Spatial Coding Research Articles

SLBRIN: A Spatial Learned Index Based on BRIN

The spatial learned index constructs a spatial index by learning the spatial distribution, which performs a lower cost of storage and query than the spatial indices. The current update strategies of spatial learned indices can only solve limited updates at the cost of query performance. We propose a novel spatial learned index structure based on a Block Range Index (SLBRIN for short). Its core idea is to cooperate history range and current range to satisfy a fast spatial query and efficient index update simultaneously. SLBRIN deconstructs the update transaction into three parallel operations and optimizes them based on the temporal proximity of spatial distribution. SLBRIN also provides the spatial query strategy with the spatial learned index and spatial location code, including point query, range query and kNN query. Experiments on synthetic and real datasets demonstrate that SLBRIN clearly outperforms traditional spatial indices and state-of-the-art spatial learned indices in the cost of storage and query. Moreover, in the simulated real-time update scenario, SLBRIN has the faster and more stable query performance while satisfying efficient updates.

In preprints: get to know your neighbours – cell interface surveillance through a molecular zip code

In preprints: get to know your neighbours – cell interface surveillance through a molecular zip code

Navigation and the efficiency of spatial coding: insights from closed-loop simulations

Spatial learning is critical for survival and its underlying neuronal mechanisms have been studied extensively. These studies have revealed a wealth of information about the neural representations of space, such as place cells and boundary cells. While many studies have focused on how these representations emerge in the brain, their functional role in driving spatial learning and navigation has received much less attention. We extended an existing computational modeling tool-chain to study the functional role of spatial representations using closed-loop simulations of spatial learning. At the heart of the model agent was a spiking neural network that formed a ring attractor. This network received inputs from place and boundary cells and the location of the activity bump in this network was the output. This output determined the movement directions of the agent. We found that the navigation performance depended on the parameters of the place cell input, such as their number, the place field sizes, and peak firing rate, as well as, unsurprisingly, the size of the goal zone. The dependence on the place cell parameters could be accounted for by just a single variable, the overlap index, but this dependence was nonmonotonic. By contrast, performance scaled monotonically with the Fisher information of the place cell population. Our results therefore demonstrate that efficiently encoding spatial information is critical for navigation performance.

Learning-Based Rate Control for High Efficiency Video Coding

High efficiency video coding (HEVC) has dramatically enhanced coding efficiency compared to the previous video coding standard, H.264/AVC. However, the existing rate control updates its parameters according to a fixed initialization, which can cause errors in the prediction of bit allocation to each coding tree unit (CTU) in frames. This paper proposes a learning-based mapping method between rate control parameters and video contents to achieve an accurate target bit rate and good video quality. The proposed framework contains two main structural codings, including spatial and temporal coding. We initiate an effective learning-based particle swarm optimization for spatial and temporal coding to determine the optimal parameters at the CTU level. For temporal coding at the picture level, we introduce semantic residual information into the parameter updating process to regulate the bit correctly on the actual picture. Experimental results indicate that the proposed algorithm is effective for HEVC and outperforms the state-of-the-art rate control in the HEVC reference software (HM-16.10) by 0.19 dB on average and up to 0.41 dB for low-delay P coding structure.

Coherent mapping of position and head direction across auditory and visual cortex.

Neurons in primary visual cortex (V1) may not only signal current visual input but also relevant contextual information such as reward expectancy and the subject's spatial position. Such contextual representations need not be restricted to V1 but could participate in a coherent mapping throughout sensory cortices. Here, we show that spiking activity coherently represents a location-specific mapping across auditory cortex (AC) and lateral, secondary visual cortex (V2L) of freely moving rats engaged in a sensory detection task on a figure-8 maze. Single-unit activity of both areas showed extensive similarities in terms of spatial distribution, reliability, and position coding. Importantly, reconstructions of subject position based on spiking activity displayed decoding errors that were correlated between areas. Additionally, we found that head direction, but not locomotor speed or head angular velocity, was an important determinant of activity in AC and V2L. By contrast, variables related to the sensory task cues or to trial correctness and reward were not markedly encoded in AC and V2L. We conclude that sensory cortices participate in coherent, multimodal representations of the subject's sensory-specific location. These may provide a common reference frame for distributed cortical sensory and motor processes and may support crossmodal predictive processing.

