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PubMed2004

Analysis of the morphological substrate for information processing in the pallidal nuclear complex of the dog brain in terms of the organizational characteristics of its afferent projections.

Axonal transport of retrograde markers was used to study the distribution of the afferent projections of the nuclei of the pallidal complex (the globus pallidus, the entopeduncular nucleus, and the ventral pallidum) from functionally diverse cortical and subcortical structures (cortical fields, substantia nigra, ventral tegmental field, and thalamus) in the dog brain. The results were used to analyze the morphological aspects both of the functional heterogeneity of the pallidum and integrative information processing, which underlie the mechanisms of adaptive behavior.

Adaptation, Psychological↗
PubMed1998

The Feigenbaum scenario as a model of the limits of conscious information processing.

The Feigenbaum scenario of the mathematical period doubling sequence from order to deterministic chaos has led to new insights about the nonlinear dynamics of a wide variety of physical and biological systems. Multiple realms from purely mechanical systems, fluid dynamics and weather to the patterns of biological growth and the dynamic of the heart, hormone and brain rhythms have been found to exhibit aspects of the Feigenbaum period doubling sequence. We explore the possibility that the Feigenbaum scenario can be extended to experiences of sensation, perception and human cognition as well. We also review the empirical data that supports the view that the Feigenbaum scenario of the period doubling sequence may portray an important limit in conscious information processing. We conclude that a major function of consciousness may be to transform the nonlinear, irrational and difficult to predict dynamics of unconscious nature into the more linear, rational and predictable psychodynamics that make human experience and social life possible.

Cognition↗
PubMedDate not supplied

Information processing with frequency-dependent synaptic connections.

The efficacy of synaptic transmission between two neurons changes as a function of the history of previous activations of the synaptic connection. This history dependence can be characterized by examining the dependence of transmission on the frequency of stimulation. In this framework synaptic plasticity can also be examined in terms of changes in the frequency dependence of transmission and not merely in terms of synaptic strength which constitutes only a linear scaling mechanism. Recent work shows that the frequency dependence of transmission determines the content of information transmitted between neurons and that synaptic modifications can change the content of information transmitted. Multipatch-clamp recordings revealed that the frequency dependence of transmission is potentially unique for each synaptic connection made by a single axon and that the class of pre-postsynaptic neuron determines the class of frequency dependence (activity independent), while the unique activity relationship between any two neurons could determine the precise values of the parameters within a specific class (activity dependent). The content of information transmitted between neurons is also formalized to provide synaptic transfer functions which can be used to determine the role of the synaptic connection within a network of neurons. It is proposed that deriving synaptic transfer functions is crucial in order to understand the link between synaptic transmission and information processing within networks of neurons and to understand the link between synaptic plasticity and learning and memory.

Algorithms↗
PubMed1997

Traumatic intrusive imagery as an emotional memory phenomenon: a review of research and explanatory information processing theories.

Intrusive imagery is both a common response to trauma and a hallmark of Posttraumatic Stress Disorder. However, its features and underlying mechanisms have not been reviewed systematically. This paper delineates the characteristics of intrusions and critically reviews the literature, conceptualizing intrusive imagery as an emotional memory phenomenon. This approach integrates otherwise separate research arenas in emotion and memory, psychobiology, pharmacology, and physiology, which converge to suggest that intrusive imagery is driven primarily by affective arousal and sympathetic nervous system reactivity. These basic and applied research findings are addressed directly by three information processing theories, which are reviewed and critiqued for their heuristic value in accounting for intrusions. Directions for research, treatment, and assessment are presented.

Adaptation, Psychological↗
PubMed1983

[Relationship between verbal information processing and CNV pattern: effects of the numbers of letter and word upon CNV components].

The present experiment was designed to examine the effects of the numbers of letter and word upon CNV components, by using a modified Sternberg's paradigm. The results indicated that CNV amplitude decreased and CNV rising time increased as a function of the numbers of letter and word. CNV resolution time increased with the number of word, while no increase in resolution time was observed with the number of letter. These findings were discussed in relation to recent information processing models.

Adolescent↗
PubMed1980

Early auditory information processing in schizophrenia: a preliminary report.

Numerous theorists have postulated that incoming environmental information is altered with schizophrenic illness, due to aberrant sensory processing in subcortical systems. Brainstem evoked potential recordings were obtained during passive auditory information processing in groups of chronic schizophrenic patients, affective disordered patients, and normals. These neuroelectric measures of brainstem and midbrain functioning suggest that the three study groups do not statistically differ in terms of latency characteristics. It is noteworthy, however, that a particular subset of chronic schizophrenic patients yielded latency characteristics falling more than one standard deviation from the total population mean under all experimental conditions.

