[Example of the use of information processing for the study of the function of 70 renal allotransplants].
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Azathioprine↗
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Stepping out of the box: information processing in the neural networks of the basal ganglia.
The Albin-DeLong 'box and arrow' model has long been the accepted standard model for the basal ganglia network. However, advances in physiological and anatomical research have enabled a more detailed neural network approach. Recent computational models hold that the basal ganglia use reinforcement signals and local competitive learning rules to reduce the dimensionality of sparse cortical information. These models predict a steady-state situation with diminished efficacy of lateral inhibition and low synchronization. In this framework, Parkinson's disease can be characterized as a persistent state of negative reinforcement, inefficient dimensionality reduction, and abnormally synchronized basal ganglia activity.
Animals↗
Hadamard NMR spectroscopy for two-dimensional quantum information processing and parallel search algorithms.
Hadamard spectroscopy has earlier been used to speed-up multi-dimensional NMR experiments. In this work, we speed-up the two-dimensional quantum computing scheme, by using Hadamard spectroscopy in the indirect dimension, resulting in a scheme which is faster and requires the Fourier transformation only in the direct dimension. Two and three qubit quantum gates are implemented with an extra observer qubit. We also use one-dimensional Hadamard spectroscopy for binary information storage by spatial encoding and implementation of a parallel search algorithm.
Algorithms↗
Information processing in the taste system of primates.
1. Analysis of the activity of single neurones in the gustatory pathways in primates (cynomolgus monkeys) shows that the tuning of neurones to the four prototypical stimuli 1.0 mol l-1 glucose, 1.0 mol l-1 NaCl, 0.001 mol l-1 quinine-HCl and 0.01 mol l-1 HCl becomes sharper as information progresses through the taste system from the first central relay in the brainstem, the nucleus of the solitary tract, via the thalamus to the primary taste cortex in the frontal operculum and insula to reach a secondary cortical taste area in the caudolateral orbitofrontal cortex. 2. Feeding monkeys to satiety with glucose has no effect on the gustatory responses of neurones in the nucleus of the solitary tract, the frontal opercular taste cortex or the insular taste cortex, but decreases the magnitude of the neuronal responses of orbitofrontal cortex taste neurones which respond to glucose to zero. 3. The responses of orbitofrontal cortex taste neurones decrease to foods on which the monkey is fed to satiety, but continue to foods which have not just been eaten, that is, they reflect sensory-specific satiety, the phenomenon in which the pleasantness of the taste of a food and its acceptability, but not those of of other foods, is decreased by eating that food to satiety. 4. It has been found that the orbitofrontal cortex taste area or areas receives inputs from different modalities: single neurones with unimodal responses to taste (47%), olfactory (12%) and visual (10%) stimuli are found in close proximity to each other. Moreover, some single neurones show multimodal convergence, responding, for example, to taste and visual inputs (17%), taste and olfactory inputs (10%), and olfactory and visual inputs (4%). Some of these multimodal single neurones have corresponding sensitivities in the two modalities: they respond best to sweet tastes (e.g. 1 mol l-1 glucose), and respond more in a visual discrimination task to the visual stimulus which signifies sweet fruit juice than to that which signifies saline; or they respond to sweet taste and, in an olfactory discrimination task, to fruit juice odour. These results suggest that multimodal representations are formed in the orbitofrontal cortex secondary and related taste areas.(ABSTRACT TRUNCATED AT 400 WORDS)
Afferent Pathways↗
Auditory information processing by normal and C. V. A. hemiplegic adults.
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Acoustic Stimulation↗
Studies of information processing in sleep.
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Acoustic Stimulation↗
Information processing during face recognition: the effects of familiarity, inversion, and morphing on scanning fixations.
