摘要:

ABSTRACTThis paper applies a functional‐evolutionary perspective to fear in the context of encounters with animals and threatening humans. It is argued that animal fear originates in a predatory defense system whose function is to allow animals to avoid and escape predators. Animal stimuli are postulated to be differentially prepared to become learned elicitors of fear within this system. Social fears are viewed as originating in a dominance/submissiveness system. The function of submissiveness is to avert attacks from dominating conspecifics. Signs of dominance paired with aversive outcomes provide for learning fear to specific individuals. Data which in general are interpreted as supportive of this conceptualization are reviewed. To explain the mechanism behind the causal relationships suggested in the evolutionary analysis, an information‐processing model is presented and empirically tested. It is argued that responses to evolutionary fear‐relevant stimuli can elicit the physiological concomitants of fear after only a very quick, “unconsciousness,’ or preattentive stimulus analysis. Support for this notion is presented from backward masking studies where it is demonstrated that conditioned autonomic responses to fear‐relevant stimuli can be elicited even with mas

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00608.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTTo investigate the generality of reported spinal monosynaptic reflex amplitude reductions in hyperkinetic children, H‐reflexes were recorded in unmedicated male hyperkinetic and age‐matched control children during relaxed wakefulness. Reflex amplitude variations were examined in response to either paired stimuli delivered at varying inter‐pair intervals (recovery function procedure) or trains of stimuli delivered at varying rates (homosynaptic depression procedure). As a group, hyperkinetic children demonstrated reflex amplitude reductions in the recovery function region of secondary facilitation (50–300 ms). However, these subjects could be divided into those showing either significantly exaggerated or reduced secondary facilitation relative to controls. Group differences present during paired‐stimuli procedures were maintained during repetitive stimulation. Furthermore, response reduction or enhancement in both paradigms extended beyond stimulus intervals encompassing the region of secondary facilitation. The results demonstrate that hyperkinetic children homogeneous for commonly utilized diagnostic criteria may exhibit disparate resting levels of spinal motoneuronal excitability which vary significantly from normal levels. Current thinking regarding bases for secondary facilitation and homosynaptic depression suggests the presence of both neurochemical and neurophysiological disregulation in hyp

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00609.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTEason, Oakley, and Flowers (1983,Physiological Psychology, 11, 18–28) have recently described changes in the B‐wave and after‐potential of the human electroretinogram (ERG) during spatial selective attention. These results suggested that centrifugal modulation of retinal input may play a role in visual attention. We investigated this effect in two experiments in which subjects attended to sequences of flashes in one visual half‐field while ignoring similar flashes in the opposite half‐field. Visual event‐related potentials (ERPs) were recorded from electrodes placed at periorbital and scalp sites, while the ERG was simultaneously recorded using a gold‐foil electrode contacting the cornealscleral surface of the right eye. Selective visual attention was evident in an enhancement of the scalp‐recorded N150 component of the visual ERP to flashes in the attended half‐field. However, no effect of attention was observed on the B‐wave or after‐potential of the ERG. Long‐latency positive shifts related to attention were demonstrated in the corneal‐scleral recording and are discussed with respect to volume

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00610.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTThe present investigation sought to determine whether the relationship between event‐related potential (ERP) principal components analysis (PCA) factor scores and analogous waveform amplitude measures could be improved by high‐ and low‐pass filtering the waveforms at a suitable cutoff value. Visual oddball ERPs were submitted to a varimax‐rotated PCA performed on the variance/covariance matrix. Principal components corresponding to P300 and Slow Wave were obtained. In keeping with the fact that the variance/covariance PCA analyzes sources of variance around the grand mean waveform, the grand mean waveform was subtracted from each of the original waveforms, and baseline‐referenced amplitude measurements were then made of P300 and Slow Wave. P300 was measured both as the maximum positive peak between 275 and 425 ms, and as the average amplitude during that interval. Slow Wave was measured as the average amplitude during the interval 400–700 ms. The P300 measurements were then repeated after high‐pass filtering the difference waveforms at 2 Hz. Slow Wave measurements were repeated after low‐pass filtering at 2 Hz. The value of 2 Hz was chosen as giving a reasonable cutoff based upon estimates of the wavelengths of the two components derived from inspection of their respective factor loading vectors.The correlation between factor scores and amplitude measurements was .94 for unfiltered Slow Wave and actually declined slightly but significantly to .91 when the waveforms were low‐pass filtered. It would appear that Slow Wave factor scores emerging from a PCA can be fairly well approximated by a time‐band measurement algorithm, and that this approximation is not improved by low‐pass filtering. For both filtered and unfiltered measurements of P300, the amplitude/factor score correlation was significantly higher for the time‐band method than for the peak method. Further, high‐pass filtering at 2 Hz improved the time‐band/factor score correlation significantly from .62 to .75. This improvement is probably because the unfiltered measurements were tapping sources of variance due both to the higher frequency P300 component as well as a simultaneously active, lower frequency Slow Wave component. Theoretical implications of t

