SEARCH · PubMed Health

Results for “Cognitive Reflection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources

PubMed1993

Heart-rate and blood-pressure responses to speech alone compared with cognitive challenges in the Stroop task.

Heart-rate and blood-pressure responses are assumed to reflect the "stressfulness" of cognitive tasks. Cardiovascular responses to speech are often assumed to be negligible. To test these assumptions, 34 middle-aged men (mean age 45.0 +/- 6.1) performed three versions of the Stroop color-conflict task, passive responding, push-button, and verbal. Although difficulty of passive responding was rated 11.8 (fairly light), push-button 16.1 (between hard and very hard), and verbal Stroop 14.5 (hard), all were significantly different. Analysis of variance showed during tasks heart-rate responses and systolic blood pressure did not differ. Recovery average heart-rate and over-all heart-rate patterns were not different for the difficult tasks but were significantly different from the easy task. Diastolic blood-pressure changes during tasks were more similar for verbal tasks despite the difference in difficulty. Stressor heart-rate and systolic blood-pressure responses did not reflect the difficulty of this stressful task. Verbalization of responses contributed significantly to cardiovascular reactivity.

Adult↗

PubMed1999

Differentiating stranger murders: profiling offender characteristics from behavioral styles.

The literature on "offender profiling" suggests that different "styles" of homicide will reflect differences in the background characteristics of the offender. To test this suggestion, hypotheses were drawn from studies of aggression to propose that murder crime scenes would reveal stylistic distinctions in the role of the aggression in the offense. It was further hypothesized that these distinctions would be clearest for those crime scene indicators that reflect the instrument (cognitive) actions that shape the offense rather than the more expressive (impulsive and emotional) components. Hypotheses about associated offender characteristics were also deduced on the assumption that the murder scene theme revealed the killers' typical styles of interpersonal transaction. To test these hypotheses MDS analyses were carried out on the crime scene and offender characteristics derived from 82 single offender, single victim stranger homicides. A multivariate structure resulted, including all three hypothesized styles, allowing 65% of the cases to be assigned to unique styles and a further 36% to be assigned to appropriate hybrids. Offender characteristics related in the anticipated way to the different crime scene styles, providing a basis for law enforcement inferences about offenders in stranger murders.

Adolescent↗

PubMed2000

A two-year longitudinal study of deferred imitation of object manipulation in a juvenile chimpanzee (Pan troglodytes) and orangutan (Pongo pygmaeus).

Changes in deferred imitation of novel actions on objects were assessed over a 2-year period in two enculturated, juvenile great apes (one chimpanzee, Pan troglodytes, and one orangutan, Pongo pygmaeus). Both apes displayed deferred imitation, and both displayed improve ments in deferred imitation over the 2-year period, although the magnitude of improvement was greater for the chimpanzee. This is, to our knowledge, the first experimental demonstration of longitudinal improvements of deferred imitation in great apes. The results were interpreted as reflecting maturationally paced cognitive differences consistent with other cognitive accomplishments in these species, and as demonstrating the influence that a species-atypical rearing environment can have on cognitive abilities in juvenile great apes.

Aging↗

PubMed2006

Effect of word and syllable frequency on activation during lexical decision and reading aloud.

This functional MRI (fMRI) study investigated the effect of lexical and syllable frequency on visual word processing during lexical decision and reading aloud. Previous research has shown a dissociation of syllable and word frequency effects in Spanish using behavioral and electrophysiological measures, suggesting that sublexical (syllabic) representations are computed and mediate the firing of lexical candidates. Here, we characterize the neuroanatomical basis of these lexical and sublexical manipulations and their dependence on task. During lexical decision, words with low vs. high lexical frequency increased activation in left frontal, anterior cingulate, supplemental motor area (SMA), and pre-SMA regions; while words with high vs. low syllable frequency increased activation in a left anterior inferior temporal region. In contrast, when the words were read aloud those with low vs. high syllable frequency increased activation in the left anterior insula, with no other significant effects. On the basis of the neuroanatomy, we propose that the contrasting effects of syllable frequency during lexical decision and reading aloud reflect two different cognitive processes in visual word processing. Specifically, words with high-frequency syllables may increase lexical competition in the inferior temporal lobe while facilitating articulatory planning in the left anterior insula.

