Neurophysiological distinctions between spatial and temporal context in episodic memory.

Age-related changes in prefrontal cortex activity are associated with behavioural deficits in both temporal and spatial context memory retrieval in older adults

Group differences in anterior hippocampal volume and in the retrieval of spatial and temporal context memory in healthy young versus older adults

Spatial context is a defining feature of episodic memories, which are often characterized as being events occurring in specific spatiotemporal contexts. In this review, I summarize research suggesting a common neural basis for episodic and spatial memory and relate this to the role of spatial context in episodic memory. I review evidence that spatial context serves as a scaffold for episodic memory and imagination, in terms of both behavioral and neural effects demonstrating a dependence of episodic memory on spatial representations. These effects are mediated by a posterior-medial set of neocortical regions, including the parahippocampal cortex, retrosplenial cortex, posterior cingulate cortex, precuneus, and angular gyrus, which interact with the hippocampus to represent spatial context in remembered and imagined events. I highlight questions and areas that require further research, including differentiation of hippocampal function along its long axis and subfields, and how these areas interact with the posterior-medial network. This article is categorized under: Psychology > Memory Neuroscience > Cognition.

Roles of human hippocampal subfields in retrieval of spatial and temporal context

SiamSTC: Updatable Siamese tracking network via Spatio-Temporal Context

This paper introduces a multi-level classification framework for the semantic annotation of urban maps as provided by a mobile robot. Environmental cues are considered for classification at different scales. The first stage considers local scene properties using a probabilistic bag-of-words classifier. The second stage incorporates contextual information across a given scene (spatial context) and across several consecutive scenes (temporal context) via a Markov Random Field (MRF). Our approach is driven by data from an onboard camera and 3D laser scanner and uses a combination of visual and geometric features. By framing the classification exercise probabilistically we take advantage of an information-theoretic bail-out policy when evaluating class-conditional likelihoods. This efficiency, combined with low order MRFs resulting from our two-stage approach, allows us to generate scene labels at speeds suitable for online deployment. We demonstrate the virtue of considering such spatial and temporal context during the classification task and analyze the performance of our technique on data gathered over almost 17 km of track through a city.

Visual context is the environment, background, and settings within which objects and associated behaviours are observed visually. A semantic interpretation of behaviour depends largely on knowledge of spatial and temporal context defining where and when it occurs, and correlational context specifying the expectation on the behaviours of correlated other objects in its vicinity. In this chapter, we address the problem of how to model computationally behavioural context for context-aware behavioural anomaly detection in a visual scene. We consider models for learning three types of behavioural context: spatial context, correlational context and temporal context. Behaviour spatial context provides situational awareness about where a behaviour is likely to take place. A public space can often be segmented by activities into a number of distinctive regions, called “semantic regions”. Behaviours of certain characteristics are expected in one region but differ from those observed in other regions. Behaviour correlational context specifies how the interpretation of a behaviour can be affected by behaviours of other objects either nearby in the same semantic region or further away in other regions. Object behaviours in a complex scene are often correlated and need be interpreted together rather than in isolation. Behaviour temporal context provides information regarding when different behaviours are expected to happen both inside each semantic region and across regions.

The responses of neurons in the visual pathway depend on the context in which a stimulus is presented. Responses to predictable stimuli are usually suppressed, highlighting responses to unexpected stimuli that might be important for behavior. Here, we established how context modulates the response of neurons in the superior colliculus (SC), a region important in orienting toward or away from visual stimuli. We made extracellular recordings from single units in the superficial layers of SC in awake mice. We found strong suppression of visual response by spatial context (surround suppression) and temporal context (adaptation). Neurons showing stronger surround suppression also showed stronger adaptation effects. In neurons where it was present, surround suppression was dynamic and was reduced by adaptation. Adaptation's effects further revealed two components to surround suppression: one component that was weakly tuned for orientation and adaptable, and another component that was more strongly tuned but less adaptable. The selectivity of the tuned component was flexible, such that suppression was stronger when the stimulus over the surround matched that over the receptive field. Our results therefore reveal strong interactions between spatial and temporal context in regulating the flow of signals through mouse SC, and suggest the presence of a subpopulation of neurons that might signal novelty in either space or time.

