Startle Probes Research Articles

Automatic facial responses to affective stimuli in high-functioning adults with autism spectrum disorder

Individuals with autism spectrum disorder (ASD) demonstrate atypical behavioural responses to affective stimuli, although the underlying mechanisms remain unclear. Investigating automatic responses to these stimuli may help elucidate these mechanisms. 18 high-functioning adults with ASDs and 18 typically developing controls viewed 54 extreme pleasant (erotica), extreme unpleasant (mutilations), and non-social neutral images from the International Affective Picture System (IAPS). Two-thirds of images received an acoustic startle probe 3s post-picture onset. Facial electromyography (EMG) activity (orbicularis, zygomaticus, corrugator), skin conductance (SCR) and cardiac responses were recorded. The adults with ASDs demonstrated typical affective startle modulation and automatic facial EMG responses but atypical autonomic (SCRs and cardiac) responses, suggesting a failure to orient to, or a deliberate effort to disconnect from, socially relevant stimuli (erotica, mutilations). These results have implications for neural systems known to underlie affective processes, including the orbitofrontal cortex and amygdala.

Viewing Loved Faces Inhibits Defense Reactions: A Health-Promotion Mechanism?

We have known for decades that social support is associated with positive health outcomes. And yet, the neurophysiological mechanisms underlying this association remain poorly understood. The link between social support and positive health outcomes is likely to depend on the neurophysiological regulatory mechanisms underlying reward and defensive reactions. The present study examines the hypothesis that emotional social support (love) provides safety cues that activate the appetitive reward system and simultaneously inhibit defense reactions. Using the startle probe paradigm, 54 undergraduate students (24 men) viewed black and white photographs of loved (romantic partner, father, mother, and best friend), neutral (unknown), and unpleasant (mutilated) faces. Eye–blink startle, zygomatic major activity, heart rate, and skin conductance responses to the faces, together with subjective ratings of valence, arousal, and dominance, were obtained. Viewing loved faces induced a marked inhibition of the eye-blink startle response accompanied by a pattern of zygomatic, heart rate, skin conductance, and subjective changes indicative of an intense positive emotional response. Effects were similar for men and women, but the startle inhibition and the zygomatic response were larger in female participants. A comparison between the faces of the romantic partner and the parent who shares the partner’s gender further suggests that this effect is not attributable to familiarity or arousal. We conclude that this inhibitory capacity may contribute to the health benefits associated with social support.

Affective engagement for facial expressions and emotional scenes: The influence of social anxiety

Pictures of emotional facial expressions or natural scenes are often used as cues in emotion research. We examined the extent to which these different stimuli engage emotion and attention, and whether the presence of social anxiety symptoms influences responding to facial cues. Sixty participants reporting high or low social anxiety viewed pictures of angry, neutral, and happy faces, as well as violent, neutral, and erotic scenes, while skin conductance and event-related potentials were recorded. Acoustic startle probes were presented throughout picture viewing, and blink magnitude, probe P3 and reaction time to the startle probe also were measured. Results indicated that viewing emotional scenes prompted strong reactions in autonomic, central, and reflex measures, whereas pictures of faces were generally weak elicitors of measurable emotional response. However, higher social anxiety was associated with modest electrodermal changes when viewing angry faces and mild startle potentiation when viewing either angry or smiling faces, compared to neutral. Taken together, pictures of facial expressions do not strongly engage fundamental affective reactions, but these cues appeared to be effective in distinguishing between high and low social anxiety participants, supporting their use in anxiety research.