Paradoxical decrease of imitation performance with age in children.

Imitation development was studied in a cross-sectional design involving 174 primary-school children (aged 6-10), focusing on the effect of actions' complexity and error analysis to infer the underlying cognitive processes. Participants had to imitate the model's actions as if they were in front of a mirror ('specularly'). Complexity varied across three levels: movements of a single limb; arm and leg of the same body side; or arm and leg of opposite body sides. While the overall error rate decreased with age, this was not true of all error categories. The rate of 'side' errors (using a limb of the wrong body side) paradoxically increased with age (from 9 years). However, with increasing age, the error rate also became less sensitive to the complexity of the action. This pattern is consistent with the hypothesis that older children have the working memory (WM) resources and the body knowledge necessary to imitate 'anatomically', which leads to additional side errors. Younger children might be paradoxically free from such interference because their WM and/or body knowledge are insufficient for anatomical imitation. Yet, their limited WM resources would prevent them from successfully managing the conflict between spatial codes involved in complex actions (e.g. moving the left arm and the right leg). We also found evidence that action side and content might be stored in separate short-term memory (STM) systems: increasing the number of sides to be encoded only affected side retrieval, but not content retrieval; symmetrically, increasing the content (number of movements) of the action only affected content retrieval, but not side retrieval. In conclusion, results suggest that anatomical imitation might interfere with specular imitation at age 9 and that STM storages for side and content of actions are separate.

Cultural and semiotic codes of Burkhanist wedding rites of the Altai-Kizhi

The Altai-Kizhi, as the central group of the Altaians, the titular ethnic group in the Republic of Altai, are the guardians of Burkhanism. Burkhanism refers to a belief system that emerged at the beginning of the 20th century as a “reformed” version of shamanism. In Soviet times, forbidden Burkhanism preserved in the intra-ethnic ritual culture, and in the post-Soviet period it began to revive. The purpose of the article is to identify Burkhanist con-cepts in the cultural and semiotic wedding codes. The material for the study was author’s own field accounts of 2020–2022, collected by the method of participant observation and interviewing informants, as well as archival records of A.V. Anokhin, an antiquarian of the early 20th century. When analyzing the source base, a comparative method of research was used. The bride’s transition into a category of married women occurs through the rite of changing the maiden hairstyle for two braids with a parting, and introducing her to the groom's ancestral hearth by ‘treating’ the fire with oil. In the ritual actions of the participants, the Burkhanist attitude towards ‘the positive’ and the observance of the custom of ‘bay’ are encoded. For the first time, on the basis of the collected material, an anthropomorphic code of the ritual practice of the wedding has been identified, associated with the key idea of Burkhanism - the veneration of Altai-deity, the upper heavenly world that provides earthly life. The temporal code of the ritual actions corresponds to the Burkhanist rule — the period of the new moon and morning is a ‘favorable’ time for proposal and marriage. The spatial code of the wedding ceremonies accounts for the contraposition of ‘east-west’, ‘right-left’, and ‘male-female’. The actional code consists in performing the ritual ‘posolon’ actions and an even number of times according to the Burkhanist symbolism. The object code involves sacred attributes — a whip, a gun, a sheath for opening bride's curtain, juniper, and dairy products for ‘feeding’ the hearth fire. The color code of the wedding is in observance of light symbols — bride's curtain, milk, and sacrificial ribbons. The verbal code is realized in the ritual texts of good wishes and songs. The character code is contained in the composition and role of the sex and age groups: elders as experts in the ritual; maternal uncles-taay and nephews of the bride and groom, whose participation means social recognition and approval of the marriage. The analysis of the wed-ding ritual actions reveals the ‘stringing’ of one code upon another, which enhances the significance of the ritual. One and the same ritual meaning can be expressed by means of different codes and by several of them simulta-neously. Despite the fact that the ritual codes are universal, their manifestation and significance in the wedding rituals of the Altai-Kizhi are unique, which is in accordance with the ideas of Burkhanism and is explained by the historical and ethno-confessional factors of the adaptation of the Altaian tribal society.

