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PubMed2006

Attentional demands of postural control: the ability to selectively allocate information-processing resources.

Most studies have suggested the process of recovering body stability requires information-processing resources, but whether adults have the ability to selectively allocate resources to maintain balance is not known. Using a variable priority dual-task paradigm the present experiment investigated the extent to which young adults are able to shift attention between a postural task and a visual spatial memory task. Our results demonstrated a significant difference in verbal response time dependent on instructional set (focus on visual spatial memory versus postural task) but no difference in body sway measurement, indicating the ability of young adults to modulate visual spatial memory task, but not postural task focus. This suggests the existence of a hierarchy within attentional tasks with postural stability being a priority to stabilize gaze and head position.

Adult↗
PubMed2000

Quantum information processing with semiconductor macroatoms.

An all optical implementation of quantum information processing with semiconductor macroatoms is proposed. Our quantum hardware consists of an array of quantum dots and the computational degrees of freedom are energy-selected interband optical transitions. The quantum-computing strategy exploits exciton-exciton interactions driven by ultrafast multicolor laser pulses. Contrary to existing proposals based on charge excitations, our approach does not require time-dependent electric fields, thus allowing for a subpicosecond, decoherence-free, operation time scale in realistic semiconductor nanostructures.

Journal Article↗
PubMed1995

Nimodipine improves information processing in substance abusers.

We examined whether nimodipine can improve information processing in healthy drug abusers using cognitive event-related potential (ERP) methodology. Placebo and 30- and 60-mg doses of nimodipine were administered on separate days in a random double-blind design to twelve male subjects, who used cocaine and/or opiates as well as alcohol and marijuana. The subjects performed the auditory rare event monitoring (AREM) task and the paired letter version of the visual continuous performance task (CPT) before oral drug administration as well as one and two hours after drug ingestion. The EEG was recorded from 7 scalp locations. The P3 component of the ERPs to the target stimulus was reduced with repeated testing on the placebo day. The 30-mg dose of nimodipine blocked the decrease in P3, which reflects stimulus evaluation in both tasks. Chronic administration of nimodipine may alleviate the cognitive deficits observed in substance abusers during abstinence and prevent treatment relapse.

Adult↗
PubMed1986

Effect of coffee on the speed of subject-paced information processing.

A continuously subject-paced and monetarily reinforced information-processing task was used to test whether caffeine might stimulate performance beyond the ceiling imposed by fatigue. A 3 X 2 design was adopted with the three doses 0, 150, and 450 mg caffeine and with decaffeinated coffee and fruit juice as vehicles. Two groups of 10 subjects selected to represent extremes on the extraversion-introversion scale participated in the experiment. The results revealed no differences between the two groups nor between the two drug vehicles, but caffeine at both dose levels improved performance significantly. Fatigue-induced performance decrements across the sessions reached significance, but no interaction was obtained between fatigue and drug action, supporting the view that caffeine can improve performance beyond a mere restoration of fatigue.

Caffeine↗
PubMed1994

Auditory information processing in sleep: late cortical potentials in an oddball paradigm.

Information processing of auditory stimuli in sleeping healthy volunteers is studied by means of an oddball paradigm. Latencies of the early (N1P2) complex are affected by NREM sleep depth and show a progressive slowing. The amplitude of the early N1 component depends on stimulus type and probability and is increased following deviant stimuli. In strict comparison with waking, late responses (N2-P3) complex only follows deviant stimuli. Both latencies and amplitude increase more in NREM than in REM sleep. Thus the early response is mainly affected by vigilance, the late response mainly depends on stimulus type. Results are discussed in terms of comparison processing, context updating and orienting response patterning hypotheses put forward in cognitive psychophysiology.

Adult↗
PubMed1993

Information-processing mediating the location-distance interference in motor short-term memory.

We reviewed the literature on basic psychological correlates of the well-known phenomenon of the location-distance interference in motor short-term memory (Kerr, 1978; Walsh, Russell, Imanaka, & James, 1979). The location-distance interference in motor short-term memory has frequently been demonstrated as an unavoidable interference phenomenon observed in the reproduction of movement location and distance in arm positioning. The most important aspect of this phenomenon is that even when a subject concentrates on a specific cue (i.e., either end-location or distance) the other cue is also coded unintentionally and, as a result, the reproduction movement guided on the basis of the specific cue is unavoidably influenced by the other nonspecific cue. In this review article, we first reviewed the literature on the basic theories and nature of short-term memory, particularly on the limited processing capacity. We then referred to the unlimited, automatic processing in visual-verbal domains, referring to the Stroop phenomenon. Finally, in conjunction with the notion of automatic processing, we examined the possible aspects of information processing which may be responsible for mediating the location-distance interference in motor short-term memory.

Cues↗
PubMed2000

Information processing in large-scale cerebral networks: the causal connectivity approach.

Today, cognitive functions are considered to be the offspring of the activity of large-scale networks of functionally interconnected cerebral regions. The interpretation of cerebral activation data provided by functional imaging has therefore recently moved to the search for the effective connectivity of activated regions, which aims at understanding the role of anatomical links in the activation propagation. Our assumption is that only causal connectivity can offer a real understanding of the links between brain and mind. Causal connectivity is based on the anatomical connection pattern, the information processing within cerebral regions and the causal influences that connected regions exert on each other. In our approach, the information processing within a region is implemented by a causal network of functional primitives, which are the interpretation of integrated biological properties. Our choice of a qualitative representation of information reflects the fact that cerebral activation data are only the approximate view, provided by imaging techniques, of the real cerebral activity. This explicit modeling approach allows the formulation and the simulation of functional and physiological assumptions about activation data. Two alternative models explaining results of the striate cortex activation described by Fox and Raichle (Fox PT, Raichle ME (1984) J. Neurophysiol 51:1109-1120; Fox PT, Raichle ME (1985) Ann Neurol 17:303-305) are provided as an example of our approach.

Animals↗
PubMed2006

Acute effects of the ampakine farampator on memory and information processing in healthy elderly volunteers.

Ampakines act as positive allosteric modulators of AMPA-type glutamate receptors and facilitate hippocampal long-term potentiation (LTP), a mechanism associated with memory storage and consolidation. The present study investigated the acute effects of farampator, 1-(benzofurazan-5-ylcarbonyl) piperidine, on memory and information processes in healthy elderly volunteers. A double-blind, placebo-controlled, randomized, cross-over study was performed in 16 healthy, elderly volunteers (eight male, eight female; mean age 66.1, SD 4.5 years). All subjects received farampator (500 mg) and placebo. Testing took place 1 h after drug intake, which was around Tmax for farampator. Subjects performed tasks assessing episodic memory (wordlist learning and picture memory), working and short-term memory (N-back, symbol recall) and motor learning (maze task, pursuit rotor). Information processing was assessed with a tangled lines task, the symbol digit substitution test (SDST) and the continuous trail making test (CTMT). Farampator (500 mg) unequivocally improved short-term memory but appeared to impair episodic memory. Furthermore, it tended to decrease the number of switching errors in the CTMT. Drug-induced side effects (SEs) included headache, somnolence and nausea. Subjects with SEs had significantly higher plasma levels of farampator than subjects without SEs. Additional analyses revealed that in the farampator condition the group without SEs showed a significantly superior memory performance relative to the group with SEs. The positive results on short-term memory and the favorable trends in the trail making test (CTMT) are interesting in view of the development of ampakines in the treatment of Alzheimer's disease and schizophrenia.

Adult↗
PubMed1992

Normal and abnormal information processing. A neuropsychological perspective on obsessive compulsive disorder.

This article presents a neuropsychological perspective on obsessive compulsive disorder (OCD) and describes some of the cognitive strengths and weaknesses that characterize the disorder. Neuroanatomic findings and theories of the neurologic basis of OCD are reviewed as are studies that use neuropsychological assessments. Findings of frontal lobe and/or basal ganglia dysfunction as well as memory deficits are emphasized. This information is then discussed in the context of cognitive-behavioral and information processing perspectives that emphasize normal patterns in anxiety and worry. The goal is to provide an integrated conceptual model of OCD, identifying the normal and abnormal information processing patterns that characterize the disorder.

Anxiety↗
PubMed2003

Association of the G1947A COMT (Val(108/158)Met) gene polymorphism with prefrontal P300 during information processing.

