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


  • This research was supported by a NATO collaborative grant (SA.5-2-05 CRG.95 1338), the Spanish Ministry of Science and Education (Projects PB97-0841, BSO2001-3211, and SEJ2004-07956), and a National Institute of Mental Health grant (P50 MH-72850).

Address reprint requests to: Jaime Vila, Facultad de Psicología, Campus La Cartuja s/n. 18011 Granada, Spain. E-mail:


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.