ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb02379.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractVisual selective attention improves our perception and performance by modifying sensory inputs at an early stage of processing. Spatial attention produces the most consistent early modulations of visual processing, which can be observed when attention is voluntarily allocated to locations. These effects of spatial attention are similar when attention is cued in a trial‐by‐trial, or sustained, fashion and are manifest as changes in the amplitudes, but not the latencies, of evoked neural activity recorded from the intact human scalp. This modulation of sensory processing first occurs within the extrastriate visual cortex and not within the striate or earlier subcortical processing stages. These relatively early spatial filters alter the inputs to higher stages of visual analysis that are responsible for feature extraction and ultimately object perception and recognition, and thus provide physiological evidence for early precategorical selection during visual attention. Moreover, the physiological evidence extends early selection theories by providing neurophysiologically precise information about the stages of visual processing affected by attent

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03400.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effects of caffeine and smoking on cognitive performance, subjective variables, heart rate, and EEG were assessed in two sessions. In one session, subjects received caffeine (2.5 mg/kg bodyweight), while in the other they received placebo. In both sessions (hey smoked a cigarette (8 cued puffs) having a nicotine yield of 1.2 mg. Caffeine produced an increase in self‐reported muscular tension and tended to increase anxiety and delta magnitude. Smoking facilitated performance of a paper‐and‐pencil math task and increased heart rate. Smoking also appeared to produce cortical activation as indexed by decreased right frontal delta, decreased right centro‐parietal theta, globally increased alpha, and increased centro‐occipital/decreased posterior‐temporal betal. Smoking also increased central/decreased posterior‐temporal beta2. Smoking and caffeine did not interact for any measure, suggesting that the epidemiological link between smoking and coffee drinking may have a non‐pharma

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03401.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractCardiovascular responses to a series of laboratory stressors were examined in middle‐aged Type A and Type B men. The subjects were 30 patients with diagnosed myocardial infarction (NYHA Class 1) and 26 age‐matched healthy controls. All subjects were nonsmokers in the normotensive range, and none were on medication. Blood pressure, heart rate, forearm blood flow and resistance, and impedance cardiography‐determined response variables were obtained during performance and recovery periods of both mental and physical tasks. The patients showed elevated reactivity in systolic blood pressure and cardiac output and prolonged systolic lime ratio during mental stress tasks and elevated total peripheral resistance and lower cardiac output and stroke volume during physical tasks, as compared with control subjects. Thus, the difference in blood pressure reactivity between patients and controls appeared to be primarily dependent on the vascular component during physical tasks, whereas the mental tasks promoted a hemodynamic response pattern more consistent with beta adrenergic activation. Type A men, irrespective of coronary status, showed larger systolic and diastolic blood pressure response to both mental and physical stress than did Type

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03402.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis study focused on the effects of common and distinctive stimulus components on the generalization of the orienting response (OR) to significant stimuli. Compound pictorial stimuli were used as the relevant items memorized by the subjects. Skin conductance responses were measured during the subsequent presentation of a stimulus sequence that included a test stimulus that shared some common components with the relevant one. The two types of stimulus components (common and distinctive) were independently manipulated. As predicted by the feature‐matching theory, both types of features affected OR generalization, but the distinctive components effect was due mainly to a large decline in OR with the introduction of the first distinctive component. As hypothesized, no interaction was observed between the effects of common and distinctive components. Contrary to expectations, similar OR generalization was obtained regardless of whether the test stimulus was constructed by deleting stimulus components from the relevant stimulus or by adding components to that stimulu