Adult↗

PubMed1995

Asymmetrical hemispheric activation and emotion: the effects of unilateral forced nostril breathing.

Relative nostril efficiency is associated with greater activation of the hemisphere contralateral to the more efficient (dominant) nostril and with improved performance on cognitive tasks which reflect the functions of that hemisphere (see Shannahoff-Khalsa, 1993, for review). In this experiment we demonstrate a similar relationship between nasal efficiency and the emotional functions of the cerebral hemispheres. Following left nostril forced breathing through the dominant nostril, subjects report a more negative emotional state, score higher on the Spielberger State Anxiety Inventory, and tell stories about an ambiguous picture that are more negative in emotional tone. These results are similar to those found with unilateral muscle contractions and therefore support the hypothesis that unilateral contractions are effective because of contralateral hemispheric activation.

Affect↗

PubMed1997

Sex differences in visual recognition memory: support for a sex-related difference in attention in adults and children.

The selectivity hypothesis of Meyers-Levy (1989) proposes that cognitive sex differences reflect underlying differences in information processing between males and females. Males are considered to be more likely to organize information in a self-related manner, whereas females are more likely to adopt a comprehensive approach to information processing. We tested this hypothesis in children (10-15 years) and adults using recognition memory tasks. Tests were devised which employed male-oriented objects, female oriented objects, or random objects. In both the child and adult samples, females performed significantly better than males on tests using random and female-oriented objects. Males performed at the level of females only when tested for recognition of male-oriented objects. These results demonstrate that this sex difference is present prior to puberty and support the concept of sex differences in information processing.

Adolescent↗

PubMed1987

Benzodiazepine pharmacodynamics: evidence for biophase rate limiting mechanisms.

Pharmacokinetics do not adequately reflect recovery from cognitive neuromotor impairment induced by most benzodiazepines. This paper examines across time the nature of the relationship of effect to serum concentration of three benzodiazepines. Using the same protocol lorazepam, alprazolam, diazepam and placebo were administered to eight healthy males at doses of 0.057, 0.029, 0.286 and 0.000 mg/kg, body weight, respectively for the first study and at 0.028, 0.014, 0.143 and 0.000 mg/kg, respectively, for the second study. After each dose administration multiple measurements were made over a period of 5.5-11.5 h using two different psychomotor performance tests. Serum drug concentrations were also measured. The profiles for diazepam and alprazolam effects demonstrate a stepwise decrement in the slopes of the concentration versus response curves across time, illustrating the rapid development of acute tolerance. In contrast, lorazepam induced a remarkably constant relationship between concentration and effect across testing intervals.

Adult↗

PubMed1984

Proline in the cerebrospinal fluid of normal subjects and Alzheimer's-disease patients, as determined with a new double-labeling assay technique.

Past studies have implicated proline involvement in the function of memory and learning. A new micromethod has been developed that is suitable for measuring proline accurately in as little as 0.1 ml of CSF. In normal human CSF, the average proline level was found to be consistently about 1.3 microM. In the CSF of patients with Alzheimer's disease and mixed dementias, the levels of proline showed no statistically significant difference from proline levels in the CSF of normal controls. Furthermore, the proline levels in the CSF of the Alzheimer's disease patients did not reflect, consistently, the cognitive deficits or the symptomatic severity of the disease. Proline levels in CSF showed no statistically significant change with the age of individuals tested.

Adult↗

PubMed1992

Regional glucose metabolic changes after learning a complex visuospatial/motor task: a positron emission tomographic study.

Regional cerebral glucose metabolic rate (GMR) quantified with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG) was measured twice in 8 young men performing a complex visuospatial/motor task (the computer game Tetris), before and after practice. After 4-8 weeks of daily practice on Tetris, GMR in cortical surface regions decreased despite a more than 7-fold increase in performance. Subjects who improved their Tetris performance the most after practice showed the largest glucose metabolic decreases after practice in several areas. These results suggest that learning may result in decreased use of extraneous or inefficient brain areas. Changes in regional subcortical glucose metabolic rate with practice may reflect changes in cognitive strategy that are a part of the learning process.

Adult↗

PubMed1992

EEG spectra in dyslexic and normal readers during oral and silent reading.

