Personality and conditioning with appetitive and aversive stimuli

Two studies examining relationships of extraversion (E), neuroticism (N) and psychoticism (P) to conditioning performance are reported. In the first, 31 male volunteers developed electrodermal CRs to appetitive or aversive stimuli of either weak or strong rated intensity. Factor analysis yielded general factors of classical CR acquisition and extinction across reinforcement type. Stability and E loaded the acquisition factor, these Ss, from post-hoc analysis, revealing superior conditioning in the strong appetitive condition. In the second study, 20 of these 31 Ss participated in two series of discrimination motor reaction time trials, in which attainment of criterion RT was reinforced by appetitive slides, and slower-than-criterion responding by aversive slides. Introversion was correlated with greater response acquisition under both conditions, although post-hoc analysis suggested that improvement under positive reinforcement did not differ from simple practice. Results are congruent with a model combining reinforcer preference with response potential to describe personality-conditioning relationships.     

Transfer of conditioned appetitive stimuli to conditioned aversive excitatory and inhibitory stimuli

The transfer of Pavlovian appetitive stimuli to Pavlovian aversive stimuli was examined in three experiments. In Experiment 1, rats received appetitive (Ap) conditioning designed to establish a flashing-light stimulus as either a CS+, CSo, or CS? for food, or to maintain it as a novel stimulus for US-alone subjects. Then, the stimulus was employed as a signal for weak shock in conditioned-emotional-response (CER) training. Both acquisition and extinction results showed that the ApCS+ facilitated and the ApCS? retarded aversive excitatory conditioning relative to the ApCSo and US-alone controls. Experiment 2 replicated the findings of Experiment 1 with both a moderate and a severe shock in CER training. In Experiment 3, different groups received the same appetitive conditioning as before, but to a flashing-light stimulus which was then employed as a signal for no shock in CER training. The ApCS? facilitated and the ApCS+ retarded aversive inhibitory conditioning relative to ApCSo and US-alone controls. Collectively, these findings establish that, in Pavlovian conditioning, transfer of an appetitive CS to an aversive excitor or inhibitor is facilitated by maintaining the initial conditioning contingency.     

Catechol-O-methyltransferase Val158Met genotype affects neural correlates of aversive stimuli processing

It was previously shown that variation of the catechol-O-methyltransferase (COMT) gene modulates brain activity during the processing of stimuli with negative valence, but not for pleasant stimuli. Here, we tested whether the COMT genotype also modulates the electrophysiological correlates of emotional processing and explored whether the environmental factor of life stress influences this effect. Using the early posterior negativity (EPN) paradigm, event-related brain potentials were measured in 81 healthy individuals during the processing of pictures that evoked emotions of positive and negative valence. As was hypothesized, the COMT genotype affected the EPN amplitudes for unpleasant stimuli, but not for pleasant ones. Specifically, Met/Met carriers respond more sensitively to unpleasant stimuli, as compared with Val/Val carriers. We did not find evidence that life stress moderates the effect of the COMT genotype on emotional stimuli processing.     

信息加工阶段与情绪刺激加工

情绪刺激的特定加工路径使其能够有效捕获注意并获得加工资源,在一定程度上反映了其加工优势。然而,由于信息加工资源的有限性,由情绪信息引发的、不受自上而下认知因素影响的加工优势并非一直存在。本文根据情绪刺激在信息加工过程不同阶段的加工特点,阐述了情绪注意效应与自上而下注意效应在知觉阶段的注意选择过程中的交互影响,以及在执行控制阶段,情绪刺激加工与执行控制功能间的相互作用。     

Differential subjective and psychophysiological responses to socially and nonsocially generated emotional stimuli

Sociality may determine the subjective experience and physiological response to emotional stimuli. Film segments induced socially and nonsocially generated emotions. Comedy (social positive), bereavement (social negative), pizza scenes (nonsocial positive), and wounded bodies (nonsocial negative) elicited four distinct emotional patterns. Per subjective report, joy, sadness, appetite, and disgust were elicited by the targeted stimulus condition. The social/nonsocial dimension influenced which emotional valence(s) elicited a skin conductance response, a finding that could not be explained by differences in subjective arousal. Heart rate deceleration was more responsive to nonsocially generated emotions. Taken together, these findings suggest that sociality affects the physiological profile of responses to emotional valence.     

