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 883 records · Page 49Linked to original sources
PubMed1998

Current theories of neuronal information processing performed by Ca2+/calmodulin-dependent protein kinase II with support and insights from computer modelling and simulation.

Ca2+/calmodulin-dependent protein kinase II (CaMKII) is concentrated in brain, and is particularly enriched in synaptic structures where it comprises 20-50% of all proteins. The abundant nature of CaMKII and its ability to phosphorylate a wide range of substrate proteins, including itself, earmarks it as a protein kinase that may have a vital role in neuronal information processing and memory. A computer model of CaMKII is investigated that incorporates recent findings about the geometrical arrangement of subunits, the mechanism of Ca(2+)-dependent subunit activation, and Ca(2+)-independent autophosphorylation. The model is framed as a system of nonlinear differential equations. It is demonstrated numerically that (1) CaMKII is tuned to be activated by stimulation protocols associated with the induction of long-term potentiation; (2) the observed slow dissociation of trapped Ca2+/calmodulin may require the autonomy site to be protected from dephosphorylation; and (3) Ca(2+)-independent kinase activity is expressed in a manner akin to a graded switch. The model validates current theories concerning how CaMKII may be a Ca2+ pulse frequency detector, a molecular switch, or a mediator of the threshold for long-term synaptic plasticity.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1976

Information processing vs visual attention during incidental learning.

The relationship between attention and incidental learning during discrimination training was studied in 30 children, aged 10 to 11. A polymetric eye-movement recorder measured direct visual attention. Consistent with previous findings, recall of incidental stimuli was greatest during the initial and terminal stages of intentional learning. Contrary to previous explanations, however, visual attention to incidental stimuli was not related to training. While individual differences in attention to incidental stimuli were predictive of recall, attention to incidental stimuli was not related to level of training. Results suggested that changes in higher order information processing rather than direct visual attention were responsible for the curvilinear learning of incidental stimuli during intentional training.

Attention↗
PubMed2003

An information-processing model of the BOLD response in symbol manipulation tasks.

Two imaging experiments were performed--one involving an algebraic transformation task studied by Anderson, Reder, and Lebiere (1996) and the other an abstraction symbol manipulation task studied by Blessing and Anderson (1996). ACT-R models exist that predict the latency patterns in these tasks. These models require activity in an imaginal buffer to represent changes to the problem representation, in a retrieval buffer to hold information from declarative memory, and in a manual buffer to hold information about motor behavior. A general theory is described about how to map activity in these buffers onto the fMRI blood oxygen level dependent (BOLD) response. This theory claims that the BOLD response is integrated over the duration that a buffer is active and can be used to predict the observed BOLD function. Activity in the imaginal buffer is shown to predict the BOLD response in a left posterior parietal region; activity in the retrieval buffer is shown to predict the BOLD response in a left prefrontal region; and activity in the manual buffer is shown to predict activity in a motor region. More generally, this article shows how to map a large class of information-processing theories (not just ACT-R) onto the BOLD response and provides a precise interpretation of the cognitive significance of the BOLD response.

Brain↗
PubMed1997

Changes in some psychophysiological parameters in speech information processing under masking noise effect.

The aim of the present work was to study the influence of masking broad-band (white), impulse and interrupted noise with intensities LAeq 60 and 90 dB(A) on the execution of some psychophysiological tasks. The following parameters were studied: pulse frequency and variation, breathing frequency and variation, vascular tone etc. The psychological tasks model different parts of the operators' activity and include: conduction of mathematical calculations at datum speed; test related to the information processing; complex optional task supplied by Piorkovski's device. After statistical processing of results by Student-Fischer's t test and monofactor dispersion analysis it was established that the masking noise effect was more strongly expressed in the execution of psychophysiological tasks connected with the main memory. Of all tested physiological parameters the changes in the peripheral circulation, expressed in elevated vascular tone of peripheral blood vessels, were the most significant.

Adult↗
PubMed1992

Effects of acute subcutaneous nicotine on attention, information processing and short-term memory in Alzheimer's disease.

