Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Information Processing”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1996

Self-organized phase transitions in neural networks as a neural mechanism of information processing.

Transitions between dynamically stable activity patterns imposed on an associative neural network are shown to be induced by self-organized infinitesimal changes in synaptic connection strength and to be a kind of phase transition. A key event for the neural process of information processing in a population coding scheme is transition between the activity patterns encoding usual entities. We propose that the infinitesimal and short-term synaptic changes based on the Hebbian learning rule are the driving force for the transition. The phase transition between the following two dynamical stable states is studied in detail, the state where the firing pattern is changed temporally so as to itinerate among several patterns and the state where the firing pattern is fixed to one of several patterns. The phase transition from the pattern itinerant state to a pattern fixed state may be induced by the Hebbian learning process under a weak input relevant to the fixed pattern. The reverse transition may be induced by the Hebbian unlearning process without input. The former transition is considered as recognition of the input stimulus, while the latter is considered as clearing of the used input data to get ready for new input. To ensure that information processing based on the phase transition can be made by the infinitesimal and short-term synaptic changes, it is absolutely necessary that the network always stays near the critical state corresponding to the phase transition point.

Animals↗
PubMed2003

The automatic and controlled information-processing dissociation: is it still relevant?

The purpose of this paper is to examine the "dual-process" information-processing model of Schneider and Shiffrin (Schneider, W., and Shiffrin, R. M., Psychol. Rev. 84: 1-66, 1977; see also Shiffrin, R. M., and Schneider, W., Psychol. Rev. 84: 127-190, 1977) in light of the research data that have accumulated since the model was introduced more than 20 years ago. First, a brief introduction of the basic model of automatic and controlled information processing will be given. Second, some alternatives to the basic model that were developed over the last two decades will be reviewed. Third, data from neuropsychology and cognitive neuroscience that have a bearing upon this framework will be considered. Finally, some comments on the current usefulness of the dual-process framework for neuropsychological research will be offered.

Alzheimer Disease↗
PubMed1991

[Changes in the rate and accuracy of information processing in the computer training of upper-grade pupils].

The basic activity of the student during the "computer training process" is the introduction and processing of information. In the dialogue regime of work, between student and computer, the velocity and accuracy of the information processing take important place. In this aspect, special attention is given to the changes in the indicated indices during the computer lesson, computer plays and the traditional training. Studies are carried out on 30 students from classes X and XI, educated in vocational school "V. Levski", the town of Pravets. For the purpose is used electron determinator with test programme, containing consecutively exposure to 50 visual stimulators in red, blue, green, yellow and white colours at 1,2 s/speed. The results as a whole show that the most favourable results concerning the computer plays, very likely could be explained with the diversion effect and the positive motivation adjustment to the activity performed. By means of dispersion analysis is established, that only the type of activity has an essential effect on the velocity and accuracy of the information processing.

Bulgaria↗
PubMed1985

The effect of methylphenidate on information processing.

Models of information processing currently popular in cognitive psychology divide the reaction process into a series of discrete separable stages. The distinction between one stage and another is verified by the additive factors method (AFM) as defined by Sternberg (1969). Task factors that do not interact with each other are inferred to affect different stages. The distinction between stimulus evaluation stages and response selection stages has been supported by brain event related potential (ERP) studies. The latency of the P300 component of the ERP is sensitive to changes in stimulus complexity but not to to changes in response complexity. The focus of this research is to determine the effects of stimulant drugs on stages of information processing using both reaction time (RT) and P300 latency within an AFM framework. Four doses of methylphenidate (MP) were used in a within-subjects design to examine the effects of MP on stimulus and response processing. We found that MP speeds RT, and that this effect does not interact with the effect of stimulus complexity on RT. MP dose interacts with response complexity, the dose for optimal speeding varying with the level of complexity. The latency of P300 is increased by stimulus complexity, and not by response complexity, nor is it affected by MP. These results show that the stimulant drug acts on processes involved in response selection, rather than in stimulus evaluation. Individual differences in drug response are dose dependent, but also point to an effect on response processing.

Adult↗
PubMed1987

The effects of selective inattention upon the electrodermal orienting reflex: a test of information-processing theory.

