Startle Eyeblink Response Research Articles

Increased Acoustic Startle Responses in IBS Patients During Abdominal and Nonabdominal Threat

Visceral hypersensitivity and symptom severity in Irritable Bowel Syndrome (IBS) are both exacerbated by stress. The eye-blink startle response represents a noninvasive measure of central defensive responding. Evidence for central hyperexcitability was studied in IBS patients by examining potentiation of the startle reflex to a nociceptive threat. Acoustic startle responses were examined in female IBS patients (n = 42) and healthy controls (n = 22) during cued periods in which an aversive abdominal or biceps stimulation was impossible (safe), possible (imminent threat) or anticipated (period just before the imminent threat), and during a threatening context (muscle stimulation pads attached but no cues for stimulation). Both groups showed potentiation of startle responses during the imminent threat condition compared with both the anticipation and safe conditions. Compared with controls, IBS subjects showed significantly larger startle responses during anticipation and imminent threat conditions after receiving an initial aversive stimulation. There were no group differences during the context threat manipulation. Moreover, in IBS patients but not controls, higher neuroticism was associated with larger startle responses during safe and anticipation conditions but not imminent threat, whereas anxiety symptoms were negatively associated with startle magnitude during imminent threat. Female IBS patients show increased startle responses to threat of aversive stimulation at both abdominal and nonabdominal sites compared with controls. The data represent the first demonstration of altered threat potentiated startle in a functional pain condition and provide support for the use of these paradigms in further evaluation of affective mechanisms in these disorders.

Anticipation of interoceptive threat in highly anxiety sensitive persons

Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context.

Uncontrollable voices and their relationship to gating deficits in schizophrenia

BackgroundPrepulse inhibition (PPI) of the startle response refers to the ability of a weak prestimulus to transiently inhibit the response to a closely following strong sensory stimulus. This effect is reduced in a number of disorders known to be associated with impaired gating of sensory, cognitive or motor information. The aim of this study was to investigate PPI deficit in relation to the dimensions of auditory hallucinations in patients with schizophrenia or schizoaffective disorder. MethodPPI of the acoustically elicited eye blink startle response was measured electromyographically in 62 patients with schizophrenia (n=55) or schizoaffective disorder (n=7) (26 of 62 with current auditory hallucinations) and 22 healthy participants matched, on average, to age and sex of the patient group. ResultsPatients, as a group, showed reduced PPI compared to healthy participants. The presence of auditory hallucinations was associated with a marked PPI deficit if the patients felt that they had no control over their occurrence and that they were unable to dismiss them. Hearing voices with a high degree of negative content was associated with high mean startle amplitude in patients with current auditory hallucinations. ConclusionsAlthough auditory hallucinations in patients with schizophrenia are theorised to result from impaired monitoring of inner speech, the inability to consciously ignore them appears to be associated with a gating deficit. Hearing voices with negative content is associated with hyper-startle responding, possibly because such voices are threatening and thus provoke anxiety.

Negative self-focused cognitions mediate the effect of trait social anxiety on state anxiety

The cognitive model of social anxiety predicts that negative self-focused cognitions increase anxiety when anticipating social threat. To test this prediction, 36 individuals were asked to anticipate and perform a public-speaking task. During anticipation, negative self-focused cognitions or relaxation were experimentally induced while self-reported anxiety, autonomic arousal (heart rate, heart rate variability, skin conductance level), and acoustic eye-blink startle response were assessed. As predicted, negative self-focused cognitions mediated the effects of trait social anxiety on self-reported anxiety and heart rate variability during negative anticipation. Furthermore, trait social anxiety predicted increased startle amplitudes. These findings support a central assumption of the cognitive model of social anxiety.

Attention and Emotional Responses to Sexual Stimuli and Their Relationship to Sexual Desire

Little is known about why individuals vary in their levels of sexual desire. Information processing models, like Barlow's (Journal of Consulting and Clinical Psychology 54:140-148, 1986) model of sexual functioning, suggest that individuals with higher sexual desire attend more and respond with more pleasant emotions to sexual cues than individuals with lower levels of sexual desire. In this study, 69 participants (36 women, 33 men) completed a dot detection task measuring attention capture by sexual stimuli and a startle eyeblink modulation task indexing the valence of emotional response to affective stimuli. Participants with high levels of sexual desire were slower to detect targets in the dot detection task that replaced sexual images but did not differ in startle eyeblink responses to sexual stimuli. The results suggest that the amount of attention captured by sexual stimuli is a stronger predictor of a person's sexual desire level than the valence of the emotional responses elicited by such stimuli.

Defensive Physiological Reactions to Rejection

We examined the hypothesis that rejection automatically elicits defensive physiological reactions in people with low self-esteem (SE) but that attentional control moderates this effect. Undergraduates (N= 67) completed questionnaire measures of SE and attentional control. Their eye-blink responses to startle probes were measured while they viewed paintings related to rejection and acceptance themes. The stimuli also included positive-, negative-, and neutral-valence control paintings unrelated to rejection. As predicted, compared with people high in SE, those low in SE showed stronger startle eye-blink responses to paintings related to rejection, but not to negative paintings. Paintings related to acceptance did not attenuate their physiological reactivity. Furthermore, attentional control moderated their sensitivity to rejection, such that low SE was related to greater eye-blink responses to rejection only among individuals who were low in attentional control. Implications of the role of attentional control as a top-down process regulating emotional reactivity in people with low SE are discussed.

Effects of olanzapine, risperidone and haloperidol on prepulse inhibition in schizophrenia patients: A double-blind, randomized controlled trial

Prepulse inhibition (PPI), whereby the startle eyeblink response is inhibited by a relatively weak non-startling stimulus preceding the powerful startle eliciting stimulus, is a measure of sensorimotor gating and has been shown to be deficient in schizophrenia patients. There is considerable interest in whether conventional and/or atypical antipsychotic medications can “normalize” PPI deficits in schizophrenia patients. 51 schizophrenia patients participated in a randomized, double-blind controlled trial on the effects of three commonly-prescribed antipsychotic medications (risperidone, olanzapine, or haloperidol) on PPI, startle habituation, and startle reactivity. Patients were tested at baseline, Week 4 and Week 8. Mixed model regression analyses revealed that olanzapine significantly improved PPI from Week 4 to Week 8, and that at Week 8 patients receiving olanzapine produced significantly greater PPI than those receiving risperidone, but not haloperidol. There were no effects of medication on startle habituation or startle reactivity. These results support the conclusion that olanzapine effectively increased PPI in schizophrenia patients, but that risperidone and haloperidol had no such effects. The results are discussed in terms of animal models, neural substrates, and treatment implications.

Postauricular and eyeblink startle responses to facial expressions

Emotional facial expressions have affective significance. Smiles, for example, are perceived as positive and responded to with increased happiness, whereas angry expressions are perceived as negative and threatening. Yet, these perceptions are modulated in part by facial morphological cues related to the sex of the expresser. The present research assessed both eyeblink startle and the postauricular reflex during happy and angry expressions by men and women. For this 14 male and 16 female undergraduates saw happy, neutral, and angry facial expressions as well as positive and negative pictures. The postauricular reflex was potentiated during happy expressions and inhibited during anger expressions; however, as expected, this pattern was more clearly found for female expressers. Conversely, the expected pattern of eyeblink startle potentiation during angry faces and inhibition during happy faces was found only for male expressers.

Impact of stimulus signal‐to‐noise ratio on prepulse inhibition of acoustic startle

Prepulse inhibition (PPI) of the human acoustic startle response is reduced in the presence of background noise of a sufficient intensity, possibly due to a reduction in signal-to-noise ratio (prepulse intensity relative to background noise). We examined this hypothesis by varying prepulse intensity and background noise intensity in order to hold three different signal-to-noise ratios constant (5, 15, and 25 dB(A) above background noise intensity). The results showed that signal-to-noise ratio proved to be a more important factor than absolute stimulus intensity in determining the degree of PPI of startle eyeblink response magnitude. Therefore, the effectiveness of a prepulse is determined by prepulse salience, not intensity, and this effectiveness is equivalent across a range of physical intensities.

Regulation of emotional responses elicited by threat‐related stimuli

The capacity to voluntarily regulate emotions is critical for mental health, especially when coping with aversive events. Several neuroimaging studies of emotion regulation found the amygdala to be a target for downregulation and prefrontal regions to be associated with downregulation. To characterize the role of prefrontal regions in bidirectional emotion regulation and to investigate regulatory influences on amygdala activity and peripheral physiological measures, a functional magnetic resonance imaging (fMRI) study with simultaneous recording of self-report, startle eyeblink, and skin conductance responses was carried out. Subjects viewed threat-related pictures and were asked to up- and downregulate their emotional responses using reappraisal strategies. While startle eyeblink responses (in successful regulators) and skin conductance responses were amplified during upregulation, but showed no consistent effect during downregulation, amygdala activity was increased and decreased according to the regulation instructions. Trial-by-trial ratings of regulation success correlated positively with activity in amygdala during upregulation and orbitofrontal cortex during downregulation. Downregulation was characterized by left-hemispheric activation peaks in anterior cingulate cortex, dorsolateral prefrontal cortex, and orbitofrontal cortex and upregulation was characterized by a pattern of prefrontal activation not restricted to the left hemisphere. Further analyses showed significant overlap of prefrontal activation across both regulation conditions, possibly reflecting cognitive processes underlying both up- and downregulation, but also showed distinct activations in each condition. The present study demonstrates that amygdala responses to threat-related stimuli can be controlled through the use of cognitive strategies depending on recruitment of prefrontal areas, thereby changing the subject's affective state.

Eye blink startle responses in behaviorally inhibited and uninhibited children

The present study examined the startle reflex as a physiological marker of behavioral inhibition. Participants were 7to 12-year-old children who had been previously identified as inhibited or uninhibited as part of an ongoing longitudinal study on the role of behavioral inhibition in the development of anxiety disorders. Analysis of their scores on the Behavioral Inhibition Scale revealed that the children were stable in their behavioral inhibition categorization as compared to the beginning of the longitudinal study. An experiment was carried out to study startle modulation effects in response to novel and familiar pictures of threatening and non-threatening facial expressions in inhibited and uninhibited children. The main results can be summarized as follows. To begin with, no modulation effect was found. That is, children did not show the expected (adult-like) startle facilitation while viewing unpleasant pictures. Second, a habituation effect was found: that is, during the testing phase children responded more intensely to the first block of slides than to the second block of slides (irrespective of slide content). Third, unexpectedly behaviorally inhibited children displayed smaller eye blink magnitudes in response to novel slides than uninhibited children. Fourth and finally, no meaningful differences were found in the patterns of startle responses of both genders.

Effects of perceptual load on startle reflex modification at a long lead interval

Inhibition of the startle eyeblink response at long lead intervals has been hypothesized to occur when attention is directed away from the modality of the startle stimulus, particularly if attention is directed to a stimulus of high perceptual load. In a test of this hypothesis, participants performed a delayed-matching-to-sample task. On each trial a pattern of dots (the sample) was followed by a second pattern of dots (the target). The task was to say whether the sample and target patterns matched. Perceptual load was manipulated by varying the number of dots in the sample. Auditory startle stimuli were presented 1200 ms after onset of the samples. A linear increase in startle magnitude was found as the number of dots increased. The results are not consistent with the hypothesis that startle inhibition occurs when the lead and startle stimuli are in different modalities under conditions of high perceptual load.

Infrared reflectance as an alternative to EMG for measuring prepulse inhibition of startle eyeblink

The "gold standard" measure of the human startle eyeblink response is the ocular electromyogram (EMG). However, EMG measurement is not always feasible, as with special populations or during functional neuroimaging. We evaluated an alternative, nonelectrical, noncontact measure that uses infrared (IR) light reflected from the eye. By simultaneously recording IR and EMG during an acoustic prepulse inhibition of startle paradigm, we were able to directly compare the two measures and evaluate the relative reliability and validity of the IR measure as an index of startle response modulation. Although fewer responses were detected using IR than EMG, both measures were equally sensitive to prepulse modulation of response amplitude, latency, and probability. We conclude that when the goal is simply to assess the effects of a prepulse on the startle response, IR reflectance is an adequate alternative to EMG.

A fMRI investigation of startle gating deficits in schizophrenia patients treated with typical or atypical antipsychotics

A key feature of schizophrenia is the inability to screen out irrelevant sensory input. Prepulse inhibition (PPI) of the startle response, a cross-species measure of sensorimotor gating, provides a valuable opportunity to study this feature. PPI is reliably impaired in schizophrenia. Animal models of disrupted PPI have proved valuable for the evaluation of antipsychotic substances. The cortico-striato-pallido-thalamic circuitry is primarily responsible for modulation of PPI in animals. We examined PPI and its brain correlates, using functional magnetic resonance imaging (fMRI), in men with schizophrenia treated with typical or atypical antipsychotics. Thirty men with schizophrenia on stable doses of typical antipsychotics (n=10), risperidone (n=10) or olanzapine (n=10; 9 with usable fMRI data) and 12 healthy men underwent psychophysiological testing and fMRI during a tactile PPI paradigm. The results showed reduced PPI of the eye-blink startle response in patients compared with healthy controls. Within the patient group, those on typical antipsychotics showed significantly impaired PPI but risperidone- or olanzapine-treated patients showed a milder (non-significant) deficit. Increased activity in the striatum, thalamus, insula, hippocampal, temporal, inferior frontal and inferior parietal regions occurred in association with PPI in controls. Patients treated with risperidone or olanzapine, but not with typical antipsychotics, showed significant activation in PPI-relevant regions. Our findings provide preliminary evidence that atypical antipsychotics positively influence PPI and partially restore associated brain functions in schizophrenia. Imaging data buttress the validity of PPI as a useful animal model of schizophrenia.

Gender differences in affective response to acute nicotine administration and deprivation

Men and women may differ in their sensitivity to the mood-modulating properties of nicotine. Male and female adult smokers were exposed to four sessions crossing two nicotine deprivation conditions (12-h deprived vs. nondeprived) with two drug conditions (nicotine vs. placebo nasal spray). Acoustic probes elicited startle eyeblink responses while viewing affective and cigarette-related slides. In-session mood ratings were collected to gauge self-reported negative affect, positive affect, and craving. Nicotine nasal spray reduced startle amplitude in both men and women following 12-h deprivation compared with smoking nondeprivation. During nondeprivation, nicotine nasal spray increased startle amplitude in women compared with placebo spray, whereas no difference was found for men. The startle results suggest that both men and women are responsive to the hedonic properties of nicotine.

Stuttering in adults: The acoustic startle response, temperamental traits, and biological factors

The purpose of this study was to investigate the relation between stuttering and a range of variables of possible relevance, with the main focus on neuromuscular reactivity, and anxiety. The explorative analysis also included temperament, biochemical variables, heredity, preonset lesions, and altered auditory feedback (AAF). An increased level of neuromuscular reactivity in stuttering adults has previously been reported by [Guitar, B. (2003). Acoustic startle responses and temperament in individuals who stutter. Journal of Speech Language and Hearing Research, 46, 233–240], also indicating a link to anxiety and temperament. The present study included a large number of variables in order to enable analysis of subgroups and relations between variables. Totally 32 stuttering adults were compared with nonstuttering controls. The acoustic startle eyeblink response was used as a measure of neuromuscular reactivity. No significant group difference was found regarding startle, and startle was not significantly correlated with trait anxiety, stuttering severity, or AAF. Startle was mainly related to calcium and prolactin. The stuttering group had significantly higher scores for anxiety and childhood ADHD. Two subgroups of stuttering were found, with high versus low traits of childhood ADHD, characterized by indications of preonset lesions versus heredity for stuttering. The study does not support the view that excessive reactivity is a typical characteristic of stuttering. The increased anxiety is suggested to mainly be an effect of experiences of stuttering. Learning outcomes: As a result of reading this article, the reader will be able to: (a) critically discuss the literature regarding stuttering in relation to acoustic startle, anxiety, and temperament; (b) describe the effect of calcium on neuromuscular reactivity; (c) discuss findings supporting the importance of early neurological incidents in some cases of stuttering, and the relation between such incidents and traits of ADHD or ADD; and (d) discuss the role of genetics in stuttering.

Startling facts about emotion in Parkinson's disease: blunted reactivity to aversive stimuli

The amygdala is closely linked to basal ganglia circuitry and plays a key role in danger detection and fear-potentiated startle. Based on recent findings of amygdalar abnormalities in Parkinson's disease, we hypothesized that non-demented patients with this illness would show blunted reactivity during aversive/unpleasant events, as indexed by diminished emotional modulation of the startle eyeblink response. To test this hypothesis, 23 idiopathic patients with Parkinson's disease and 17 controls viewed standardized sets of aversive, pleasant and neutral pictures for 6 s each. During this time, white noise bursts (50 ms, 95 db) were binaurally presented to elicit startle eyeblink responses, measured from electrodes over the orbicularis oculi. After viewing each picture, subjects provided ratings of valence and arousal. The Parkinson's disease patients were in the early to middle stages of their disease, not demented or depressed, and were tested 'on' dopaminergic medication. The two groups were similar in age, education, gender and cognitive screening status. The control group had larger startle responses when viewing negative, aversive pictures than neutral or pleasant pictures. As predicted, startle enhancement during aversive pictures was significantly muted in the Parkinson's disease patients. This blunting was not due to abnormalities in the mechanics of the startle eyeblink per se. Nor was it related to depression symptoms, medications (psychotropics), or failure to perceive/appreciate the negative meaning of aversive pictures (i.e. normal valence ratings). Reduced startle reactivity in the disease group was related to disease severity (Hoehn-Yahr) and occurred in the context of reduced arousal ratings of aversive pictures. These findings of blunted startle reactivity add to the literature on emotional changes associated with Parkinson's disease. The basis for this muted reactivity is unknown but may involve an amygdala-based translational defect whereby the results of cognitive appraisal are not appropriately transcoded into somato-motor-arousal responses normally associated with an aversive motivational state. This may arise from faulty dopaminergic gating of the amygdala, resulting in 'inhibition' of the amygdala in the manner described by Marowsky et al. (Marowsky A, Yanagawa Y, Obata K, Vogt E. Neuron 2005; 48: 1025-37). More broadly, the findings of muted reactivity to aversive stimuli may reflect a 'bradylimbic' affective disturbance in patients with Parkinson's disease. Future studies are needed to address whether the physiologic blunting observed here might be a useful correlate of apathy.

Processing of own versus other names differentially affects startle reflex modification

Previous research suggests that the startle eyeblink response may be differentially modified at very short latencies by words that attract more versus fewer attentional resources. These studies were conducted using threat and non-threat words as stimuli. The goal of the present study was to examine whether startle blink modification is similarly affected by differential attention when one's own name versus another name is used as a lead stimulus. Fifty-six undergraduates were presented repeatedly with their own name or another name displayed visually, followed (60, 120, 300, or 2000 ms later) by an acoustic startling noise burst. Startle magnitude was differentially modified by own versus other names, primarily at the 60 and 120 ms lead intervals. Other names demonstrated greater magnitude potentiation at the 60 ms interval and greater magnitude inhibition at the 120 ms lead interval compared with own names, suggesting the startle modification paradigm is sensitive to early attentional processes engaged during the reading of non-threat-related words.

Physical Activity, Negative Affect, and the Reflex Physiology of Emotion

Physical activity participation is consistently associated with improved mood in both healthy individuals and those diagnosed with a mood or anxiety disorder. Yet there is little evidence to support that physical activity affects the physiological outputs from brain systems that govern emotion. Because changes in emotion presumably underlie changes in mood, it is important to examine the physiology of emotion in the context of physical activity participation as well as individual differences in negative affect. PURPOSE: To examine the effects of physical activity history in the modulation of emotional reactivity among individuals with low and high negative affect. METHOD: Participants (n = 72) were selected from Introduction to Psychology classes based on their scores for depression, trait anxiety and physical activity history on a pre-screening questionnaire. To verify affective and physical activity status, upon arrival to the laboratory participants completed the Beck Depression Inventory, the Trait Anxiety Inventory, and Blair's (1984) 7-day physical activity history interview. Each participant was then prepared for the electromyographic recording of the corrugator supercilii (facial frowning) and orbicularis oculi (eye blink) muscles, then viewed valence-homogeneous blocks of 36 pleasant, 36 neutral, and 36 unpleasant pictures in a counterbalanced order. Each picture was shown for 6 seconds, all 36 pictures in a block were presented consecutively, and there was a 3-min inter-block interval. Startle eye blink responses were elicited and recorded every 30 seconds after the delivery of a loud (95 dB) brief (50 ms) acoustic stimulus through headphones. RESULTS: Preliminary analyses showed that those who reported high negative did not show the expected increase in facial frowning during the unpleasant pictures; however, this was evident only in those who also reported low levels of physical activity. Furthermore, this lack of unpleasant responsiveness, compared to the normally physically active and low negative affect participants, persisted throughout the pictures to approximately 60 seconds after the unpleasant pictures had ceased. In addition, individuals with low negative affect who also reported normal levels of physical activity responded with less facial frowning during the viewing of neutral pictures compared to those with high negative affect and/or low levels of physical activity. CONCLUSION: These data suggest that individuals with high negative affect may fail to respond appropriately to unpleasant affective stimuli, and that being physically active may promote a healthy emotional response system. Support: NIH F32-MH066601.

Loss of emotional experience after traumatic brain injury: Findings with the startle probe procedure.

The authors used affective modulation of the eyeblink startle response to examine the impact of traumatic brain injury (TBI) on emotional reactions to pictures. Participants were 13 individuals with severe TBI and 24 controls. Participants were presented with pictures that differed in affective valence (e.g., mutilated bodies, erotic couples, and household objects) while the eyeblink startle response to an acoustic probe was measured. Startle amplitude was used to assess valence of emotional response, and startle latency was used to index interest in the pictures. Subjective ratings of the affect and arousal elicited by the various pictures were also obtained. TBI impaired startle potentiation to unpleasant pictures but not startle attenuation to pleasant pictures. Further, subjective ratings indicated that TBI participants found unpleasant pictures less arousing than did controls. The results are consistent with recent evidence of differential impairment in negative versus positive emotions after TBI and are discussed in relation to 2 competing explanations of startle modulation.