Psychophysiological response patterns in vascular and muscle-contraction headaches

The psychophysiological response patterns of 43 headache subjects were compared to the response patterns of 11 nonheadache control subjects. The headache group was composed of subjects diagnosed as suffering from either muscle-contraction (N=11),classic migraine (N=11),common migraine (N=11),or mixed (N=10)headache. Discriminant analyses indicated that (1) the headache groups could be perfectly differentiated from the nonheadache control group after a period of relaxation and during a period of psychological stress and (2) the stress condition differentiated among the various headache groups. In general, the headache groups showed a higher level of arousal and were more responsive to stress. Also, the response pattern profiles differed among the headache groups in the stress condition. Muscle-contraction subjects tended to respond with higher frontal EMG, and classic migraine and mixed headache groups tended to respond with larger cardiovascular responses. This research was supported in part by a N.I.H. Biomedical Grant awarded to Louisiana State University.     

Effect of positive and negative emotion on stimulus-preceding negativity prior to feedback stimuli

Stimulus-preceding negativity (SPN) was recorded to investigate the effect of positive and negative emotion on the SPN preceding feedback stimuli. In the time-estimation task in which an acoustic stimulus was presented 3 s after a voluntary movement, (1) the negative valence (aversive band noise and pure tone) and (2) the positive valence (reward and no-reward) of feedback stimuli were manipulated. During noise conditions, participants received the band noise as a feedback stimulus except when their time estimations were accurate. They received a monetary reward for accurate time estimations under the reward conditions. The prefeedback SPN was larger under reward than no-reward conditions. In addition, the prefeedback SPN in the noise condition was larger compared with the pure tone condition. Our results appear to suggest that emotional anticipation is important in eliciting the prefeedback SPN.     

An insecure base: Attachment style and orienting response to positive stimuli

In adults as in infants, psychological attachment to close others provides a “secure base” for exploration and pursuit of opportunities. Insecure attachment is likely to interfere with this function. The present study examined the association of individual differences in adult attachment style with peripheral physiological measures of automatic orienting to several kinds of positive, rewarding stimuli. Attachment style was largely unrelated to extent of heart rate deceleration in response to the appearance of positive emotion‐eliciting images. However, attachment avoidance was associated with reduced skin conductance responding to the onset of several kinds of positive stimuli. These findings suggest that working models of relationships with close others have complex implications for the early stages of responding to opportunities for reward presented by the environment.     

Empathy-related responses to moving film stimuli depicting human and non-human animal targets in negative circumstances

Research supports an "ingroup empathy hypothesis" of higher empathy-related psychophysiological responses towards individuals of the same ethnicity. However, little research has investigated empathy-related responses to non-human targets graded for phylogenetic relatedness. Participants (N=73) were presented with film stimuli depicting humans, primates, quadruped mammals and birds in victimized circumstances. Phasic skin conductance responses (SCR) and subjective empathy-related ratings to the film clips increased as phylogenetic similarity to humans increased across animal groups, revealing an empathic bias towards human stimuli. Participants also completed a trait empathy scale. High trait empathy participants gave higher subjective empathy ratings than moderate and low trait empathy participants. Low trait empathy participants showed less corrugator electromyographic activity than moderate and high empathy participants. The moderate trait empathy participants showed higher SCR than the high group. The results confirm an effect of phylogenetic similarity in subjective self-report and psychophysiological measures of empathy-related responses. Additionally, convergence between subjective and objective measures of empathy-related responses was observed.     

Psychophysiological response of ADHD children to reward and extinction

In this study, we examined heart rate and skin conductance levels of 18 children with attention-deficit hyperactivity disorder (ADHD) and 18 normal children as they performed a repetitive motor task during reward and extinction conditions. Fowles (1980, Psychophysiology, 17, 87–104; 1988, Psychophysiology, 25, 373–391) suggested that psychophysiological responsivity reflects activity in two of Gray's (1982, The neuropsychology of anxiety, Oxford University Press; 1987, The psychology of fear and stress, Cambridge University Press) motivational systems; heart rate reactivity during reward reflects activity in the behavioral activation system, and skin conductance reactivity during extinction reflects activity in the behavioral inhibition system. As predicted, control children showed increased heart rate when reward was present and increased skin conductance when reward was removed. Compared with controls, ADHD children failed to show increased skin conductance levels during extinction, suggesting a weak behavioral inhibition system. ADHD children also displayed faster heart rate habituation to reward.     

Interaction of CO2 and positive and negative exercise stimuli on the ventilation in man

Ventilatory response curves to CO₂ were determined at rest and during different workloads and pedal rates, of negative and positive exercise in four subjects. It appeared that the slope of only the lower part of the curvilinear ventilatory response curve to CO₂ (at low stimuli) shows a significant positive correlation with the metabolism, independent of the type of excercise, force or speed of muscle contraction. The slope of the higher part was only determined by the CO₂ stimulus. An interaction of low CO₂ stimuli with an unknown exercise-stimulus is suggested, which results in a response of the ventilation to CO₂, proportional to the metabolism.     

