What you give is what you get: Payment of one randomly selected trial induces risk-aversion and decreases brain responses to monetary feedback.

In economic studies, it is standard practice to pay out the reward of only one randomly selected trial (pay-one) instead of the total reward accumulated across trials (pay-all), assuming that both methods are equivalent. We tested this assumption by recording electrophysiological activity to reward feedback from participants engaged in a decision-making task under both a pay-one and a pay-all condition. We show that participants are approximately 12% more risk averse in the pay-one condition than in the pay-all condition. Furthermore, we observed that the electrophysiological response to monetary rewards, the reward positivity, is significantly reduced in the pay-one condition relative to the pay-all condition. The difference of brain responses is associated with the difference in risky behavior across conditions. We concluded that the two payment methods lead to significantly different results and are therefore not equivalent.

Suggested visual blockade during hypnosis: Top-down modulation of stimulus processing in a visual oddball task.

Several theories of hypnosis assume that responses to hypnotic suggestions are implemented through top-down modulations via a frontoparietal network that is involved in monitoring and cognitive control. The current study addressed this issue re-analyzing previously published event-related-potentials (ERP) (N1, P2, and P3b amplitudes) and combined it with source reconstruction and connectivity analysis methods. ERP data were obtained from participants engaged in a visual oddball paradigm composed of target, standard, and distractor stimuli during a hypnosis (HYP) and a control (CON) condition. In both conditions, participants were asked to count the rare targets presented on a video screen. During HYP participants received suggestions that a wooden board in front of their eyes would obstruct their view of the screen. The results showed that participants' counting accuracy was significantly impaired during HYP compared to CON. ERP components in the N1 and P2 window revealed no amplitude differences between CON and HYP at sensor-level. In contrast, P3b amplitudes in response to target stimuli were significantly reduced during HYP compared to CON. Source analysis of the P3b amplitudes in response to targets indicated that HYP was associated with reduced source activities in occipital and parietal brain areas related to stimulus categorization and attention. We further explored how these brain sources interacted by computing time-frequency effective connectivity between electrodes that best represented frontal, parietal, and occipital sources. This analysis revealed reduced directed information flow from parietal attentional to frontal executive sources during processing of target stimuli. These results provide preliminary evidence that hypnotic suggestions of a visual blockade are associated with a disruption of the coupling within the frontoparietal network implicated in top-down control.

Suggested deafness during hypnosis and simulation of hypnosis compared to a distraction and control condition: A study on subjective experience and cortical brain responses.

Hypnosis is a powerful tool to affect the processing and perception of stimuli. Here, we investigated the effects of hypnosis on the processing of auditory stimuli, the time course of event-related-potentials (ERP; N1 and P3b amplitudes) and the activity of cortical sources of the P3b component. Forty-eight participants completed an auditory oddball paradigm composed of standard, distractor, and target stimuli during a hypnosis (HYP), a simulation of hypnosis (SIM), a distraction (DIS), and a control (CON) condition. During HYP, participants were suggested that an earplug would obstruct the perception of tones and during SIM they should pretend being hypnotized and obstructed to hear the tones. During DIS, participants' attention was withdrawn from the tones by focusing participants' attention onto a film. In each condition, subjects were asked to press a key whenever a target stimulus was presented. Behavioral data show that target hit rates and response time became significantly reduced during HYP and SIM and loudness ratings of tones were only reduced during HYP. Distraction from stimuli by the film was less effective in reducing target hit rate and tone loudness. Although, the N1 amplitude was not affected by the experimental conditions, the P3b amplitude was significantly reduced in HYP and SIM compared to CON and DIS. In addition, source localization results indicate that only a small number of neural sources organize the differences of tone processing between the control condition and the distraction, hypnosis, and simulation of hypnosis conditions. These sources belong to brain areas that control the focus of attention, the discrimination of auditory stimuli, and the organization of behavioral responses to targets. Our data confirm that deafness suggestions significantly change auditory processing and perception but complete deafness is hard to achieve during HYP. Therefore, the term 'deafness' may be misleading and should better be replaced by 'hypoacusis'.

Drive for thinness and attention toward specific body parts in a nonclinical sample.

OBJECTIVE: To examine the differences between participants scoring high versus low on a drive for thinness construct concerning their visual attention toward specific body parts. We hypothesized that participants scoring high on the drive for thinness subscale would show increased attention to body regions, which are important in the assessment of body weight and thinness like the waist, hips, legs, and arms. METHOD: We examined eye-gaze behavior of a nonclinical sample of 51 male and female college students with an eye-tracking system as they were looking at pictures of young, attractive males and females. In addition, we used the Eating Disorder Inventory to measure drive for thinness. RESULTS: Participants with increased scores on the drive for thinness subscale looked longer and more often to the waist, hips, legs, and arms as compared with low scorers. In addition, they showed decreased attention toward the head or face. CONCLUSION: The results indicate that participants scoring high on drive for thinness show an attentional bias toward body regions that are associated with assessing changes in weight. However, they neglected the face, which is the most important source of social and affective information when looking at others.

An electrophysiological analysis of coaching in Blackjack.

Recent research has demonstrated that a negative deflection in the event-related potential (ERP) that is usually elicited by errors, negative performance feedback, and monetary losses, and which has been associated with response monitoring and reinforcement learning, is also present when we observe others. In the present study we aimed to extend these findings to the domain of coaching behavior. In many contexts of human social life, advice is given by experts to novices, e.g., teachers or parents to scholars or children. However, their advice is sometimes rejected. Here we show that a rejection of one's advice elicits the same negative potential as when one receives negative feedback about one's own behavior.

Attentional Blink to emotional and threatening pictures in spider phobics: electrophysiology and behavior.

When two targets have to be identified in a rapid serial visual presentation (RSVP) paradigm, perception of the second target (T2) becomes significantly impaired if it is displayed 200-500 ms after the first target (T1), a phenomenon labeled as "Attentional Blink" (AB). Here we investigate 14 spider phobics and 16 controls in an RSVP paradigm with neutral T1s. T2 pictures were neutral, emotional (positive or negative) or threatening (spiders for spider phobics). In addition, event-related potentials in response to T2 targets were analyzed. Both spider phobics and controls correctly identified positive and negative T2s more often than neutral T2s, indicating a reduction of the AB effect caused by emotional stimuli. In addition, spider phobics detected spider T2s more frequently than all other T2s. Furthermore, significantly larger P300 amplitudes accompanied detection of spider T2s in the spider phobics as compared to the controls. Based on recent theoretical accounts of the AB effect, results indicate a phobia-related post-perceptual consolidation bias of threatening information in spider phobic subjects.

Event-related brain potentials and affective responses to threat in spider/snake-phobic and non-phobic subjects.

We investigated cortical responses and valence/arousal ratings of spider phobic, snake phobic, and healthy subjects while they were processing feared, fear-relevant, emotional neutral, and pleasant stimuli. Results revealed significantly larger amplitudes of late ERP components (P3 and late positive complex, LPC) but not of early components (N1, P2, N2) in phobics when subjects were processing feared stimuli. This fear-associated increase of amplitudes of late ERP components in phobic subjects was maximal at centro-parietal and occipital brain sites. Furthermore, phobics but not controls rated feared stimuli to be more negative and arousing than fear-relevant, emotional neutral, and pleasant stimuli. Since late ERP components and valence/arousal ratings were only significantly increased when phobic subjects but not when healthy controls were processing feared stimuli, the present data suggest that P3 and LPC amplitudes represent useful neural correlates of the emotional significance and meaning of stimuli.

Brain activation to phobia-related pictures in spider phobic humans: an event-related functional magnetic resonance imaging study.

