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PubMed2003

Two-level hierarchy with sparsely and temporally coded patterns and its possible functional role in information processing.

We study the stability of two types of mixed states in an oscillator neural network model. Patterns to be stored are represented by complex variables whose amplitudes are either 0 (silent state) or 1 (firing state) and whose phases represent the timing of firing. The mixed states are defined in terms of a certain type of average over some specified number s of memory patterns. We define two types of such mixed states, each of which corresponds to a different type of restriction placed on this set of s memory patterns. The stability of each type is investigated both theoretically and numerically. We find that only one type of a mixed state, which consists of temporally correlated patterns, is stable. Finally, we discuss a possible functional role of such mixed states in information processing.

Mental Processes↗
PubMed1998

Information processing and antiretroviral therapy in HIV-1 infection.

Computerized reaction time (RT) tasks are sensitive measures of subclinical HIV-related mental slowing. We previously reported that nondemented HIV-seropositive patients on antiretroviral therapy at the time of testing had faster choice RTs compared to matched untreated seropositive participants. In the present study, we evaluated the performance of 163 nondemented HIV-seropositive participants on a reaction time version of the Stroop task as a function of antiretroviral status. Persons on antiretroviral therapy at the time of testing had significantly faster reaction times than untreated individuals, although treated asymptomatic participants showed significantly less Stroop interference than treated symptomatic participants. These effects could not be attributed to differences in demographic variables, disease status, substance abuse, or psychological distress. These data indicate that central information processing is faster for patients treated with antiretroviral compounds compared to untreated patients, and suggest that reaction time tasks may have significant potential utility in clinical trials of neuroprotective compounds.

AIDS Dementia Complex↗
PubMed2000

Scopolamine impairs information processing in the hippocampus and performance of a learned eyeblink response in alert cats.

The object of this work was to determine whether the changes in field activity and neuronal excitability recorded in the hippocampus during eyeblink classical conditioning are induced by the cholinergic input, and their relationships with the conditioned response performance. The pyramidal layer field activity, its response to fornix stimulation and eyelid responses were recorded during paired tone-air puff presentations, under scopolamine (25, 50 and 100 microg/kg) or saline administration, following well-established eyeblink conditioning in a trace paradigm in cats. Scopolamine impaired behavioral performance, and, in the hippocampus, disrupted conditioned stimulus-evoked field potential, high frequency shift in field activity, and paired presentation-induced hyperexcitability. These findings indicate that the cholinergic input participates in hippocampal information processing in a way that allows precise conditioned response performance and memory trace formation.

Animals↗
PubMed2001

Using cognitive science methods to assess the role of social information processing in sexually coercive behavior.

Seventy-four undergraduate men completed cognitive performance tasks assessing perceptual organization, classification, and category learning, as well as self-report measures relevant to sexual coercion. The stimuli were slides of Caucasian women who varied along affect and physical exposure (i.e., sensuality) dimensions. Data were analyzed using a weighted multidimensional scaling model, signal-detection theory analyses, and a connectionist learning model (RASHNL; J. K. Kruschke & M. K. Johansen, 1999). Individual differences in performance on the classification and category-learning tasks were congruent with individual differences in perceptual organization. Additionally, participants who showed relatively more attention to exposure than to affect were less sensitive to women's negative responses to unwanted sexual advances. Overall, the study demonstrates the feasibility and utility of cognitive science methods for studying information processing in psychopathology.

Adolescent↗
PubMed1980

Evolution of canine information processing under conditions of natural and artificial selection.

The paper first argues that under conditions of domestication animals are necessarily selected (incidentally or otherwise) for (1) responsitivity to a broad band of stimuli and (2) behavioral plasticity. The consequent tractability of domestic animals is contrasted with the stimulus-boundness and response stereotypy of the fixed action patterns observed in wild animal behavior. It is suggested that this difference accounts for the differential trainability of wolves and dogs. The second section of the paper presents observational evidence that although capacity for observational learning. It is then noted that since observational learning requires recognition of means-ends relationships this conclusion is inconsistent with the claim that wolf behavior is largely instinct-bound. Finally, these conclusions are reconciled by hypothesizing that the wolf possesses a "duplex" information-processing system, a primitive "instinctual" system that mediates basic survival responses and a more recently acquired "cognitive" system that evolved as the wolf became a group hunter. Neurobehavioral and developmental comparisons of wolf and dog suggest that these two systems have become integrated into a single scheme in the course of the dog's domestication.

Animals↗
PubMed2004

Absence of rapid sensory adaptation in neocortex during information processing states.

One prominent feature of sensory responses in neocortex is that they rapidly adapt to increases in frequency, a process called "sensory adaptation." Here we show that sensory adaptation mainly occurs during quiescent states such as anesthesia, slow-wave sleep, and awake immobility. In contrast, during behavior-ally activated states, sensory responses are already adapted. For instance, during learning of a behavioral task, when an animal is very alert and expectant, sensory adaptation is mostly absent. After learning occurs, and the task becomes routine, the level of alertness lessens and sensory adaptation becomes robust. The primary sensory thalamocortical pathway of alert and expectant animals is in the adapted state, which may be required for adequate sensory information processing.

Adaptation, Physiological↗
PubMed1982

Information-processing load and variability of visual evoked potentials.

5 subjects were assigned two tasks during which they were simultaneously presented brightness-changes of the spot light on the CRT and the speech in a foreign language. They were asked to count the number of the changes in the visual task and listen to the speech to discern the content in the auditory task. A pair of averaged visual evoked potentials (VEP) to the brightness-changes were obtained for each task to calculate a subset correlation as an index of the variance of VEP. The mean correlation coefficient of VEP across the subjects was significantly higher during the visual task than that in the auditory task. This means that VEP was more stable during the visual task. The result suggests that the subset correlation measure might be available to evaluate visual information-processing load.

Adult↗
PubMed2003

Information processing and movement optimization during development: kinematics of cyclical pointing in 5- to 11-year-old children.

The authors studied the development of movement control in speed-accuracy tradeoff conditions in children aged 5-11 years and in adults performing cyclical pointings. Twelve difficulty levels (IDs), ranging from 2 to 6.58 bits, were defined (P. M. Fitts, 1954). Peak and time to peak velocity, acceleration, and deceleration, and acceleration profiles as a function of hand position (Hooke's portraits) were analyzed. Movement time decreased with age and was less affected by ID. Peak velocity and acceleration increased, acceleration and deceleration were decreasingly time consuming, and movement profiles turned to increased harmonicity with age and task easiness. Nevertheless, the developmental trends differed between parameters. Gain in velocity seemed chiefly dependent on improved muscular cooperation patterns before 7 years of age and on improved information processing from age 7 onward; achievement of an optimized strategy in the speed-accuracy tradeoff occurred at age 11 years.

Acceleration↗
PubMed1988

Specific forms of facial EMG response index emotions during an interview: from Darwin to the continuous flow hypothesis affect-laden information processing.

Previous research has demonstrated that mild negative emotional imagery and unpleasant sensory stimuli lead to greater electromyographic activity over the brow muscle region than mild positive imagery and stimuli, even in the absence of significant changes in visceral and general facial EMG activity. Previous research has not addressed whether electromyographic responses over the brow region are a sensitive and specific index of emotions, however, since a multiplicity of events lead to changes in brow activity. In this research, facial electromyographic and audiovisual recordings were obtained while individuals were interviewed about themselves. Afterwards, individuals were asked to describe what they had been thinking of during specific segments of the interview marked by distinctive electromyographic responses over the brow region in the context of ongoing but stable levels of activity elsewhere in the face. The results are interpreted in terms of a continuous flow hypothesis of affect-laden information processing.

Electromyography↗
PubMed1989

Type I protein kinase C isozyme in the visual-information-processing pathway of monkey brain.

Previously using PKC isozyme-specific antibodies for immunoblot analysis, we demonstrated the heterogeneous distribution of PKC isozymes in various regions of monkey and rat brains and that type I PKC was most abundant in cerebellum, hippocampus, amygdala, and cerebral cortex (Huang et al.: J Biol Chem 262:15714-15720, 1987). Using these antibodies, we have also demonstrated that type I, II, and III PKC are products of PKC genes gamma, beta, and alpha, respectively (Huang et al.: Biochem Biophys Res Commun 149:946-952, 1987). By immunocytochemical analysis, type I PKC-specific antibody showed strong reactivity in various types of neuron in hippocampal formation, amygdala, cerebellum, and neocortex. In hippocampal formation, granule cells of dentate gyrus and pyramidal cells of hippocampus were heavily stained. By immunoblot analysis, relative levels of PKC isozymes in several areas of monkey cerebral cortex involved in the visual information processing and storage were determined. Both type II and III PKCs appeared to be evenly distributed and at moderate levels, type I PKC formed a gradient of increasing concentration rostral along the cerebral cortex of occipital to temporal and then to the limbic areas. Neurobehavioral studies have demonstrated that the neocortical and limbic areas of the anterior and medial temporal regions participate more directly than the striate, prestriate, and posterior temporal regions in the storage of visual representations and that both hippocampus and amygdala are important in the memory formation. As type I PKC is present at high levels in hippocampus, amygdala, and anterior temporal lobe, we predict that the type I protein kinase C may participate in the plastic changes important for mnemonic function.

Animals↗
PubMed2000

[Mood-congruent effect in self-relevant information processing: a study using an autobiographical memory recall task].

