Exogenous cortisol exerts effects on the startle reflex independent of emotional modulation

Exogenous cortisol's modulation of the acoustic startle reflex (ASR) was te sted alone and during exposure to affectively valenced photographs in healt hy men and women. During nonmodulated startle, oral hydrocortisone had a bi phasic dose effect, with 5 mg increasing and 20 mg decreasing, eyeblink ref lex magnitude compared to placebo. During emotion modulation, 20 mg of hydr ocortisone reduced reflex magnitude without affecting the usual pattern of modulation across positive, neutral, and negatively affective slides. Gende r differences were not found in either relationship. These findings illustr ate dose-dependent effects of cortisol on the startle pathway independent o f emotional state and consistent across genders. (C) 2001 Elsevier Science Inc. All rights reserved.