Temporal response patterns of the human sinus node to brief carotid baroreceptor stimuli.

1. A new technique, timed, quantitative neck suction was used to establish in normal man the temporal response patterns of the sinus node to brief baroreceptor stimuli. 2. Maximum sinus node inhibition occurred when stimuli were delivered about 0-75 sec before the anticipated appearance of the subsequent P wave; less pulse interval prolongation occurred when stimuli were delivered earlier, or later in the cardiac cycle. 3. The timing of maximum sinus node responsiveness appeared to be independent of base-line cardiac cycle length. 4. The duration of the baroreceptor-cardiac reflex are (the time from the onset of baroreceptor stimulation until the earliest occurrence of pulse interval prolongation) averaged 0-24 sec. 5. Pulse interval prolongation was proportional to baroreceptor stimulus strength and duration. 6. The results suggest that in man, sinus node responsiveness to baroreceptor stimuli depends critically upon the timing of stimuli within the cardiac cycle.     

Exercise induced asthma: response to disodium cromoglycate in skin-test positive and skin-test negative subjects

Thirty-nine asthmatic subjects, aged 5-50 and each with a history of exercise-induced asthma, were classified according to their skin response to prick tests using nineteen common antigens. Ten had negative skin tests, four responded only to D. farinae and twenty-five had multiple positive responses. Each patient then carried out three exercise tests on a treadmill, each test on a separate day. A control test was followed, in random order, by an exercise test after administration of disodium cromoglycate or of a placebo. In all groups, the mean fall in peak expiratory flow rate was less after disodium cromoglycate than after placebo, but the difference was significant only for the skin-test positive groups. Similarly, positive skin-test groups had a higher incidence of drug responders than did the negative skin-test group. These observations are discussed.     

Expansion of CD16 positive and negative human NK cells in response to tumor stimulation

NK cells are innate immune lymphocytes that express a vast repertoire of germ‐line encoded receptors for target recognition. These receptors include inhibitory and activating proteins, among the latter of which is CD16, a low affinity binding Fc receptor. Here, we show that human NK cells expand in response to stimulation with various tumor cell lines. We further demonstrate that the tumor‐derived expansion of NK cells is accompanied by rapid, cell‐dependent, changes in CD16 expression levels. We show that in NK cells expanded in response to the EBV‐transformed cell line 721.221, CD16 is shed and therefore approximately half of the expanded 721.221‐derived NK‐cell population does not express CD16. We also show, in contrast, that in response to 1106mel cells, CD16 expression is maintained on the cell surface of the expanded NK cells due to an antibody‐dependent mechanism. Our results may provide a basis for the selective expansion of NK cells that may be used for tumor immunotherapy.     

Emotionally negative stimuli are resistant to repetition priming

The study was aimed at testing whether the repetition priming was influenced by affective valence of visual stimuli. Neutral and emotionally negative words and images were shown in the right or in the left visual field. Each of the stimuli was repeated twice, with 2 to 4 other stimuli presented between repetitions. The subjects' task was detection of a stimulus. Responses were given by index finger of the left or right hand. The task was the same for all stimuli, the new and the repeated ones. Reaction times were measured and analyzed. The effects of repetition priming were significant only for neutral stimuli: repeated items were detected faster than the new ones. For emotionally negative items, generally no priming was observed. Interestingly, new emotionally negative stimuli were detected significantly faster in comparison to neutral stimuli. The results are discussed in relation to attentional processes involved in processing of affective stimuli.     

Cytokines and costimulatory molecules: positive and negative regulation of the immune response to Cryptococcus neoformans

Cytokines are small proteins or glycoproteins that transmit information from one cell to another. Most cells in the body secrete and respond to cytokines and their effects have been described on a myriad of cellular functions. Cytokine interactions may not be linear, thus making the system extremely intricate and with unpredictable features. Therefore, each model of disease may be unique, with its own mechanism of autoregulation dictated by positive and negative feedback involving cytokines and costimulatory molecules. The emergence of some cytokines over others in the course of Cryptococcus neoformans infection may characterize a positive or negative outcome of cryptococcosis. Much less is known about the influence of costimulatory molecules in regulating C. neoformans immune response. The available information indicates a critical role for proinflammatory cytokines such as tumor necrosis factor alpha and interleukin 12 (IL-12). The positive role of interferon gamma in infected tissue as an inducer of antimicrobial function of innate immune cells and as positive feedback for IL-12 induction appears to be indisputable. In vitro studies indicate that costimulatory molecule expression appears to be regulated on antigen-presenting cells by C. neoformans and increased expression of B7-1 and CD40 on these cells may promote a protective response. These studies await confirmation in an in vivo system. The interplay between cytokines and costimulatory molecules has been scarcely explored and additional details are needed to better understand how they convey positive and negative information to immune cells in response to C. neoformans.     