Cardiovascular dynamics during classical appetitive and aversive conditioning in laboratory primates

This report describes changes in the rate of rise of left and right intraventricular pressures during aversive and appetitive conditioning procedures in chair-restrained rhesus monkeys. The conditioning paradigm consisted of a one-minute tone followed, in the one case, by an electric shock, and in the other, by the delivery of Purina monkey pellets. The conditional cardiovascular response was characterized by short latency, highly significant elevations in the derivatives of both ventricular pressures as well as a marked arterial pressor response and tachycardia. The magnitude of the conditional response to the classical aversive procedure was somewhat larger than that to appetitive conditioning. These alterations in the rate of development of intraventricular pressure can be attributed largely to augmentation in the sympathetic neural input to the heart and contribute to an analysis of selective aspects of the nervous regulation of the heart in intact, behaviorally conditioned animals.     

Personality traits of the behavioural approach and inhibition systems: associations with processing of emotional stimuli

This study examined the relationships of the traits associated with Gray's behavioural approach system (BAS) and behavioural inhibition system (BIS) with cognitive processing of emotional information. Initially, participants completed questionnaires covering trait impulsivity and anxiety, and BAS and BIS sensitivities. They were then tested individually. After completing a questionnaire of current positive and negative moods, they completed three tasks measuring processing of pleasant, unpleasant and neutral information. Consistent with Gray’s theory, the results showed that impulsivity and BAS sensitivity were associated with the processing of pleasant information, while anxiety and BIS sensitivity were associated with the processing of unpleasant information. These findings imply that Gray’s BAS–BIS theory can be extended to cognitive processing of emotional information.     

BIS/BAS responses to emotional cues: Self report, autonomic measure and alpha band modulation

The study explored the effect of the subjective evaluation and of BIS/BAS (Behavioral Inhibition and Activation System) differences on psychophysiological and brain oscillation measures, in response to pleasant/unpleasant and high/low arousing stimuli. Skin conductance response, heart rate, and electromyography, and alpha frequency band, were registered, during viewing IAPS figures. Both BIS and BAS measures were significant in modulating behavioral, autonomic and brain responses, with a clear dichotomy BAS-appetitive/positive BIS-withdrawal/negative sensitivity. Withdrawal (BIS) and appetitive (BAS) behavior showed opposite patterns of responses by the subjects within the frontal cortical site more than other sites. In addition, a specific frontal lateralization effect was found as a function of BIS (more right-side activation for negative cues) and BAS (more left-side activation for positive cues). Moreover, autonomic variables and frequency band were found to be effected by arousal rating per se, with an increased response to high arousal in comparison with low arousal and neutral stimuli. The effects of subjective evaluation and individual differences were discussed in the light of the coping activity of emotion comprehension.     

The costs and benefits of processing emotional stimuli during rapid serial visual presentation

Using a dual-target identification task during rapid serial visual presentation (RSVP), we examined facilitation and interference effects exerted by emotional stimuli. Emotionally arousing first targets (T1s) were encoded with higher accuracy than neutral T1s. At the same time, identification of a second neutral target (T2) was impaired reflecting a failure of disengaging attention from arousing T1s. Similar interference was triggered by arousing filler stimuli that were not voluntarily searched for in the RSVP stream (Experiment 2). In Experiment 3, we showed that interference is reduced (though facilitation for arousing T1s is maintained) when the second task itself involves variations in emotional arousal. Vice versa, when arousal associated with the T2 stimulus was predictable, interference recurred (Experiment 4). Our findings indicate that the perceived emotional intensity of a stimulus is a determinant of successful identification during RSVP: Encoding of arousing stimuli is reliably facilitated. Interference effects with subsequent processing arise independently and are strongly modulated by the overall task context and specific processing strategies.     

