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Biomedical subjects

D M Tucker

Publications and source records attributed to D M Tucker.

At least 73 records · Page 4Linked to original sources
PubMed1984

Asymmetry of facial expression in spontaneous emotion.

The observation that emotional expressions are more intense on the left side of the face is consistent with other evidence of the importance of the right hemisphere in emotional communication. However, the question has been raised whether it is truly spontaneous emotional expressions or only posed facial displays that show a left-sided asymmetry. We surreptitiously examined facial asymmetry during spontaneous emotional expressions as subjects remembered happy or sad experiences. These were contrasted with the subjects' posed expressions of happy or sad emotions. Both of these procedures resulted in more intense expressions on the left side of the face. The left-sided advantage was stronger during the spontaneous than the posed displays, and was observed for both happy and sad emotions.

Dominance, Cerebral↗
PubMed1984

Iron status and brain function: serum ferritin levels associated with asymmetries of cortical electrophysiology and cognitive performance.

Levels of serum ferritin and iron were examined in relation to cognitive performance and quantitative EEG measures in 69 normal university students. Higher levels of serum ferritin were associated with greater activation of the left hemisphere relative to the right, indicated by less power in the EEG spectra from left hemisphere electrodes. Iron status was significantly related to cognitive performance on two of the cognitive tasks, and these relationships were consistent with the EEG asymmetries: higher ferritin predicted greater verbal fluency but poorer nonverbal auditory task performance. These results suggest that body iron stores are relevant to specific neurophysiological processes supporting attention.

Cognition↗
PubMed1984

Asymmetric cognitive function in anorexia nervosa.

Three anorexics, one at normal weight, were examined, with a neuropsychological battery including the Halstead-Reitan tests. Their data were contrasted with that of 24 psychiatric controls matched for age, sex and IQ. Individually and as a group the anorexics showed above average verbal/academic scores and impaired spatial skills, whereas visual-motor and problem solving skills were equivalent to controls. Somatosensory recognition was impaired bilaterally in all three patients, and motor skills were low in the two emaciated patients. Other sensory tests and intermanual comparisons of sensory and motor skills were not impaired relative to controls. The findings suggest that a spatial reasoning deficit may be a predisposing or maintaining factor in this disorder. High verbal skills, in contrast, may reflect substantial left hemisphere contributions to the anorexic's cognitive style.

Adult↗
PubMed1984

Plasma substrate response in men and women during marathon running.

Venous blood samples from three male and four female subjects were taken in conjunction with a 26.2-mi marathon race prior to the start (control), at 17 mi, and immediately after the finish. Plasma concentrations of glucose and free fatty acids (FFA) were determined, and the ratio of unsaturated to saturated FFA (U/S FFA) was calculated. Compared to the control value, glucose was unchanged at the finish despite a slight increase at 17 mi (not significant). FFA increased significantly (p less than 0.05) from control to finish and from 17 mi to finish in both groups. The U/S FFA ratio also increased progressively from control to finish. No significant differences were found between male and female groups for any of the measured values. We conclude that blood glucose is maintained at normal levels during prolonged heavy exercise in trained women as in men, and that FFA availability increases with time during strenuous exercise in both sexes.

Adult↗
PubMed1983

Multivariate analysis of EEG coherence: stability of the metric, individual differences in patterning and response to arousal.

When coherence is computed among all pairs of a multichannel EEG, the resultant matrix can be de-structured with conventional multivariate analysis procedures to characterize the patterning of electrophysiologic information at each frequency band of the EEG across brain regions. Six right-handed young men had EEG data recorded from left and right frontal, temporal, parietal, and occipital locations during three visits to the laboratory at one week intervals. During each session, data were recorded during a relaxation period, an alert resting period, and as loud white noise was presented. Factor analysis of coherence matrices showed a model pattern of a large posterior factor and an anterior factor, both of which were right-lateralized, plus a residual factor that was most often left-lateralized. Four of the six men showed this pattern on each occasion, particularly for the delta and the theta bands. Two men showed variant patterns, which were also stable over time. A priori de-structuring of the matrix into partial multiple intrahemispheric and inter-hemispheric coherences also showed generally higher coherences on the right side, with the exception of left occipital inter-hemispheric values. Effects of arousal manipulations were not striking, but the factor patterns suggested increases in right hemisphere coherence for the alpha and beta bands during high arousal.

Adult↗
PubMed1983

Lateralized cognitive style and self-description.