EEGs of extensively screened dyslexics and normal readers were recorded while they read easy and difficult texts silently and orally, and during two other verbal tasks which also differed in overt speaking but had no reading component: narrative speaking and listening to a story. Mid-temporal, central and parietal leads were referenced to linked ears and to Cz. Large differences between tasks and between groups were found. With the linked ears reference, power was higher in all bands in oral reading than in silent reading, with the largest change occurring in the temporal leads. In the theta and low beta bands the difference between oral and silent reading was greater for controls than for dyslexics. These effects were not accounted for by differences in reading speed or in difficulty. Similar results were found in two cohorts of subjects. The difference between groups in theta was found only in the reading tasks. In contrast, the group difference in low beta was also found in the change from listening to speaking. This implies that the oral-silent group difference in theta is related to some aspect of the reading tasks other than the presence or absence of overt speaking, and that the low beta group difference is related to some aspect of overt speaking rather than to reading per se. With the Cz reference no group differences were found. It is suggested that the groups differ in the reading strategies they use, and the degree to which they shift strategy between the silent and oral tasks. We hypothesize that these cognitive differences are reflected in the theta activity from the temporal lobe. While there were many differences between the tasks in alpha power and asymmetry, no group differences involving alpha were found.

Adolescent↗

PubMed1989

Retrieval from semantic and letter-initial categories in patients with Parkinson's disease.

We report the impaired performance by a group of 27 patients with Parkinson's disease (vs matched controls) on semantic and letter-initial verbal fluency tasks, carried out in both single and alternating category conditions. Individual differences in fluency were significantly correlated with confrontation picture naming scores in the patient group, but not in control subjects. However, the PD patients showed no significant correlation between verbal fluency scores, and rate of reciting days of the week as rapidly as possible. Both controls and patients produced more items when retrieving words from a single category than when alternately retrieving words from two categories. The magnitude of the decrement was nonetheless no greater in the patient than in the control population. This finding shows that "task switching" per se is not impaired in PD. We suggest that the verbal fluency deficit, while it may in part be attributed to motor-speech factors, primarily reflects an underlying cognitive disorder.

Cues↗

PubMed1985

Extending formant transitions may not improve aphasics' perception of stop consonant place of articulation.

Synthetic speech stimuli were used to investigate whether aphasics' ability to perceive stop consonant place of articulation was enhanced by the extension of initial formant transitions in CV syllables. Phoneme identification and discrimination tests were administered to 12 aphasic patients, 5 fluent and 7 nonfluent. There were no significant differences in performance due to the extended transitions, and no systematic pattern of performance due to aphasia type. In both groups, discrimination was generally high and significantly better than identification, demonstrating that auditory capacity was retained, while phonetic perception was impaired; this result is consistent with repeated demonstrations that auditory and phonetic processes may be dissociated in normal listeners. Moreover, significant rank order correlations between performances on the Token Test and on both perceptual tasks suggest that impairment on these tests may reflect a general cognitive rather than a language-specific deficit.

Adult↗

PubMed1990

Mesocorticolimbic dopaminergic systems and emotional states.

We have used the technique of in vivo voltammetry with carbon fibre electrodes to investigate further the involvement of ascending mesencephalic dopaminergic systems in emotional states in freely moving rats. In Sprague-Dawley rats, forced locomotion caused an increase in extracellular DOPAC levels in the striatum and nucleus accumbens but not in the prefrontal cortex. Immobilization (4 min) or systemic injection of the anxiogenic agent methyl-beta-carboline carboxylate enhanced extracellular DOPAC in both prefrontal cortex and nucleus accumbens but not in striatum whereas tail-pinch provoked a selective increase in this parameter in the nucleus accumbens. These data suggest that mesolimbic and mesocortical dopaminergic systems can be specifically activated by certain kinds of anxiogenic stimuli. To evaluate the relationship between emotional status and the response of mesocortical dopaminergic neurons to stress, we investigated the effects of stressful conditions on dopamine metabolism in the prefrontal cortex of 2 genetically selected lines of rats which differ drastically in their level of emotionality. Introduction of the animals into an unfamiliar environment, application of a high-intensity loud noise or immobilization were associated with an increase in extracellular cortical DOPAC levels in the hypoemotional (RHA) but not in the hyperemotional (RLA) line. These results suggest that the increase in cortical dopamine metabolism induced by stress is not connected to the emotional reaction caused by the aversive nature of the stressor but may reflect activation of cognitive processes in an attempt to cope with the stressor.