BIS/BAS responses to emotional cues: Self report,autonomic measure and alpha band modulation

The study explored the effect of the subjective evaluation and of BIS/BAS (Behavioral Inhibition and Activation System) differences on psychophysiological and brain oscillation measures, in response to pleasant/unpleasant and high/low arousing stimuli. Skin conductance response, heart rate, and electromyography, and alpha frequency band, were registered, during viewing IAPS figures. Both BIS and BAS measures were significant in modulating behavioral, autonomic and brain responses, with a clear dichotomy BAS-appetitive/positive BIS-withdrawal/negative sensitivity. Withdrawal (BIS) and appetitive (BAS) behavior showed opposite patterns of responses by the subjects within the frontal cortical site more than other sites. In addition, a specific frontal lateralization effect was found as a function of BIS (more right-side activation for negative cues) and BAS (more left-side activation for positive cues). Moreover, autonomic variables and frequency band were found to be effected by arousal rating per se, with an increased response to high arousal in comparison with low arousal and neutral stimuli. The effects of subjective evaluation and individual differences were discussed in the light of the coping activity of emotion comprehension.     

Burying by rats in response to aversive and nonaversive stimuli

Previous investigations have shown that rats bury a variety of conditioned and unconditioned aversive stimuli. Such burying has been considered as a species-typical defensive reaction. In the present studies, rats buried spouts filled with Tabasco sauce, or condensed milk to which a taste aversion was conditioned, but did not bury water-filled spouts or spouts filled with a palatable novel food (apple juice) to which a taste aversion was not conditioned. However, in other experiments rats consistently and repeatedly buried Purina Rat Chow, Purina Rat Chow coated with quinine, and glass marbles. This indicates that a variety of stimuli, not all aversive or novel, evoke burying by rats. Whereas the behavior may reasonably be considered as a species-typical defensive behavior in some situations, the wide range of conditions that occasion burying suggests that the behavior has no single biological function.     

Signaling and affective functions of conditioned aversive stimuli in an appetitive choice discrimination: US intensity effects

Different groups of rats received Pavlovian aversive conditioning in which US-shock intensity (0.25–1.0 mA) and CS-US correlation (+, 0, ?) were factorially varied. Then, the CS was administered for each group contingent upon the reinforced response in an appetitive choice discrimination. Absolute and ratio measures of speed of running in the presence of the CS showed that, at the start of discrimination training, CS+ suppressed and CS- facilitated performance. However, later in training but prior to any evidence of choice learning, these speed effects reversed, with the magnitude of both the initial and reversed effects being a positive function of US intensity. Consistent with the reversal of speeds, associative (choice) measures showed that CS+ facilitated and CS- retarded discrimination learning relative to CSo and, within limits, these effects were also amplified by stronger USs. The findings suggest that a CS has both affective (motivational) and signaling (associative) functions and that both are influenced by US intensity; however, the CS's affective property is rapidly extinguished in the presence of a hedonicly different reinforcer, while leaving the CS's signaling property largely intact. Hence, the CS functions as a transformed signal for the new (appetitive) reinforcer and facilitates or retards learning by mediating the reinforcer's presence (CS+) or absence (CS-).     

On the directionality of key pecking during signals for appetitive and aversive events

Pigeons were exposed to a signal paired with either blackout or blackout plus shock and to another signal paired with food superimposed on a baseline of concurrent variable-interval reinforcement of pecks on two keys. The signals were changes of color of one of the two keys. The rate of pecking both keys during the signal paired with blackout or blackout plus shock was lower than the baseline rate of pecking (a conditioned emotional response), but the decrease in pecking was greater on the signal key. When the intensity of shock was increased, the rate of pecking did not decrease further on the signal key but did decrease on the other key. Rate of pecking during the signal paired with food increased sharply on the signal key (an autoshaping effect) and decreased sharply on the other key. These results support a view that there are two effects of the interaction between classical and instrumental conditioning, a stimulus-directed effect and a generalemotional effect.     