This single-blind, placebo controlled study reports on the effects of administering three acute doses of nicotine (0.4, 0.6 and 0.8 mg) subcutaneously to a group of Alzheimer's disease (DAT) patients (n = 22), young adult controls (n = 24), and normal aged controls (n = 24). The study extends our previous findings obtained using smaller groups of subjects. Drug effects were examined on three computerised tests: the first measuring rapid visual information processing, sustained visual attention and reaction time (RVIP task); a delayed response matching to location-order task measuring sustained visual attention and visual short-term memory (DRMLO task); and a finger tapping test measuring simple reaction time (FT task). The critical flicker fusion test (CFF) was used as a measure of perception and the WAIS digit span forwards (DS), of auditory short-term memory. Tests were graded in difficulty, titrated to avoid floor and ceiling effects so that meaningful, direct comparisons between groups could be made. Nicotine significantly improved sustained visual attention (in both RVIP and DRMLO tasks), reaction time (in both FT and RVIP tasks), and perception (CFF task--both ascending and descending thresholds). Nicotine administration did not improve auditory and visual short-term memory. There were no consistent, overall patterns of difference in performance between smokers and non-smokers in the control groups, or between males and females in any group. Despite the absence of change in memory functioning, these results demonstrate that DAT patients have significant perceptual and visual attentional deficits which are improved by nicotine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Change of mechanical parameters as a possible means for information processing by the neuron].

The depolarization of neuronal membrane during cAMP injection by means of both iontophoresis and pressure was shown. Neuron blowing by solutions without cAMP gave the similar effect. The effect of cAMP can be differentiated in the presence of phosphodiesterase inhibitors. The experiments support the hypothesis that cyclic nucleotides and mechanical excitation interact with intraneuronal mechanical analog device (MAD) which consists of microtubules and microfilaments. It is supposed that MAD controlled by cyclic nucleotides and Ca2+ is the intraneuronal information processing system.

Animals↗
PubMed2007

fMRI study of effort and information processing in a working memory task.

It is unclear how effort translates into brain function. In this study we endeavored to identify the activity in a working memory task that is related to the allocation of mental resources. Such activity, if present, would be a likely candidate to explain how effort works in terms of brain function. Eleven healthy participants performed a Sternberg task with a memory-set of one, three, or five consonants in an fMRI study. Probe stimuli were either one consonant or one digit. We expected digits to be processed automatically and consonants to require working memory. Because the probe type was unpredictable and subjects had to respond as fast as possible, we expected subjects to allocate mental resources on the basis of the memory-set size, not the probe type. Accordingly, we anticipated that activity in regions involved in effort would be a function of the size of the memory-set, but independent of the type of probe. We found that the reaction-time for digits increased in line with our expectation of automatic processing and the reaction time for letters increased in line with our expectation of controlled processing. fMRI revealed that activity in the right ventral-prefrontal cortex changed as a function of effort. The ventral anterior cingulate cortex and hypothalamus showed reduced activity as a function of effort. Activity in regions regarded as pivotal for working memory (among others, the left dorsolateral prefrontal cortex, anterior cingulate cortex) appeared to be predominantly related to information processing and not involved in effort.

Adult↗
PubMed1997

[EEG correlates of different methods of information processing in response selection].

The lateralized readiness potential as a measure of response tendencies has become a relevant method in experimental psychology within the last decade. This measure delivers information about response preparation long before the overt response. Applying the method of measuring event-related lateralizations (ERL) of the EEG to posterior sites, correlates of processing of spatial information and of response selection have been found. The present study investigated the topographical distribution of asymmetries at the moment of response selection. Response selection was assumed to be reflected in a discrete peak of parietal asymmetries. At this time point two distinct topographies were found that might reflect two different types of information processing. If response selection was based on spatial information a parieto-occipital maximum was found. In contrast, if centrally presented symbolic stimuli were used for response selection, lateralizations were largest at central (motor areas) and at parietal sites.

Adult↗
PubMed2006

Adaptability and the integration of computer-based information processing into the dynamics of organizations.

The structure of a system influences its adaptability. An important result of adaptability theory is that subsystem independence increases adaptability [Conrad, M., 1983. Adaptability. Plenum Press, New York]. Adaptability is essential in systems that face an uncertain environment such as biological systems and organizations. Modern organizations are the product of human design. And so it is their structure and the effect that it has on their adaptability. In this paper we explore the potential effects of computer-based information processing on the adaptability of organizations. The integration of computer-based processes into the dynamics of the functions they support and the effect it has on subsystem independence are especially relevant to our analysis.

Electronic Data Processing↗
PubMed2006

Influence of major antiepileptic drugs on attention, reaction time, and speed of information processing: results from a randomized, double-blind, placebo-controlled withdrawal study of seizure-free epilepsy patients receiving monotherapy.