BACKGROUND: A common functional polymorphism, G1947A, of the catechol-O-methyltransferase (COMT) enzyme has gained interest in schizophrenia research because of its critical involvement in cortical dopamine catabolism and frontal lobe function. An assumed mechanism of dopamine is the reduction of noise in prefrontal neural networks during information processing. Therefore, the hypothesis was tested whether a variation of the COMT genotype is associated with prefrontal noise, which is in part reflected by the frontal P300 amplitude. It was predicted that homozygous Met allele carriers have a lower frontal P300 amplitude. METHODS: The P300 component (auditory oddball) was recorded in 49 schizophrenic patients and 170 healthy control subjects. Three single nucleotide polymorphisms (SNPs) of the COMT gene (G1947A, C1883G, and G1243A) were investigated. RESULTS: We observed a significant effect of G1947A COMT genotype on frontal P300 amplitude, with evidence for a genotype x diagnosis interaction. Lower frontal P300 amplitudes occurred in homozygous carriers of the Met allele, particularly in schizophrenic patients. CONCLUSIONS: The association of the frontal P300 amplitude with the G1947A COMT genotype further emphasizes the functional role of this SNP. As the finding was mainly observed in schizophrenic patients, this may indicate that additional factors are required to interact with COMT genotype to affect prefrontal function. The smaller frontal P300 amplitude in Met carriers suggests that the amount of noise in prefrontal neural networks during information processing might be in part under genetic control, which is mediated by dopamine.

Acoustic Stimulation↗
PubMed1977

Very short-term memory dysfunction in schizophrenia. Defective short time constant information processing in schizophrenia.

Disordered, very short-term memory (VSTM) has been hypothesized as the fundamental cognitive deficit in schizophrenia. We describe a method that measures VSTM using self-stimulated auditory average evoked potentials. This paradigm allows the VSTM hyothesis to be tested relatively free of superficial attentional and motivational artifacts. The experimental results are consistent with a VSTM dysfunction in schizophrenia. Very short-term memory dysfunction is discussed in light of recent blink reflex evidence that there is a short time constant information processing system with a time base similar to VSTM (ie, 1 to 1,000 msec). This leads to new testable hypotheses about information processing and VSTM in schizophrenia. It also lays the basis for interpreting this phenomenon as a pathologic exaggeration of an adaptive neurophysiologic mechanism.

Adaptation, Psychological↗
PubMed1996

Bulbocortical interplay in olfactory information processing via synchronous oscillations.

Emergence of synchronous oscillatory activity is an inherent feature of the olfactory systems of insects, mollusks and mammals. A class of simple computational models of the mammalian olfactory system consisting of olfactory bulb and olfactory cortex is constructed to explore possible roles of the related neural circuitry in olfactory information processing via synchronous oscillations. In the models, the bulbar neural circuitry is represented by a chain of oscillators and that of cortex is analogous to an associative memory network with horizontal synaptic connections. The models incorporate the backprojection from cortical units to the bulbar oscillators in particular ways. They exhibit rapid and robust synchronous oscillations in the presence of odorant stimuli, while they show either nonoscillatory states or propagating waves in the absence of stimuli, depending on the values of model parameters. In both models, the backprojection is shown to enhance the establishment of large-scale synchrony. The results suggest that the modulation of neural activity through centrifugal inputs may play an important role at the early stage of cortical information processing.

Animals↗
PubMedDate not supplied

Electrodermal activity as an indicator of information processing in a nonaversive differential classical conditioning paradigm.

Most investigations of information processing in human Pavlovian autonomic conditioning focussed on the role of awareness of the contingency of the conditioned stimulus (CS) and the unconditioned stimulus (UCS). While in these studies only the qualitative information of the CS (UCS occurring vs not occurring) was varied, the present experiment was designed to vary the quantitative information of the CS. In a differential conditioning paradigm, using a letter reproduction task as nonaversive UCS, electrodermal responses to different degrees of CS information content were investigated. Twenty subjects experienced two different conditions in a within subject design. In one condition only the number of letters used in the following UCS was presented as CS+, while in the other condition the CS already contained the whole UCS information. Both conditions led to significant differences in magnitudes of electrodermal responding.

Adult↗
PubMed2006

Information-processing modules and their relative modality specificity.

This research uses fMRI to understand the role of eight cortical regions in a relatively complex information-processing task. Modality of input (visual versus auditory) and modality of output (manual versus vocal) are manipulated. Two perceptual regions (auditory cortex and fusiform gyrus) only reflected perceptual encoding. Two motor regions were involved in information rehearsal as well as programming of overt actions. Two cortical regions (parietal and prefrontal) performed processing (retrieval and representational change) independent of input and output modality. The final two regions (anterior cingulate and caudate) were involved in control of cognition independent of modality of input or output and content of the material. An information-processing model, based on the ACT-R theory, is described that predicts the BOLD response in these regions. Different modules in the theory vary in the degree to which they are modality-specific and the degree to which they are involved in central versus peripheral cognitive processes.