Animals↗

PubMed1985

P300 in major depressive disorder.

This study presents evidence of differences in the P3 (P300) component of the event-related potential (ERP) between major depressed patients and normal controls. ERPs were collected to visual stimuli in a modified continuous performance task. For each subject, the peak of the P3 (also N2 and P2) component was identified for four different electrode sites and three trial types (target, background, and unexpected). P3 amplitude was significantly smaller in the depressed group to target, but not to background stimuli. P3 latency differences were for the most part nonsignificant. Recent evidence suggests that P3 amplitude may not only reflect higher level cognitive functions, but also some degree of emotional involvement for the subject. It is suggested that a decrease in task involvement could account for the smaller P3 in depressives.

Adult↗

PubMed1989

Evoked potentials and psychopathy: a commentary on Raine.

Raine's (1989) paper on evoked potentials and psychopathy is critically reviewed and is found to be wanting at both a conceptual and an empirical level. Conceptually it ignores important issues surrounding the term 'psychopathy' and proposes a theoretical model of psychopathy based on a tripartite division of evoked potentials (early, middle and late) which ignores differences between stimulus modalities. Empirically, the extended sensation seeking model is not well substantiated by the data reviewed. An alternative approach is outlined which views psychopathy in the sense of chronic socially-deviant behaviour as reflecting a maturational deficit, and psychopathy in the personality deviation sense as reflecting deficits in cognitive appraisal processes. This approach embraces the pathological sensation-seeking aspect of psychopathy as well as other important aspects not addressed by Raine's model (lack of moral reasoning and characteristic style of coping both in impersonal and inter-personal contexts.

Brain↗

PubMed1988

A method for the assessment of body image disturbance in patients with eating disorders.

This paper describes a new method for assessing body image disturbances in eating disordered patients. Fifteen bulimic, 25 anorexic, and 24 normal controls served as subjects. All subjects were matched for age and height, and bulimics and controls were matched for weight as well. All subjects completed the Perceived Body Image Scale (PBIS), which required subjects to report on how they see themselves when they look in the mirror, how they think they look, and how they feel themselves to be, reflecting the perceptual, cognitive, and affective aspects of body image, respectively. Subjects also selected their ideal. An objective rating was made. Objective ratings had a high correlation with the subject's weight. Results showed that both eating disorder groups demonstrated more apparent body image disturbance than controls, and that the bulimics showed significantly greater body image dissatisfaction than anorexics or controls. The potential use of the PBIS as a research and clinical instrument is discussed.

Adolescent↗

PubMed1987

Event-related brain potentials and the perception of a phonetic continuum.

Competing predictions concerning phoneme discrimination were tested by means of event-related potentials. In research on speech perception, one tradition stems from the physiology of the auditory system whereas another emphasizes categorical perception which involves a marked psychological component. The stimuli were the end points of the Finnish (i)-(y) continuum together with the intermediate boundary sound. Two of these stimuli were presented in each block of trials. One (the 'standard') had a high probability while the other (the 'deviant') was rare. The so-called mismatch negativity (MMN) component of the ERP in response to deviant stimuli showed a large amplitude and short latency when these two stimuli were pure vowels (i) and (y). When the boundary stimulus and one of the pure vowels comprised the stimulus pair, a smaller and more delayed MMN occurred. This result may be taken as support that the discrimination occurs at a basic physiological level. On the other hand, cognitive perception was reflected in the different latencies of the P3 component to (i) and (y). In sum, the results lend support to multilevel hybrid models in the explanation of vowel perception.

Adult↗

PubMed1994

Words and pseudowords elicit distinct patterns of 30-Hz EEG responses in humans.

Meaningful words, such as moon, and physically similar but meaningless pseudowords, such as noom, were presented visually in a lexical decision task. The EEG was recorded from 17 scalp electrodes. Significant differences between both stimulus classes were observed in evoked spectral responses of the 'gamma-band' approximately 30 Hz. A hemisphere by wordness interaction demonstrated that 30-Hz spectral power over the left hemisphere was reduced after pseudowords only. These results indicate that gamma-band responses reflect the different cognitive processes induced by words and pseudowords. A possible explanation is the following. Synchronous activation of large cortical cell assemblies takes place after word presentation but not after presentation of pseudowords.

Brain↗