Landmark-based spatial navigation across the human lifespan.

Human spatial cognition has been mainly characterized in terms of egocentric (body-centered) and allocentric (world-centered) wayfinding bhavior. It was hypothesized that allocentric spatial coding, as a special high-level cognitive ability, develops later and deteriorates earlier than the egocentric one throughout lifetime. We challenged this hypothesis by testing the use of landmarks versus geometric cues in a cohort of 96 deeply phenotyped participants, who physically navigated an equiangular Y maze, surrounded by landmarks or an anisotropic one. The results show that an apparent allocentric deficit in children and aged navigators is caused specifically by difficulties in using landmarks for navigation while introducing a geometric polarization of space made these participants as efficient allocentric navigators as young adults. This finding suggests that allocentric behavior relies on two dissociable sensory processing systems that are differentially affected by human aging. Whereas landmark processing follows an inverted-U dependence on age, spatial geometry processing is conserved, highlighting its potential in improving navigation performance across the lifespan.

Lullabies and Algys in the Semiosphere of the Sakha Culture: Linguistic Aspect

The article analyzes the language and cultural code of lullaby songs and maternity incantations (algyss) which belong to the oldest layer of the Yakut folklore. The addressees are the patron goddesses of clans Aiysyt and the guardian goddesses Ieyekhsit. Understanding of the cultural text language leads to the finding of prototypical conceptual meanings in the consciousness of the ancient Sakha. The novelty of the research lies in the identification of the sign nature of lullabies and incantations, which until now have not been the subject of interest for the Yakut linguists. The aim of the paper is to analyze the semiotic signs and symbols of lullaby songs and maternity spells in semiosphere of the Sakha culture. The article is based on archival materials and published folklore texts. Archaic texts are endowed with magical functions: procreative and apotropaic. In the ritual songs, especially in the rites of transition, both the action code and the sound code (moaning, sound repetitions, the manner of singing: diyeretiya or daegeretiyaҥ) are combined and coexist. Sound behavior in the house of a woman in labor during and after the delivery is strictly regulated. Special sacredness is expressed by allegorical messages about the approach of childbirth, which are expressed by the time code. A syntagmatic series of auspicious signs is presented: the numerical characteristic is joined by color and spatial ones, which model the theme of creation of the Universe and Man. The theme of creation is presented through the technological code of making the cradle. The ambivalence of archaic representation generated by the anthropic functions time/birth, our own/foreign, up/down, and death/life is observed. The symbol of the child is traditionally an egg and a bird, as for gender terms, the symbol of a boy is a knife, the symbol of a girl is a scissor. Wishes for the child’s good fortune are displayed by the concept of cold, which preserves the fact of the negative attitude of the Sakha people from the south to the northern Arctic climate. The sound song code is expressed by a set of cultural codes: the action code, which is defined as a set of ritual and ceremonial actions to achieve the hearing of the patron goddess of childbirth; the time code, corresponding to the three-dimensional universe; the spatial code, represented by the eight-member horizontal and nine-tier vertical model. Sign systems of folk culture functioning in lullabies and incantations are inseparable from their pragmatics. They are “folded messages” which eventually represent archetypal beliefs of ancient Sakha, which are deciphered as a result of semiotic and linguistic research.

Allocentric information represented by self-referenced spatial coding in the primate medial temporal lobe.