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00611.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00612.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTHeart rate and various metabolic and ventilatory indices were monitored while 24 young males engaged in two psychologically challenging tasks, mental arithmetic and Raven's matrices. Each task was structured to present subjects with three levels of difficulty: easy, hard, and impossible. Measurements were also made while subjects undertook graded isotonic exercise on a bicycle ergometer; for each subject, heart rate was plotted against oxygen consumption over the various exercise loads. Knowing oxygen consumption during the psychological tasks, these regression equations permitted the calculation of expected heart rates during each task condition, and thus the computation of ‘additional heart rate’ as the difference between actual and predicted heart rate values. Cardiac activity, whether represented as additional heart rate or as the difference between resting and task heart rate levels, was sensitive to variations in difficulty level. In both tasks the easy condition elicited significantly less cardiac activity than both the hard and the impossible conditions. Changes in oxygen consumption and carbon dioxide production did not vary significantly with difficulty. Subjects' self‐reports of active engagement and arousal paralleled the cardiac effects; in both tasks the easy condition was experienced as relatively unengaging and unaro

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00613.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00614.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTForty female volunteers participated in a study to investigate whether facial EMGs could be used as measures of affect during sexual arousal. Audiotaped narratives were used to induce the following affect‐sexual states: 1) pleasant affect + sexual arousal, 2) unpleasant affect + sexual arousal, 3) pleasant affect + no sexual arousal, and 4) unpleasant affect + no sexual arousal. EMG activity was recorded bilaterally from the corrugator and zygomatic muscle regions. Corrugator muscle activity was significantly greater in response to the unpleasant stimulus conditions. This relationship held for both the non‐sexual and sexual conditions, suggesting that corrugator muscle activity may provide a reliable index of negative affect during sexual arousal. Zygomatic activity was significantly greater during the sexual as compared to the non‐sexual stimuli, but did not increase as a function of pleasant affect. Greater left than right corrugator muscle activity was observed in response to the sexual stimuli. Left muscle superiority was also noted for zygomatic muscle activity, in response to the sexual unpleasant stimulus. Issues related to the interpretation of lateralized muscle activity are disc

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00615.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00616.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTIn conditions demanding selective attention, the stimuli to be attended elicit an event‐related brain potential (ERP) component called the processing negativity (PN). However, some previous results might be interpreted as suggesting that even the stimuli to be ignored elicit some PN, at least if they physically resemble those to be attended. This “generalization’ of PN was studied by presenting three equiprobable tones differing in pitch in random order, one of the tones at a time being the target to be counted. The small pitch separation between the three tones was of different magnitude in different blocks. A PN was observed in the ERPs to the counted stimuli but was even elicited, though with a smaller amplitude, by the nontargets, at least by those which physically resembled the targets. The latter, “generalized’ PN was larger in amplitude with a smaller pitch separation between the nontarget and target stimulus. These results support the interpretation that PN reflects a cerebral matching process between the sensory input and a voluntarily maintained neuronal representation of the stimulus to be attended, the “attentional trace.’ Moreover, these results indicate rather high discrimination accuracy of this stimulus‐selection mechanis

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1986.tb00617.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY