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spatial coding metastructure for single-sensor impact region recognition

SMART MATERIALS AND STRUCTURES 2024年第10期33卷 105041-105041页

作者： Jiang, Tianxi Zhou, Tianyue Wang, Xihao Li, Tianqi Jin, Hu Zhang, Shiwu Peng, Zhi-Ke He, Qingbo Univ Sci & Technol China Inst Humanoid Robots Dept Precis Machinery & Precis Instrumentat Hefei 230026 Peoples R China Shanghai Jiao Tong Univ State Key Lab Mech Syst & Vibrat Shanghai 200240 Peoples R China Ningxia Univ Sch Mech Engn Yinchuan 750021 Peoples R China

The rapid development of aircraft has created a strong demand for structural health monitoring, but current methods that rely on multiple sensor fusion suffer from complex hardware systems. Computational sensing with metastructures provides a promising approach to reduce sensing cost, but the lack of calibrated information makes it challenging to identify impact regions. In this study, we propose a concept of spatial coding metastructure for impact region recognition with a single sensor. Owing to the multi-order local resonance effect, the metastructures are capable of producing multiple vibration modulations over a wide frequency band. We demonstrate that the frequency-dependent vibration modulation effects of the metastructures on different test regions are distinguishable, a characteristic referred to as spatial coding. This characteristic enables impact regions to be accurately recognized with only a single sensor by using machine learning methods. Our work not only presents promising application prospects for condition monitoring of aircraft and other mechanical systems, but also inspires the development of safer and more efficient systems in various industries.

关键词： spatial coding metastructure impact region recognition single sensor

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Entity-oriented spatial coding scheme and its application for spatial topology

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地球空间信息科学学报（英文版） 2024年第1期27卷 183-201页

作者： Weining Zhu Department of Marine Informatics Ocean CollegeZhejiang UniversityHangzhouChina

Based on a newly proposed spatial data model spatial Chromatic Model(SCM),we developed a spatial coding scheme,called the full-coded Ordinary Arranged Chromatic Diagram(full-OACD).As a type of spatial tessellation,full-OACD partitions a geographic space into a number of subspaces,such as cells,edges,and *** subspaces are called spatial particles and are assigned with unique codes chromatic *** generation,structure,computation,and properties of full-OACD are *** between particulate chromatic codes and spatial topology are ***-OACD is a kind of new discrete spatial coordinate system where the information of real-world entities is ***-OACD provides an informative and meaningful spatial coding framework for spatial topological analysis and many other potential applications in geospatial information science.

关键词： spatial data model spatial coding spatial tessellation spatial topology

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Impaired spatial coding of the hippocampus in a dentate gyrus hypoplasia mouse model

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2025年第5期122卷 e2416214122页

作者： Chen, Xiaojing Cheng, Ning Wang, Cheng Knierim, James J. Southern Univ Sci & Technol Brain Res Ctr Sch Life Sci Dept Neurosci Shenzhen 518055 Peoples R China Johns Hopkins Univ Zanvyl Krieger Mind Brain Inst Baltimore MD 21218 USA Chinese Acad Sci Shenzhen Inst Adv Technol Brain Cognit & Brain Dis Inst Shenzhen 518055 Peoples R China Johns Hopkins Univ Solomon H Snyder Dept Neurosci Baltimore MD 21218 USA Johns Hopkins Univ Dept Psychol & Brain Sci Baltimore MD 21218 USA Johns Hopkins Univ Kavli Neurosci Discovery Inst Baltimore MD 21218 USA

The hippocampal dentate gyrus (DG) is thought to orthogonalize inputs from the entorhinal cortex (pattern separation) and relay this information to the CA3 region. In turn, attractor dynamics in CA3 perform a pattern completion or error correction operation before sending its output to CA1. In a mouse model of congenital hypo-plasia of the DG, a deficiency in the Wntless (Wls) gene, specifically in cells expressing Gfap- Cre, which targets neuronal progenitors, led to an almost total absence of dentate granule cells and modestly impaired performance in spatial tasks. Here, we investigated the physiological consequences of granule cell loss in these mice by conducting in vivo calcium imaging from CA1 principal cells during behavior. The spatial selectivity of these cells was preserved without the DG. On a linear track, place fields in mutant mice were more likely to be near track terminals and to encode the distance from the start point in each running direction. In an open box, CA1 cells in mutant mice exhibited reductions in the percentage of place cells, in spatial information, and in place field stability. The reduction in place field stability across repeated exposures to the same environment resulted in a reduction in the differential representations of two different contexts in mutant mice compared to wild- type mice. These results suggest that DG helps to stabilize CA1 spatial representations, especially in 2- D environments, and that the lack of stability across similar environments may play a key role in the deficits of animals with DG dysfunction in discriminating different environments.

