Oral cortisol does not affect startle eye blink magnitude, nor startle habituation
Sá, D. F., Römer, S., Schulz, A., Wager, J., and Schächinger, H.
Abteilung für Klinische Physiologie, Universität Trier
Oral cortisol was described to impact startle responsiveness, but conflicting results have been reported. Furthermore, no data have been reported on whether oral cortisol administration affects the short-term habituation of startle responses after repeated presentation of acoustic startle probes in humans. Therefore, this study investigated reflexive eye blink responses (EMG technology) to six (inter stimulus interval = 10 s) brief (50 ms) and intense (105 dB) binaural acoustic white noise startle stimuli in 81 healthy subjects, 60 minutes after receiving a single oral 30 mg cortisol (n=40) dose, or placebo (n=41, control condition). Cortisol administration did neither affect startle eye blink response magnitude to acoustic noise probes, nor the decline of startle eye blink responsiveness seen during repeated acoustic startle stimulation. We conclude, that excess cortisol in resting humans does not affect startle, nor short-term startle habituation.