Event-related brain potentials and affective responses to threat in spider/snake-phobic and non-phobic subjects Wolfgang H.R. Miltner * , Ralf H. Trippe, Silke Krieschel, Ingmar Gutberlet, Holger Hecht, Thomas Weiss Department of Biological and Clinical Psychology, Friedrich Schiller University, Am Steiger 3//1, D-07743 Jena, Germany Received 10 November 2004; received in revised form 25 January 2005; accepted 27 January 2005 Abstract We investigated cortical responses and valence/arousal ratings of spider phobic, snake phobic, and healthy subjects while they were processing feared, fear-relevant, emotional neutral, and pleasant stimuli. Results revealed significantly larger amplitudes of late ERP components (P3 and late positive complex, LPC) but not of early components (N1, P2, N2) in phobics when subjects were processing feared stimuli. This fear-associated increase of amplitudes of late ERP components in phobic subjects was maximal at centro-parietal and occipital brain sites. Furthermore, phobics but not controls rated feared stimuli to be more negative and arousing than fear-relevant, emotional neutral, and pleasant stimuli. Since late ERP components and valence/arousal ratings were only significantly increased when phobic subjects but not when healthy controls were processing feared stimuli, the present data suggest that P3 and LPC amplitudes represent useful neural correlates of the emotional significance and meaning of stimuli. D 2005 Elsevier B.V. All rights reserved. Keywords: ERP; Valence; Arousal; Animal phobia; Fear 1. Introduction Phobic fear in humans is more frequently elicited by objects like snakes, spiders, or rodents than by any other object of our every-day environment (Agras et al., 1969; Marks, 1969). Fear of these stimuli represents the core group of animal phobias with almost equal prevalence among different populations (9–14%) and a clear domi- nance in females. Whether this preference of phobic responses to a subgroup of animals is based on phylogenetic preparedness (Seligman, 1971; McNally, 1987; O ¨ hman et al., 1995) or due to other evolutionary-based information processing systems in the human brain (LeDoux, 1996) or whether it is the result of conditioning or otherwise acquired cognitive schemata (Beck and Emery, 1985) and memory functions (Bower, 1981; Williams et al., 1997; Lang et al., 2000) is still a matter of debate. However, there is general agreement that the presence of these stimuli in the environ- ment of phobics grants these objects salient meaning by significantly pulling subjects attention towards them, increasing arousal and negative emotional feelings of threat and the induction of flight/fight responses (Williams et al., 1997; Lang et al., 2000). In the past, evidence for the salience of threatening stimuli was demonstrated by a number of studies indicating that the processing/encoding of such stimuli is significantly biased in clinically anxious subjects and subjects with high- trait anxiety scores (Williams et al., 1997). Researchers became particularly interested to disentangle individual differences of involuntary attention to threat and demon- strated that attention of anxious subjects is automatically pulled to threatening stimuli (MacLeod, 1991, 1999; MacLeod and Mathews, 1991; Logan and Goetsch, 1993; Williams et al., 1997). Results were based on different information processing paradigms including dichotic-listen- 0167-8760/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpsycho.2005.01.012 * Corresponding author. Tel.: +49 3641 9451450; fax: +49 3641 9451452. E-mail address: wolfgang.miltner@uni-jena.de (W.H.R. Miltner). International Journal of Psychophysiology 57 (2005) 43 – 52 www.elsevier.com/locate/ijpsycho