Social stimuli increase physiological reactivity but not defensive responses.

Emotional reactions are crucial in survival because they provide approach and withdrawal behaviors. However, an unsolved question is whether the social content of the affective stimuli has a specific effect on emotional responses. We studied whether the social content of affective pictures influenced the defensive response and response mobilization. For this purpose, we recorded startle blink reflex (a defensive response) and skin conductance responses (a measure of unspecific physiological reactivity or arousal) in 73 participants while they viewed a series of 81 pictures of varying affective valence and social content. Our results revealed that defense response, as indicated by increases in the magnitude of the startle blink reflex, was mainly dependent on threatening or unpleasant cues, but was unrelated to the social content of the pictures. The social content, however, had an influence on pleasant stimuli, provoking an increase in resource mobilization, as reflected by changes in electrodermal activity. Hence, the social content of the affective stimuli may increase the physiological arousal elicited by pleasant stimuli, and it appears to be unrelated to the defense reactivity provoked by unpleasant stimuli.

Psychophysiological, behavioral, and cognitive indices of the emotional response: a factor-analytic study.

Previous research on the components of the emotional response employing factor analytic studies has yielded a two-factor structure (Lang, Greenwald, Bradley, & Hamm, 1993; Cuthbert, Schupp, Bradley, Birbaumer, & Lang, 2000). However, the startle blink reflex, a widely employed measure of the emotional response, has not been considered to date. We decided to include two parameters of the startle reflex (magnitude and latency) in order to explore further how this response fits into the two-factor model of emotion. We recorded the acoustic startle blink response, skin conductance response, heart rate, free viewing time, and picture valence and arousal ratings of 45 subjects while viewing 54 pictures from the International Affective Picture System (IAPS; 18 unpleasant, 18 neutral, and 18 pleasant). Factorizations of all measures gave a two-factor solution (valence and arousal) that accounted for 70% of the variance. Although some measurements, including heart rate change, did not behave as predicted, our results reinforce the two-dimension model of the emotion, and show that startle fits into the model.

Psychophysiological, Behavioral, and Cognitive Indexes of the Emotional Response: A Factor-Analytic Study

Previous research on the components of the emotional response employing factor analytic studies has yielded a two-factor structure (Lang, Greenwald, Bradley, & Hamm, 1993; Cuthbert, Schupp, Bradley, Birbaumer, & Lang, 2000). However, the startle blink reflex, a widely employed measure of the emotional response, has not been considered to date. We decided to include two parameters of the startle reflex (magnitude and latency) in order to explore further how this response fits into the two-factor model of emotion. We recorded the acoustic startle blink response, skin conductance response, heart rate, free viewing time, and picture valence and arousal ratings of 45 subjects while viewing 54pictures from the International Affective Picture System (IAPS; 18 unpleasant, 18 neutral, and 18 pleasant). Factorizations of all measures gave a two-factor solution (valence and arousal) that accounted for 70% of the variance. Although some measurements, including heart rate change, did not behave as predicted, our results reinforce the two-dimension model of the emotion, and show that startle fits into the model (AU)

La investigación previa sobre los componentes de la respuesta emocional empleando estudios de análisis factorial ha proporcionado una estructura de dos factores (Lang,Greenwald, Bradley y Hamm, 1993; Cuthbert, Schupp, Bradley, Birbaumer y Lang, 2000).Sin embargo, el parpadeo reflejo de sobresalto, una medida ampliamente empleada de respuesta emocional, no se ha considerado hasta la fecha. Decidimos incluir dos parámetros del reflejo de sobresalto (magnitud y latencia) para explorar si esta respuesta se ajusta al modelo bifactorial de la emoción. Registramos el parpadeo reflejo de sobresalto acústico, la respuesta de conductancia de la piel, la tasa cardiaca, el tiempo de visión, y las evaluaciones de valencia y de arousal de 45 sujetos mientas miraban 54 representaciones del IAPS (18 desagradables, 18 neutrales, y 18 agradables). La factorización de todas las medidas proporcionó una solución de dos factores (valencia y arousal) que explicaban el 70% de la varianza. Aunque algunas medidas, incluyendo el cambio en tasa cardiaca, no se comportaban como se había predicho, nuestros resultados refuerzan el modelo bidimensional de la emoción y demuestran que el sobresalto se ajusta al modelo (AU)

The effect of content and physical properties of affective pictures on emotional responses.