Using event-related functional magnetic resonance imaging we investigated blood oxygen level dependent brain activation in spider phobic and non-phobic subjects while exposed to phobia-related pictures (spiders) and non-phobia-related pictures (snakes and mushrooms). In contrast to previous studies, we show significantly increased amygdala activation in spider phobics, but not in controls, during presentation of phobia-relevant visual stimuli. Furthermore, phobia-specific increased activation was also found in the insula, the orbitofrontal cortex and the uncus. Our study confirms the role of the amygdala in fear processing and provides insights into brain activation patterns when animal phobics are confronted with phobia-related stimuli.

Eye movements and behavioral responses to threatening and nonthreatening stimuli during visual search in phobic and nonphobic subjects.

Spider-phobic and nonphobic subjects searched for a feared/fear-relevant (spider) or neutral target (mushroom) presented in visual matrices of neutral objects (flowers). In half of the displays, the mushroom target was paired with a spider distractor, or a spider target was paired with a mushroom distractor. Although all subjects responded faster to the neutral target than to the feared/fear-relevant target, phobics were slower to respond than nonphobics when a mushroom target was presented with a spider distractor. Their eyes appeared to be drawn to the feared distractor before fixating neutral targets. A further experiment indicated no group differences when subjects merely judged the homogeneity of matrices. Thus, threat seems to capture the attention of phobics only when it is part of a background that subjects are explicitly instructed to ignore.

Pain-related and negative semantic priming enhances perceived pain intensity.

BACKGROUND: Negative affective and pain-related cues, such as pictures or words, have been shown to act as primes and enhance the perceived intensity of subsequent painful events. For pain-related semantic primes, it remains unclear whether this effect depends on negative valence itself or, specifically, on the pain-relatedness of the words. OBJECTIVES: To investigate the effect of pain-related, negative affective (pain-unrelated) and neutral semantic primes on the perception of subsequent noxious target stimuli. METHODS: Pain ratings in response to noxious electrical stimulation of light and moderate intensity were examined in 39 healthy subjects after subjects were exposed to semantic primes of different meaning and valence (pain-related, negative, positive and neutral adjectives) presented with different interstimulus intervals (0 ms, 500 ms and 1500 ms). RESULTS: Increased pain ratings of noxious stimuli were observed following pain-related and negative compared with neutral primes. DISCUSSION: The results support the motivational priming theory for semantic stimuli, indicating that affectively negative semantic primes increase subjective pain intensity. However, a specific pain-related priming effect was not reliably demonstrated. Additionally, it is shown that experimental parameters (ie, stimulus intensity and interstimulus interval) modify the extent of negative and pain-related semantic priming. CONCLUSIONS: Verbal priming plays a role for the perception of noxious stimuli in a time-dependent manner.

How bad was it? Differences in the time course of sensitivity to the magnitude of loss in problem gamblers and controls.

Previous research has shown that pathological gamblers show various cognitive distortions, especially in interpreting near losses. Using a modified blackjack task, we investigated the electrophysiological responses to near and full losses in problem gamblers and controls. We assessed the event-related brain potentials (ERPs) of 20 problem gamblers and 21 controls at two time points following negative game outcomes. We also studied the behavioral changes after near and full loss experiences. Between 270 and 320 ms following a loss, controls but not gamblers showed a differential ERP response to near and full losses suggesting that a near loss is evaluated more negatively than a full loss. However, between 430 and 480 ms after a loss, the ERPs of both, gamblers and controls, showed a differential response as a function of the type of loss. Both groups became more cautious in their subsequent gambling behavior following near loss. The present study revealed differences in the time course of processing negative feedback in problem gamblers and normal controls, which might be due to gamblers preoccupation with gains rather than with losses.

Neural correlates of fair behavior in interpersonal bargaining.

Research findings show that proposers make surprisingly fair offers in the ultimatum and dictator games, an observation that contradicts predictions of classical game theory. The present functional magnetic resonance imaging (fMRI) study examines brain activities of proposers that contribute to fair and unfair behaviors. We hypothesized that egoistic and altruistic motives of proposers affect fairness differentially in the two games. fMRI analysis revealed that the 28% of fair offers in the present ultimatum game were related to enhanced activity in prefrontal areas, in particular, in regions involved in reward and theory of mind. This corroborates the idea that egoistic motives are primarily responsible for fair offers in this game, which we denote as strategic fairness. Fair offers in the dictator game, however, were related to increased activity in the dorsal anterior cingulate cortex and the posterior cingulate cortex. This supports the idea that altruistic motives primarily drive fair offers in the dictator game, denoted here as altruistic fairness.

The influence of the magnitude, probability, and valence of potential wins and losses on the amplitude of the feedback negativity.

We assessed the influence of the variables outcome potential, feedback valence, magnitude, and probability on the amplitude of the feedback negativity (FN). Outcome potential was defined as the a priori valence of an upcoming feedback, that is, is there a potential win or potential loss? All these variables have been studied previously, although never together, but the findings have been contradictory. We analyzed the event-related potential (ERP) after feedback presentation in a reinforcement-learning task to examine the effects of all the variables on feedback negativity. Our results show that outcome potential, feedback valence, probability, and magnitude all influence feedback related ERPs. Taken together, the findings suggest that ERPs in the time range of the feedback negativity are primarily driven by positive outcomes (reinforcement) rather than negative outcomes (punishment).

Dissociation of acquisition and expression of fear conditioned responses under working memory load.

Previously, it has been suggested that high working memory load (WML) prevents associative learning and, thus, conditioned responses (CRs) during differential-delay fear conditioning. However, previous studies did not distinguish between the effects of WML on the acquisition versus the expression of the CRs. In the present study, we reinvestigated this issue by manipulating WML during either acquisition or postconditioning and showed that the absence of a differential CR under high WML does not indicate the absence of the acquisition of this CR. Thus, a significant CR was observed during a task-free postconditioning phase, and there was no CR during the preceding acquisition phase with high WML. Conversely, a normally acquired CR was impaired by high WML during the postconditioning phase. The results suggest that high WML affects the expression of the CR. If they are not experimentally separated, the effects of WML on the acquisition and expression of the CR may occur together, and the findings may be erroneously interpreted as indicating a lack of associative learning.

Why humans deviate from rational choice.

Rational choice theory predicts that humans always optimize the expected utility of options when making decisions. However, in decision-making games, humans often punish their opponents even when doing so reduces their own reward. We used the Ultimatum and Dictator games to examine the affective correlates of decision-making. We show that the feedback negativity, an event-related brain potential that originates in the anterior cingulate cortex that has been related to reinforcement learning, predicts the decision to reject unfair offers in the Ultimatum game. Furthermore, the decision to reject is positively related to more negative emotional reactions and to increased autonomic nervous system activity. These findings support the idea that subjective emotional markers guide decision-making and that the anterior cingulate cortex integrates instances of reinforcement and punishment to provide such affective markers.

Dissociation of Pe and ERN/Ne in the conscious recognition of an error.

We evaluated the relationship between conscious awareness and the ERN/Ne and Pe in a digit entering task. On each trial, participants rated the accuracy of their responses on a three-point scale (incorrect, unsure, correct). The ERN/Ne was present on incorrect trials judged as incorrect. The Pe was evident on the same trials but also on correct and incorrect trials judged as unsure. We propose that the ERN/Ne occurs when there is an incorrect execution of a correct motor plan and the representation of the correct response is available for comparison with the actual response. The mismatch information that results from this comparison can be transferred to the Pe process and conscious awareness. However, the Pe process and conscious awareness do not only depend on this transfer of information from the ERN/Ne process. The Pe also occurs when there is uncertainty about the correctness of the motor plan, whether or not the plan is, in fact, correct.

Hypersensitivity to reward in problem gamblers.