Photoacoustic imaging (PAI) is an emerging biomedical imaging modality that harnesses pulsed laser light to generate ultrasound waves through thermoelastic expansion, enabling high-resolution, non-invasive visualization of tissue structure and function at clinically relevant depths. By combining the optical contrast of molecular imaging with the spatial precision of ultrasound, PAI offers a unique capability to assess physiological and pathological processes in vivo. Its relatively low cost, safety, and imaging speed make it a highly promising tool for a wide range of clinical applications, including oncology and vascular medicine. The clinical adoption of PAI, however, has been limited by challenges in interpreting its data without sufficient spatial, temporal, and biophysical context. This thesis addresses this limitation by developing methods that incorporate contextual information across these dimensions, enabling more accurate and clinically meaningful PAI analysis. The lack of spatial context was addressed with a framework for reconstructing threedimensional (3D) volumes from sets of two-dimensional (2D) images. The central innovation of this approach lies in the use of an optical pattern that encodes spatial information through specific light-absorption characteristics. An extension of the pattern, adding fiducial markers, further enables the multimodal fusion of PAI with magnetic resonance imaging (MRI) and computed tomography (CT), thereby situating PAI within the established clinical imaging landscape. The lack of temporal context, addressed by pattern-based longitudinal registration of 3D PAI volumes, enables a more comprehensive assessment of disease status and progression. Third, a digital twin model was introduced to analyze unexpected clinical observations by disentangling physiological mechanisms from photoacoustic image formation processes. To demonstrate the broad applicability of these methods, they were validated in diverse clinical settings, with applications ranging from cancer therapy to vascular disease diagnosis. In a clinical study on peripheral artery disease, optical pattern-based PAI successfully detected ischemia and muscular heterogeneities, indicating benefits over conventional 2D approaches by combining spatial and temporal context. This thesis also presents the first evidence that PAI can non-invasively capture molecular changes induced by radiotherapy in patients with head and neck cancer. In this study, digital twin modeling further provided a mechanistic explanation for unexpected oxygenation measurements, revealing that these anomalies arose from signal distortions in regions with low blood volume. In conclusion, this work establishes the concept of context-aware PAI, integrating spatial and temporal, multimodal, and biophysical information to enhance both interpretability and clinical trust. By demonstrating feasibility in clinical studies, it outlines a pathway for translating context-aware PAI into routine medical practice.

Wire Arc Additive Manufacturing allows the cost-effective manufacturing of customized, large-scale metal parts. As the post-process quality assurance of large parts is costly and time-consuming, process monitoring is inevitable. In the present study, a context-aware monitoring solution was investigated by integrating machine, temporal, and spatial context in the data analysis. By analyzing the voltage patterns of each cycle in the oscillating cold metal transfer process with a deep neural network, temporal context was included. Spatial context awareness was enabled by building a digital twin of the manufactured part using an Octree as spatial indexing data structure. By means of the spatial context awareness, two quality metrics—the defect expansion and the local anomaly density—were introduced. The defect expansion was tracked in-process by assigning detected defects to the same defect cluster in case of spatial correlation. The local anomaly density was derived by defining a spherical region of interest which enabled the detection of aggregations of anomalies. By means of the context aware monitoring system, defects were detected in-process with a higher sensitivity as common defect detectors for welding applications, showing less false-positives and false-negatives. A quantitative evaluation of defect expansion and densities of various defect types such as pore nests was enabled.

NASA Ames' Exploration Ground Data Systems (xGDS) supports rapid scientific decision making by synchronizing information in time and space, including video and still images, scientific instrument data, and science and operations notes in geographic and temporal context. We have deployed xGDS at multiple NASA field analog missions over the past decade. In the last two years, we have participated in SUBSEA, a multi-institution collaborative project*. SUBSEA used the research ship E/V Nautilus along with its two remotely operated vehicles (ROVs), Hercules and Argus, to explore deep ocean volcanic vents as an analog for ocean worlds (e.g. Enceladus). This work allowed us to compare the existing oceanographic operations methods and technologies used for ocean exploration with corresponding tools and approaches developed and used at NASA. In the first year of SUBSEA we observed existing remote science operations from the Inner Space Center (ISC)**. In the second year, we deployed xGDS at ISC to complement existing capabilities with xGDS tools designed to support remote Nautilus science operations from the ISC. During operations, video, ROV position and instrument telemetry were streamed from the ship to the ISC. As the science team watched dive operations, they could annotate the data with observations that were relevant to their work domain. Later, the team members could review the data at their own pace to collaboratively develop a dive plan for the next day, which had to be delivered on a fixed daily schedule. The opportunity to compare operations under different conditions enabled us to make several key observations about conducting remote science and planning operations efficiently: (i) Reviewing data collaboratively and interactively with temporal and spatial context was critical for the remote science team's ability to plan dive operations on the Nautilus. (ii) Science team members were actively engaged with the remote dive operations because they could interact with the collected data and visualize it as they desired. (iii) Being able to replay past events at accelerated speeds, and jump to points in time and spaced based on search results, provided efficient access to critical points of interest in a massive volume of data, so the remote science team could deliver plans on time. * SUBSEA (Systematic Underwater Biogeochemical Science and Exploration Analog) is a multi-institution collaboration supported by NASA, NOAA's Office of Exploration Research (OER), the Ocean Exploration Trust (OET) and the University of Rhode Island's Graduate School of Oceanography (GSO). ** ISC is GSO's telepresence operations facility.

