The substituted amphetamines 4-chloroamphetamine (PCA), 3,4-methylenedioxymethamphetamine (MDMA) and fenfluramine (FEN) share the common neurochemical action of acutely releasing central serotonin (5-HT), and yet their behavioral effects are quite different. The present study evaluated the effects of these compounds on acoustic and tactile startle reflexes. PCA and MDMA were qualitatively simil...

This study used a prospective design to investigate startle reactivity following trauma exposure. Startle response was evaluated using loud tones during which measures of eyeblink electromyogram (EMG) and heart rate (HR) were collected. Participants were 40 female sexual or physical assault survivors assessed at 1 month and 6 months postassault. There were no significant differences in startle ...

The Antisocial personality disorder (ASPD), one of the most common co-morbid psychiatric disorders in heroin-dependent patients, is associated with a lack of affective modulation. The present study aimed to compare the affect-modulated startle responses of opioid-maintained heroin-dependent patients with and without ASPD relative to those of healthy controls. Sixty participants (20 heroin-depen...

Affective modulation of the eyeblink startle reflex, by unpleasant slides, was found to be limited to subjects high on Harm Avoidance (HA; Cloninger, 1986); low HA subjects did not respond to unpleasant slides with potentiated startle reflexes. This result provides a replication of Corr, Wilson, Fotiadou, Kumari, Gray, Checkley and Gray (1995a), and supports the hypothesis that individual diffe...

Inhalation of low concentrations of carbon dioxide (CO2) triggers anxious behaviours in rodents via chemosensors in the amygdala, and increases anxiety, autonomic arousal and hypervigilance in healthy humans. However, it is not known whether CO2 inhalation modulates defensive behaviours coordinated by this network in humans. We examined the effect of 7.5% CO2 challenge on the defensive eye-blin...

Aims: Acoustic startle response in rats is used to model sensorimotor reactivity. The aim of the study was to determine whether acoustic startle response in alcohol-na"ive rats predicts subsequent increased voluntary alcohol drinking or alcohol preference. Methods: Startle responses to 90, 95 and 100 decibel (dB) white noise stimuli presented in counterbalanced semi-randomized order were tested...

BACKGROUND Previous studies have indicated that the startle reflex is potentiated by phasic, but not by tonic, heat pain, although the latter is seen as more strongly associated with emotional responses and more similar to clinical pain. The threat value of pain might be a decisive variable, which is not influenced alone by stimulus duration. OBJECTIVE This study aimed at comparing startle re...

We investigated emotional disturbances in 36 schizophrenia patients, 48 of their first-degree relatives, and 56 controls to determine if abnormal affective startle modulation could be associated with genetic risk for schizophrenia. Both patients and relatives had a pattern of startle modulation indistinguishable from controls, with potentiated startle amplitude while viewing negative valence sl...

The startle response, a set of reflex behaviours intended to prepare the organism to face a potentially threatening stimulus, can be modulated by several factors as, for example, changes in affective state, or previous presentation of a weak stimulus (a phenomenon termed Pre-Pulse Inhibition [PPI]). In this paper we analyse whether the induction of positive or negative affective states in the p...

Using the startle reflex methodology, researchers have shown that darkness, a phylogenetically relevant aversive context for humans, elicits fear responses. The present study replicated these findings in an ecologically valid situation, a virtual tunnel drive. Furthermore, the study focused on the question whether the darkness-enhanced startle response is modulated by an additional task involve...