Exogenous cortisol exerts effects on the startle reflex independent of emotional modulation (original) (raw)
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Psychoneuroendocrinology, 2011
This study examined the effects of oral administration of 20 mg hydrocortisone on baseline and fear-potentiated startle in 63 male veterans with or without PTSD. The procedure was based on a two-session, within-subject design in which acoustic startle eyeblink responses were recorded during intervals of threat or no threat of electric shock. Results showed that the magnitude of the difference between startle responses recorded during anticipation of imminent shock compared to "safe" periods was reduced after hydrocortisone administration relative to placebo. This effect did not vary as a function of PTSD group nor were there were any significant group differences in other indices startle amplitude. Findings suggest that the acute elevations in systemic cortisol produced by hydrocortisone administration may have fear-inhibiting effects. This finding may have implications for understanding the role of hypothalamic-pituitary-adrenal (HPA)-axis function in vulnerability and resilience to traumatic stress.
Cortisol and DHEA-S are associated with startle potentiation during aversive conditioning in humans
Psychopharmacology, 2006
Rationale-Fear conditioning reliably increases the startle reflex and stress hormones, yet very little is known about the effect of stress hormones on fear-potentiated startle. Cortisol and the sulfate ester of dehydroepiandrosterone (DHEA-S) are involved in stress and anxiety. Evidence suggests that low cortisol/DHEA-S ratio has a buffering effect on stress and anxiety in preclinical and clinical studies, suggesting that there may be a relationship between fear-potentiated startle and cortisol and DHEA-S activity.
Biological Psychiatry, 2011
The debilitating effects of chronic glucocorticoids excess are well-known, but comparatively little is understood about the role of acute cortisol. Indirect evidence in rodents suggests that acute cortisone could selectively increase some forms of long-duration aversive states, such as "anxiety," but not relatively similar, briefer aversive states, such as "fear." However, no prior experimental studies in humans consider the unique effects of cortisol on anxiety and fear, using well-validated methods for eliciting these two similar but dissociable aversive states. The current study examines these effects, as instantiated with short-and long-duration threats.
Endogenous cortisol suppression with metyrapone enhances acoustic startle in healthy subjects
Hormones and Behavior, 2009
Previous human studies have shown that excess cortisol sufficient to fully occupy central nervous system (CNS) corticosteroid receptors may reduce startle eye blink. The present study tested whether cortisol depletion and the resulting reduction in activity of CNS corticosteroid receptors has the opposite effect. In a single-blind, placebo-controlled, randomized study, eye blink EMG responses to 105 dB acoustic startle stimuli were assessed in 25 healthy subjects who received oral metyrapone (1500 mg) to suppress endogenous cortisol production, while 24 controls received oral placebo. As expected, metyrapone significantly reduced salivary cortisol, indicating effective endogenous cortisol suppression. Startle eye blink responses were significantly increased in the metyrapone group. Short-term habituation of the startle reflex was not different between groups. Our results suggest that startle is enhanced during depletion of cortisol. This effect may be mediated by CNS mechanisms controlling cortisol feedback.
European Neuropsychopharmacology, 2014
The stress hormone cortisol has been shown to affect hemodynamic activity of human brain structures, presumably via a nongenomic mechanism. However, behavioral implications of this finding remain unknown. In a placebo-controlled, blinded, cross-over design the rapid effects of IV hydrocortisone (5 mg) on cross-modal integration of simultaneous, unilateral visual and acoustic signals in a challenging startle and reaction time (RT) paradigm were studied. On two separate days 1 week apart, 24 male volunteers responded by button push to either up-or down pointing triangles presented in random sequence in the periphery of one of the visual hemifields. Visual targets were accompanied by unilateral acoustic startle noise bursts, presented at the same or opposite side. Saccadic latency, manual RT, and startle eye blink responses were recorded. Faster manual reactions and increased startle eye blink responses were observed 11-20 min after hydrocortisone administration when visual targets and unilateral acoustic startle noises were presented in the same sensory hemi-field, but not when presented in opposite sensory hemi-fields. Our results suggest that a nongenomic, cortisol-sensitive mechanism enhances psychomotor and startle reactions when stimuli occur in the same sensory hemi-field. Such basic cognitive effects of cortisol may serve rapid adaptation and protection against danger stimuli in stressful contexts.