Defensive Mobilization in Specific Phobia: Fear Specificity, Negative Affectivity, and Diagnostic Prominence

Understanding of exaggerated responsivity in specific phobia-its physiology and neural mediators-has advanced considerably. However, despite strong phenotypic evidence that prominence of specific phobia relative to co-occurring conditions (i.e., principal versus nonprincipal disorder) is associated with dramatic differences in subjective distress, there is yet no consideration of such comorbidity issues on objective defensive reactivity. A community sample of specific phobia (n = 74 principal; n = 86 nonprincipal) and control (n = 76) participants imagined threatening and neutral events while acoustic startle probes were presented and eyeblinks (orbicularis occuli) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured. Principal specific phobia patients far exceeded control participants in startle reflex and autonomic reactivity during idiographic fear imagery. Distinguishing between single and multiple phobias within principal phobia and comparing these with nonprincipal phobia revealed a continuum of decreasing defensive mobilization: single patients were strongly reactive, multiple patients were intermediate, and nonprincipal patients were attenuated-the inverse of measures of pervasive anxiety and dysphoria (i.e., negative affectivity). Further, as more disorders supplanted specific phobia from principal disorder, overall defensive mobilization was systematically more impaired. The exaggerated responsivity characteristic of specific phobia is limited to those patients for whom circumscribed fear is the most impairing condition and coincident with little additional affective psychopathology. As specific phobia is superseded in severity by broad and chronic negative affectivity, defensive reactivity progressively diminishes. Focal fears may still be clinically significant but not reflected in objective defensive mobilization.

Differential cigarette-related startle cue reactivity among light, moderate, and heavy smokers

In this study, we examined the relationship between the level of daily cigarette consumption and the startle response to affective and cigarette-related cues among treatment-seeking smokers. Before receiving any behavioral or pharmacological treatment, 136 smokers attended a baseline laboratory session, during which we recorded their reflexive eyeblink responses to acoustic startle probes while they were viewing pleasant, unpleasant, neutral, and cigarette-related pictures. We found that 1) cigarette-related and pleasant pictures similarly reduced the startle magnitude compared to neutral pictures; 2) the magnitude of startle modulation rendered by pleasant or unpleasant pictures did not differ among light, moderate, and heavy smokers; and 3) startle attenuation by cigarette-related pictures was greater in heavy smokers than in light smokers. These results suggest that similar to pleasant stimuli, cigarette-related cues are motivationally salient for smokers, and that this salience increases with nicotine dependence.

Objective Measures of Emotion Related to Brand Attitude: A New Way to Quantify Emotion-Related Aspects Relevant to Marketing

With this study we wanted to test the hypothesis that individual like and dislike as occurring in relation to brand attitude can be objectively assessed. First, individuals rated common brands with respect to subjective preference. Then, they volunteered in an experiment during which their most liked and disliked brand names were visually presented while three different objective measures were taken. Participant's eye blinks as responses to acoustic startle probes were registered with electromyography (EMG) (i) and their skin conductance (ii) and their heart rate (iii) were recorded. We found significantly reduced eye blink amplitudes related to liked brand names compared to disliked brand names. This finding suggests that visual perception of liked brand names elicits higher degrees of pleasantness, more positive emotion and approach-oriented motivation than visual perception of disliked brand names. Also, skin conductance and heart rate were both reduced in case of liked versus disliked brand names. We conclude that all our physiological measures highlight emotion-related differences depending on the like and dislike toward individual brands. We suggest that objective measures should be used more frequently to quantify emotion-related aspects of brand attitude. In particular, there might be potential interest to introduce startle reflex modulation to measure emotion-related impact during product development, product design and various further fields relevant to marketing. Our findings are discussed in relation to the idea that self reported measures are most often cognitively polluted.

Variables involved in the cue modulation of the startle reflex in alcohol‐dependent patients

Cue modulation of the startle reflex is a paradigm that has been used to understand the emotional mechanisms involved in alcohol dependence. Attenuation of the startle reflex has been demonstrated when alcohol-dependent subjects are exposed to alcohol-related stimuli. However, the role of clinical variables on the magnitude of this response is unknown. The objective of this study was to determine the relationship between a number of clinical variables-severity of alcoholism, family history of alcoholism (FHA+), personality traits related to the sensitivity to reward-and the startle reflex response when subjects with alcohol dependence were viewing alcohol-related cues. After detoxification, 98 participants completed self-report instruments and had eye blink electromyograms measured to acoustic startle probes [100-millisecond burst of white noise at 95 dB(A)] while viewing alcohol-related pictures, and standardised appetitive, aversive and neutral control scenes. Ninety-eight healthy controls were also assessed with the same instruments. There were significant differences on alcohol-startle magnitude between patients and controls. Comparisons by gender showed that women perceived alcohol cues and appetitive cues more appetitive than men. Male and female patients showed more appetitive responses to alcohol cues when compared with their respective controls. Our patients showed an appetitive effect of alcohol cues that was positively related to severity of alcohol dependence, sensitivity to reward and a FHA+. The data confirmed that the pattern of the modulation of the acoustic startle reflex reveals appetitive effects of the alcohol cues and extended it to a variety of clinical variables.

Effects of simulated microgravity on brain plasticity: A startle reflex habituation study

There is limited but increasing evidence that space environment, namely weightless condition, may affect astronauts' cerebral neurotransmitters and cognitive performance. The present experiment hypothesized that learning and brain plasticity are affected by simulated microgravity condition. To this aim, 22 male subjects matching astronauts' characteristics were divided in two groups, Head-Down Bed Rest (HDBR) and Sitting Control. After 3-h bed rest (or sitting condition) subjects started a picture viewing task during which 30 acoustic startle probes (100dBA loudness), divided into three consecutive blocks, were delivered through headphones while startle reflex amplitude was measured from the EMG of the orbicularis oculi muscle. Habituation analysis of the startle reflex showed a normal reflex inhibition across blocks in sitting controls and no habituation in HDBR subjects. Results point to a microgravity-induced lack of startle reflex plasticity in subjects matching astronauts, a learning deficit which may affect the success of long-term space missions.

Aversive Imagery in Panic Disorder: Agoraphobia Severity, Comorbidity, and Defensive Physiology

Panic is characterized as a disorder of interoceptive physiologic hyperarousal, secondary to persistent anticipation of panic attacks. The novel aim of this research was to investigate whether severity of agoraphobia within panic disorder covaries with the intensity of physiological reactions to imagery of panic attacks and other aversive scenarios. A community sample of principal panic disorder (n = 112; 41 without agoraphobia, 71 with agoraphobia) and control (n = 76) participants imagined threatening and neutral events while acoustic startle probes were presented and the eye-blink response (orbicularis oculi) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured. Overall, panic disorder patients exceeded control participants in startle reflex and heart rate during imagery of standard panic attack scenarios, concordant with more extreme ratings of aversion and emotional arousal. Accounting for the presence of agoraphobia revealed that both panic disorder with and without situational apprehension showed the pronounced heart rate increases during standard panic attack imagery observed for the sample as a whole. In contrast, startle potentiation to aversive imagery was more robust in those without versus with agoraphobia. Reflex diminution was most dramatic in those with the most pervasive agoraphobia, coincident with the most extreme levels of comorbid broad negative affectivity, disorder chronicity, and functional impairment. Principal panic disorder may represent initial, heightened interoceptive fearfulness and concomitant defensive hyperactivity, which through progressive generalization of anticipatory anxiety ultimately transitions to a disorder of pervasive agoraphobic apprehension and avoidance, broad dysphoria, and compromised mobilization for defensive action.

Modulation of nociceptive and acoustic startle responses to an unpredictable threat in men and women