PURPOSE: All major antiepileptic drugs (AEDs) have been reported to be associated with cognitive side effects. Uncertainty exists regarding the degree of cognitive effects, primarily because many studies do not adhere to basic standards of methodology and design. The aim of this study was to assess the effect of discontinuation of AEDs in patients receiving monotherapy on measures of attention, reaction time, and speed of information processing. METHODS: The 150 subjects who had been seizure free>2 years on drug monotherapy went through a randomized, double-blind, placebo-controlled study. Each patient was included for 12 months or until seizure relapse. Cognitive function was assessed with the California Computerized Assessment Package at baseline and 7 months after discontinuation. RESULTS: The major finding in this study is that discontinuation of major AEDs significantly improved performance on tests that require complex cognitive processing under time pressure. The difference in speed of cognitive processing between the two groups on these tasks was between 24 to 43 ms. Simple tasks of attention and reaction time revealed no significant differences between the discontinuation group and the nondiscontinuation group. Most of the subjects in the study were medicated with carbamazepine (CBZ) and valproate (VPA). The outcome of discontinuation of CBZ was similar to the outcome for the total study population, whereas withdrawal of VPA revealed only a nonsignificant tendency in the same direction. CONCLUSIONS: The results suggest that seizure-free epilepsy patients receiving monotherapy can obtain improvement in cognitive function if they discontinue AED treatment.

Adolescent↗
PubMed2006

Sequence of information processing for emotions based on the anatomic dialogue between prefrontal cortex and amygdala.

The prefrontal cortex and the amygdala have synergistic roles in regulating purposive behavior, effected through bidirectional pathways. Here we investigated the largely unknown extent and laminar relationship of prefrontal input-output zones linked with the amygdala using neural tracers injected in the amygdala in rhesus monkeys. Prefrontal areas varied vastly in their connections with the amygdala, with the densest connections found in posterior orbitofrontal and posterior medial cortices, and the sparsest in anterior lateral prefrontal areas, especially area 10. Prefrontal projection neurons directed to the amygdala originated in layer 5, but significant numbers were also found in layers 2 and 3 in posterior medial and orbitofrontal cortices. Amygdalar axonal terminations in prefrontal cortex were most frequently distributed in bilaminar bands in the superficial and deep layers, by columns spanning the entire cortical depth, and less frequently as small patches centered in the superficial or deep layers. Heavy terminations in layers 1-2 overlapped with calbindin-positive inhibitory neurons. A comparison of the relationship of input to output projections revealed that among the most heavily connected cortices, cingulate areas 25 and 24 issued comparatively more projections to the amygdala than they received, whereas caudal orbitofrontal areas were more receivers than senders. Further, there was a significant relationship between the proportion of 'feedforward' cortical projections from layers 2-3 to 'feedback' terminations innervating the superficial layers of prefrontal cortices. These findings indicate that the connections between prefrontal cortices and the amygdala follow similar patterns as corticocortical connections, and by analogy suggest pathways underlying the sequence of information processing for emotions.

Amygdala↗
PubMed1996

Stimulus-driven facilitation and inhibition of visual information processing in environmental and retinotopic representations of space.

This contribution deals with two major issues on visual/spatial attention. One is the issue of facilitation and inhibition; that is, under what conditions facilitatory modulation occurs, and under what other conditions inhibitory modulation occurs. The other issue is that of spatial representation; in what type of spatial representation do these modulations occur, retinotopic or environmental? In the first half of this article, We review the latest studies employing various psychophysical measures to assess spatially-selective modulation of visual information processing. We also summarize our latest results on reaction time, indicating a dissociation of two visual functions, detection/orientation and feature discrimination. Based on these chunks of knowledge, we raise a questions about the spatial coordinate system in which the facilitatory and/or inhibitory modulations occur. We then provide results of two reaction-time experiments which partly answer the question.

Attention↗
PubMedDate not supplied

Basic information processing and higher cognition: does the mammalian cerebral cortex deal with them at different hierarchical levels?

1. The primary visual cortex has been generally considered as a feature processing area where the neurons code for basic stimulus attributes, such as orientation, colour and direction of movement. Higher cognitive functions, such as attention and memory, were believed to be mediated by extrastriate regions at higher levels in a hierarchy of visual areas. However, the experiments reported here suggest that the function of the primary visual cortex is more than basic information processing in at least two respects. 2. First, significant modulation of visual responses occur in the primary visual cortex (V1) of the monkey depending upon attentional factors. There appears to be a feedback to V1 from extrastriate regions that facilitates neuronal responses in areas of attention and suppresses responses in other regions of the visual field. 3. Second, one would expect a region that is concerned with coding basic stimulus features to be rather resistant to plastic changes, as cells need to be reliable feature detectors for meaningful behaviour by the organism. However, the experiments on anaesthetized cats reported here show that a subset of neurons in visual area 17 of the cat have a potential for synaptic plasticity. Their response properties can undergo long-term changes under certain circumstances. To induce these changes, specific visual stimuli were combined with iontophoretic administration of NMDA and the GABA antagonist, bicuculline, which are believed to provide the molecular milieu for long-term potential and long-term depression.