Information-processing theories of the orienting reflex (OR) predict that disruptions of attention which impede the registration of a stimulus in memory should retard habituation of the OR. Studies examining effects of selective inattention upon rate of habituation of skin conductance responses (SCRs) to concurrently presented stimuli have yielded inconsistent results. We employed a dichotic vigilance task calling for selective attention to either male-voice or female-voice words. Comparisons between previously attended versus nonattended stimuli were subsequently conducted for habituation of SCR, as well as for a direct measure of recognition memory. Although there were unequivocal differences in long-term memory between attended and non-attended material, there was no clear evidence for corresponding differences in either initial magnitude or rate of habituation of SCR. These data, which replicated results from an earlier study, failed to demonstrate an effect of memory on the OR as predicted by information-processing theories.

Attention↗
PubMed1989

Biological information processing: the use of information for the support of function.

In biological systems, the processing and use of information has evolved out of the need for survival in the face of an uncertain environment. As a consequence, the information-function relationship in these systems is shaped by their adaptability characteristics. In contrast, the information-function relationship in man-designed, goal-oriented organizational systems depends on the ability of the information processing system to support the achievement of the organization's goals. In this paper we use results from adaptability theory in the analysis of control-related aspects of the information-function relationship in man-designed organizational systems. In particular, we use a conceptual model of organizational control to characterize features of functional and control structures and their effect on the adaptability of these systems. The concept of implicit control and a design principle for adaptability-enhancing information systems are derived for this analysis.

Adaptation, Physiological↗
PubMedDate not supplied

An integrated model of emotion processes and cognition in social information processing.

Literature on the contributions of social cognitive and emotion processes to children's social competence is reviewed and interpreted in the context of an integrated model of emotion processes and cognition in social information processing. Neurophysiological and functional evidence for the centrality of emotion processes in personal-social decision making is reviewed. Crick and Dodge's model is presented as a cognitive model of social decision making, and a revised model is proposed into which emotion processes are integrated. Hypotheses derived from the proposed model are described.

Brain↗
PubMed1995

Aging, caffeine, and information processing: an event-related potential analysis.

Structural and energetic processes in information processing were studied in young and elderly subjects. A visually focussed selective search task was used, in which subjects had to select relevant information, followed by controlled memory search processes to locate a target item. Caffeine was used to manipulate the energetic state of the subjects. During task performance event-related potentials (ERPs) and reaction time (RT) were recorded. Subjects were 15 young and 15 elderly healthy, non-smoking, moderate caffeine consumers (250-600 mg/day). Before the experimental sessions they abstained from caffeine for > or = 12 h. In the experiment subjects received 250 mg caffeine or placebo dissolved in decaffeinated coffee. RT data seem to indicate that aging effects are at least partly due to a shift in the speed-accuracy trade-off. ERP results provide evidence for decreased levels of energy resources in the elderly. The identification of relevant information and stimulus evaluation processes were delayed in the elderly, suggesting an additional effect of aging on structural processes. Caffeine improved performance and increased the amplitude of the N1, N2b, and P3b, in both young and old subjects. These results suggest that caffeine makes more energy resources available for task performance. The effects of aging on P3b latency were counteracted by caffeine. Other caffeine effects did not differ significantly between young and elderly subjects.

Adolescent↗
PubMed1998

Poor concentration and the ability to process information after glandular fever.

The symptom of poor concentration and the ability to process information were measured prospectively in 245 subjects three times in the 6 months after glandular fever or an ordinary upper respiratory tract infection. The effects of the different infections, having a fatigue state, a psychiatric disorder, sleep disturbance, and estimates of premorbid intelligence were also assessed. The most frequent complaint of poor concentration and the worst information processing occurred at the onset of the infection, but these problems decreased over time, and were not related to each other. Multiple regression modeling showed that higher socioeconomic class and vocabulary IQ were associated with information processing ability at all three interviews. In contrast, logistic regression modeling showed that the symptom of poor concentration was associated with the severity of general psychiatric morbidity (CIS score) followed by suffering from a fatigue state. These results suggest that the ability to process information after these particular infections is related to estimates of premorbid IQ, whereas poor concentration is related independently to both psychiatric morbidity and a fatigue state, but not the particular infection itself.