The present study examined whether a moderately aversive abdominal threat would lead to greater enhancement in affect- and pain-related defensive responding as indexed by the acoustic startle reflex (ASR) and nociceptive flexion reflex (NFR) in women compared to men. We also predicted sex differences in threat-related autonomic arousal measured by skin conductance responses (SCRs) to acoustic startle 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 9–21seconds following period onset. Unpredictable abdominal threat potentiated both ASR and NFR responses compared to periods signaling safety. SCRs to acoustic startle probes and noxious sural nerve stimulation were also significantly elevated during the threat vs safe periods. No sex differences in ASR or startle-evoked SCRs 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 SCRs to sural nerve stimulation than males. Our findings indicate that both affect- and pain-related defense and arousal systems are strongly influenced by threat of an aversive, unpredictable event, a situation associated with anticipatory anxiety. Females, compared to males, showed greater nociceptive responding and pain modulation when exposed to an unpredictable threatening context, whereas affect-driven ASR responses showed no such sex differentiation.Unpredictable threat enhanced arousal and affect-related defensive responses across males and females, whereas nociceptive and sympathetic responses to noxious sural nerve stimulation showed sex-dependent effects.

Patients with premenstrual dysphoric disorder have increased startle modulation during anticipation in the late luteal phase period in comparison to control subjects

The acoustic startle response (ASR) is a withdrawal reflex to sudden or noxious auditory stimuli and, most importantly, an unbiased measure of emotional processing of appetitive and aversive stimuli. By exposing subjects to fearful situations, such as aversive pictures, the ASR may be enhanced, suggesting that amygdala modulates the startle circuit during threat situations. As one previous study, investigating affective modulation of the ASR in women with premenstrual dysphoric disorder (PMDD), discovered no difference during picture viewing it is possible that the mood changes observed in PMDD relate to anxious anticipation rather than to direct stimulus responding. Hence we sought to examine the effects of PMDD on picture anticipation and picture response. Sixteen PMDD patients and 16 controls watched slide shows containing pleasant and unpleasant pictures and positive and negative anticipation stimuli during the follicular and luteal phase of the menstrual cycle. Simultaneously, semi-randomized startle probes (105 dB) were delivered and the ASR was assessed with electromyography. Compared with control subjects, PMDD patients displayed an enhanced startle modulation by positive and negative anticipation stimuli in the luteal phase of the menstrual cycle. This finding was mainly driven by increased modulation in the luteal phase in comparison to the follicular phase among PMDD patients but also by an increased modulation in patients compared to controls during luteal phase. This suggests that the neural circuits underlying response to emotional anticipation are more sensitive during this period and emphasize the need of examining the neural correlates of anticipatory processes in women with PMDD.

A startling absence of emotion effects: Active attention to the startle probe as a motor task cue appears to eliminate modulation of the startle reflex by valence and arousal

Research has shown that during emotional imagery, valence and arousal each modulate the startle reflex. Here, two imagery-startle experiments required participants to attend to the startle probe as a simple reaction time cue. In Experiment 1, four emotional conditions differing in valence and arousal were examined. Experiment 2, to accentuate potential valence effects, included two negative high arousal, a positive high arousal and a negative low arousal condition. Imagery effectively manipulated emotional valence and arousal, as indicated by heart rate and subjective ratings. Compared to baseline, imagery facilitated startle responses. However, valence and arousal failed to significantly affect startle magnitude in both experiments and startle latency in Experiment 1. Results suggest that emotional startle modulation is eclipsed when the probe is significant for task completion and/or cues a motor response. Findings suggest that an active, rather than defensive, response set may interfere with affective startle modulation, warranting further investigation.

Psychophysiological responses to inspiratory resistive loads

Fear of interoceptive sensations is relevant for a number of psychiatric and somatic disorders. Pappens et al. (2010, Biol. Psychol. 84, 98–103) reported elevated skin conductance responses (SCR), subjective fear, and a paradoxical lack of startle potentiation during aversive respiratory stimulation with an inspiratory resistive load (IRL). This study aimed to replicate these findings and to explore whether the lack of startle potentiation during an aversive IRL is related to attentional allocation to the IRL. Reaction times to the acoustic startle probe served as an indirect index of attentional focus on the respiratory stimulus. The earlier findings on SCR and subjective fear were replicated. However, startle potentiation occurred for the aversive IRL with a 1500 ms lead interval, and reaction times to the acoustic probe were not slower for the aversive IRL compared to other types of lead stimuli. This suggests that startle potentiation during aversive respiratory stimulation with IRLs only occurs when an exteroceptive task limits attentional allocation to the interoceptive experience.