Variations in the serotonin-transporter gene are associated with attention bias patterns to positive and negative emotion faces

Both attention biases to threat and a serotonin-transporter gene polymorphism (5-HTTLPR) have been linked to heightened neural activation to threat and the emergence of anxiety. The short allele of 5-HTTLPR may act via its effect on neurotransmitter availability, while attention biases shape broad patterns of cognitive processing. We examined individual differences in attention bias to emotion faces as a function of 5-HTTLPR genotype. Adolescents (N = 117) were classified for presumed SLC6A4 expression based on 5-HTTLPR—low (SS, SL_G, or L_GL_G), intermediate (SL_A or L_AL_G), or high (L_AL_A). Participants completed the dot-probe task, measuring attention biases toward or away from angry and happy faces. Biases for angry faces increased with the genotype-predicted neurotransmission levels (low > intermediate > high). The reverse pattern was evident for happy faces. The data indicate a linear relation between 5-HTTLPR allelic status and attention biases to emotion, demonstrating a genetic mechanism for biased attention using ecologically valid stimuli that target socioemotional adaptation.     

Psychophysiological discriminants of depression at rest and in response to stress

Examined heart rate, skin conductance, and finger pulse amplitude at rest and in response to stress in a group of 10 chronically depressed Ss and a closely matched set of controls. While all physiological channels revealed a significant main effect attributable to the conditions of rest, anticipation of stress, and stress, only the skin conductance channel revealed a significant group effect. No significant interaction effect was revealed for any of the channels. The results indicate that skin conductance level may have some potential in assessing the level of depression in clients and that attempts to control directly skin conductance level, as in biofeedback, may prove to be a useful adjunct in the treatment of depression with the characteristics employed in this study.     

Ventilatory response to CO2 at rest and during positive and negative work in normoxia and hyperoxia

Summary Ventilation versus alveolar relationships were determined by the steady-state method in 6 normal male subjects at rest and during positive and negative work at one load in both normoxic and hyperoxic condition. In 5 subjects the slopes of the lines during positive and negative work increased in normoxia as compared with rest. This effect was less evident in hyperoxia. It was also found that the slopes of the lines in positive and in negative work were about the same in both normoxic and hyperoxic conditions. Oxygen uptake and CO₂ production during positive work is higher than during negative work.These results suggest that: 1) the disagreement between various authors on the change of the slope of the line may be due to the differences in the method of calculation of the slope or the method of the determination of lines; 2) the stimuli from the muscle spindles in the working muscle during exercise probably do not contribute to the increase in ventilatory response to CO₂; 3) the increased slope of the normoxic line during exercise may be due to the interaction of several factors such as impulses from working muscles, chemosensitivity of central or peripheral chemoreceptors, adrenal-sympathetic pathways or temperature; 4) respiratory oscillations of or do not seem to influence the respiratory response to CO₂.This study was supported in part by a grant from the Netherlands Organization for the Advancement of Pure Research (Z.W.O.)     

Temporal patterns of the rabbit's nictitating membrane response to compound and component stimuli under mixed CS-US intervals

The acquisition of the rabbit's nictitating membrane response to a tone and light compound and to its components was examined when compound presentations were reinforced at one conditioned stimulus-unconditioned stimulus (CS-US) interval and individual component presentations were reinforced at another CS-US interval. Examination of the time course of the CRs revealed that (a) despite the mixture of CS-US intervals, conditioned response (CR) timing remained accurate, that is, CRs reached their peaks at the alternative points of US delivery; (b) the momentary magnitude of the CR to the compound was predominantly an additive function of the CR magnitude to the individual components; but (c) there was modest evidence of differentiation between the compound as a unit and the individual components. The results are discussed in terms of their implications for the study of the neural substrates of temporal and sensory integration as they modulate CR acquisition.     

Heart rate response is longer after negative emotions than after positive emotions

Summary. Recent ambulatory findings showing comparable cardiovascular effects of positive and negative emotions are not consistent with the assumed etiological role of negative affect in stress-related diseases. We tested the hypothesis that regardless of initial reactivity, responses associated with negative emotions would be prolonged compared to responses associated with positive emotions. During 8 h, 33 healthy subjects from a general population reported their emotional arousal, emotional valence and physical activity and recorded their heart rates (HR) after a beep at each 60th min (‘initial HR’; T0), followed by two ‘prolonged activation’ recordings, respectively 5 min later (T1) and 10 min later (T2). While emotional arousal and activity predicted initial HR, prolonged activation at T1 was solely predicted by emotional valence (negative affect) at T0, independent of emotional recovery. The results lend support to the hypothesis that cardiovascular activation after negative emotions last longer than after positive emotions. This finding is consistent with the view that prolonged activation, and not so much reactivity, might be a mechanism underlying the etiological role of negative emotions (‘stress’) in somatic disease. Perseverative cognition (worry, rumination) might be responsible for this prolonged activation.