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Biomedical subjects

Jaime Vila

Publications and source records attributed to Jaime Vila.

11 recordsLinked to original sources
PubMed2006

Fearful and sexual pictures not consciously seen modulate the startle reflex in human beings.

BACKGROUND: Animal and human studies consistently have demonstrated that the startle reflex elicited by intense auditory stimulation is enhanced by the previous presentation of fear-evoking stimuli. There is also growing and varied evidence of the nonconscious processing of fear stimuli in human beings eliciting brain and autonomic fear responses. METHODS: We report two studies using the startle probe paradigm and the backward-masking procedure to examine the modulation of the eye-blink component of the startle reflex by consciously and nonconsciously presented emotional pictures. RESULTS: Conscious and nonconscious presentation of fearful pictures amplified the magnitude of the startle reflex in both studies. The opposite tendency was observed for conscious and nonconscious presentation of sexually attractive pictures in the second study. CONCLUSIONS: These findings support the notion that negative (and possibly positive) biologically relevant stimuli can be nonconsciously processed, presumably via amygdala activation, and can affect behavioral responding.

Acoustic Stimulation↗
PubMed2005

Subjective and physiological reactivity to chocolate images in high and low chocolate cravers.

Cue-reactivity to chocolate images was assessed using self-report and physiological measures. From a pre-screening sample of 454, young women were selected and assigned to high and low chocolate craving groups (N = 36/group). The experimental procedure consisted in the elicitation and measurement of the cardiac defense and startle reflexes while viewing chocolate and standard affective images selected from the International Affective Picture System. In response to chocolate images, high cravers reported more pleasure and arousal but less control than low cravers. In high cravers, viewing chocolate images inhibited the cardiac defense but potentiated the startle reflex, as compared to low cravers. The results confirmed at the physiological level that the motivational state that underlies the experience of chocolate craving include both appetitive (inhibition of the defense reflex) and aversive (potentiation of the startle response) components. The findings supported a motivational conflict theory of chocolate craving.

Adult↗
PubMed2005

Non-conscious modulation of cardiac defense by masked phobic pictures.

The present study investigated the modulation of cardiac defense by presenting emotional pictures under both effective and non-effective masking procedures. The aim was to test Ohman's model of pre-attentive processing of fear. Participants were 48 women volunteers with intense fear of spiders. The stimulus to elicit cardiac defense was a white noise of 105 dB, 500 ms duration and instantaneous risetime. Subjects had two trials of picture-noise presentation-one with a picture of a spider and one with a picture of a flower-, either under an effective masking procedure (30 ms duration) or a non-effective masking procedure (500 ms duration). Order of presentation was counterbalanced. Dependent variables were heart rate and subjective assessment of the noise. Results showed an increased cardiac response in the first trial and a less reduced cardiac response in the second trial when the noise was preceded by the phobic picture under both masking procedures. The response was accompanied by an increase in the subjective unpleasantness of the noise. These results provide support to Ohman's theoretical model.

Acoustic Stimulation↗
PubMed2005

Differentiation between protective reflexes: cardiac defense and startle.

Rise time and duration are two parametric characteristics of the eliciting stimulus frequently used to differentiate among psychophysiological reflexes. The present research varied the duration (study 1) and rise time (study 2) of an intense acoustic stimulus to dissociate cardiac defense and cardiac startle using the eyeblink response as the external criterion of startle. In each study, 100 participants were presented with five white noise stimuli of 105 dB under one of five duration (50, 100, 250, 500, and 1000 ms) or rise time (0, 24, 48, 96, and 240 ms) conditions. Cardiac defense was affected by stimulus duration, present only in the 500- and 1000-ms conditions, but not by stimulus rise time, present in all rise time conditions. Rise time affected blink startle, but did not selectively alter the short latency accelerative component of the heart rate response, thus questioning whether it reflects startle.

Adolescent↗
PubMed2003

Relative effects of harassment, frustration, and task characteristics on cardiovascular reactivity.

Effects of anger induction procedures such as frustration and harassment on cardiovascular reactivity have been demonstrated in a wide range of experimental situations. Similarly, heightened cardiovascular reactivity has been associated with a diverse range of tasks involving active coping, competition and interpersonal interaction. The present study sought to directly compare the relative effects of these two important ways of inducing cardiovascular changes. One hundred and five university students performed two tasks that differed in the degree of active coping and interpersonal competition: a competitive psychomotor task and a problem-solving task. States of anger were induced during both tasks by means of harassment, frustration or frustration+harassment. Task-related changes in heart rate, systolic blood pressure, diastolic blood pressure, pulse volume amplitude and respiratory sinus arrhythmia amplitude were monitored. The competitive psychomotor task produced greater cardiovascular reactivity than did the problem-solving task. Harassment and frustration+harassment provoked more cardiovascular reactivity than did frustration alone. However, harassment and frustration+harassment had the greatest cardiovascular effects in the competitive task, whereas frustration had the greatest cardiovascular effects in the problem-solving task. In this sense, the increases on cardiovascular reactivity seem to depend on the interaction between anger induction procedures and the context in which anger is provoked.