This paper presents the results of a qualitative study on the social representation of violence among young Chileans who have been involved in violence. Starting from interview-data that show their subjective perspective, a conceptual model of their social representation is constructed that identifies elements that favor or inhibit the violent actions. Results show two types of factors involved in the transgression of the "limit of violence": personal characteristics and contextual elements, making the distinction between the temporal context (the moment of violence) and the spatial context (the place of violence). In addition, the young participants of this study establish a relationship between their violent actions and the perception of threat, especially regarding their social identity. In this relationship, the function of violent actions is the neutralization of this threat. This understanding constitutes the nucleus of their social representation of violence. Implications for preventive strategies and community interventions are discussed. This work presents the results of a qualitative study on the social representation of violence among young Chileans who have been involved in violence. Starting from interview-data that show their subjective perspective, a conceptual model of their social representation is constructed that identifies elements that favor or inhibit the violent actions. Results show that these young people’s social representations of violence include two types of factors involved in the transgression of the “limit of violence”: personal characteristics and contextual elements, making the distinction between the temporal context (the moment of violence) and the spatial context (the place of violence). With regard to these contextual elements, the subjective meaning is more important than the moments or places by themselves. In addition, the young participants of this study establish a relationship between their violent actions and the perception of threat, especially regarding their social identity. In this relationship, the function of violent actions is the neutralization of this threat. This understanding constitutes the nucleus of their social representation of violence. Implications for community interventions are discussed. [1] This research received financial support from Fundación Paz Ciudadana, Chile.

Integrated Development Environments (IDEs) provide tool support to automate many source code editing tasks. Traditionally, IDEs use only the spatial context, i.e., the location where the developer is editing, to generate candidate edit recommendations. However, spatial context alone is often not sufficient to confidently predict the developer’s next edit, and thus IDEs generate many suggestions at a location. Therefore, IDEs generally do not actively offer suggestions and instead, the developer is usually required to click on a specific icon or menu and then select from a large list of potential suggestions. As a consequence, developers often miss the opportunity to use the tool support because they are not aware it exists or forget to use it. To better understand common patterns in developer behavior and produce better edit recommendations, we can additionally use the temporal context, i.e., the edits that a developer was recently performing. To enable edit recommendations based on temporal context, we present Overwatch, a novel technique for learning edit sequence patterns from traces of developers’ edits performed in an IDE. Our experiments show that Overwatch has 78% precision and that Overwatch not only completed edits when developers missed the opportunity to use the IDE tool support but also predicted new edits that have no tool support in the IDE.

Episodic memory often is conceptualized as a uniquely human system of long-term memory that makes available knowledge accompanied by the temporal and spatial context in which that knowledge was acquired. Retrieval from episodic memory entails a form of first–person subjectivity called autonoetic consciousness that provides a sense that a recollection was something that took place in the experiencer's personal past. In this paper I expand on this definition of episodic memory. Specifically, I suggest that (1) the core features assumed unique to episodic memory are shared by semantic memory, (2) episodic memory cannot be fully understood unless one appreciates that episodic recollection requires the coordinated function of a number of distinct, yet interacting, “enabling” systems. Although these systems—ownership, self, subjective temporality, and agency—are not traditionally viewed as memorial in nature, each is necessary for episodic recollection and jointly they may be sufficient, and (3) the type of subjective awareness provided by episodic recollection (autonoetic) is relational rather than intrinsic—i.e., it can be lost in certain patient populations, thus rendering episodic memory content indistinguishable from the content of semantic long-term memory.

Episodic memory is memory for experiences within a specific temporal and spatial context. Episodic memories decline early in Alzheimer’s Disease (AD). Recollection of episodic memories can fail with both AD and aging, but familiarity and recollection memory uniquely fail in AD. Finding a means to differentiate specific memory failures in animal models is critical for translational research. Four cotton top tamarins participated in an object recognition test. They were exposed to two unique objects placed in a consistent context for 5 daily sessions. Next a delay of 1 day or 1 week was imposed. Subjects’ memory of the objects was tested by replacing one of the familiarized objects with a novel one. The tamarins looked longer at the novel object after both delays, an indication of remembering the familiar object. In other tests, the test pair was relocated to a new location or presented at a different time of day. With context changes, tamarins showed greater interest in the novel object after a 1-week delay but not after a 1-day delay. It seems that context changes disrupted their recollection of recent events. But the monkeys showed accurate familiarity memory across context changes with longer delays.