Where we make ocular fixations when viewing an object likely reflects interactions between 'external' object properties and internal 'top-down' factors, as our perceptual system tests hypotheses and attempts to make decisions about our environment. These scanning fixation patterns can tell us how and where the visual system gathers information critical to specific tasks. We determined the effects of the internal factors of expertise, experience, and ambiguity on scanning during a face-recognition task, in eight subjects. To assess the effects of expertise, we compared upright with inverted faces, since it is hypothesized that inverted faces do not access an orientation-dependent face-expert processor. To assess the effects of experience, we compared famous with novel faces, as famous faces would have stronger internal representations than anonymous ones. Ambiguity in matching seen and remembered faces was manipulated with morphed faces. We measured three classes of variables: (i) total scanning time and fixations; (ii) the spatial distribution of scanning; and (iii) the sequence of scanning, using first-order Markov matrices for local scan structure and string editing for global scan structure. We found that, with inverted faces, subjects redistributed fixations to the mouth and lower face, and their local and global scan structure became more random. With novel or morphed faces, they scanned the eyes and upper face more. Local scan structure was not affected by familiarity, but global scan structure was least random (most stereotyped) for novel upright faces. We conclude that expertise (upright faces) leads to less lower-face scanning and more predictable global patterns of information gathering. Experience (famous faces) leads to less upper-face scanning and more idiosyncratic global scan structures, suggesting a superseding influence of facial memories. With morphed faces, subjects return to the upper face to resolve ambiguity, implying a greater importance of this region in face recognition.
Adult↗
Brain architecture and mechanisms that underlie language: an information-processing analysis.
A neural network model for naming visual objects and their attributes, and understanding certain simple types of sentences has been presented. The model is based on neural processes rather than linguistic or symbolic constructs. The following are the major structural features of the model: 1. Memory stores are associative networks that perform an analysis of their inputs in real time. This analysis converts the input pattern into a "recognition pattern" that depends on the specific stored information and its location in the store. 2. The naming store is an analyzer network that converts the sensory encoding of a sentence into a "sentence pattern". The sentence pattern is obtained by averaging the recognition signals from several memory locations in the naming store. Because of the organization of words in the naming store, sentence patterns are an encoding of the structure of the sentences. 3. The sentence store is an associative memory store that recognizes sentence patterns and associates with each one an "instruction sequence" or "program" that specifies how the system should respond to the sentence. It is the enabling of access to this "program" that constitutes "understanding." Sentences are understood in real time, without the explicit grammatical analysis that is usual in sentence-understanding systems. Understanding a sentence involves two functionally distinct processes: (1) associating with its sentence pattern an instruction sequence that specifices what to do in order to generate an appropriate response to the sentence matching that pattern: for example, to look in the visual field for an object, determine its location, and so on, and (2) analysis of the tokens in the sentence that indicate specific attributes or entities to look for or determine.
Association↗
Visual information processing: topography of brain electrical activity.
Multichannel recordings allow the non-invasive assessment of the electrical fields of the brain. Topographical analysis of EEG and EPs should not be restricted to the qualitative graphical display of maps at many time points instead of time series at many recording points. It is mandatory that quantitative methods are applied to EEG and evoked potential data in order to extract relevant information from such series of maps. For spontaneous EEG data the spatial analysis of frequency bands is of major interest while evoked potential fields are analyzed in terms of latencies and amplitudes of individual components. The computation of global field power, global dissimilarity as well as the location of potential maxima, minima or centroids enable a meaningful data reduction and the statistical evaluation of the effects of different experimental conditions and the comparison of various clinical populations. In a similar way multivariate statistical techniques may be employed in order to detect characteristic potential field configurations. Topographical methods to analyze brain electrical activity are illustrated with multichannel data evoked by localized visual stimuli and by stereoscopic stimulation as well as with evoked potential data obtained during perceptual learning experiments.
Brain↗
The relationship between cognitive status and visual information processing.