Repetitive exposure: Brain and reflex measures of emotion and attention

Effects of massed repetition on the modulation of the late positive potential elicited during affective picture viewing were investigated in two experiments. Despite a difference in the number of repetitions across studies (from 5 to 30), results were quite similar: The late positive potential continued to be enhanced when participants viewed emotional, compared to neutral, pictures. On the other hand, massed repetition did prompt a reduction in the late positive potential that was most pronounced for emotional pictures. Startle probe P3 amplitude generally increased with repetition, suggesting diminished attention allocation to repeated pictures. The blink reflex, however, continued to be modulated by hedonic valence, despite massive massed repetition. Taken together, the data suggest that the amplitude of the late positive potential during picture viewing reflects both motivational significance and attention allocation.

Three methodologies for measuring the acoustic startle response in early infancy

The present study investigated whether three methodologies currently used in animal as well as human adult startle research could be adapted for measuring the startle response in 5-month-old infants. The three methods performed: an automated and computerized recording of the infants' whole-body motor reactions (Automated Infant Motor Movement Startle Seat, AIMMSS); a coding of the infants' facial muscular contractions involved in the startle response (FACS, Baby FACS); an analysis of the infants' eyeblink intensity in response to the startle probes (Eye-Blink Strength scale). The results showed that these methods accurately registered the latency and intensity parameters of the reactions to acoustic startle stimuli. A correlational analysis showed, also, that the three methods registered the same motor reaction measuring the infant acoustic startle response in a consistent way.

Psychopathic traits predict startle habituation but not modulation in an emotional faces task

The psychophysiological correlates of psychopathic traits in normal-range samples have been a topic of recent interest in studies of the biological basis of personality. It is well established that psychopaths demonstrate abnormal patterns of startle potentiation while viewing emotionally evocative pictures, but this effect has not been demonstrated using pictures of facial affect. Recent research has also indicated that an individual’s rate of habituation to an acoustic startle probe may be a reliable correlate of certain personality traits; however, this has not been investigated with psychopathic personality traits. We measured psychopathic personality traits in non-incarcerated young adults and investigated startle physiology while participants viewed pictures of facial affect. We found that psychopathic personality traits had no effect on startle modulation by emotional face category; however, the antisocial dimension of psychopathic traits was strongly associated with slower rates of habituation to the startle probe. This finding highlights the relevance of psychopathy’s underlying constructs of emotional functionality and behavioral inhibition, and suggests a relationship between basic sensory habituation and the broader concept of inhibition as it relates to personality and behavior.

Emotional Vulnerability in Borderline Personality Disorder Is Cue Specific and Modulated by Traumatization

A general emotional vulnerability (intense, easily triggered affective reactions) is considered a core symptom in borderline personality disorder (BPD), but evidence from psychophysiological studies for this hypothesis is not very consistent. Given the high comorbidity of posttraumatic stress disorder (PTSD) in BPD patients, current comorbid PTSD might also modulate emotional reactivity. In the present study using a script-driven imagery paradigm, idiographic aversive, disorder-specific (scenes about rejection and abandonment), and standard unpleasant, neutral, and pleasant scripts were presented to investigate emotional reactivity in patients with BPD. Forty nonmedicated BPD patients and 32 healthy control subjects first read and then imagined the scripts. Acoustic startle probes were presented during reading and imagery and the eye-blink responses, as well as changes in heart rate and skin conductance level were recorded. Imagery of disorder-specific scripts resulted in a clear potentiation of the startle responses and increased autonomic arousal in BPD patients but not in control subjects. Borderline personality disorder patients with current comorbid PTSD (n = 26 out of 40) showed attenuated startle potentiation during aversive imagery that was not the case in BPD patients without current PTSD. This effect was most pronounced in BPD patients with severe PTSD. Scenes about rejection and abandonment are specifically able to activate defensive response mobilization in BPD patients. These findings suggest that BPD patients are not more physiologically reactive to emotional cues in general but show increased emotional vulnerability if borderline-specific schemas are activated. Moreover, emotional reactivity is attenuated in BPD patients with PTSD.

Anger and cardiovascular startle reactivity in normotensive young males

Anger has been implicated in the etiology of hypertensive disease. Trait anger has been linked to enhanced cardiovascular responsiveness. However, whether this association reflects differences in context appraisal or a general hyper-reactivity of the cardiovascular system remains unclear. We studied the cardiovascular response to acoustic startle probes in 76 healthy Caucasian males in different affective contices (pleasant, neutral, and unpleasant). All participants completed the State-Trait-Anger-Expression-Inventory (STAXI) by Spielberger and the results were analysed with stepwise regression analysis according to the anger scores and traditional risk factors for hypertension. Our study reveals differential modulation of the cardiovascular response to startle stimuli by affective pictures in the dimensions “valence” for heart rate and “arousal” for blood pressure. Anger-in was identified as the most important determinant for blood pressure responses in unpleasant context, while anger-out was associated with less cardiovascular activation in neutral context. This is the first study that relates trait anger to cardiovascular reactivity and affective reflex modulation in normotensive subjects. We could demonstrate an interaction of affective context and trait anger for cardiovascular (hyper-)reactivity. Increased cardiovascular reactivity for higher scores of anger-in in unpleasant context may indicate enhanced sympathetic reactivity and constitute a risk factor for the development of essential hypertension.

A psychophysiological investigation of laterality in human emotion elicited by pleasant and unpleasant film clips

BackgroundResearch on laterality in emotion suggests a dichotomy between the brain hemispheres. The present study aimed to investigate this further using a modulated startle reflex paradigm.MethodsWe examined the effects of left and the right ear stimulation on the modulated startle reflex (as indexed by eyeblink magnitude, measured from the right eye) employing short (2 min) film clips to elicit emotions in 16 right-handed healthy participants. The experiment consisted of two consecutive sessions on a single occasion. The acoustic startle probes were presented monaurally to one of the ears in each session, counterbalanced across order, during the viewing of film clips.ResultsThe findings showed that eyeblink amplitude in relation to acoustic startle probes varied linearly, as expected, from pleasant through neutral to unpleasant film clips, but there was no interaction between monaural probe side and foreground valence.ConclusionsOur data indicate the involvement of both hemispheres when affective states, and associated startle modulations, are produced, using materials with both audio and visual properties. From a methodological viewpoint, the robustness of film clip material including audio properties might compensate for the insufficient information reaching the ipsilateral hemisphere when using static pictures. From a theoretical viewpoint, a right ear advantage for verbal processing may account for the failure to detect the expected hemispheric difference. The verbal component of the clips would have activated the left hemisphere, possibly resulting in an increased role for the left hemisphere in both positive and negative affect generation.

The serotonin transporter gene and startle response during nicotine deprivation

Affective startle probe methodology was used to examine the effects of nicotine administration and deprivation on emotional processes among individuals carrying at least one s allele versus those with the l/l genotype of the 5-Hydroxytryptamine (Serotonin) Transporter Linked Polymorphic Region, 5-HTTLPR in the promoter region of the serotonin transporter gene [solute ligand carrier family 6 member A4 ( SLC6A4) or SERT]. Smokers ( n = 84) completed four laboratory sessions crossing deprivation (12-h deprived vs. non-deprived) with nicotine spray (nicotine vs. placebo). Participants viewed affective pictures (positive, negative, neutral) while acoustic startle probes were administered. We found that smokers with the l/l genotype showed significantly greater suppression of the startle response when provided with nicotine vs. placebo than those with the s/s or s/l genotypes. The results suggest that l/l smokers, who may have higher levels of the serotonin transporter and more rapid synaptic serotonin clearance, experience substantial reduction in activation of the defensive system when exposed to nicotine.