José Luís Mata

Psychophysiological correlates of chronic worry: cued versus non-cued fear reaction.

Worry has been defined as a chain of thoughts and images that promote mental attempts to avoid anticipation of potential threats. From this perspective worry can be conceptualized as a state of anticipatory anxiety or non-cued fear reaction. The present study examines high and low chronic worriers during cued and non-cued defense reaction paradigms and during resting and self-induced worry periods. The non-cued procedure was based on the cardiac defense paradigm, whereas the cued procedure was based on the startle probe paradigm using pleasant, neutral and unpleasant pictures as cues. High worriers, compared to low worriers, showed (a) a greater cardiac defense response in the non-cued fear response paradigm, (b) no differences in eye-blink in the startle probe paradigm, (c) reduced skin conductance reactivity during the startle probe paradigm and (d) reduced Respiratory Sinus Arrhythmia, accompanied by increased respiratory rate and decreased expiratory period, during the resting period. These results support the notion of chronic worry as a state of anticipatory anxiety, accompanied by indices of reduced vagal control, that modulates non-cued defense reactions.

Communalities and differences in fear potentiation between cardiac defense and eyeblink startle

This study examines similarities and differences in fear potentiation between two protective reflexes: cardiac defense and eyeblink startle. Women reporting intense fear of animals but low fear of blood or intense fear of blood but low fear of animals viewed pictures depicting blood or the feared animal for 6 s in 2 separate trials in counterbalanced order. An intense burst of white noise, able to elicit both a cardiac defense response and a reflexive startle blink, was presented 3.5 s after picture onset. Both cardiac and blink responses were potentiated when highly fearful individuals viewed fearful pictures. However, differences appeared concerning picture order. This pattern of results indicates communalities and differences among protective reflexes that are relevant for understanding the dynamics of emotional reflex modulation.

Dissociation between the cognitive and interoceptive components of mindfulness in the treatment of chronic worry.

OBJETIVES Despite the increasing interest in mindfulness, the basic components and action mechanisms of mindfulness remain controversial. The present study aims at testing the specific contribution of two components of mindfulness -attention to cognitive experience (metacognition) and awareness of interoceptive sensations (metainteroception)- in the treatment of chronic worry. METHOD Forty five female university students with high scores in the Penn State Worry Questionnaire were split into three groups: a mindfulness cognitive training group, a mindfulness interoceptive training group, and a non-intervention control group. Participants were assessed before and after the intervention using physiological indices of autonomic regulation (skin conductance, heart rate, heart rate variability, and respiratory sinus arrhythmia) and self-report indices of mindfulness and clinical symptoms (chronic worry, depression, positive and negative affect, and perceived stress). RESULTS Both mindfulness training groups showed significant improvement after the intervention in self-report indices of mindfulness and clinical symptoms. However, the interoceptive training group was superior in also showing significant improvement in the physiological indices of autonomic regulation. LIMITATIONS The relatively small sample size may have increased the probabilities of type I and II errors. Our Intervention program was relatively short. The participants were all female. CONCLUSIONS These results support the hypothesis that, in the context of treating chronic worry, the interoceptive and cognitive components can be somewhat dissociated and that, when both components are applied separately, compared to a non-intervention condition, the interoceptive component is more effective.

Habituation and sensitization of protective reflexes: Dissociation between cardiac defense and eye-blink startle

We examined the habituation and recovery of two protective reflexes, cardiac defense and eye-blink startle, simultaneously elicited by a white noise of 500ms as a function of the time interval between stimulus presentations. Participants were 90 volunteers (54 women) randomly distributed into 6 inter-trial interval (ITI) conditions. They all received three presentations of the stimulus with a time interval of 30min between the first and third noise. The timing of the second noise was manipulated in six steps, using a between-group design, in order to increase the ITI between Trials 1 and 2 and symmetrically decrease the ITI between Trials 2 and 3. Cardiac defense showed fast habituation at the shortest ITI (2.5min), but reduced habituation and increased recovery at the longest ITI (27.5min). In contrast, eye-blink startle showed sensitization irrespective of the ITI. This pattern of findings highlights dissociations between protective reflexes when simultaneously examined. The results are discussed in the context of the cascade model of defense reactions.

Relationships between baroreceptor cardiac reflex sensitivity and cognitive performance: modulations by gender and blood pressure.

This study aimed at replicating and extending previous results on the association between baroreceptor reflex sensitivity (BRS) and cognitive performance. Thirty men and 31 women performed an arithmetic task. After adjusting for numerical aptitude and effort, no predictors of performance were found in men. In women, the relationships between BRS and parameters related to correct responses were modulated by blood pressure (BP). BRS was inversely associated with these parameters for participants with BP>1 SD above the mean, whereas the associations were positive in participants with BP<1 SD below the mean. Also for women, BRS was positively associated with number of errors during the task. These results suggest that the relation between BRS and performance varies as a function of the type of cognitive processes assessed and that the central nervous system effects of the baroreceptors on cognitive functioning are modulated by gender and BP.

Mathematical detection of aortic valve opening (B point) in impedance cardiography: A comparison of three popular algorithms.

The preejection period (PEP) is an index of left ventricle contractility widely used in psychophysiological research. Its computation requires detecting the moment when the aortic valve opens, which coincides with the B point in the first derivative of impedance cardiogram (ICG). Although this operation has been traditionally made via visual inspection, several algorithms based on derivative calculations have been developed to enable an automatic performance of the task. However, despite their popularity, data about their empirical validation are not always available. The present study analyzes the performance in the estimation of the aortic valve opening of three popular algorithms, by comparing their performance with the visual detection of the B point made by two independent scorers. Algorithm 1 is based on the first derivative of the ICG, Algorithm 2 on the second derivative, and Algorithm 3 on the third derivative. Algorithm 3 showed the highest accuracy rate (78.77%), followed by Algorithm 1 (24.57%) and Algorithm 2 (13.82%). In the automatic computation of PEP, Algorithm 2 resulted in significantly more missed cycles (48.57%) than Algorithm 1 (6.3%) and Algorithm 3 (3.5%). Algorithm 2 also estimated a significantly lower average PEP (70 ms), compared with the values obtained by Algorithm 1 (119 ms) and Algorithm 3 (113 ms). Our findings indicate that the algorithm based on the third derivative of the ICG performs significantly better. Nevertheless, a visual inspection of the signal proves indispensable, and this article provides a novel visual guide to facilitate the manual detection of the B point.