For living organisms, the ability to acquire information regarding the external space around them is critical for future actions. While the information must be stored in an allocentric frame to facilitate its use in various spatial contexts, each case of use requires the information to be represented in a particular self-referenced frame. Previous studies have explored neural substrates responsible for the linkage between self-referenced and allocentric spatial representations based on findings in rodents. However, the behaviors of rodents are different from those of primates in several aspects; for example, rodents mainly explore their environments through locomotion, while primates use eye movements. In this review, we discuss the brain mechanisms responsible for the linkage in nonhuman primates. Based on recent physiological studies, we propose that two types of neural substrates link the first-person perspective with allocentric coding. The first is the view-center background signal, which represents an image of the background surrounding the current position of fixation on the retina. This perceptual signal is transmitted from the ventral visual pathway to the hippocampus (HPC) via the perirhinal cortex and parahippocampal cortex. Because images that share the same objective-position in the environment tend to appear similar when seen from different self-positions, the view-center background signals are easily associated with one another in the formation of allocentric position coding and storage. The second type of neural substrate is the HPC neurons' dynamic activity that translates the stored location memory to the first-person perspective depending on the current spatial context.

No conclusive evidence for number-induced attentional shifts in a temporal order judgement task.

The Spatial Numerical Association of Response Codes (SNARC) effect refers to the observation that relatively small (e.g., 1) and large numbers (e.g., 9) elicit faster left- and right-sided manual responses, respectively. In a variation known as the attentional SNARC effect, merely looking at numbers caused a left- or right-ward shift in covert spatial attention, depending on the number's magnitude. In our study, we probed the notion that numbers induce shifts of spatial attention in accordance with their position on a mental number line (MNL). Critically, we removed any putative spatial response code that may contaminate the responses. We used a square and a tilted square as targets, thereby situating the decisive response dimension in the ventral, non-spatial processing stream. In two experiments where numbers were used as non-informative cues preceding a temporal order judgement (TOJ) task, we did not observe a deflection of the locus of spatial attention as a function of the numerical magnitude of the cue. In a third experiment, finding a significant modulation of TOJ performance as a function of the pointing direction of arrow cues allowed us to rule out the possibility that the absence of any significant modulation in Experiments 1 and 2 was due to a lack of sensitivity of our task set-up. We conclude from the current findings that the spatial codes that the perception and naming of numbers potentially elicit are not in and by themselves sufficient to elicit deflections of spatial attention.

Organization of hippocampal CA3 into correlated cell assemblies supports a stable spatial code.

Hippocampal subfield CA3 is thought to stably store memories in assemblies of recurrently connected cells functioning as a collective. However, the collective hippocampal coding properties that are unique to CA3 and how such properties facilitate the stability or precision of the neural code remain unclear. Here, we performed large-scale Ca2+ imaging in hippocampal CA1 and CA3 of freely behaving mice that repeatedly explored the same, initially novel environments over weeks. CA3 place cells have more precise and more stable tuning and show a higher statistical dependence with their peers compared with CA1 place cells, uncovering a cell assembly organization in CA3. Surprisingly, although tuning precision and long-term stability are correlated, cells with stronger peer dependence exhibit higher stability but not higher precision. Overall, our results expose the three-way relationship between tuning precision, long-term stability, and peer dependence, suggesting that a cell assembly organization underlies long-term storage of information in the hippocampus.

Spatial coding in the hippocampus and hyperpallium of flying owls

The elucidation of spatial coding in the hippocampus requires exploring diverse animal species. While robust place-cells are found in the mammalian hippocampus, much less is known about spatial coding in the hippocampus of birds. Here we used a wireless-electrophysiology system to record single neurons in the hippocampus and other two dorsal pallial structures from freely flying barn owls (Tyto alba), a central-place nocturnal predator species with excellent navigational abilities. The owl's 3D position was monitored while it flew between perches. We found place cells-neurons that fired when the owl flew through a spatially restricted region in at least one direction-as well as neurons that encoded the direction of flight, and neurons that represented the owl's perching position between flights. Many neurons encoded combinations of position, direction, and perching. Spatial coding was maintained stable and invariant to lighting conditions. Place cells were observed in owls performing two different types of flying tasks, highlighting the generality of the result. Place coding was found in the anterior hippocampus and in the posterior part of the hyperpallium apicale, and to a lesser extent in the visual Wulst. The finding of place-cells in flying owls suggests commonalities in spatial coding across mammals and birds.

