Temporal Information Processing: A Survey

Temporal Information Processing is a subfield of Natural Language Processing, valuable in many tasks like Question Answering and Summarization. Temporal Information Processing is broadened, ranging from classical theories of time and language to current computational approaches for Temporal Information Extraction. This later trend consists on the automatic extraction of events and temporal expressions. Such issues have attracted great attention especially with the development of annotated corpora and annotations schemes mainly TimeBank and TimeML. In this paper, we give a survey of Temporal Information Extraction from Natural Language texts

A Neural Network Model for the Spatial and Temporal Response of Retinal Ganglion Cells

This article introduces a quantitative model of early visual system function. The model is formulated to unify analyses of spatial and temporal information processing by the nervous system. Functional constraints of the model suggest mechanisms analogous to photoreceptors, bipolar cells, and retinal ganglion cells, which can be formally represented with first order differential equations. Preliminary numerical simulations and analytical results show that the same formal mechanisms can explain the behavior of both X (linear) and Y (nonlinear) retinal ganglion cell classes by simple changes in the relative width of the receptive field (RF) center and surround mechanisms. Specifically, an increase in the width of the RF center results in a change from X-like to Y-like response, in agreement with anatomical data on the relationship between α- and -cell RF profiles. Simulations of model response to various spatio-temporal input patterns replicate many of the classical properties of X and Y cells, including transient (Y) versus sustained (X) responses, null-phase responses to alternating gratings in X cells, on-off or frequency doubling responses in Y cells, and phase-independent on-off responses in Y cells at high spatial frequencies. The model's formal mechanisms may be used in other portions of the visual system and more generally in nervous system structures involved with spatio-temporal information processing

Spatial and temporal information processing in the sea urchin embryo: modular and intramodular organization of the CyIIIa gene cis-regulatory system

The CyIIIa cytoskeletal actin gene of Strongylocentrotus purpuratus is expressed specifically in the aboral ectoderm. In earlier work we identified a 2.3 kb cis-regulatory region that is necessary and sufficient for correct spatial and temporal expression of a CyIIIa.CAT gene. This region includes about 20 sites of specific protein-DNA interaction, at which at least nine different transcription factors may be bound. All except two of these factors have been cloned. In this work we have analyzed by deletion or mutagenesis each specific interaction. A specific function was identified for every binding site examined. These individual functions include control of amplitude and timing of expression at different phases of embryogenesis, and control of spatial expression. We show that particular negative regulatory interactions are required to repress expression of the CyIIIa.CAT construct in oral ectoderm and in skeletogenic mesenchyme at different stages. In further experiments we determined the overall functional organization of the CyIIIa cis-regulatory system, and we show that this system is modular in its regulatory structure. The ‘proximal module’ (with respect to the transcription start site) extends upstream for about 800 base pairs, and includes nine target sites serviced by six different transcription factors. Its major role is to establish CyIIIa expression in the aboral ectoderm territory as the blastomere founder cells are specified and the oral-aboral axis is determined, and to activate the CyIIIa gene late in cleavage. The ‘middle module,’ which lies upstream of the proximal module, acquires major control of CyIIIa function after the blastula stage. It includes six target sites, serviced by four different factors. The middle module is responsible for a sharp increase in expression occurring during gastrulation, mediated by the positively acting factors that bind within it. The middle module also includes sites at which two different negatively acting spatial control factors bind, the functions of which are required for correct spatial expression late in embryogenesis. The ‘distal module’ contains a number of sites at which a positively acting factor binds, but this module exercises no spatial regulatory function. Interactions within the distal module are required for the normal levels of function of both the proximal and middle modules

Temporal Information Processing in Short- and Long-Term Memory of Patients with Schizophrenia

Cognitive deficits of patients with schizophrenia have been largely recognized as core symptoms of the disorder. One neglected factor that contributes to these deficits is the comprehension of time. In the present study, we assessed temporal information processing and manipulation from short- and long-term memory in 34 patients with chronic schizophrenia and 34 matched healthy controls. On the short-term memory temporal-order reconstruction task, an incidental or intentional learning strategy was deployed. Patients showed worse overall performance than healthy controls. The intentional learning strategy led to dissociable performance improvement in both groups. Whereas healthy controls improved on a performance measure (serial organization), patients improved on an error measure (inappropriate semantic clustering) when using the intentional instead of the incidental learning strategy. On the long-term memory script-generation task, routine and non-routine events of everyday activities (e.g., buying groceries) had to be generated in either chronological or inverted temporal order. Patients were slower than controls at generating events in the chronological routine condition only. They also committed more sequencing and boundary errors in the inverted conditions. The number of irrelevant events was higher in patients in the chronological, non-routine condition. These results suggest that patients with schizophrenia imprecisely access temporal information from short- and long-term memory. In short-term memory, processing of temporal information led to a reduction in errors rather than, as was the case in healthy controls, to an improvement in temporal-order recall. When accessing temporal information from long-term memory, patients were slower and committed more sequencing, boundary, and intrusion errors. Together, these results suggest that time information can be accessed and processed only imprecisely by patients who provide evidence for impaired time comprehension. This could contribute to symptomatic cognitive deficits and strategic inefficiency in schizophrenia

Temporal Information Processing and Stability Analysis of the MHSN Neuron Model in DDF

Implementation of a neuron like information processing structure at hardware level is a burning research problem. In this article, we analyze the modified hybrid spiking neuron model (the MHSN model) in distributed delay framework (DDF) for hardware level implementation point of view. We investigate its temporal information processing capability in term of inter-spike-interval (ISI) distribution. We also perform the stability analysis of the MHSN model, in which, we compute nullclines, steady state solution, eigenvalues corresponding the MHSN model. During phase plane analysis, we notice that the MHSN model generates limit cycle oscillations which is an important phenomenon in many biological processes. Qualitative behavior of these limit cycle does not changes due to the variation in applied input stimulus, however, delay effect the spiking activity and duration of cycle get altered

What's an internal clock for? From temporal information processing to temporal processing of information

International audienceThe existence of an internal clock and its involvement in information processing has been investigated in humans using the experimental protocol of Treisman et al. (1990) [Treisman et al., 1990. Perception, 19, 705 – 743]. In this protocol, a periodical stimulation, which is assumed to drive an internal clock, is delivered during a reaction time (RT) task. The accelerating or slowing down effects of the periodical stimulation, according to its frequency, allowed an estimate to be made of a simple harmonic of the frequency of the internal clock. The estimate was close to 21 Hz. In the framework of the serial model of information processing, the present work investigates the involvement of the internal clock in the transmission of information between processing stages during RT. The data tend to support the idea that the internal clock allows the transfer of information from one stage to the next one at definite moments only, periodically distributed in time. According to our results, and recent data from the literature on electric cortical oscillations, we propose a model of an internal clock sending periodic inhibition, which would permit an increased signal/noise ratio in the processing and the transmission of information in the central nervous system