Effects of Cold Pressor Stress on the Human Startle Response
Citation: Deuter CE, Kuehl LK, Blumenthal TD, Schulz A, Oitzl MS, et al. (
Effects of Cold Pressor Stress on the Human Startle Response
Christian E. Deuter 0
Linn K. Kuehl 0
Terry D. Blumenthal 0
Andre Schulz 0
Melly S. Oitzl 0
Hartmut Schachinger 0
Andrew H. Kemp, University of Sydney, Australia
0 1 Department of Clinical Psychophysiology, Institute of Psychobiology, University of Trier , Trier, Germany , 2 Department of Psychiatry and Psychotherapy, Charite University Medicine , Berlin, Germany , 3 Department of Psychology, Wake Forest University , Winston-Salem , North Carolina, United States of America, 4 Research Unit INSIDE, Division of Clinical and Health Psychology, University of Luxembourg , Luxembourg, Luxembourg , 5 Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research and Leiden University Medical Center, University of Leiden , Leiden , The Netherlands
Both emotion and attention are known to influence the startle response. Stress influences emotion and attention, but the impact of stress on the human startle response remains unclear. We used an established physiological stressor, the Cold Pressor Test (CPT), to induce stress in a non-clinical human sample (24 student participants) in a within-subjects design. Autonomic (heart rate and skin conductance) and somatic (eye blink) responses to acoustic startle probes were measured during a pre-stress baseline, during a three minutes stress intervention, and during the subsequent recovery period. Startle skin conductance and heart rate responses were facilitated during stress. Compared to baseline, startle eye blink responses were not affected during the intervention but were diminished afterwards. These data describe a new and unique startle response pattern during stress: facilitation of autonomic stress responses but no such facilitation of somatic startle eye blink responses. The absence of an effect of stress on startle eye blink responsiveness may illustrate the importance of guaranteeing uninterrupted visual input during periods of stress.
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Stress is regarded to be an adaptive reaction to an adverse
stimulus or situation. The stress response is a multi-level, complex
shift in the organisms physiological and psychological functioning
[1]. The physiological stress response allocates bodily resources to
facilitate quick, evasive actions at the expense of more long term,
regenerative functions. Acute stress involves an endocrinal
response [2] and activation of the sympathetic nervous system
[3], and influences somatic motor behaviour and psychological
adjustments.
In contrast to the low-level, biological adaptations, that meet the
change in energy demands, stress effects on basic psychological
processes, and interaction with attention and emotion, are less well
understood. Some studies found an attentional bias for aversive,
threatening stimuli under stress exposure [4,5], while others found
no [6,7] or even opposing effects, with less attention for negative
stimuli after stress manipulation [8,9]. However, differences of
independent and dependent variables used in the above cited
studies complicate the search for answers. The experimental
paradigm of startle eye blink modification may provide a
biologybased measure of emotional and attentional effects that might
clarify these questions.
The startle response is a fast defensive mechanism that protects
the organism against potential injury. Elicited by abrupt and
intense stimuli in various sensory modalities, the startle response
protects the organism against imminent physical harm in a natural
setting, e.g. due to a predator or a blow [10]. Somatic muscle
contractions and activation of the autonomic nervous system
(ANS) represent the two major components of the response.
Sudden contractions of facial and flexor skeletal muscles induce a
defensive posture and protect essential parts of the body.
Acceleration of heart rate and increased skin conductance
responses (SCR) indicate an activation of the ANS and prepare
the organism for action, e.g. fight or flight [11].
The emotional context in which startle is elicited may modulate
the response magnitude in one of two directions. Positive
emotional states attenuate and negative states enhance the startle
response. Such affective startle modulation has been explained in
terms of motivational priming: aversive emotional stimuli prime
the defensive motivational system and thereby facilitate defensive
reflexes, whereas appetitive emotional stimuli inhibit defensive
reflexes [12]. Experimental paradigms have employed a diverse
array of emotional stimuli with positive or negative hedonic
valence, such as pictures [13], films [14], music [15], odours
[16],or anxiety-inducing darkness [17]. Also, placebo effects of
neutral stimuli [18] and the imagination [19] or anticipation [20]
of emotional content modulate the startle response.
However, although it is typical that psychological ratings
indicate a negatively valenced emotiona (...truncated)