The aim of this research was to study the influence of both the emotional content and the physical characteristics of affective stimuli on the psychophysiological, behavioral and cognitive indexes of the emotional response. We selected 54 pictures from the IAPS, depicting unpleasant, neutral, and pleasant contents, and used two picture sizes as experimental conditions (120 x 90 cm and 52 x 42 cm). Sixty-one subjects were randomly assigned to each experimental condition. We recorded the startle blink reflex, skin conductance response, heart rate, free viewing time, and picture valence and arousal ratings. In line with previous research (e.g., Bradley, Codispoti, Cuthbert, and Lang, 2001), our data showed an effect of the affective content on all the measurements recorded. Importantly, effects of the size of the affective pictures on emotional responses were not found, indicating that the emotional content is more important than the formal properties of the stimuli in evoking the emotional response.

The effect of content and physical properties of affective pictures on emotional responses

The aim of this research was to study the influence of both the emotional content and the physical characteristics of affective stimuli on the psychophysiological, behavioral and cognitive indexes of the emotional response. We selected 54 pictures from the IAPS, depicting unpleasant, neutral, and pleasant contents, and used two picture sizes a sexperimental conditions (120 × 90 cm and 52 × 42 cm). Sixty-one subjects were randomly assigned to each experimental condition. We recorded the startle blink reflex, skin conductance response, heart rate, free viewing time, and picture valence and arousal ratings. In line with previous research (e.g., Bradley, Codispoti, Cuthbert, & Lang, 2001), our data showed an effect of the affective content on all the measurements recorded.Importantly, effects of the size of the affective pictures on emotional responses were not found, indicating that the emotional content is more important than the formal properties of the stimuli in evoking the emotional response (AU)

El objetivo de esta investigación fue estudiar la influencia del contenido emocional y delas características físicas de los estímulos afectivos sobre los índices psicofisiológicos, conductuales y cognitivos de la respuesta emocional. Seleccionamos 54 imágenes delIAPS, representando contenidos desagradables, neutros y agradables y usamos dos tamaños de imagen como condiciones experimentales (120 × 90 cm y 52 × 42 cm). Los 61 sujetos que conformaban la muestra experimental se asignaron de forma aleatoria a cada condición experimental. Registramos el parpadeo reflejo de sobresalto, la respuesta de conductancia de la piel, la frecuencia cardiaca, el tiempo de visión y las estimaciones de valencia afectiva y arousal de las imágenes. De acuerdo con la investigación previa(p. ej., Bradley, Codispoti, Cuthbert y Lang, 2001), nuestros datos mostraron un efecto del contenido afectivo en todas las medidas registradas. Nuestros resultados no mostraron, sin embargo, efectos del tamaño de las imágenes afectivas sobre ninguna de las medidas registradas, lo que indica que el contenido afectivo es más importante que las propiedades formales de los estímulos para provocar respuestas emocionales (AU)

Uncovering the relationship between defence and orienting in emotion: cardiac reactivity to unpleasant pictures.

This research was aimed at studying the relationship between the cardiovascular reactivity to an intense auditory stimulus and the subsequent cardiac response evoked by affective visual stimuli in fifty-five subjects who underwent a cardiac reactivity task (presentation of an intense acoustic stimulus), followed by a picture viewing task (54 pictures selected from the International Affective Picture System). Heart rate (HR), electrodermal activity and corrugator supercilii electromyographic activity were recorded. Subjects were divided into two groups - high accelerators and low accelerators - on the basis of the first heart rate acceleration obtained in the cardiac reactivity task. Pictures evoked different cardiac response patterns in each subject group. Unpleasant pictures promoted a lower initial HR deceleration and a higher final acceleration in high accelerators than in low accelerators. This pattern of response was more marked with body damage pictures. Moreover, a relationship was found between the first acceleration promoted by the acoustic stimulus and the HR response waveform to the body damage pictures. These results show that, in an unselected sample of subjects, a subgroup tended to respond to loud stimuli with higher HR acceleration and sympathetic activation and to respond defensively to unpleasant pictures (as found by less initial HR deceleration and higher final HR acceleration), rather than manifesting an orienting response. The elicitation of the defence response by a brain fear system, in which the amygdala is a key structure, is also discussed.

Amigdala, corteza prefrontal y especializacion hemisferica en la experiencia y expresion emocional / Amygdala, prefrontal cortex, and hemispheric specialization in emotional experience and expression

Los datos provenientes de la neurociencia señalan a varias estructuras, tanto subcorticales como corticales, relacionadas con la conducta emocional. Tanto los datos derivados de la investigación con sujetos normales como los procedentes de estudios que han empleado pacientes con daño cerebral y técnicas de neuroimagen funcional en sujetos normales, señalan a la amígdala como una estructura fundamental en la emoción, particularmente en la respuesta a estímulos de contenido negativo. Además, una creciente cantidad de estudios han encontrado que diferentes regiones de la corteza prefrontal, concretamente la orbital y medial, participan en distintos aspectos de la emoción. En este artículo revisaremos los datos que se tienen en la actualidad acerca de la implicación de estas estructuras en la conducta emocional así como la especialización hemisférica (AU)