Adolescent↗
PubMed2000

Information processing in multigame environments modeling the evolution of sex via punctuated equilibria.

Uncertain environments are properly described by probability distributions which, as usual, can be collapsed or conditioned into distributions with reduced uncertainty through the processing of environmental information. Organisms which force this collapse gain evolutionary advantage by being able to employ strategies in a known environment rather than in a merely probable one. The accrued benefit gained from processing information can be precisely quantified by comparing benefits returned using distributions prior to, and after collapse, and these often large and immediate benefits can amply justify the evolutionary cost of information processing systems. More importantly, the evolution of information processing systems must necessarily occur in a predictable evolutionary sequence from less complex to more complex. Practical applications include modeling the evolution of sex modeled here as a sequence from asexual reproduction, to single gene exchange, to gene packet exchange, to same species packet exchange, and finally to sexual reproduction, sexual selection, Red Queen contests and so on. Modeling this sequence requires extensions to game theory originally designed to model a single game, to allow the simultaneous operation of many games. This extension is called a multigame environment. The dynamical evolution of the development sequence shows punctuated equilibria.

Animals↗
PubMed1985

Hypotheses on mnemonic information processing by the brain.

From a neuropsychological point of view, hypotheses are offered on the possible action of the brain in the processing of mnemonic information for long-term storage (or for retrieval of long-term stored information). It is argued that strict relations between damage of circumscribed brain structures and amnesia, as they have been suggested in recent case reports, are questionable for several reasons: Firstly, the involved regions differ between cases; secondly, there is some counter-evidence from other cases in which similar neuronal damage failed to result in lasting amnesic disturbances; thirdly, it is hypothesized that even from circumscribed brain damage it is not justifiable to conclude that the lesioned structure is solely or principally responsible for the observed mnemonic changes, as the brain acts in an integrative way, that is, on the basis of a wide-spread network of neuronal information processing. On the basis of these and related arguments, hypotheses and models on mnemonic information processing in the intact and in the damaged brain are derived. With these hypotheses even the frequent observation of interindividual differences in mnemonic information processing finds a possible explanation which is in conformity to known anatomical circuits and connections and to principles of neuronal coding.

Amnesia↗
PubMed1983

Hemispheric differences in preferred modes of information processing and the aging process.

The notion of "preferred modes of information processing" as indexed by direction of lateral eye movements during information processing, and the finding of significant declines in "fluid" as compared to "crystallized" intelligence as a function of the aging process, are related in this paper. Results suggest differential declines in information processing abilities as a function of preferred mode of information processing in older subjects. Old right movers perform significantly better than old left movers on tasks tapping both fluid and crystallized intelligence. Old left movers perform significantly more poorly on these tasks when compared to young left movers, while no differences between young and old right movers obtain. The results suggest that old persons may be more at the mercy of their preferred mode of information processing than young subjects and that those who prefer to process information in their right hemisphere are more detrimentally affected by this preference.

Adolescent↗
PubMed1998

Cortical areas with enhanced activation during object-centred spatial information processing. A PET study.

The phenomenon of object-centred unilateral neglect suggests that some neural networks process spatial information relative to reference objects. To examine object-centred information processing, we measured regional cerebral blood flow in 11 normal subjects with PET. During each PET scan, a subject viewed a sample stimulus followed by a cue on a video screen. The sample consisted of two polygons, termed 'objects', each located in a corner of the screen. A small target spot appeared in a corner of each polygon. There were two tasks: the visuomotor task and the matching-to-sample task. In the visuomotor task, the subject moved a joystick in a direction indicated by either the location of the target spot inside the object (if object-centred coordinates were operative) or the location of the object relative to the video screen (if screen-centred coordinates were operative). In the matching-to-sample task, the subject moved the joystick to report whether the relevant spatial information (object- or screen-centred) in the cue matched the sample. In both the visuomotor and the matching-to-sample task, use of object-centred (versus screen- or viewer-centred) information caused augmented activation in the inferior occipitotemporal cortex, bilaterally, in the left superior occipital gyrus, and in both the thalamus and the brainstem. In addition, in the visuomotor task such activation occurred in the right posterior parietal cortex and in the left ventral premotor, dorsolateral prefrontal and anterior supplementary motor areas. These findings suggest the involvement of the occipitotemporal cortex and a broad frontoparietal network when, as in the visuomotor task, object-centred information guides movement. When the same data underlie declarative reports, as in the matching-to-sample task, the occipitotemporal cortex remains engaged but the frontoparietal network diminishes in importance.

