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

Abstract

Exogenous cortisol's modulation of the acoustic startle reflex (ASR) was tested alone and during exposure to affectively valenced photographs in healthy men and women. During nonmodulated startle, oral hydrocortisone had a biphasic dose effect, with 5 mg increasing and 20 mg decreasing, eyeblink reflex magnitude compared to placebo. During emotion modulation, 20 mg of hydrocortisone reduced reflex magnitude without affecting the usual pattern of modulation across positive, neutral, and negatively affective slides. Gender differences were not found in either relationship. These findings illustrate dose-dependent effects of cortisol on the startle pathway independent of emotional state and consistent across genders.