to high food inflation, which causes them to have low dietary diversity. Besides, the necessary and luxury goods, respectively, were rice, beans, spaghetti, and meat; and millet, yam, Irish potatoes, semovita, fish and groundnut. Meanwhile, maze, garri, and palm oil were established to be inferior commodities. Besides rice and semovita being everyday goods, they demand high price-sensitive commodities. Consequently, to maintain the status quo in the households’ welfare, the onus lies on policymakers to compensate consumers if there is a rise in the prices of local rice, indomie and groundnut oil. The study advises policymakers to increase the productivity of those food items projected to witness the steep-to-gentle rise in demand, and government should endeavour to adopt macro-economic policies with human-face so as to cushion/soften households’ economic hardship in the study area.

Phase-aided online self-correction method for high-accuracy three-dimensional measurement.

The binocular structured light 3D measurement system is widely used in situ industrial inspection and shape measurement, where the system structure is generally unstable due to mechanical loosening or environmental disturbance. Timely corrections to the changing structural parameters thus is an essential task for online high-accuracy measurement, which is difficult for traditional unidirectional fringe projection methods to self-correct the structural change. To this end, we propose an online self-correction method based on the investigation that orthogonal fringe projection can intrinsically relax the constraint on the epipolar geometry relationship and provide bidirectional phases for accurate corresponding point searching. Since orthogonal fringe projection may sacrifice the measurement efficiency, we further design a searching strategy by locally unwrapping one directional phase to reduce the number of projection patterns. Experimental results demonstrate that the proposed method is effective for online self-correction of unstable system structure to achieve high-accuracy 3D measurement under complex measurement environments.

Ultra-fine bubble irrigation promotes coffee (Coffea arabica) seedling growth under repeated drought stresses

ABSTRACT Coffee plants are likely to be highly susceptible to changes in climate, and several statistical studies based on projections of altered precipitation patterns have predicted negative effects on coffee growth including the loss of suitable cultivation areas in most coffee-producing countries. Increased drought occurrences owing to climate change are expected to be a new challenge for stable coffee production, because coffee production relies heavily on stable rainfall conditions. In recent years, ultra-fine bubble (UFB) water has been reported to be effective in alleviating environmental stresses for plant growth, especially drought stress. The objective of the present study was to determine the effect of UFB water irrigation on the growth of coffee seedlings to mitigate the stress of repeated droughts. To simulate an environment with frequent droughts, six pot experiments were conducted over 3 years by applying repeated drought stress to coffee plants in a greenhouse. The results showed that UFB water had a remarkable growth-promoting effect on coffee seedlings under drought conditions. In contrast, no significant effect on coffee growth was observed in the environment with sufficient nutrients, in which additional fertilizer was used. UFB water significantly increases the root length and surface area of coffee plants, which may promote water absorption and prevent leaf senescence (leaf cell collapse) under drought conditions. This leads to coffee plants adapting to drought conditions. Therefore, UFB water irrigation may be an effective measure to promote coffee growth in drought conditions.

Heterogeneity in the projections and excitability of tyraminergic/octopaminergic neurons that innervate the Drosophila reproductive tract.

Aminergic nuclei in mammals are generally composed of relatively small numbers of cells with broad projection patterns. Despite the gross similarity of many individual neurons, recent transcriptomic, anatomic and behavioral studies suggest previously unsuspected diversity. Smaller clusters of aminergic neurons in the model organism Drosophila melanogaster provide an opportunity to explore the ramifications of neuronal diversity at the level of individual cells. A group of approximately 10 tyraminergic/octopaminergic neurons innervates the female reproductive tract in flies and has been proposed to regulate multiple activities required for fertility. The projection patterns of individual neurons within the cluster are not known and it remains unclear whether they are functionally heterogenous. Using a single cell labeling technique, we show that each region of the reproductive tract is innervated by a distinct subset of tyraminergic/octopaminergic cells. Optogenetic activation of one subset stimulates oviduct contractions, indicating that the cluster as a whole is not required for this activity, and underscoring the potential for functional diversity across individual cells. Using whole cell patch clamp, we show that two adjacent and morphologically similar cells are tonically inhibited, but each responds differently to injection of current or activation of the inhibitory GluCl receptor. GluCl appears to be expressed at relatively low levels in tyraminergic/octopaminergic neurons within the cluster, suggesting that it may regulate their excitability via indirect pathways. Together, our data indicate that specific tyraminergic/octopaminergic cells within a relatively homogenous cluster have heterogenous properties and provide a platform for further studies to determine the function of each cell.