Adolescent↗
PubMed2000

Unfixing the fixed pie: a motivated information-processing approach to integrative negotiation.

Negotiators tend to believe that own and other's outcomes are diametrically opposed. When such fixed-pie perceptions (FPPs) are not revised during negotiation, integrative agreements are unlikely. It was predicted that accuracy motivation helps negotiators to release their FPPs. In 2 experiments, accuracy motivation was manipulated by (not) holding negotiators accountable for the manner in which they negotiated. Experiment 1 showed that accountability reduced FPPs during face-to-face negotiation and produced more integrative agreements. Experiment 2 corroborated these results: Accountable negotiators revised their FPPs even when information exchange was experimentally held constant. Experiment 2 also showed that accountability is effective during the encoding of outcome information. Negotiators appear flexible in their reliance on FPPs. which is consistent with a motivated information-processing model of negotiation.

Adult↗
PubMed2006

Generating optical Schrödinger kittens for quantum information processing.

We present a detailed experimental analysis of a free-propagating light pulse prepared in a "Schrödinger kitten" state, which is defined as a quantum superposition of "classical" coherent states with small amplitudes. This kitten state is generated by subtracting one photon from a squeezed vacuum beam, and it clearly presents a negative Wigner function. The predicted influence of the experimental parameters is in excellent agreement with the experimental results. The amplitude of the coherent states can be amplified to transform our "Schrödinger kittens" into bigger Schrödinger cats, providing an essential tool for quantum information processing.

Journal Article↗
PubMed1998

A comparison of normal forgetting, psychopathology, and information-processing models of reported amnesia for recent sexual trauma.

This study assessed memories for sexual trauma in a nontreatment-seeking sample of recent rape victims and considered competing explanations for failed recall. Participants were 92 female rape victims assessed within 2 weeks of the rape; 62 were also assessed 3 months postassault. Memory deficits for parts of the rape were common 2 weeks postassault (37%) but improved over the 3-month window studied (16% still partially amnesic). Hypotheses evaluated competing models of explanation that may account for reported recall deficits. Results are most consistent with information-processing models of traumatic memory.

Adolescent↗
PubMed1990

Visual information processing of computed topographic electrical activity brain maps.

Effective display of computer-generated biomedical images draws on computer graphics and image processing, display technology and human factors, visual psychophysics and perception, cognitive psychology, and the new field of scientific data visualization. In converting from raw, acquired data to a visual display, developers need to know the limitations of the data and of the display technology. To obtain reliable inferences about the clinical or physiological state of the patient requires that the computer display be matched to the visual information-processing competence and limitations of human observers. The issues that should be considered by both developers and users of computer-based display technologies to enhance clinical performance in observation and diagnosis are surveyed with reference to electrical activity brain maps.

Brain↗
PubMed1976

Attention and information processing in schizophrenia.

The performance of 20 acute schizophrenics and 10 depressives, matched for age, verbal intelligence, and pre-morbid functioning, was assessed on a choice reaction-time card-sorting task. Stimulus and response uncertainty were varied independently, and there were two main conditions, distraction and no distraction. The schizophrenics were slower than the depressives over all the functions examined in the study. Schizophrenics were significantly more affected by increases in response uncertainty than the depressives. Although there was a tendency for the schizophrenic group to be more affected by distraction and by increasing stimulus uncertainty, these differences were not significant. There was no significant interaction between the effects of stimulus and response uncertainty, nor between the effects of distraction and stimulus uncertainty. The effects of distraction increased with increasing response uncertainty. The results are discussed in relation to two models of information processing, suggested by Broadbent (1971) and by Sternberg (1969). Such models allow a more detailed examination of the cognitive abnormalities found in schizophrenia.

Adult↗
PubMed1989

Social interaction and speed of information processing following very severe head-injury.

Eighteen adults who had suffered a very severe closed head-injury more than 18 months previously and required long-term rehabilitative support were compared with a closely matched control group. Unlike previous studies, which have reported negative personality change involving an increase in aversive behaviour, our behavioural observation data suggest that a global reduction in behavioural productivity, or negative symptomatology, characterizes social interaction by this group. This resulted in their being judged less socially skilled, less likeable and less interesting, and thus less reinforcing to interact with. Speed of information processing was specifically impaired for the closed head-injury group, although this did not correlate with global behavioural ratings of social interaction behaviour. It is suggested that low behavioural productivity may be associated with family burden, and that the low quantity of social interaction experienced by severely head-injured adults may reflect the unreinforcing nature of their interactions.

Adult↗
PubMed1993

On dopaminergic modulation of temporal information processing.

Temporal processing of durations in the range of seconds or more (i.e. time estimation) is cognitively mediated, whereas processing of brief durations in the range of milliseconds (i.e. time perception) appears to be beyond cognitive control and based on neural counting mechanisms. Although there is some evidence from animal and human studies suggesting that the internal timing mechanism underlying time perception is modulated by the effective level of brain dopamine, the findings are not conclusive. Therefore, the effects of pharmacologically induced changes in D2 receptor activity on temporal information processing were evaluated. In a double-blind design, either 3 mg of haloperidol, 150 mg of remoxipride, or placebo were administered in a single oral dose. Performance on time estimation was significantly impaired by both haloperidol and remoxipride as compared with placebo. Both drugs obviously affected cognitive mechanisms underlying temporal processing of durations in the range of seconds. On the other hand, only haloperidol produced a significant decrease in performance on time perception as compared with placebo and remoxipride, whereas the remoxipride and placebo groups did not differ significantly. The differential effects of haloperidol and remoxipride on performance on time perception suggest that D2 receptor activity in the basal ganglia may play a critical role in timing of brief durations in the range of milliseconds.

Acoustic Stimulation↗
PubMed1991

Analysis of information processing stages using event-related potentials.

The event-related potential (ERP) was recorded to identify the time epochs during which different independent variables have their effects on stages in a memory search task. Stimulus intensity, memory set size and response type were varied. For the most part, the order and timing of effects (evaluated by Principal Components Analysis of within-subjects ERP differences) were consistent with the presumed underlying stages, except for early effects of response type prior to memory set effects (suggesting precategorical target recognition). The usefulness of this type of analysis for the investigation of information processing stages is discussed.

Adult↗
PubMed1979

Intrahemispheric visual-motor information processing and cerebral functional lateralization.

A series of stimuli, words and faces, were presented tachistoscopically to 24 dextrals and 12 sinistrals. The stimuli were presented to one eye at a time and the subjects were instructed to respond to specific words or stimuli with a specific hand. The results indicate that (1) cerebral functional asymmetry is related to handedness; in the dextrals, the left hemisphere is more specialized in verbal recognition, while in the sinistrals, the right hemisphere is more specialized in recognizing non-verbal material. (2) An ipsilateral hand-and-eye combination is a valid method of measuring intrahemispheric information processing, provided that the tachistoscopically presented visual stimuli are capable of inciting specialized hemispheric function. The dominant relationship among the crossed and non-crossed visual pathways is discussed.

Adult↗
PubMed1986

Information processing deficits in anhedonia and perceptual aberration: a psychophysiological analysis.

Building on recent reports of psychophysiological deviance in two groups believed to be at risk for psychosis, the present study sought to identify corresponding cognitive deviance in these groups. Subjects defined according to Chapman's questionnaires on physical anhedonia (n = 16) and perceptual aberration (n = 16) were tested in an auditory discrimination task while brain wave and autonomic activity was monitored. Although the discrimination performance of at-risk subjects equaled that of controls (n = 16), significant group differences occurred in event-related brain potential and heart rate responses. Interpreted within an information processing model of the discrimination task, these results suggest a deficit in the use of memory templates by anhedonics, for which they can compensate if given adequate stimulus input.

Adolescent↗
PubMed1996

The human cerebellum and temporal information processing--results from a PET experiment.

Changes of cerebellar blood flow were studied in normal humans using positron emission tomography (PET). A motor driven peg marked pairs of lines on subjects' right hands at different velocities. Subjects had to decide whether the second line was marked slower or faster than the first. Estimation of velocity (compared with control, i.e. presentation of lines at constant velocity) led to increases of regional cerebral blood flow (rCBF) in the left cerebellar hemisphere and vermis. Presentation of lines at constant velocity (compared with rest) activated the right cerebellar hemisphere. We conclude that the cerebellum is involved in temporal information processing even in the absence of motor output. This process can be separated from mere presentation of somatosensory stimuli.

Adult↗
PubMed1989

Information-processing skill and speech-reading.

Two measures of verbal inference-making ability (a sentence-completion test; SCT, and a word-completion test; WCT) and one test of working memory capacity were examined in relation to speech-reading performance. The results demonstrated that the SCT proved to be the only variable that was substantially correlated with speech-reading performance. The contribution from working memory capacity and the WCT test to speech-reading is mainly via their contribution to the SCT. Skilled SCT-performance was particularly tied to speech-reading conditions with a low level of contextual information accompanying the speech-reading task. No general or specific difference was found between hearing-impaired and normally-hearing subjects in the speech-reading test, thus indicating that speech-reading performance cannot be predicted by factors related to the hearing-impairment. Rather, information-processing skills seem to be decisive.

Adult↗