The pattern of the mood-congruent effect in an autobiographical memory recall task was investigated. Each subject was randomly assigned to one of three experimental conditions: positive mood, negative mood (induced with music), and control groups (no specific mood). Subjects were then presented with a word at a time from a list of trait words, which were pleasant or unpleasant. They decided whether they could recall any of their autobiographical memories related to the word, and responded with "yes" or "no" buttons as rapidly and accurately as possible. After the task, they were given five minutes for an incidental free recall test. Results indicated that the mood-congruent effect was found regardless of whether there was an autobiographical memory related to the word or not in both positive and negative mood states. The effect of moods on self-relevant information processing was discussed.

Adult↗
PubMed1992

Some consequences of early harsh discipline: child aggression and a maladaptive social information processing style.

Although a number of studies have reported a relation between abusive parental behavior and later aggressive behavior in the victim, many of these investigations have had methodological limitations that make precise interpretation of their results problematic. In the present study, we attempted to determine whether harsh parental discipline occurring early in life was associated with later aggression and internalizing behavior in children, using a prospective design with randomly selected samples to avoid some of these methodological difficulties. Structural equation modeling indicated a consistent relation between harsh discipline and aggression in 2 separate cohorts of children. This relation did not appear to be due to possible confounding factors such as child temperament, SES, and marital violence, although there was some indication in our data that the latter variables were related to child aggression. In addition, our analyses suggested that the effect of harsh discipline on child aggression may be mediated at least in part by maladaptive social information processing patterns that develop in response to the harsh discipline.

Adaptation, Psychological↗
PubMed1997

Information processing in spider phobics: the Stroop colour naming task may indicate strategic but not automatic attentional bias.

Recent research suggests that it is possible to differentiate preconscious and strategic processing of threat stimuli using the Stroop colour naming task. masked and unmasked versions of the Stroop were administered to spider phobics, non-phobic controls and phobics whose fears did not include that of spiders. Colour naming times were recorded to neutral words, spider words and words whose emotionality was comparable to spider words. Results indicated that, in the unmasked condition only, the colour naming of spider words was slower in the spider phobics relative to both the other words types. Further analysis of the data indicated that this result was unlikely to be an effect of word emotionality and was specific to threat. Although the results are broadly consistent with information processing approaches to the understanding of anxiety, the value of this type of paradigm to the understanding of clinical anxiety is questionable.

Adult↗
PubMed1989

Parkinson's disease: a conceptualization of neuropsychological deficits within an information-processing framework.

Parkinson's disease patients are frequently impaired in a variety of neuropsychological tasks involving memory, perceptual motor performance and cognitive flexibility. Although various theories have been forwarded to explain specific impairments, few attempts have been made to account for all the deficits within a single theoretical framework. Furthermore, the frequent occurrence of dementia, the adverse side effects of medication and the motor symptoms of the disease tend to interfere with neuropsychological performance. This has hindered the clear delineation of the neuropsychological profile of Parkinsonian patients. The present paper examines the evidence for intellectual deficits in non-demented Parkinson's disease patients. A number of problems inherent in cognitive research on Parkinson's disease are discussed. The contribution of dementia, motor symptom severity and medication in the expression of these intellectual impairments is examined. It is suggested that many of the neuropsychological deficits described in Parkinson's disease may result from a common underlying deficit in some aspect of information processing. Although it is not possible to pinpoint the precise mechanism(s) involved on the basis of the available evidence, several possibilities are suggested by cognitive and electrophysiological data.

Cognition Disorders↗
PubMed1994

Chemoarchitectonics of axonal and perikaryal acetylcholinesterase along information processing systems of the human cerebral cortex.

The distribution of axonal and perikaryal acetylcholinesterase (AChE) was studied in whole-brain sections. All cytoarchitectonic sectors and cortical layers of the human cerebral cortex contained AChE-rich axons. These axons displayed multiple varicosities which appeared to come in contact with AChE-rich and AChE-poor cortical perikarya. The upper layers of cortex tended to contain the highest density of AChE-rich axons. The AChE-rich axons were more dense in limbic-paralimbic areas of cortex than in primary sensory-motor and association areas. Within unimodal sensory association areas, the parasensory (upstream) sectors had a slightly lesser density of AChE-rich axons than the downstream sectors. Within paralimbic areas, the nonisocortical sectors displayed a distinctly higher density of AChE-rich axons than the more differentiated isocortical sectors. These observations indicate that the distribution of AChE-rich axons displays orderly variations that obey the organization of information processing systems in the cerebral cortex.

Acetylcholinesterase↗
PubMed2006

Disturbances of visual information processing in early states of psychosis and experimental delta-9-tetrahydrocannabinol altered states of consciousness.