A scale of hemispheric preference in cognitive style was related to self-report measures of emotional functioning, with the hypothesis that persons who rely on cognition characteristic of one hemisphere may also manifest emotional characteristics of that hemisphere. In two studies, university students characterizing themselves as preferring a cognitive style representative of right hemisphere processes endorsed more positive emotional orientations. This finding may suggest a more optimistic attitude, but may also reflect a tendency to deny negative traits; a right hemispheric cognitive style was associated with a positive self-report bias. These observations in normals have interesting parallels to the changes in emotional orientation and self-description bias that follow lateralized brain lesions or temporal lobe epilepsy.

Adult↗
PubMed1982

Plasma volume and blood metabolites in middle-aged runners during a warm-weather marathon.

Plasma volume (PV), blood-borne substrate, and electrolyte responses to a warm weather (WBGT 15.5-24.5 degrees C) marathon race were observed in four male and two female runners averaging 48 years of age. Additionally, continuous recordings were made of heart rate (HR) in three, and of rectal temperature (Tre) in two of the men. The race was finished by three of the men, with an average time of 3.61 h, a running pace estimated to require from 60-66% of the runner's VO2 max. Near steady state levels for HR and Tre, ranging from 140-165 beats . min-1 and from 38.5-39.3 degrees C, respectively, were reached early in the race. Total and percentage weight losses for the finishers were 2.52 kg and 3.9%, 2.18 kg and 3.4%, 4.77 kg and 6.7%, respectively; corresponding reductions in PV for these runners were 5.4%, 13.2%, and 27.4%. Pre-race control and immediate post-race serum glucose concentrations averaged 109 and 154 mg . dl-1 respectively. Final blood lactate values ranged from 11-42 mg . dl-1. Thus, it may be concluded that middle-aged runners who were successful in completing the marathon in a warm environment did so while maintaining steady state levels of HR and Tre. Although only water was ingested during the race, serum glucose for the finishing runners remained above, while serum [Na+] and [Cl-] remained within +/- 8% of, control values throughout the run. Complete data obtained from only one of the runners suggest that the initial exercise-induced reduction in PV is not augmented by subsequent cumulative dehydration provided water intake during the race is sufficient to limit weight loss to less than 4%.

Adult↗
PubMed1982

Longitudinal study of brain function and depletion of iron stores in individual subjects.

Seven men living in a controlled research unit showed decrements in iron stores due to repeated phlebotomy. For each subject, weekly measures of cognitive task performance, electroencephalographic (EEG) power and Event-Related Potentials (ERPs) were examined in relation to serum ferritin level. No reliable relationships of ferritin level to cognitive performance ability were observed. Some EEG findings appeared similar to previous observations on EEG data and iron status in cross-sectional research. For four of the seven subjects, asymmetries of EEG power in the occipital electrodes appeared related to the decline in iron status over time.

Adult↗
PubMed1981

Right frontal lobe activation and right hemisphere performance. Decrement during a depressed mood.

Evidence from psychiatric patients has suggested that depressive affect may coincide with a decrement in the functioning of the right cerebral hemisphere. We have observed that college students who reported greater depression also reported less vivid imagery. Students undergoing experimental induction of depressive and euphoric moods in the laboratory showed an auditory attentional bias and impaired imagery during the depression condition, while their arithmetic task performance was unchanged. A second mood-induction experiment indicated a depressed mood to be characterized by asymmetrical EEG activation over the frontal lobes, with relatively greater activity in the right frontal region. These observations suggest that anterior regions of the brain may modulate the differential effects of emotional arousal on the information-processing capacities of the cerebral hemispheres.

Arousal↗
PubMed1981

Comparison of verbal IQ, Tactual Performance, Seashore Rhythm and Finger Oscillation Tests in the blind and brain-damaged.

Presented a brief clinical report that compared the performance of blind patients (N = 60) with and without neurologic disorder on verbal subtests of the WAIS, Tactual Performance Test, Seashore Rhythm Test and Finger Oscillation Test. Results suggest that the tactual performance test is the most useful neuropsychologic measure in differentiating non-brain-damaged and brain-damaged blind patients. Results also suggest the possibility of limited recovery of right hemisphere functioning in blind, brain-damaged patients because of loss of visual input.

Adolescent↗
PubMed1981

Dietary fiber and personality factors as determinants of stool output.

We examined effects of fiber on stool output, since this is one of the primary mediating variables for the hypothesized relationship between fiber and disease. Total neutral detergent fiber in the dietary fiber source was predictive of stool weight but not frequency. Substantial individual differences in stool output remained when dietary factors were controlled. Personality measures were used to predict stool weight and frequency independently of diet, and accounted for about as much variance in stool output as did dietary fiber. These results suggest that personality factors predispose some persons to low stool output. These individuals may benefit particularly from dietary fiber.

Adolescent↗