Adolescent↗
PubMed2004

Interhemispheric functional synchronization at the first step of visual information processing in humans.

OBJECTIVE: We examined the interhemispheric functional synchronization of the visual cortex using coherence (Coh) analysis. METHODS: Achromatic or isoluminant chromatic sinusoidal grating stimuli were presented to each hemifield at a rate of 8 reversals/s to record steady-state visual-evoked potentials (S-VEPs) in 10 healthy subjects. Four recording electrodes were placed at O1, O2, P3 and P4, referred to an electrode at Cz. A total of 50 responses of 1 s epoch were averaged, and were subjected to discrete fast Fourier transforms to yield the amplitude and phase of the 8 Hz component. Ordinary and partial Coh values were also calculated. RESULTS: For both achromatic and chromatic stimuli, the 8 Hz amplitudes of O1 and O2 were significantly larger than those of P3 and P4 without any significant difference between O1 and O2. The phase lag between O1 and O2 was approximately 30 degrees (latency shift 10.4 ms). Partial Coh between O1 and O2 at 8 Hz was significantly greater than that of the unstimulated condition, and this was only observed at 8 Hz. CONCLUSIONS: These results suggest that interhemispheric synchronization in the occipital area occurs despite the nature of the visual stimuli. Therefore, the activation of interhemispheric connection is important for the early stage of the visual information processing. SIGNIFICANCE: Our results indicate that the first step of the visual information processing requires interhemispheric functional synchronization.

Adult↗
PubMed1995

Information-processing correlates of reported sexual abuse in eating-disordered and comparison women.

A history of sexual abuse during childhood or adulthood is reported by a large number of eating-disordered and nonclinical women. However, the cognitive consequences of such abuse are not fully understood. An adaptation of the Stroop test is described, examining information-processing correlates of reported sexual abuse and of clinicians' judgments of the relevance of that abuse to the formulation of cases. Words related to sexual abuse impaired color-naming in eating-disordered and comparison women who reported a history of such abuse. This Stroop interference effect was greater in those eating-disordered women where the abuse was judged to be relevant to their psychopathology. It was also associated with the characteristics of the abuse (use of force, identity of abuser, time since the abuse). Finally, the Stroop interference effect was associated with the degree of bulimic psychopathology in the eating-disordered women who reported abuse. In particular, the frequency of binging was significantly greater in those eating-disordered women who had reported abuse, but that difference was a product of the correlation of the two variables with the degree of information processing bias. A two-stage model of cognitive reaction to sexual abuse is proposed, integrating these effects with the existing literature. The utility of this measure as a research and clinical tool requires further consideration in other clinical groups.

Adult↗
PubMed2003

Information processing in long delay memory-guided saccades: further insights from TMS.

The performance of memory-guided saccades with two different delays (3 s and 30 s of memorisation) was studied in eight subjects. Single pulse transcranial magnetic stimulation (TMS) was applied simultaneously over the left and right dorsolateral prefrontal cortex (DLPFC) 1 s after target presentation. In both delays, stimulation significantly increased the percentage of error in amplitude of memory-guided saccades. Furthermore, the interfering effect of TMS was significantly higher in the short delay compared to that of the long delay paradigm. The results are discussed in the context of a mixed model of spatial working memory control including two components: First, serial information processing with a predominant role of the DLPFC during the early period of memorisation and, second, parallel information processing, which is independent from the DLPFC, operating during longer delays.

Adult↗
PubMed1994

Alphanumeric sequencing: a report on a brief measure of information processing used among persons with multiple sclerosis.

Alphanumeric Sequencing involves the alternating recitation of counting and the alphabet. We report data on the use of this measure with two clinical samples of persons with multiple sclerosis, having either the chronic progressive (n = 23) or relapsing-remitting form (n = 52) of the disease. Patients were administered Alphanumeric Sequencing and several other tests of information-processing speed/capacity and short-term memory. Chronic progressive MS patients performed worse than 23 healthy controls on both the speed and error components of the test, while relapsing-remitting patients were worse than 35 controls only on the total time to complete the task. The time score was correlated with several measures of information processing and short-term memory.

Adult↗