Space of a Peasant House in Beliefs and Ceremonies Associated with Spirits-“masters” of Loci (Russian Mythological Texts of Perm Region)

A reconstruction of the traditional mythological ideas of the Russian inhabitants of the Perm region about the peasant house is carried out. The structural elements and premises of the hut are considered, which are perceived by the bearers of the tradition as places of contact with the spirits — “owners” of the loci. The analysis of the mythological texts recorded on the territory of the region about the bannik, the brownie, the domovoy, the leshy and the mermaid has been carried out. This material reveals a circle of rooms and elements of the Russian hut, in which, according to legend, spirits live. Permian beliefs are compared with common Slavic ones. It is concluded that the places of contact between a person and the “host” spirits are those elements of the house that are the sacred centers of the hut (oven, table) or represent its periphery (attic, golbets, closet, kitchen, bathroom, corridor, corner) or borders (door, threshold, porch, window, roof, floor, ceiling, mat). At the same time, such characteristics of these elements as “internal — external”, “upper — lower”, “central — peripheral” turn out to be important, reflecting the opposition “one’s own — someone else’s” that is basic for Slavic culture. There is a partial modernization of the spatial code in the beliefs of the Russians of the Perm region, which leads to a slight transformation of the tradition. New ideas are built into existing cultural models (the bathroom is on a par with other non-residential premises).

The Online Construction of Digital Spatial Representation in Alphanumeric Mixed Situations Is Not Automaticity

SNARC effect is called the joint effect of spatial digital response coding, which is the proof of the connection between number and space. There are mainly theoretical explanations, such as the mental number line explanation of long-term memory, the working memory explanation of short-term memory, and the dual path pattern explanation. Recent studies have demonstrated that SNARC effect is the online construction of digits in working memory during task execution, and the online construction of digits SNARC effect is interfered by letter processing in the mixed situation of digits and letters, which further supports the hypothesis of working memory. Although online encoding of SNARC effect has been proved, it is not clear whether online encoding of digital spatial representation in the mixed alphanumeric context has automaticity, and if so, whether it will be interfered by letter processing. In this study, three digit color judgment experiments were conducted, and the ratio of digits to letters was 1:1. 1:6. The paper explores whether the online construction of digital space representation is automaticity in the mixed interference situation of 6:1. To investigate the interference of letter processing on digital SNARC effect, explore whether the interference is regulated by the proportion of number letters, and further explore the automatic mechanism of the interference of letter processing on digital space coding. The results showed that SNARC effect was not observed in the mixed numbers and letters at different proportions. It shows that the online construction of digital space representation in the mixed alphanumeric situation does not have automaticity. When the task does not directly activate the size order information of the number letters, the letters will interfere with the online construction of the number SNARC effect, which is not proportional adjustment.

Behavioral status modulates CA2 influence on hippocampal network dynamics.

Dynamic interactions between the subregions of the hippocampus are required for the encoding and consolidation of memory. While the interplay and contributions of the CA1 and CA3 regions are well understood, we continue to learn more about how CA2 differentially contributes to the organization of network function. For example, CA2 place cells have been reported to be less spatially tuned during exploration, but uniquely capable of coding place while an animal stops. Here we applied chemogenetics to transiently silence CA2 pyramidal cells and found that CA2 influences hippocampal dynamics in a state-dependent manner. We find that during rest, CA2 inhibition reduces synchronization across regions (CA1, CA2, CA3) and frequency bands (low-gamma- and ripple-band). Moreover, during new learning CA1 place field formation is slower in the absence of CA2 transmission and during pausing, CA1 pyramidal cells are less excitable without CA2 drive. On the network level, a novel convolutional neural network (SpikeDecoder) was employed to show subregion and state-dependent changes in spatial coding that agree with our observations on the single cell level. Together these data suggest additional novel roles for CA2 in governing and differentiating hippocampal dynamics under discrete behavioral states.

