The review of the noise effects literature shows that the most documented reaction of animals newly or infrequently exposed to low-altitude aircraft and sonic booms is the “startle effect.” Although an observer’s interpretation of the startle effect is behavioral (e.g., the animal runs in response to the sound or flinches and remains in place), it does have a physiological basis. The startle ef...

Previously, we demonstrated that transection of the fimbria/fornix blocked the excitatory effect of corticotropin-releasing hormone (CRH) on startle (CRH-enhanced startle), suggesting that the hippocampus and its efferent target areas that communicate via the fimbria may be critically involved in CRH-enhanced startle. The bed nucleus of the stria terminalis (BNST) receives direct projections fr...

The magnitude of the acoustic startle response can be reduced by a relatively weak sound presented immediately before the startle-eliciting sound; this phenomenon has been termed prepulse inhibition (PPI). Previous studies reported that PPI was present in the decerebrate rat, indicating that the primary neural pathways mediating PPI are located in the brainstem. The present study investigated t...

Drugs thought to increase intracellular levels of cAMP were infused intrathecally into the subarachnoid space of the lumbar spinal cord, and the effects on the acoustic startle response in rats were measured. Intrathecal infusions of the cAMP analogs dibutyryl cAMP or 8-bromo cAMP (12.5-100 micrograms) produced marked, dose-dependent increases in startle amplitude compared to the infusion of ar...

Prepulse inhibition (PPI) is the decrease of startle reflex amplitude when a slight stimulus is previously generated. This paradigm may provide valuable information about sensorimotor gating functionality. Here we aimed at determining the inhibited and uninhibited startle response of capuchin monkeys (Sapajus spp.), and to evaluate the role of the superior colliculus in PPI. Capuchin monkeys we...

In this study, the lethal toxicity, behavioral responses and hematotoxicity of formulated chlorpyrifos on Clarias gariepinus was evaluated. C. gariepinus fingerlings were exposed to 0.2 mg/L, 0.25 mg/L, 0.3 mg/L, 0.35 mg/L and 0.4 mg/L of the active ingredient chlorpyrifos to determine the lethal concentrations and behavioral effects. C. gariepinus juveniles (38.84±7.67g) were then exposed to 0...

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...

Abstract This article analyses the function and form of acoustic startle events (ASEs) in trailers for fifty US horror films released between 2011 2015. There are 173 ASEs sample, ranging from one up to a maximum ten, with median three per trailer. exhibit different types relationships figure ground, some preceded by silence anticipated viewer while others unanticipated intrude on scenes relyin...

Facial self-resemblance has been associated with positive emotional evaluations, but this effect may be biased by self-face familiarity. Here we report two experiments utilizing startle modulation to investigate how the processing of facial expressions of emotion is affected by subtle resemblance to the self as well as to familiar faces. Participants of the first experiment (I) (N = 39) were pr...

The psychophysiological startle response pattern associated with peritraumatic dissociation (DISS) was studied in 103 survivors of a life-threatening cardiac event (mean age 61.0 years, SD 13.95). Mean time period since the cardiac event was 37 (79 IQD) months. All patients underwent a psychodiagnostic evaluation (including the Peritraumatic Dissociative Experiences Questionnaire) and a psychop...