BACKGROUND: Recent research has begun to examine the neurophysiologic basis of pathological gambling. However, direct evidence of a behavioral deficit and an accompanying neurofunctional deviation in a realistic gambling context such as Black Jack has not yet been reported. METHODS: Electroencephalogram was recorded while 20 problem gamblers and 21 control participants played a computerized version of Black Jack. Participants were asked to decide at point scores between 11 and 21 whether they wanted to take another card ("hit") to arrive closer to 21 than the opponent (simulated by computer) or not to take another card ("sit") to avoid going over 21 ("bust"). RESULTS: At a critical point score of 16, problem gamblers decided more often to hit despite losses due to a bust on the preceding trial, whereas control participants decided more often to sit under these conditions. Furthermore, problem gamblers showed more reward-related positive amplitudes in the event-related brain potential than control participants after successful hit decisions at 16. CONCLUSIONS: Here we provide experimental evidence for high-risk taking behavior in gamblers and its correlate in event-related brain potentials. Our results suggest that high-risk-taking behavior in problem gamblers is associated with an increased reward-related neural response to infrequent successes of this behavior.

Decision-making under risk: an fMRI study.

Recent research has focused on decision-making under risk and its neural bases. Two kinds of bad decisions under risk may be defined: too risky decisions and too cautious decisions. Here we show that suboptimal decisions of both kinds lead to increased activity in the anterior cingulate cortex in a Blackjack gambling task. Moreover, this increased activity is related to the avoidance of the negatively evaluated decision under risk. These findings complement other results suggesting an important role of the dorsal anterior cingulate cortex in reward-based decision-making and conflict resolution.

How do brain areas communicate during the processing of noxious stimuli? An analysis of laser-evoked event-related potentials using the Granger causality index.

Several imaging techniques have identified different brain areas involved in the processing of noxious stimulation and thus in the constitution of pain. However, only little is known how these brain areas communicate with one another after activation by stimulus processing and which areas directionally affect or modulate the activity of succeeding areas. One measure for the analysis of such interactions is represented by the Granger Causality Index (GCI). In applying time-varying bivariate and partial variants of this concept (tvGCI), the aim of the present study was to investigate the interaction of neural activities between a set of scalp electrodes that best represent the brain electrical neural activity of major cortical areas involved in the processing of noxious laser-heat stimuli and their variation in time. Bivariate and partial tvGCIs were calculated within four different intervals of laser-evoked event-related potentials (LEPs) including a baseline period prior to stimulus application and three intervals immediately following stimulus application, i.e., between 170 and 200 ms (at the N2 component), between 260 and 320 ms (P2 component), and between 320 and 400 ms (P3 component of LEPs). Results show some similarities, but also some striking differences between bivariate and partial tvGCIs. These differences might be explained by the nature of bivariate and partial tvGCIs. However, both tvGCI approaches revealed a directed interaction between medial and lateral electrodes of the centroparietal region. This result was interpreted as a directed interaction between the anterior cingulate cortex and the secondary somatosensory cortex and the insula, structures that are significantly involved in the constitution of pain.

Brain activation upon selective stimulation of cutaneous C- and Adelta-fibers.

Thermal and nociceptive cutaneous stimuli activate the brain via two types of nerve fibers, slightly myelinated Adelta-fibers with moderate conduction velocity and unmyelinated C-fibers with slow conduction velocity. Differences in central processing upon selective stimulation of these two fiber types in healthy human subjects still remain poorly understood. By means of event-related functional magnetic resonance imaging the present study investigated brain activation in response to stimulation of Adelta- and C-fibers in healthy subjects. We used the stimulation of tiny skin areas to perform a selective stimulation upon cutaneous C-fibers. Besides similar activation in several brain areas in response to both kinds of stimulation, we observed pronounced brain activation to selective C-fiber stimulation as compared to Adelta-fiber stimulation in the right frontal operculum and anterior insula. Based on a putative function of these structures we suggest that the C-fiber system might be engaged in homeostatic and interoceptive functions in a manner other than the Adelta-fiber system, producing a signal of greater emotional salience.