关键词： dentate gyrus place cell spatial coding Wnt calcium imaging

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Scene semantics affects allocentric spatial coding for action in naturalistic (virtual) environments

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SCIENTIFIC REPORTS 2024年第1期14卷 1-12页

作者： Baltaretu, Bianca R. Schuetz, Immo Vo, Melissa L. -H. Fiehler, Katja Justus Liebig Univ Giessen Dept Expt Psychol Otto-Behaghel-Str 10F D-35394 Giessen Hessen Germany Goethe Univ Frankfurt Dept Psychol D-60323 Frankfurt Hesse Germany

Interacting with objects in our environment requires determining their locations, often with respect to surrounding objects (i.e., allocentrically). According to the scene grammar framework, these usually small, local objects are movable within a scene and represent the lowest level of a scene's hierarchy. How do higher hierarchical levels of scene grammar influence allocentric coding for memory-guided actions? Here, we focused on the effect of large, immovable objects (anchors) on the encoding of local object positions. In a virtual reality study, participants (n = 30) viewed one of four possible scenes (two kitchens or two bathrooms), with two anchors connected by a shelf, onto which were presented three local objects (congruent with one anchor) (Encoding). The scene was re-presented (Test) with 1) local objects missing and 2) one of the anchors shifted (Shift) or not (No shift). Participants, then, saw a floating local object (target), which they grabbed and placed back on the shelf in its remembered position (Response). Eye-tracking data revealed that both local objects and anchors were fixated, with preference for local objects. Additionally, anchors guided allocentric coding of local objects, despite being task-irrelevant. Overall, anchors implicitly influence spatial coding of local object locations for memory-guided actions within naturalistic (virtual) environments.

关键词： spatial coding Scene semantics Scene perception Memory-guided action Virtual reality

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A sub-region combination scheme for spatial coding in a high-frequency SSVEP-based BCI

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JOURNAL OF NEURAL ENGINEERING 2023年第4期20卷 046018-046018页

作者： Hu, Ruochen Ming, Gege Wang, Yijun Gao, Xiaorong Tsinghua Univ Dept Biomed Engn Beijing Peoples R China Chinese Acad Sci Inst Semicond State Key Lab Integrated Optoelect Beijing Peoples R China Univ Chinese Acad Sci Sch Future Technol Beijing Peoples R China Chinese Inst Brain Res Beijing Peoples R China

Objective. In studying the spatial coding mechanism of visual evoked potentials, it is significant to construct a model that shows the relationship between steady-state visual evoked potential (SSVEP) responses to the local and global visual field stimulation. In order to investigate whether SSVEPs produced by sub-region stimulation can predict that produced by joint region stimulation, a sub-region combination scheme for spatial coding in a high-frequency SSVEP-based brain-computer interface (BCI) is developed innovatively. Approach. An annular visual field is divided equally into eight sub-regions. The 60 Hz visual stimuli in different sub-regions and joint regions are presented separately to participants. The SSVEP produced by the sub-region stimulation is superimposed to simulate the SSVEP produced by the joint region stimulation with different spatial combinations. A four-class spatially-coded BCI paradigm is used to evaluate the simulated classification performance, and the performance ranking of all simulated SSVEPs is obtained. Six representative stimulus patterns from two performance levels and three stimulus areas are applied to the online BCI system for each participant. Main results. The experimental result shows that the proposed scheme can implement a spatially-coded visual BCI system and realize satisfactory performance with imperceptible flicker. Offline analysis indicates that the classification accuracy and information transfer rate (ITR) are 89.69 & PLUSMN;8.75% and 24.35 & PLUSMN;7.09 bits min(-1) with 3 s data length under the 3/8 stimulus area. The online BCI system reaches an average classification accuracy of 87.50 & PLUSMN;9.13% with 3 s data length, resulting in an ITR of 22.48 & PLUSMN;6.71 bits min(-1) under the 3/8 stimulus area. Significance. This study proves the feasibility of using the sub-region's response to predict the joint region's response. It has the potential to extend to other frequency bands and lays a foundation for future

