When fear forms memories: threat of shock and brain potentials during encoding and recognition

Unpredictable threat increases early event-related potential amplitudes and cardiac acceleration: A brain-heart coupling study

In the face of unpredictable threat, rapid processing of external events and behavioral mobilization through early psychophysiological responses are crucial for survival. While unpredictable threat generally enhances early processing, it would seem adaptive to particularly increase sensitivity for unexpected events as they may signal danger. To examine this possibility, n = 77 participants performed an auditory oddball paradigm and received unpredictable shocks in threat but not in safe contexts while a stream of frequent (standard) and infrequent (deviant) tones was presented. We assessed event-related potentials (ERP), heart period (HP), and time-lagged within-subject correlations of single-trial EEG and HP (cardio-EEG covariance tracing, CECT) time-locked to the tones. N1 and P2 ERP amplitudes were generally enhanced under threat. The P3 amplitude was enhanced to deviants versus standards and this effect was reduced in the threat condition. Regarding HP, both threat versus safe and unexpected versus expected tones led to stronger cardiac acceleration, suggesting separate effects of threat and stimulus expectancy on HP. Finally, CECTs revealed two correlation clusters, indicating that single-trial EEG magnitudes in the N1/P2 and P3 time-windows predicted subsequent cardiac acceleration. The current results show that an unpredictable threat context enhances N1 and P2 amplitudes and cardiac acceleration to benign auditory stimuli. They further suggest separable cortical correlates of different effects on cardiac activity: an early N1/P2 correlate associated with threat-effects on HP and a later P3 correlate associated with expectedness-effects. Finally, the results indicate that unpredictable threat attenuates rather than enhances the processing of unexpected benign events during the P3 latency.

Does Expecting Matter? The Impact of Experimentally Established Expectations on Subsequent Memory Retrieval of Emotional Words

Previous studies have confirmed that different degrees of expectation, including the bipolarity of the expected and unexpected, as well as an intermediate level (no expectation), can affect memory. However, only a few investigations have manipulated expectation through experimentally established schema, with no consideration of how expectation impacts both item and source memory. Furthermore, stimulus emotionality may also impact memory. Therefore, we conducted a study to investigate the effects of three levels of expectation on item and source memory while considering the impact of stimulus emotionality. The experiment began with a phase dedicated to learning the rules. In the subsequent study phase, negative and neutral words were manipulated as expected, no expectation, and unexpected, based on these rules. This was followed by tasks focused on item and source memory. The study found that there was a "U-shape" relationship between expectation and item memory. Additionally, the study revealed the distinct impacts of expectation on item and source memory. When it came to item memory, both expected and unexpected words were better remembered than those with no expectations. In source memory, expected words showed memory inferiority for expectation-irrelevant source information, but an advantage for expectation-relevant source information. Stimulus emotionality modulated the effect of expectation on both item and source memory. Our findings provide behavioral evidence for the schema-linked interactions between medial prefrontal and medial temporal regions (SLIMM) theory, which proposes that congruent and incongruent events enhance memory through different brain regions. The different patterns between item and source memory also support dual-process models. Moreover, we speculate that processing events with varying levels of emotionality may undermine the impact of expectation, as implied by other neural investigations.

Sensitivity of late ERP old/new effects in source memory to self-referential encoding focus and stimulus emotionality

In episodic memory, the old/new effect, the contrast of the waveforms elicited by the correctly recognized studied items and the correctly rejected novel items, has been broadly concerned. However, the contribution of self-referential encoding to the old/new effect in source memory (i.e., source-SRE), is far from clarification; further, it remains unclear whether the contribution is susceptible to the factor of stimulus emotionality. To address these issues, adopting the event-related potential (ERP) technique, this study applied words of three types of emotional valences (positive, neutral, vs. negative) in the self-focus vs. external-focus encoding tasks. In the course of the test, four ERP old/new effects were identified: (a) the familiarity- and recollection-reflected mid-frontal effect (FN400) and late positive component (LPC) were both independent of source-SRE and stimulus emotionality; (b) the reconstruction-driven late posterior negativity (LPN) exhibited an adverse pattern of source-SRE and was susceptible to the emotional valence by encoding focus; and (c) the right frontal old/new effect (RFE), reflecting post-retrieval process, exhibited a source-SRE in emotional words. These effects provide compelling evidence for the influences of both stimulus valence and encoding focus on SRE in source memory, especially during the late processes. Further directions considering more perspectives are put forward.