Arrival time diagnosis method of high refrequency hard X-ray free electron laser

X-ray free electron laser (XFEL) pulse time diagnosis technology is often used to detect the relative arrival time of XFEL pulse and auxiliary laser near the experimental station. It is an important auxiliary technology and provides a reference signal for the pump-probe pulse in the XFEL laser pump-probe experiment. With the development of XFEL towards high repetition frequency and short pulse, higher requirements are put forward for diagnostic frequency, pump sample and resolution in time diagnosis. The technology is realized by the pump-probe method and optical cross-correlation method. When the XFEL pulse is incident on the high-bandwidth semiconductor solid target instantaneously, the complex refractive index of the solid target will change, then the arrival time of XFEL will be encoded in the mutation space. In thiswork, we design an XFEL pulse arrival time diagnostic device based on two methods: spatial coding and spectral coding. In this framework, the interaction between X-ray and solid target is explored by Beer's absorption theory and atomic scattering theory. Therefore, the response to X-ray absorption and refractive index in this process are investigated, and the solid target selection model is developed. This model is used to analyze the influence of solid target type and thickness in diagnosis, while avoiding situations where the sample is too hot due to a lot X-ray absorption. Moreover, the influence of hard X-ray on sample temperature at high frequency is considered, and the samples suitable for different X-ray bands are given. The chirped pulse modulation in spectral coding is analyzed, and the influence of dispersion medium and pulse parameters on the diagnostic resolution of spectral coding are obtained. Finally, the error effects of X-ray, spatial coding and spectral coding on the results are analyzed, and the analysis methods and consideration factors of the two coding methods are given. This work is of great significance in using the XFEL pulse arrival time diagnostic device.

Time-space united coding spread spectrum single photon counting imaging method

In this paper, we demonstrate a new imaging architecture called time-space united coding spread spectrum single photon counting imaging technique by combining the space coding based single-pixel imaging technology and spread spectrum time coding based scanning imaging technology. This method has the advantages of range ambiguity-free and large time-bandwidth product. Under the interference of noise, this method can accurately restore depth images. In this work, the time-space united correlation nonlinear detection model based on single photon detection, forward imaging model and signal-to-noise ratio model is derived, and the depth image is restored by convex optimization inversion algorithm. The theoretical model and simulation experiments show that compared with the traditional single pixel imaging method based on spatial coding, this method improves the quality of scene reconstruction. Using m-sequence as time coding, imaging has higher noise robustness. In addition, compared with the traditional space coding single pixel imaging technology, the imaging mean square error of the proposed method is reduced by 4/5 and the imaging mean squared error is reduced by 9/10 after introducing the second correlated method. The proposed imaging architecture in this paper may provide a new path for non-scanning lidar imaging methods.

THE CULTURAL CODES OF THE LIBRETTO IN THE OPERA “RUSLAN AND LUDMILA” BY M. I. GLINKA

The problem of the study of cultural codes is relevant in various fields of humanities, including art studies. In the polycode structure of the libretto of the opera “Ruslan and Lyudmila” by M. I. Glinka, a set of different codes recreating a fabulous picture of the world is investigated. Among the most significant codes there are genre, wedding, geographical, natural landscape, subject, vital, spiritual, onomastic, national, mythological, spatial and temporal codes. The reconstruction is carried out on the basis of methodological approaches developed in folklore studies, literary studies and linguistics.

Collaborative Layout Optimization for Ship Pipes Based on Spatial Vector Coding Technique

Collaborative Layout Optimization for Ship Pipes Based on Spatial Vector Coding Technique