BIS,BAS, and response conflict: Testing predictions of the revised reinforcement sensitivity theory

Gray’s (1970) reinforcement sensitivity theory (RST) was recently updated (Gray & McNaughton, 2000), but the changes have not received extensive empirical validation. The study tests three novel predictions of the revised RST. First, the behavioral activation system (BAS) is expected to be sensitive to both conditioned and unconditioned incentives. Second, the behavioral inhibition system (BIS) is expected to be sensitive to conflicting incentives such as between unconditioned and conditioned stimuli, and not to avoidance responses or aversive stimuli alone. Third, during approach-avoidance conflicts only, BAS is expected to moderate BIS responses to conflict such that individuals with high BAS show the strongest effect of BIS. In order to test these hypotheses, we developed a novel incentive task that crosses approach/avoidance conditioned responses to appetitive/aversive unconditioned stimuli. Conflict between unconditioned and conditioned stimuli occurred on the approach-aversive and avoid-appetitive trials. Results confirm the predictions and provide support for the revised RST.     

A time of change: Behavioral and neural correlates of adolescent sensitivity to appetitive and aversive environmental cues

Adolescence is a developmental period that entails substantial changes in affective and incentive-seeking behavior relative to both childhood and adulthood, including a heightened propensity to engage in risky behaviors and experience persistent negative and labile mood states. This review discusses the emotional and incentive-driven behavioral changes in adolescents and their associated neural mechanisms, focusing on the dynamic interactions between the amygdala, ventral striatum, and prefrontal cortex. Common behavioral changes during adolescence may be associated with a heightened responsiveness to incentives and emotional cues while the capacity to effectively engage in cognitive and emotion regulation is still relatively immature. We highlight empirical work in humans and animals that addresses the interactions between these neural systems in adolescents relative to children and adults, and propose a neurobiological model that may account for the nonlinear changes in adolescent behavior. Finally, we discuss other influences that may contribute to exaggerated reward and emotion processing associated with adolescence, including hormonal fluctuations and the role of the social environment.     

Mapping the apetitive and aversive systems with emotional pictures using a block-design fMRI procedure

Negative emotional pictures from the International Affective Pictures System (IAPS) have been successful in mapping brain areas related to the aversive system. However, the capacity of positive emotional pictures to study the brain areas related to the appetitive system (i.e., nucleus accumbens, prefrontal cortex) is less established. In this study, we used a block fMRI design to investigate this issue, including emotional pictures as background while participants performed a vowel-consonant discrimination task. Importantly, participants were heterosexual males and all positive pictures were related to erotic couples, opposite-sex erotica, or romantic scenes. Negative pictures were similar to those used in previous studies. Results were consistent with previous studies using event-related designs, showing activation of amygdala, lateral prefrontal cortex, and occipito-temporal areas, but positive pictures showed a significant activation in the left nucleus accumbens. These findings provide evidence of the utility of block designs in emotional research (positive emotional pictures).     

Effects of alcohol on psychophysiological hyperreactivity to nonaversive and aversive stimuli in men at high risk for alcoholism

Psychophysiological reactivity to nonaversive (1-KHz, 70-db tones) and aversive stimuli (shock) was examined in nonalcoholic men with multigenerational family histories (MFH) of alcoholism and family history negative (FH-) men, while sober and after consuming alcohol. In comparison with FH- Ss, sober MFH Ss had significantly larger skin conductance (SC) orienting responses (ORs), shorter OR latencies, slower habituation rates to the tones, and larger increases in heart rate and vasoconstriction to the shock. Alcohol dampened the magnitude of the SC-OR to the tones and the degree of cardiovascular reactivity to the shocks and increased the habituation rate to the tones in MFH Ss only. Alcohol consumption also increased the SC-OR recovery time in FH- Ss only. The MFH Ss' pattern of psychophysiological hyperreactivity is discussed in terms of a potential dysfunction in stimulus-response regulation.