The priming effects of emotional vocal expressions on face encoding and recognition: An ERP study

Previous studies have suggested that emotional primes, presented as visual stimuli, influence face memory (e.g., encoding and recognition). However, due to stimulus-associated issues, whether emotional primes affect face encoding when the priming stimuli are presented in an auditory modality remains controversial. Moreover, no studies have investigated whether the effects of emotional auditory primes are maintained in later stages of face memory, such as face recognition. To address these issues, participants in the present study were asked to memorize angry and neutral faces. The faces were presented after a simple nonlinguistic interjection expressed with angry or neutral prosodies. Subsequently, participants completed an old/new recognition task in which only faces were presented. Event-related potential (ERP) results showed that during the encoding phase, all faces preceded by an angry vocal expression elicited larger N170 responses than faces preceded by a neutral vocal expression. Angry vocal expression also enhanced the late positive potential (LPP) responses specifically to angry faces. In the subsequent recognition phase, preceding angry vocal primes reduced early LPP responses to both angry and neutral faces and late LPP responses specifically to neutral faces. These findings suggest that the negative emotion of auditory primes influenced face encoding and recognition.

Anticipatory threat responses mediate the relationship between mindfulness and anxiety: A cross-sectional study

Increasing research has shown that mindfulness-based interventions can effectively alleviate anxiety; however, the underlying neural mechanism has not yet been elucidated. Recent studies suggest that abnormal and excessive anticipatory responses to unpredictable threats play an important role in anxiety symptoms. Mindfulness refers to the non-judgmental awareness of the present moment's real experience, which is antithetical to the future-oriented thinking processes involved in anxiety-oriented cognition and its corresponding emotion regulation tactics. Thus, mitigating anticipatory threat responses may be a potential mechanism by which mindfulness alleviates anxiety. This study aimed to detect the possible mediating effects of anticipatory threat responses on the relationship between mindfulness and anxiety. A total of 35 trait-anxious (TA) individuals and 36 low-anxious (LA) individuals were recruited to participate in the predictable and unpredictable threat test. Self-reported intolerance of uncertainty (IU) and electroencephalographic responses to uncertainty were recorded. TA individuals reported more IU and less mindfulness, and exhibited significantly higher late positive potential (LPP) and longer reaction time (RT) than LA individuals in the unpredictable negative threat condition. In addition, there were significant mediating effects of the LPP amplitude and RT in the uncertain threats on the relationship between mindfulness and anxiety. The data from this study verified that mitigating anticipatory threat responses (including self-reported IU, behavioral RT, and LPP amplitude) might be the potential mechanism by which mindfulness alleviates anxiety. These findings may have practical implications for the development and optimization of mindfulness treatments for anxiety.

Social threat and safety learning in individuals with adverse childhood experiences: electrocortical evidence on face processing, recognition, and working memory

BACKGROUND

Adverse childhood experiences (ACEs) are often associated with stress and anxiety-related disorders in adulthood, and learning and memory deficits have been suggested as a potential link between ACEs and psychopathology.

OBJECTIVE

In this preregistered study, the impact of social threat learning on the processing, encoding, and recognition of unknown faces as well as their contextual settings was measured by recognition performance and event-related brain potentials.

METHOD

Sixty-four individuals with ACEs encoded neutral faces within threatening or safe context conditions. During recognition, participants had to decide whether a face was new or had been previously presented in what context (item-source memory), looking at old and new faces. For visual working memory, participants had to detect changes in low and high load conditions during contextual threat or safety.

RESULTS

Results showed a successful induction of threat expectation in persons with ACEs. In terms of face and source recognition, overall recognition of safe and new faces was better compared to threatening face-compounds, with more socially anxious individuals having an advantage in remembering threatening faces. For working memory, an effect of task load was found on performance, irrespective of threat or safety context. Regarding electrocortical activity, an old/new recognition effect and threat-selective processing of face-context information was observed during both encoding and recognition. Moreover, neural activity associated with change detection was found for faces in a threatening context, but only at high task load, suggesting reduced capacity for faces in potentially harmful situations when cognitive resources are limited.

CONCLUSION

While individuals with ACE showed intact social threat and safety learning overall, threat-selective face processing was observed for item/source memory, and a threatening context required more processing resources for visual working memory. Further research is needed to investigate the psychophysiological processes involved in functional and dysfunctional memory systems and their importance as vulnerability factors for stress-related disorders.