The present investigation involved an examination of susceptibility to visual masking of older adults displaying evidence of Alzheimer's disease and healthy, cognitively intact older adults. Results indicated that the cognitively impaired group was more susceptible to the perceptual interference of a visual mask than was the cognitively intact group. In addition, the impaired group was found to be particularly susceptible to masking by a visual pattern (which had similar figural characteristics to target stimuli) as compared to masking by random noise (which had figural characteristics unrelated to the target). Finally, susceptibility to masking was found to be negatively correlated with performance on the Information subtest of the Wechsler Adult Intelligence Scale-Revised and with rated level of cognitive functioning. It was concluded that this pattern of results represents an acceleration of changes in perceptual processing typically associated with normal human aging.
Aging↗
Post-training medial septal stimulation improves spatial information processing in BALB/c mice.
The experiment reported here was designed to highlight the effects of medial septal nucleus electrical stimulation on memory processes. To that end, we have used a learning task carried out in a 4-hole board in which animals were successively presented with the location of 2 baited holes. Under these conditions, the consequence of a weak stimulation (30 microA peak to peak, 80 s in duration) applied 30 s after acquisition of these 2 separate spatial informations was assessed on a retention test 24 h later. The results indicated that performance of stimulated animals was improved by medial septal stimulation as shown by an increase in the time duration of exploration of the second previously baited hole. However, post-training stimulation also produced a significant avoidance of the first previously baited hole not observed in the control groups. These results suggest that medial septal stimulation improves retroactive inhibition involved in working memory processes, thus leading to better retention of this kind of learning situation.
Animals↗
Clubgoers and their trendy cocktails: implications of mixing caffeine into alcohol on information processing and subjective reports of intoxication.
Alcoholic drink preferences in college students have made an interesting shift recently, with trends in consumption leaning toward caffeinated alcohol in various forms (e.g., Red Bull and vodka or caffeinated beers such as Anheuser-Busch's B-to-the-E). Despite the dramatic rise in popularity of these beverages, little research has examined the combined effects of alcohol and caffeine, which is problematic for adequately informing the public about the risk or lack thereof of these drinks. The purpose of this study was to directly investigate the acute effects of alcohol and caffeine, alone and in combination, on well-validated measures of cognitive performance and subjective intoxication in social drinkers. Participants (N = 12) performed a psychological refractory period task that measured dual-task interference as the prolonged reaction time to complete the 2nd of 2 tasks performed in close temporal sequence. Performance was tested under 2 active doses and 1 placebo dose of caffeine (0.0 mg/kg, 2.0 mg/kg, and 4.0 mg/kg) in combination with 1 active dose and 1 placebo dose of alcohol (0.0 g/kg and 0.65 g/kg). As expected, alcohol impaired task performance by increasing dual-task interference and increasing errors. The coadministration of caffeine counteracted the effects of alcohol on interference but had no effect on the degree to which alcohol increased errors. Subjective measures of intoxication showed that coadministration of caffeine with alcohol reduced participants' perceptions of alcohol intoxication compared with administration of alcohol alone. The results highlight the complexity of drug interactions between alcohol and caffeine.
Acoustic Stimulation↗
Information processed from brief visual displays by learning-disabled boys.
The spans of apprehension of learning-disabled and normal boys were compared by means of a forced-choice letter-recognition task involving tachistoscopic exposures of letter displays. This task provides an estimate of the span that is relatively insensitive to memory or motivational influences. In Experiment 1, the spans of learning-disabled and normal boys were compared under 4 information conditions: with no noise letters present or with 2, 4, or 8 noise letters present. Experiments 2-4 examined 3 possible interpretations of the deficit in the span of apprehension observed for learning-disabled boys in Experiment 1. In Experiment 2, the possibility that the noise letters were more distracting for learning-disabled boys was examined by varying the amount of physical similarity and redundancy between the signal and noise letters. In Experiment 3, the possibility that the visual afterimage of the letter displays faded more rapidly for the learning-disabled boys was examined. In Experiment 4, the possibility that the learning-disabled boys were slower to pick up information from the decaying afterimages was examined. The results of these three experiments indicated that the decreased spans of apprehension observed for the learning-disabled boys in Experiment 1 resulted either from greater distractiveness or from the slower pickup of information, or both. The implications for visual training are discussed.