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03403.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractWe investigated central nervous system correlates of simple phobie fear, Regional cerebral blood flow (rcBF) was measured using position emission tomography(PFT) in eight volunteers with symptomatic spider phobia that were exposed to visual phobogenic and neutral stimuli Diazepam (0.1 mg/kg body weight i.v.) or placebo was administered under double blind conditions after initial PFT scans. The PFT scans were then repeated. The presence of fear was confirmed by rating procedures and increased number of nonspecific electrodermal fluctuations and by higher heart rate during phobic than during neutral stimulation. Phobic as compared to neural stimulation elevated the retional to whole brain (relative) CBF in the secondary visual cortex but reduced relative rCBF in the hippocampus, prefrontal, orbitofrontal, ttemporopolar, and posterior cingulated cortex. Dia/epam treatment did not affect the relative rCBF or the subjective or physiological fear indices. The observed rCPF pattern replicates our previous findings in snake phobics (M. Fredrikson et al.[1993]Psychophysiology, 30, 127, 131 G. Wik et al. [1993]Psychiatry Research (Neuroimaging), 50, 15–24) and indicated that fear and anxiety affect cortical areas outside the classic limbie system area

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03404.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis study was designed to examine some of the psychoneuroendocrine effects of exercise‐induced emotional experiences and the mediating effects of environmental setting and subjects’ attentional focus. Trained runners were tested during an outdoor run and two indoor treadmill running conditions. Excretions of catecholamines and Cortisol significantly increased after all running conditions but not after a control condition. Results indicate that patterns of endocrine and concomitant emotional change through exercise differ when environmental setting and attentional focus are altered in such a way that a normally pleasant task such as running becomes tedious and negatively evaluated. These findings support the notion that setting, attention, and cognitive appraisal may alter the emotional experience associated with physical exerc

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03405.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAuditory event‐related potentials (ERPs) in response to 50‐ms tones were recorded from the human scalp. A standard stimulus (p= .88) and three different deviants were randomly presented via earphones. There were two one‐dimensional deviants (one frequency and one location deviant) and one two‐dimensional deviant, with changes in both frequency and location. In one condition, subjects read a book and ignored the auditory stimuli, whereas in another condition they tried to discriminate deviants from standards. In the ignore condition, the two‐dimensional deviant elicited an enhanced mismatch negativity (MMN) as compared with the MMNs elicited by the one‐dimensional deviants. The temporal and the topographic distributions of the two‐dimensional MMNs could be modeled by adding the one‐dimensional MMNs. This additivity of the MMNs probably results from the independent activity of separate neural populations generating the frequency and the location MMN. In the attend condition, the deviance‐related ERP effects were not additive in the N2b and P3 range, implicating that the neural processes involved in the conscious detection of changes in location and frequency wer

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03406.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe reliability of resting electroencephalogram (EEG) power spectra was assessed for 49 normal and 44 schizophrenic subjects. We specifically examined internal consistency reliability to determine how much EEG data are necessary to ensure small measurement error. Twenty‐one 8‐s epochs of resting EEG were collected from each subject from site Cz. Epochs containing artifacts or blinks were eliminated. Power was computed in the bands delta (0.125–3 Hz), theta (3.125–8 Hz), alpha (8.125–13 Hz), betal (13.125–20 Hz), beta2 (20.125–25 Hz), and beta3 (25.125–30 Hz). Internal consistency was computed using coefficient alpha (Cronbach, 1951). Results for both groups indicated that eight artifact‐free epochs of data were sufficient to give a coefficient alpha value of around .9. The schizophrenic and normal groups did not differ with respect to coefficient alpha. The proportion of artifacts in the data from the schizophrenics indicated that to obtain eight artifact‐free epochs from members of each group, 40% more data would be required from

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03407.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe startle reflex response increases during aversive stimulus processing. This study examined whether differing response sets affected startle potentiation during anticipation of an aversive event. Two groups received a noxious noise blast following a 6‐s warning cue. Subjects in the active group could press a switch to stop the noise; yoked passive subjects received the same noises with no control. Subjects in a yoked control group heard a soft tone following cue offset. Acoustic startle probes were presented during some of the warning periods and during some of the intertrial intervals. The major finding was that the active and passive groups did not differ in startle potentiation. In comparison with controls, startle reactions for both groups were larger and faster during the warning cue than between trials. The results suggest that the startle reflex indexes defensive response mobilization independently of specific task demand

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1995.tb03408.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY