Trait emotions and affective modulation of the startle eyeblink: On the unique relationship of trait anger.

We examined relationships among individual differences in trait emotions and the emotion-modulated startle-eyeblink response. In particular, we examined the extent to which trait anger, which is negative in valence, would be associated with a pattern of approach motivation in startle eyeblink responses to appetitive stimuli. Self-reported trait emotions were compared with emotion-modulated startle eyeblink responses to auditory probes during appetitive, aversive, and neutral pictures. Results revealed that trait anger, enjoyment, and surprise were each associated with greater blink inhibition to appetitive pictures, indicating an approach motivational response. No other trait emotions were associated with startle eyeblink responses to appetitive or aversive pictures. These results support the idea that trait anger, although experienced as a negative emotion, is associated with an approach-related motivational response to appetitive stimuli at basic, reflexive levels of processing. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Emotion and motivation II: Sex differences in picture processing.

Adhering to the view that emotional reactivity is organized in part by underlying motivational states--defensive and appetitive--we investigated sex differences in motivational activation. Men's and women's affective reactions were measured while participants viewed pictures with varied emotional and neutral content. As expected, highly arousing contents of threat, mutilation, and erotica prompted the largest affective reactions in both men and women. Nonetheless, women showed a broad disposition to respond with greater defensive reactivity to aversive pictures, regardless of specific content, whereas increased appetitive activation was apparent for men only when viewing erotica. Biological and sociocultural factors in shaping sex differences in emotional reactivity are considered as possible mediators of sex differences in emotional response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotion deficits in schizophrenia: Timing matters.

The past two decades of research on emotional response in schizophrenia has demonstrated that people with schizophrenia do not have a marked deficit in reported emotional experience in the presence of emotionally evocative stimuli. However, the extent to which people with schizophrenia maintain their emotional state to guide future behavior remains a largely unexplored area of investigation. In the present study, we tested hypotheses about whether people with schizophrenia maintained their emotional state in the absence of emotionally evocative stimuli. In addition to reported emotional experience, we measured startle response magnitude both during the viewing and after the offset of emotional pictures to assess whether people with schizophrenia (n = 31) and without schizophrenia (n = 28) differ in their patterns of immediate response to emotional pictures and in their patterns of maintenance of these responses. Our findings indicated that people with and without schizophrenia did not differ in their self-report or startle response magnitude during presentation of emotional pictures. However, healthy controls maintained these responses after the stimuli were removed from view, but people with schizophrenia did not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Common and distinct patterns of affective response in dimensions of anxiety and depression.

The authors examined the time course of affective responding associated with different affective dimensions--anxious apprehension, anxious arousal, and anhedonic depression--using an emotion-modulated startle paradigm. Participants high on 1 of these 3 dimensions and nonsymptomatic control participants viewed a series of affective pictures with acoustic startle probes presented before, during, and after the stimuli. All groups exhibited startle potentiation during unpleasant pictures and in anticipation of both pleasant and unpleasant pictures. Compared with control participants, symptomatic participants exhibited sustained potentiation following the offset of unpleasant stimuli and a lack of blink attenuation during and following pleasant stimuli. Common and unique patterns of affective responses in the 3 types of mood symptoms are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The emotion probe: Studies of motivation and attention.

Emotions are action dispositions, states of vigilant readiness that vary widely in reported affect, physiology, and behavior. They are driven, however, by only 2 opponent motivational systems, appetitive and aversive subcortical circuits that mediate reactions to primary reinforcers. Using a large emotional picture library, reliable affective psychophysiologies are shown, defined by the judged valence (appetitive/pleasant or aversive/unpleasant) and arousal of picture percepts. Picture-evoked affects also modulate responses to independently presented startle probe stimuli. In other words, they potentiate startle reflexes during unpleasant pictures and inhibit them during pleasant pictures, and both effects are augmented by high picture arousal. Implications are elucidated for research in basic emotions, psychopathology, and theories of orienting and defense. Conclusions highlight both the approach's constraints and promising paths for future study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective individual differences and startle reflex modulation.

Potentiation of startle has been demonstrated in experimentally produced aversive emotional states, and clinical reports suggest that potentiated startle may be associated with fear or anxiety. To test the generalizability of startle potentiation across a variety of emotional states as well as its sensitivity to individual differences in fearfulness, the acoustic startle response of 17 high- and 15 low-fear adult Ss was assessed during fear, anger, joy, sadness, pleasant relaxation, and neutral imagery. Startle responses were larger in all aversive affective states than during pleasant imagery. This effect was enhanced among high fear Ss, although follow-up testing indicated that other affective individual differences (depression and anger) may also be related to increased potentiation of startle in negative affect. Startle latency was reduced during high- rather than low-arousal imagery but was unaffected by emotional valence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The impact of changes in spatial distance on emotional responses.

Drawing on motivational approaches to emotion, the authors propose that the perceived change in spatial distance to pictures that arouse negative emotions exerts an influence on the significance of these pictures. Two experiments induced the illusion that affective pictures approach toward the observer, recede from the observer, or remain static. To determine the motivational significance of the pictures, emotional valence and arousal ratings as well as startle responses were assessed. Approaching unpleasant pictures were found to exert an influence on both the valence and the arousal elicited by the pictures. Furthermore, movement of pleasant or neutral pictures did not influence startle responses, while the second experiment showed that approaching unpleasant pictures elicited enhanced startle responses compared to receding unpleasant pictures. These findings support the view that a change of spatial distance influences motivational significance and thereby shapes emotional responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diazepam blocks fear-potentiated startle in humans.

The effects of an anxiolytic drug (diazepam) on emotional responses to aversive stimuli were investigated using physiological measures, including the startle probe reflex. Participants were 54 university students assigned to either a placebo group or a 10 mg or 15 mg diazepam group in a doubleblind design. Blink responses to intermittent noise probes were recorded during viewing of neutral and unpleasant slides. Consistent with prior animal work, diazepam blocked startle potentiation during aversive stimulus processing without decreasing the overall magnitude of startle responses. These findings suggest that a common defensive state mediates startle reflex potentiation in animals and humans and that this index of fear can be used to assess the emotional effects of different drugs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rapid picture presentation and affective engagement.

Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intoxication level and emotional response.

We used affective modulation of the eye-blink component of the startle reflex to examine effects of three levels of alcohol intoxication and a no-intoxication control on emotional responses to pleasant, neutral, and unpleasant pictures. Non-problematic student drinkers (n = 101; 48 female) were randomly assigned to intoxication groups. Normal inhibition of startle during exposure to pleasant pictures was intact across groups. In contrast, potentiation of startle during viewing of unpleasant pictures was evident in the no- and low-intoxication groups, compared to the intermediate- and high-intoxication groups, in which it was significantly reduced. This pattern suggests that a direct and selective anxiolytic effect of alcohol can occur at higher levels of intoxication without an analogous impact on response to emotionally positive stimuli at similar levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender differences in the negative affective priming of aggressive behavior.

The negative affective priming of aggression was examined across different aversive contexts (general stress exposure and frustration) with a laboratory aggression paradigm that measured the intensity of shocks participants delivered to a putative employee. Participants' emotional responses were gauged via startle eyeblink reactions and self-report mood ratings. Aside from gender differences in overall aggression, men but not women exposed to general stress showed significant increases in aggression across blocks. However, frustration produced increases in aggression in both genders. Although both genders showed robust startle increases during stress, startle activation was related to increases in aggression in men and decreases in aggression in women. These findings suggest that general stress and experiences of negative emotion trigger physical aggressive responses more strongly in men than in women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related affective modulation of the startle eyeblink response: Older adults startle most when viewing positive pictures.

Previous studies reveal age by valence interactions in attention and memory, such that older adults focus relatively more on positive and relatively less on negative stimuli than younger adults. In the current study, eyeblink startle response was used to measure differences in emotional reactivity to images that were equally arousing to both age groups. Viewing positive and negative pictures from the International Affective Picture System had opposite effects on startle modulation for older and younger adults. Younger adults showed the typical startle blink pattern, with potentiated startle when viewing negative pictures compared to positive pictures. Older adults, on the other hand, showed the opposite pattern, with potentiated startle when viewing positive pictures compared to viewing negative and neutral pictures. Potential underlying mechanisms for this interaction are evaluated. This pattern suggests that, compared with younger adults, older adults are more likely to spontaneously suppress responses to negative stimuli and process positive stimuli more deeply. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Emotional Response in Patients With Frontal Brain Damage: Effects of Affective Valence and Information Content.

The authors investigated the role of the frontal lobes in the emotional response in 19 patients with brain damage and 23 control subjects. They studied the modulation of the startle blink reflex by affective pictures, and other autonomic responses. Patients showed a dissociation between the startle reflex and the affective valence ratings of the pictures, as a result of a low inhibition of the startle reflex by pleasant pictures. Pictures elicited lower skin conductance responses (SCRs) in patients than in controls, whereas the groups did not differ in the SCRs prompted by less significant acoustic stimuli. The findings point to the frontal lobe as a structure involved in the emotional response and in the physiological emotional arousal related to the complexity of the stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional learning, hedonic change, and the startle probe.

A multiple-response analysis of aversive learning was conducted in human Ss. For each S, 2 pictorial stimuli were presented, 1 paired with electric shock. After training, the magnitude of the acoustic startle eyeblink reflex elicited in the context of the shocked picture increased dramatically and was significantly larger than for reflexes elicited during the nonshocked stimulus. Five different picture contents were tested in separate groups: Reflex potentiation was larger for pictures rated as pleasant than pictures rated as unpleasant. CRs were also evident for skin conductance, heart rate, and affective judgments. Different systems reflected different aspects of the acquired fear response: Conductance change covaried with arousal, and startle probe magnitude varied with affective valence (pleasure). The neurophysiological implications of the data are elucidated, and parallels drawn between animal and human S findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensation Seeking and the Aversive Motivational System.

Sensation seeking (SS) has traditionally been viewed as a phenomenon of the appetitive motivational system. The limited SS research exploring contributions from the aversive motivational system reveals greater anxious reactivity to dangerous activities among low sensation seekers. The present study extends this line of work by comparing levels of fear and anxiety during anticipation of predictable and unpredictable aversive stimuli across high- and low-SS groups. Low sensation seekers displayed greater fear-potentiated startle (FPS) to predictable aversive stimuli, and only those low on SS showed FPS and skin conductance response effects during experimental contexts in which aversive stimuli were delivered unpredictably. Findings implicate enhanced apprehensive anticipation among those low on SS as a potential deterrent for their participation in intense and threatening stimulus events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flexible emotional responsiveness in trait resilience.

Field studies and laboratory experiments have documented that a key component of resilience is emotional flexibility—the ability to respond flexibly to changing emotional circumstances. In the present study we tested the hypotheses that resilient people exhibit emotional flexibility: (a) in response to frequently changing emotional stimuli and (b) across multiple modalities of emotional responding. As participants viewed a series of emotional pictures, we assessed their self-reported affect, facial muscle activity, and startle reflexes. Higher trait resilience predicted more divergent affective and facial responses (corrugator and zygomatic) to positive versus negative pictures. Thus, compared with their low-resilient counterparts, resilient people appear to be able to more flexibly match their emotional responses to the frequently changing emotional stimuli. Moreover, whereas high-trait-resilient participants exhibited divergent startle responses to positive versus negative pictures regardless of the valence of the preceding trial, low-trait-resilient participants did not exhibit divergent startle responses when the preceding picture was negative. High-trait-resilient individuals, therefore, appear to be better able than are their low-resilient counterparts to either switch or maintain their emotional responses depending on whether the emotional context changes. The present findings broaden our understanding of the mechanisms underlying resilience by demonstrating that resilient people are able to flexibly change their affective and physiological responses to match the demands of frequently changing environmental circumstances. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sustained and transient modulation of performance induced by emotional picture viewing.

We investigated how viewing task-irrelevant emotional pictures affects the performance of a subsequent nonemotional visual detection task. Subjects performed target-detection trials following the offset of individual unpleasant, pleasant, and neutral pictures. Sustained interference occurred when subjects viewed unpleasant pictures (mutilated bodies) in a sequential, "blocked" fashion. Such slowing down of reaction time appeared to build up with time, consistent with the instatement of a defensive emotional state. With a randomized picture presentation, only a transient interference effect was observed, consistent with increased attentional demands during the processing of unpleasant pictures. During blocked presentation of affiliative pleasant pictures, reaction times were faster, suggesting the activation of appetitive motivational systems. Ultimately, both attentional and motivational systems are intricately tied in the brain and, together, determine behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In dubio pro defensio: Initial activation of conditioned fear is not cue specific.

This study explored the time course of conditioned fear response expression. Two neutral male facial expressions served as conditioned stimuli (CS) in a differential trace conditioning that involved either an aversive (n=14) or a nonaversive (n=12) unconditioned stimulus (UCS) in a between-subjects design. Skin conductance response (SCR) to the CSs and startle response magnitudes to acoustic probes presented at early (250 ms) or late (1,750 ms) probe times after CS onset were measured. As expected, conditioned SCR discrimination was observed in both aversive and nonaversive learning, whereas the conditioned potentiation of the startle response was only observed for the aversive UCS condition. Interestingly, conditioned startle discrimination was specific for the later probe time. In contrast, conditioned fear potentiation of the startle response at the early probe time was equally pronounced for CS+ and CS-. These findings suggest that fear-eliciting neural structures are rapidly activated in fear learning, whereas the expression of inhibitory conditioning requires more time, presumably reflecting the involvement of cortical top-down control processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simple and infected pancreatic pseudocysts. Methods of ultrasonography-guided percutaneous needle aspiration: results

The adaptive control of behaviour requires brain mechanisms for the selection (i.e. activation and suppression) of responses, as well as mechanisms for the modulation of the response vigour. The concept of motivation postulates the existence of brain centres that regulate the selection and strength of behavioural responses. The present paper provides examples from the behavioural neurosciences for brain mechanisms that lead to adaptive changes of an organisms responsiveness to external stimuli. The mammalian startle response is a simple defensive behaviour which is mediated by an oligosynaptic pathway located in the lower brainstem. The startle response is enhanced by aversive states (fear, anxiety) and attenuated by appetitive states (pleasure), which can be regarded as an example of motivational priming. Furthermore, the startle response is inhibited by a weak sensory stimulus presented shortly before the startling stimulus. The suppression of startle by a prepulse is an example of sensorimotor gating, a principle that is important for the hierarchical organisation of behaviour. This paper describes the neuronal mechanisms underlying the modulation (prepulse inhibition and fear potentiation) of the startle response in rats, and discusses the possible adaptive significance of these different phenomena of behavioural plasticity.