Recent data on alterations of the endogenous cannabinoid system in schizophrenia have raised the question of its functional role in this disease. The psychoactive compound of Cannabis sativa, delta-9-tetrahydrocannabinol (Delta9-THC), has been shown to induce psychotic symptoms, but it is unknown to what extend prodromal states of psychoses are reflected by these experimental approaches. This study compares four groups of subjects: antipsychotic-naïve patients suffering from acute paranoid schizophrenic or schizophreniform psychosis (SZ), patients in the prodromal state (IPS), healthy controls without any pharmacological intervention (HC) and a second group of healthy volunteers who were orally administered synthetic Delta9-THC (Dronabinol) (HC-THC). Neither SZ and IPS nor HC received the experimental drug. All subjects were assessed using the Brief Psychiatric Rating Scale (BPRS) and the Binocular Depth Inversion Illusion Test (BDII). The latter represents a sensitive measure of impaired visual information processing that manifests in various experimental and naturally occurring psychotic states. BDII values were well comparable in SZ, IPS and HC-THC, and all groups differed significantly to HC. The BPRS revealed no significant difference between HC-THC and IPS while both were significantly different from SZ and HC, respectively. Our results suggest that Delta9-THC-induced altered states of consciousness may serve as a useful tool for modeling psychotic disorders, particularly their prodromal states. Furthermore, they provide insight into the perceptual and psychopathological alterations induced by Delta9-THC, which is essential for the understanding of the pro-psychotic effects of herbal cannabis preparations with highly enriched Delta9-THC content.

Acute Disease↗
PubMed1989

Cyclical changes in emotional information processing in sleep and dreams.

Our scientific tools have rapidly advanced in recent decades. Urine tests and hormone assays allow us to know exactly where a woman is in her menstrual cycle and to document precisely her hormonal rhythms. Sleep-laboratory techniques allow us to know exactly when someone is dreaming so that we can obtain that communication that Freud prized so highly. Furthermore, we now have quantifiable means to measure accessibility to nonverbal mental representations, which derive from important advances in theory and method in cognitive psychology in the last several decades. None of the studies we surveyed combined these tools. The sleep-laboratory studies did not document menstrual-cycle phase with either temperature or hormone levels. Moreover, the relationship between their findings and daily functioning is still unclear. The psychoanalytic study by Benedek and Rubenstein carefully documented cycle phase, but statements about fantasy and conflict were large and sweeping and the focus was on drive-related rather than information processing effects. Careful work must be done by modern investigators before the field of medical psychoanalysis can address the basic questions of mind-body functioning that are at issue here. We have presented one approach to entering the communication network of mind-brain functioning, that is, the application of the dual-code model to dreams, in the context of the influence of hormones across the menstrual cycle. Although prior research has demonstrated cyclical fluctuations of psychodynamic themes in dream content (Baron, 1977; Benedek & Rubenstein, 1939a, b; Hertz & Jensen, 1975; Lewis & Burns, 1975; Swanson & Foulkes, 1968), the existence of a cyclical cognitive pattern as regulated by gonadal function has not previously been explored. While the findings are preliminary and limited, this is the first study to provide evidence that there are psycholinguistic styles characteristic of different phases in the menstrual cycle, and that this variation in verbal expression reflects a correspondence between hormone production and the ability to access and communicate nonverbal representations. Although the relationship between referential activity and phases of the menstrual cycle represents a statistical relationship and is hardly conclusive, the article does demonstrate how the dual-code model permits us to translate our psychoanalytic observations into operational terms. This provides one means of access to the network of communication between neuropeptides and mental representation, or in more general terms, between body and mind.

Adult↗
PubMed1979

Selective adaptation to frequency-modulated tones: evidence for an information-processing channel selectively sensitive to frequency changes.

Exposure to an FM tone elevates FM threshold but not AM threshold. This holds for a wide range of frequency deviations (delta F = +/- 0.4 Hz- +/- 30 Hz at least) provided that modulation frequency is low (fm = 2 Hz), but if fm is somewhat higher (e.g., 8 Hz) the finding only holds for small frequency deviations. FM threshold can rise with time up to an adapting duration of at least 1200 s, through this buildup depends on frequency deviation. Exposure to an AM tone elevates AM threshold, but not FM threshold, over a wide range of modulation depths (at least m = 5%--50%). Quasi-FM (QFM) adapting tones resemble FM adapting tones in their effects upon FM and AM sensitivities, even though QFM and AM adapting tones have identical power spectra. Exposure to a pure tone produces no difference between FM and AM threshold elevations. These data can be explained if the human auditory pathway contains separate information-processing channels for AM and FM signals whose sensitivities do not overlap even with suprathreshold stimuli. We suppose that the FM channel (but not the AM channel) is sensitive to changing differences (or ratios) between signals from different sites along the basilar membrane.

Adaptation, Psychological↗