Animals↗
PubMed2005

Information processing in the mammalian olfactory system.

Recently, modern neuroscience has made considerable progress in understanding how the brain perceives, discriminates, and recognizes odorant molecules. This growing knowledge took over when the sense of smell was no longer considered only as a matter for poetry or the perfume industry. Over the last decades, chemical senses captured the attention of scientists who started to investigate the different stages of olfactory pathways. Distinct fields such as genetic, biochemistry, cellular biology, neurophysiology, and behavior have contributed to provide a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. So far, the combination of these approaches has been most effective at the cellular level, but there are already signs, and even greater hope, that the same is gradually happening at the systems level. This review summarizes the current ideas concerning the cellular mechanisms and organizational strategies used by the olfactory system to process olfactory information. We present findings that exemplified the high degree of olfactory plasticity, with special emphasis on the first central relay of the olfactory system. Recent observations supporting the necessity of such plasticity for adult brain functions are also discussed. Due to space constraints, this review focuses mainly on the olfactory systems of vertebrates, and primarily those of mammals.

Animals↗
PubMed1997

Verbal knowledge and speed of information processing as mediators of age differences in verbal fluency performance among older adults.

Age-related declines in verbal fluency among a large sample of older adults were investigated. Background variables, verbal knowledge, and speed of processing were examined as predictors of verbal fluency and as mediators of age effects. As expected, age-related declines were greater on the excluded letter fluency task than on the initial letter fluency task. Verbal knowledge was a better predictor of initial letter fluency than speed of processing, whereas the reverse was true for excluded letter fluency. However, speed of processing accounted for more of the age-related variance in both fluency measures than the other predictors. There was no evidence of verbal knowledge compensating for age-related declines in verbal fluency. Results suggest that verbal fluency performance is well maintained in late life and that any age-related decline appears to be mainly due to declines in speed of information processing.

Aged↗
PubMed2006

Information processing of sexual abuse in elders.

Sexual abuse is considered to be a pandemic contemporary public health issue, with significant physical and psychosocial consequences for its victims. However, the incidence of elder sexual assault is difficult to estimate with any degree of confidence. A convenience sample of 284 case records were reviewed for Post-Traumatic Stress Disorder (PTSD) symptoms. The purpose of this paper is to present the limited data noted on record review on four PTSD symptoms of startle, physiological upset, anger, and numbness. A treatment model for information processing of intrapsychic trauma is presented to describe domain disruption within a nursing diagnosis of rape trauma syndrome and provide guidance for sensitive assessment and intervention.

Aged↗
PubMed2004

Firing rates and dynamic correlated activities of ganglion cells both contribute to retinal information processing.

In the present study, the electrical activities of paired retinal ganglion cells, under full field light stimuli with a variety of chromatic configurations, were recorded from a small functioning piece of retina using multi-electrode array (MEA). Neurons that had increased firings at light-ON and -OFF transients and did not show color-opponent properties were investigated. Single neuronal analysis showed that firing rate of each individual neuron was dependent on the intensity of illumination. Multi-unit analyses revealed that adjacent neurons often fired in synchrony in response to light stimulation. However, in some cases, the strength of correlation between the paired neurons was higher when the retina was exposed to red or green light, and the correlation was attenuated when yellow or white light was given. This seems to suggest that the ensemble activity of non-color-opponent ganglion cells might partly participate in color-information processing, with the red- and green-pathway inputs influencing each other. Such arrangement reflects principle of parsimony: the firing rates of single neuron represent the luminance intensity, and the correlated activities may tell the brain about the color information.

Action Potentials↗
PubMed2002

Facilitation of local information processing in the attentional blink as indexed by the shooting line illusion.

Perception of the second of two rapidly sequential targets is impaired if the temporal lag between them is relatively short. This attentional blink (AB) is said to occur because the first target preoccupies attentional resources, leading to a shortage of attention for, and subsequent failure of judgement of, the second target. In the present study, we examined whether the attention which is preoccupied by the first target carries the common characteristic of spatial attention, that is local facilitation of information processing. To index the facilitation, we presented an attention-sensitive probe known as the shooting line illusion in which observers see a progressively drawn line from the attended end to the other. We found that illusory motion was perceived to emanate from the end where the first target was presented. This result demonstrates the inherently spatial nature of attention, even when it is defined by temporal and symbolic variables.

Adult↗