关键词： brain-computer interfaces steady-state visual evoked potentials spatial coding sub-region combination

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Sharing spatial information in a virtual environment: How do visual cues and configuration influence spatial coding and mental workload?

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VIRTUAL REALITY 2020年第4期24卷 695-712页

作者： Milleville-Pennel, Isabelle Mars, Franck Pouliquen-Lardy, Lauriane Univ Nantes LS2N Cent Nantes CNRS BP 92101 F-44321 Nantes 03 France

When sharing virtual collaborative environments, operators exchange spatial statements that refer to the objects' positions in the virtual space. If operators are to understand each other, they need to develop a common spatial frame of reference and then choose a space coding to describe the objects' positions. In this paper, we consider how the content of a virtual environment can influence communication between users. We designed two studies in which one participant (the speaker) had to indicate the position of one object to another participant (the addressee). The virtual environment was sometimes enriched by additional (proximal and distal) visual cues. In study 1, we considered statements production. We observed that the speakers most often used the avatar of their partner as a spatial reference to indicate a localization in the virtual space (i.e., Addressee-Centered coding) despite it increases their mental workload. Nevertheless, in complex situations, they also used distal cues to speak to the addressees (i.e., Exocentric coding of the space). In study 2, we considered statements comprehension. Addressee-Centered coding and Exocentric coding were used by the speakers in various spatial configurations to indicate the object position. We observed that Exocentric coding is the most difficult to manage for the addressee. These results indicate that speakers implemented the principle of less collaborative effort by adopting a way of exchanging information based on an asymmetrical cognitive cost, taking into consideration each other's difficulties. This allows a balanced mental workload to be maintained between the two operators throughout the task.

关键词： Common spatial frame of reference spatial coding Mental workload Least collaborative effort Virtual environments

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Cellular Mechanisms of spatial coding in Area CA3

Cellular Mechanisms of Spatial Coding in Area CA3

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作者： Rashid, Shannon Kristine New York University

学位级别：Ph.D., Doctor of Philosophy

Dendrites of pyramidal neurons integrate different sensory inputs, and non-linear dendritic computations drive feature selective tuning and plasticity. Yet little is known about how dendrites themselves represent the environment, the degree to which they are coupled to their soma, and how that coupling is sculpted with experience. In order to answer these questions, we developed a novel preparation in which we image soma and connected dendrites in a single plane across days using in vivo two-photon microscopy. Using this preparation, we monitored spatially tuned activity in area CA3 of the hippocampus in head-fixed mice running on a linear track. We identified “place dendrites”, which can stably and precisely represent both familiar and novel spatial environments. Dendrites could display place tuning independent of their connected soma and even their sister dendritic branches, the first evidence for branch-specific tuning in the hippocampus. In a familiar environment, spatially tuned somata were more decoupled from their dendrites as compared to non-tuned somata. This relationship was absent in a novel environment, suggesting an experience dependent selective gating of dendritic spatial inputs. We then built a data-driven multicompartment computational model constrained by our experimental data, and showed that branch specific tuning is both necessary and sufficient for the correlations observed. Our model predicts that place cells exhibiting branch-specific tuning have more flexible place fields, while neurons with homogenous or co-tuned dendritic branches have higher place field stability. These findings demonstrate that spatial representation is organized in a branch-specific manner within dendrites of hippocampal pyramidal cells. Further, spatial inputs from dendrites to soma are selectively and dynamically gated in an experience-dependent manner, endowing both flexibility and stability to the cognitive map of space. Silencing of somatostatin-positive interneuro

关键词： spatial coding Pyramidal neurons Dendrites Plasticity Selective tuning Somata Hoppocampus Cognitive map Somatostatin-positive interneurons Sensory inputs

