Modulation of nociceptive and acoustic @entity427 responses to an unpredictable threat in @entity1 and XXXX .

@entity1 @entity148 @entity158 @entity272 @entity427
The present study examined whether a moderately aversive abdominal threat would lead to greater enhancement in affect- and @entity158 -related defensive responding as indexed by the acoustic @entity427 reflex (ASR) and nociceptive flexion reflex (NFR) in @entity1 compared to @entity1 . We also predicted sex differences in threat-related autonomic arousal measured by @entity272 ( @entity272 ) to acoustic @entity427 and noxious sural nerve stimulation. Unpredictable threat was manipulated by alternating 30-second safe ("no abdominal stimulation will be given") and threat ("abdominal stimulation may occur at anytime") periods. The experiment consisted of 2 blocks, each containing 4 safe and 4 threat periods in which the ASR or NFR was randomly probed 9-21 seconds following period onset. Unpredictable abdominal threat potentiated both ASR and NFR responses compared to periods signaling safety. @entity272 to acoustic @entity427 probes and noxious sural nerve stimulation were also significantly elevated during the threat vs safe periods. No sex differences in ASR or @entity427 -evoked @entity272 emerged. However, nociceptive responding was moderated by sex; females showed significant increases in NFR magnitudes across both safe and threat periods compared to males. Females also showed greater threat-potentiated @entity272 to sural nerve stimulation than males. Our findings indicate that both affect- and @entity158 and arousal systems are strongly influenced by threat of an aversive, unpredictable event, a situation associated with anticipatory @entity148 . Females, compared to males, showed greater nociceptive responding and @entity158 modulation when exposed to an unpredictable threatening context, whereas affect-driven ASR responses showed no such sex differentiation.