Adolescent↗
PubMed1985

[EEG correlates of information processing in acute and remittent schizophrenic patients].

Studies of the EEG correlates of information processing in normals indicate that different cognitive processing of information is correlated with different functional brain states. Studies in experimental psychology have demonstrated a communication and performance deficit in schizophrenics which indicates a deviation in one or more stages of information processing. Accordingly it can be hypothesized that the functional brain states as manifested in the EEG during information processing in schizophrenics are different from these states in normals or former schizophrenics. The paper tested this hypothesis in drug-free acute and former schizophrenics, neurotics and normals. The results indicate 1) that acute schizophrenics show a deviant electrical brain state during information processing; 2) former schizophrenics in a good clinical remission have electrical brain states during information processing which in some aspects are normalised, and in other aspects still differ from these states in normals and neurotics. The importance of these physiological findings for the assessment of the efficacy of the biological and psychological treatments in schizophrenia is discussed.

Alpha Rhythm↗
PubMed1993

Information processing and attention dysfunctions in schizophrenia.

Abnormalities of information processing have played a central role in understanding schizophrenia since the time of Kraepelin and Bleuler. Clearly, schizophrenia spectrum patients have profound problems focusing attention on salient cues and overcoming the disrupting effects of distracting stimuli. Theoretically, such patients are rendered vulnerable to stimulus inundation, cognitive fragmentation, and thought disorder induced by this inability to adequately process self-generated cognitive cues and stimuli from the complex world that surrounds us. Adding to the strength of such theories, investigators have made considerable progress in clarifying the functional significance and neurobiological basis of information-processing/attentional dysfunctions. This article focuses on our understanding of information-processing/attentional dysfunctions in schizophrenia. The relevant material will be presented in four parts: (1) an overview; (2) a review of specific, conceptual issues in information-processing research of the group of schizophrenias, including the roles of antipsychotic medications and generalized versus specific deficits; (3) a review of 10 common techniques used to tap the information processing and attention dysfunctions of schizophrenia patients; recent advances and novel applications of these techniques in "boundary" populations such as high-risk children and schizotypal patients are discussed and psychopharmacological probes, animal models, and basic strategies are also reviewed; and (4) an integration and suggestions for future directions in information-processing/attention research in schizophrenia. Overall, information-processing research provides an important viewpoint from which we can understand the group of schizophrenias.

Attention↗
PubMed2001

Information processing in dendrites II. Information theoretic complexity.

In the companion paper, we established a rationale for exploring the general principles of dendritic processing using a class of Boolean functions-the Multi-Cube Units (MCUs). Here, we use this approach to further characterise dendritic processing using ideas from information theory and studies in complexity. The starting point is a novel decomposition of a Boolean function's total mutual information (between input variables and the output). Each component of the decomposition is a mutual information measure with respect to a single input, conditioned on a subset of the remaining inputs. We call this decomposition the information spectrum and conceive of it as a re-representation of the function in the information domain. Furthermore, the information spectrum of a Boolean function may be assigned a complexity value using the approximate entropy introduced by Pincus (Pincus, S. M. (1991). Approximate entropy as a measure of system complexity. Proc. Natl. Acad. Sci. USA, 88, 2297-2301). Using Monte Carlo methods, we provide evidence that the information spectral complexity of MCUs is larger than that of any other class of Boolean function. We explain this phenomenon in terms of information flow through the 2-stage MCU architecture. Under our modelling assumptions, the implication for biological neural processing is that dendrites implement functions that have maximal information spectral complexity with respect to the class of multivariate functions from which they are drawn.

Animals↗