Startle modulation before, during and after exposure to emotional stimuli
2002
Although affective modulation of the startle reflex is a highly replicable effect, the majority of studies have administered startle probes during exposure to affective stimuli. To examine more comprehensively the temporal course of startle potentiation, we assessed blink modulation before, during and immediately after exposure to positive, negative and neutral pictures. During each trial, cues about the affective content of pictures were presented, after which acoustic startle probes were delivered either before picture onset, during picture onset or immediately after picture offset. As expected, we observed a linear relation between picture valence and startle amplitude during picture viewing. Surprisingly, startle amplitude was larger while anticipating pleasant and unpleasant pictures relative to neutral pictures. No significant effects were observed during the offset phase. These results indicate that startle modulation is conditional upon temporal factors linked to stimulus onset and offset. ᮊ
Startle reflex as a physiological measure of emotion regulation
In the present study, the startle blink reflex is used as a measure of emotion regulation to affective picture stimuli. Based on the biphasic theory of emotion, it is hypothesized that the startle response will be largest in magnitude in the presence of negative emotional stimuli . It is also hypothesized that when attempting to decrease emotion, participants will show smaller blink magnitudes to negative images, and larger blink magnitudes when attempting to decrease emotion to positive images due to the aversive nature of the startle reflex. The present study highlights the difficulty of finding emotion regulation to positive images with the startle blink paradigm. Participants were 6 female undergraduate students who viewed negative, positive and neutral affective picture stimuli, and attempted to either maintain or suppress their emotional responses to the images. Emotion modulation of the startle response was recorded before regulation instruction onset. Significant differences were found in blink magnitude for emotion modulation between positive and negative images, but neutral images were not significantly different from either. For negative images, blink magnitudes during emotion suppression were significantly smaller than when maintaining emotion. No significant regulation differences were found for the positive images.
Modulation of the Startle Reflex during Brief and Sustained Exposure to Emotional Pictures
Psychology, 2013
Previous investigations using pictures to elicit an emotional response have shown that the startle reflex habituates over time due to decreased excitation in the obligatory startle processing pathway, an effect that is independent of emotion modulation aspects of the startle response. However, in some instances, startle magnitude has been selectively potentiated during sustained exposure to passively viewed unpleasant pictures. This study assessed startle modulation during brief, alternating and sustained exposure to emotional pictures. Self-reported ratings of emotion were collected online with picture viewing to determine if any change in startle magnitude was observable in explicit emotional responses. Self-reported ratings of pleasantness and arousal were no different across the brief and sustained picture presentations. However, a significant main effect (independent from emotion category) of presentation condition was found for startle magnitudes, showing that, contrary to previous research involving passive picture viewing, mean startle magnitudes during sustained exposure were reduced relative to brief exposure. These findings are likely the result of a general habituation of the startle reflex in the obligatory pathway. The findings are also discussed in terms of the effect of the concurrent emotion rating task, which may have differently affected the cumulative effects of emotion exposure compared to passive picture viewing.
Short communication Startle modulation before, during and after exposure to emotional stimuli
2000
Although affective modulation of the startle reflex is a highly replicable effect, the majority of studies have administered startle probes during exposure to affective stimuli. To examine more comprehensively the temporal course of startle potentiation, we assessed blink modulation before, during and immediately after exposure to positive, negative and neutral pictures. During each trial, cues about the affective content of pictures were presented, after which acoustic startle probes were delivered either before picture onset, during picture onset or immediately after picture offset. As expected, we observed a linear relation between picture valence and startle amplitude during picture viewing. Surprisingly, startle amplitude was larger while anticipating pleasant and unpleasant pictures relative to neutral pictures. No significant effects were observed during the offset phase. These results indicate that startle modulation is conditional upon temporal factors linked to stimulus onset and offset. ᮊ
Emotion-modulated startle reflex during reappraisal: Probe timing and behavioral correlates
Behavioral Neuroscience, 2018
Down-regulation of negative emotions has been shown to reliably inhibit the emotion-modulated startle reflex, but it remains unclear whether the timing of the startle probe influences the quantification of emotion regulation with this measure. Moreover it is not known, whether the degree of startle inhibition corresponds to the subjective attenuation of negative emotions. Therefore the two main goals of the study were first to systematically analyze the effect of probe time on startle inhibition. Second, we aimed to explore the association between subjectively perceived down-regulation of arousal and valence and the degree of startle inhibition. We presented negative and neutral pictures to N = 47 participants. Pictures were paired with the instruction to reappraise or to maintain the emotions elicited by these pictures. Probes were delivered at three different times during a 12.5 s regulation phase and the startle response was measured with electromyography. Valence and arousal ratings were assessed after each trial. Results revealed no significant impact of probe time on startle inhibition during reappraisal. Startle inhibition and perceived down-regulation of arousal were significantly and positively correlated, whereas perceived down-regulation of valence was not. The results provide important implications for future studies in terms of startle probe timing and shed light onto the interpretation of startle inhibition as an indicator of subjective attenuation of negative emotions.