Attention↗
Memory capacity and intelligence: novel techniques for evaluating rival models of a fundamental information-processing mechanism.
Data from a fundamental cognitive task in which participants discriminate the relative frequency of visual or auditory binary stimuli were examined. Accuracy on this task correlates well with psychometric intelligence. The experimental paradigm is highly tractable, lending itself to rigorous analyses of precisely defined simulation models. Numerous models are evaluated, using multiple comparisons between response patterns of individual (and pooled) participants and predictive measures based on simulations for each trial sequence. Implications for theoretical accounts of short-term memory, discrimination, and absolute judgement as well as the measurement of individual differences in cognitive ability, are discussed. The results suggest a reinterpretation of memory capacity and support a new kind of model (with a single estimable parameter) in which discrete, valued units of information are stochastically displaced by further input.
Acoustic Stimulation↗
Differential hemisphere processing of information in schizophrenia.
Ten paranoid and 10 nonparanoid schizophrenics, 10 nonschizophrenic psychiatric controls, and 10 normal controls were presented with two types of dot enumeration task, structured and unstructured dot arrays, tachistoscopically. The tasks were designed to elicit left and right hemisphere functioning through automatic and controlled information-processing strategies. The findings indicated that the two tasks failed to separate information-processing strategies as intended. The display size effects were found to be significant in both tasks for all the groups. In the case of the structured task, paranoids and nonparanoids both performed significantly more accurately in the right as compared with the left hemisphere. Unlike the other three groups, the nonparanoid group was found to process the dots in both tasks using an automatic strategy but this was so only in the left hemisphere. In the right, they performed like other groups. The findings thus point to a left hemisphere deficit in the nonparanoids.
Adolescent↗
[Morphological analysis of information processing in basal ganglia of mammals].
The article reviews published and own data on special features of organization of afferent cortical and infracortical correctional systems of the total striopallidaric nuclear complex in various species of mammals. The article focuses on analysis of organization of these flows in a dog being a classical object of behavioural experiments and a rare object of neuromorphological studies. It was discovered that the general trend towards segregated and converged flows of functionally different information at the level of striopallidum is retained in all tested mammals, being an evidence of the fundamental nature of the discussed principles of organization of the projection systems of basal ganglia. The reviewed morphological data confirm reliability of the presented concept of basal ganglia functioning.
Afferent Pathways↗
Efficiency of visual information processing in children at-risk for dyslexia: habituation of single-trial ERPs.
To investigate underlying learning mechanisms in relation to the development of dyslexia, event-related potentials to visual standards were recorded in five-year-old pre-reading children at-risk for familial dyslexia (n=24) and their controls (n=14). At the end of second grade the children aged 8 years were regrouped into three groups according to literacy level and risk factor. Single-trial analyses revealed N1 habituation in the normal-reading controls, but not in the normal-reading at-risks, and a N1 amplitude increase in the group of poor-reading at-risks and poor-reading controls. No P3 habituation was found in either group. The normal-reading at-risk group exhibited the longest N1 and P3 latencies, possibly compensating for their reduced neuronal activity during initial information extraction. In contrast, the poor-reading group only showed prolonged P3, and their increase in (initial small) N1 amplitude together with normal N1 latencies, suggests inefficient processing in an early time window, which might explain automatisation difficulties in dyslexic readers.
Brain↗
Flexibility in the structure of human information processing.
The studies reported in this chapter argue for a flexible organization of higher mental processes, including perceptual and attentional systems in the visual modality and attentional systems related to action. There is electrophysiologic evidence that the visual perceptual system has a modularized structure, and that selection of perceived features is adjustable to sensory, conceptual, and utility constraints, both with respect to the hierarchy of selection cues and the transmission of information between perception and action. A distributed neural network subserves these functions and may therefore provide a source for plasticity and reorganization after brain damage by flexibility in the allocation of resources to various stages of stimulus analysis.
Cognition↗