Adaptation, Psychological↗
PubMed2003

A new look at cardiac defense: attention or emotion?

The study of cardiac defense has a long tradition in psychological research both within the cognitive approach--linked to Pavlov, Sokolov, and Graham's work on sensory reflexes--and within the motivational one--linked to the work of Cannon and subsequent researchers on the concepts of activation and stress. These two approaches have been difficult to reconcile in the past. We summarize a series of studies on cardiac defense from a different perspective, which allows integration of the traditional approaches. This new perspective emphasizes a sequential process interpretation of the cardiac defense response. Results of descriptive and parametric studies, as well as those of studies examining the physiological and psychological mechanisms underlying the response, show a complex response pattern with both accelerative and decelerative components, with both sympathetic and parasympathetic influences, and with both attentional and emotional significance. The implications of this new look at cardiac defense are discussed in relation to defensive reactions in natural settings, the brain mechanisms controlling such reactions, and their effects on health and illness.

Adult↗
PubMed2003

The rhythm of the heart in the blink of an eye: emotion-modulated startle magnitude covaries with heart rate variability.

Emotion-modulated startle is a robust phenomenon that has been demonstrated in a wide range of experimental situations. Similarly, heart rate variability (HRV) has been associated with a diverse range of processes including affective and attentional regulation. The present study sought to examine the relationship between these two important measures of affective behavior. Ninety female participants viewed pleasant, neutral, and unpleasant pictures while exposed to acoustic startle stimuli. The eyeblink startle was recorded both during the affective foregrounds and during intertrial intervals. HRV was assessed during a resting baseline and relationships between HRV and startle magnitudes examined. Results indicated that resting HRV was inversely related to startle magnitude during both intertrial intervals and affective foregrounds. In addition, the participants with the highest HRV showed the most differentiated emotion-modulated startle effects, whereas those with the lowest HRV, compared to those with the highest HRV, showed significantly potentiated startle to neutral foregrounds and marginally potentiated startle to pleasant foregrounds. The findings are consistent with models that posit that prefrontal cortical activity modulates subcortical motivation circuits. These results have important implications for the use of startle probe methodology and for HRV in the study of emotional regulation and dysregulation.

Adult↗
PubMed2003

Startle reflex modulation, affective ratings and autonomic reactivity in incarcerated Spanish psychopaths.

Startle probe modulation during affective picture viewing was assessed in a Spanish prison population. As for North American inmates, psychopaths failed to display normal blink potentiation during unpleasant slides even though their evaluative judgments and autonomic reaction to affective stimuli paralleled those of other inmate and noninmate participants. The results suggest that diminished defense activation characterizes psychopaths despite cultural differences.

Adult↗
PubMed2002

Revisiting the James versus Cannon debate on emotion: startle and autonomic modulation in patients with spinal cord injuries.

James' hypothesis that impaired peripheral physiology in patients with spinal cord injuries (SCI) impairs emotional processing, as manifested in the modulation of physiological responses and in the subjective component of emotions, was examined in the present study. A pilot study confirmed the utility of Lang's picture viewing paradigm in a group of 78 students using the Spanish norms of the International Affective Picture System. In the main study, 19 patients with SCI and 19 well controls matched for sex, age and education were examined. Results showed: (1) no differences between SCI and control participants in the valence and arousal ratings of the pictures; (2) similar heart rate modulation in both groups, i.e. the unpleasant pictures produced greater deceleration than the pleasant ones; and (3) no decrease in emotional experience in the SCI group compared with the control group. The implications of the results for the James versus Cannon controversy on the theory of emotions are discussed.

Acoustic Stimulation↗
PubMed2002

The Aggression Questionnaire: a validation study in student samples.

The goal of this study was to examine the psychometric properties of the Aggression Questionnaire (AQ) in Spain. The AQ is a 29-item instrument designed to measure the different dimensions of the hostility/anger/aggression construct. It consists of 4 subscales that assess: (a) anger, (b) hostility, (c) verbal aggression, and (d) physical aggression. In Study 1, reliability, construct validity, and convergent validity were evaluated in a group of 384 male and female university students. Test-retest reliability was evaluated using a group of 154 male and female university students. The results of the factor analysis were similar to the scale structure claimed for this instrument. The subscales also showed internal consistency and stability over time. The AQ and its subscales were also compared with the scales and subscales of the Spielberger State-Trait Anger Expression Inventory (STAXI), the Cook-Medley Hostility Scale (Ho), the Buss-Durkee Hostility Inventory (BDHI), and the Jenkins Activity Survey-Form H (JASE-H). The results show that the AQ evaluates some aspects of anger, such as Anger-Trait and Anger-Out, rather than other elements, such as Anger-In or Anger-State. In Study 2, two new male groups were used to evaluate the criterion validity of the AQ: 57 prison inmates and 93 university students, finding that this instrument discriminated between the scores obtained by common offenders and university students.

Adult↗