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On Information Metrics for spatial coding

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NEUROSCIENCE 2018年第0期375卷 62-73页

作者： Souza, Bryan C. Pavao, Rodrigo Belchior, Hindiael Tort, Adriano B. L. Univ Fed Rio Grande do Norte Brain Inst Natal RN Brazil Univ Fed Rio Grande do Norte Fac Hlth Sci Trairi Natal RN Brazil Albert Einstein Coll Med Dept Neurosci Bronx NY 10467 USA

The hippocampal formation is involved in navigation, and its neuronal activity exhibits a variety of spatial correlates (e.g., place cells, grid cells). The quantification of the information encoded by spikes has been standard procedure to identify which cells have spatial correlates. For place cells, most of the established metrics derive from Shannon's mutual information (Shannon, 1948), and convey information rate in bits/s or bits/spike (Skaggs et al., 1993, 1996). Despite their widespread use, the performance of these metrics in relation to the original mutual information metric has never been investigated. In this work, using simulated and real data, we find that the current information metrics correlate less with the accuracy of spatial decoding than the original mutual information metric. We also find that the top informative cells may differ among metrics, and show a surrogate-based normalization that yields comparable spatial information estimates. Since different information metrics may identify different neuronal populations, we discuss current and alternative definitions of spatially informative cells, which affect the metric choice. (C) 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

关键词： place cell place field spatial coding information spike train analysis hippocampus

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spatial coding in sonar imaging

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ELECTRONICS LETTERS 2017年第17期53卷 1222-1224页

作者： Wang, Jingxi Guo, Xin Ge, Feng-Xiang Arce, Gonzalo R. Beijing Normal Univ Beijing Peoples R China Huawei Technol Co Ltd Beijing Peoples R China Univ Delaware Newark DE 19716 USA

A practical deployment is presented for sonar imaging with fewer transmitters and receivers. spatial coding via transmit beamforming is used for target detection and localisation. Transmit beamforming reduces the ambiguity in a model and improves imaging performance. To reconstruct the resultant underdetermined system of equations, a sparse signal reconstruction framework is used, and the inverse problem is solved by using an iterative optimisation algorithm. Deployment is optimised for better target detection and localisation performance. Successful sonar imaging reconstruction is guaranteed by the restricted isometry property with high probability. A numerical simulation shows that the proposed method can detect and localise targets efficiently, with better imaging results than those attained by conventional methods or the compressive sensing method without spatial coding.

关键词： sonar imaging image coding sonar detection object detection transmitters receivers array signal processing inverse problems iterative methods optimisation image reconstruction probability spatial coding transmitter receiver beamforming target detection target localisation sparse signal reconstruction framework inverse problem iterative optimisation algorithm sonar imaging reconstruction restricted isometry property probability numerical simulation compressive sensing method

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Social priming of hemispatial neglect affects spatial coding: Evidence from the Simon task

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CONSCIOUSNESS AND COGNITION 2016年 45卷 1-8页

作者： Arend, Isabel Aisenberg, Daniela Henik, Avishai Ben Gurion Univ Negev Dept Psychol POB 653 Beer Sheva Israel Ben Gurion Univ Negev Zlotowski Ctr Neurosci Beer Sheva Israel

In the Simon effect (SE), choice reactions are fast if the location of the stimulus and the response correspond when stimulus location is task-irrelevant;therefore, the SE reflects the automatic processing of space. Priming of social concepts was found to affect automatic processing in the Stroop effect. We investigated whether spatial coding measured by the SE can be affected by the observer's mental state. We used two social priming manipulations of impairments: one involving spatial processing-hemispatial neglect (HN) and another involving color perception - achromatopsia (ACHM). In two experiments the SE was reduced in the "neglected" visual field (VF) under the HN, but not under the ACHM manipulation. Our results show that spatial coding is sensitive to spatial representations that are not derived from task-relevant parameters, but from the observer's cognitive state. These findings dispute stimulus-response interference models grounded on the idea of the automaticity of spatial processing. (C) 2016 Published by Elsevier Inc.

关键词： spatial coding Social priming Simon effect Hemispatial neglect Achromatopsia

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