Spatiotemporal Dynamics of Affective and Semantic Valence Among Women

As an important dimension of emotional assessment, valence can refer to affective valence reflecting an emotional response, or semantic valence reflecting knowledge about the nature of a stimulus. A previous study has used repeated exposure to separate these two similar cognitive processes. Here, for the first time, we compared the spatiotemporal dynamics of the affective and semantic modes of valence by combining event-related potentials with repeated exposure. Forty-seven female participants were assigned to the feeling-focused and semantic-focused groups and thereafter repeatedly viewed the pictures selected for the study. Self-report behavioral results showed that post-test scores were significantly lower than pre-test scores in the feeling-focused group, while the differences between the two tests were not significant in the semantic-focused group. At the neural level, N2 amplitudes decreased and early late positive potential amplitudes increased in both groups, suggesting that the participants perceived the repeated pictures more fluently and retrieved the traces of the stimulus spontaneously regardless of the valence they judged. However, the late positive potential amplitudes in anterior areas and the activity of the middle frontal gyrus were attenuated in the feeling-focused group; however, this component in posterior areas and the activity of the precentral gyrus were increased in the semantic-focused group. Therefore, the processes of affective and semantic valence are similar in the early stages of image perception and retrieval, while in the later stage of valence judgment, these processes show different brain activation patterns. The results provide electrophysiological evidence for the differences in psychological processes when judging the two modes of valence.

A multinomial modelling approach to face identity recognition during instructed threat

To organise future behaviour, it is important to remember both the central and contextual aspects of a situation. We examined the impact of contextual threat or safety, learned through verbal instructions, on face identity recognition. In two studies (N = 140), 72 face-context compounds were presented each once within an encoding session, and an unexpected item/source recognition task was performed afterwards (including 24 new faces). Hierarchical multinomial processing tree modelling served to estimate individual parameters of item (face identity) and source memory (threat or safety context) as well as guessing behaviour. Results show that language was highly effective in establishing threatening and safe context conditions. In Study 1, a fleeting picture stream (1 s per picture) led to poor item and source recognition. Prolonged presentation times (Study 2 with 6 s per picture) improved face memory but no contextual modulation was observed. Thus, incidental face learning was surprisingly poor and rapidly changing contextual settings might have interfered with the accurate encoding of face identity information and item-source binding.

Effects of affective content and motivational context on neural gain functions during naturalistic scene perception

Visual scene processing is modulated by semantic, motivational, and emotional factors, in addition to physical scene statistics. An open question is to what extent those factors affect low-level visual processing. One index of low-level visual processing is the contrast response function (CRF), representing the change in neural or psychophysical gain with increasing stimulus contrast. Here we aimed to (a) establish the use of an electrophysiological technique for assessing CRFs with complex emotional scenes and (b) examine the effects of motivational context and emotional content on CRFs elicited by naturalistic stimuli, including faces and complex scenes (humans, animals). Motivational context varied by expectancy of threat (a noxious noise) versus safety. CRFs were measured in 18 participants by means of sweep steady-state visual evoked potentials. Results showed a facilitation in visuocortical sensitivity (contrast gain) under threat, compared with safe conditions, across all stimulus categories. Facial stimuli prompted heightened neural response gain, compared with scenes. Within the scenes, response gain was smaller for scenes high in emotional arousal, compared with low-arousing scenes, consistent with interference effects of emotional content. These findings support the notion that motivational context alters the contrast sensitivity of cortical tissue, differing from changes in response gain (activation) when visual cues themselves carry motivational/affective relevance.

Is color source retrieval sensitive to emotion? Electrophysiological evidence from old/new effects

It has been proved that item memory and source memory are two dissociable processes, as reflected by differential influence at behavioral and electrophysiological levels, the latter being evidenced by the ERP old/new effects. Specially for source memory, the retrieval of color source may be unique from recollecting other types of contextual information, which can be seen from the late posterior negativity (LPN). However, the mediation of emotional valence on the old/new effects for verbal stimuli encoded in colors remains unknown. Adopting words of three emotional valences (i.e., positive, neutral, and negative), with their displayed colors serving as sources, the current experiment aimed to explore the sensitivity of old/new effects to emotion for both item memory and source memory. Results demonstrated that: the FN400 that reflects familiarity was recorded and it was sensitive to emotional valence across both memory tasks; the mediation of emotional valence was absent in recollection-reflected LPC, neither for item memory nor for source memory; an association between LPN and color source retrieval was confirmed, with reliable amplitudes for neutral words but not for emotional words. These data were discussed in terms of the dual-process model and other accounts. Future research directions were recommended.

Evaluating the Association of High Trait Anxiety With a Bias in Familiarity-Based Recognition of Emotional Stimuli

Abstract. In the past decades the role of cognitive biases as maintaining factors of anxiety has been widely researched. This theoretical framework assumes that vulnerability self-referential thoughts promote a hyper-vigilant mode of processing environmental stimuli. In this mode, threatening information increases attentional capture and therefore encoding and retrieval of such stimuli is enhanced. Although this attentional bias has been confirmed, the evidence concerning the memory bias is contradictory. Our hypothesis is that the bias in memory is expressed through the pattern of recognition. Particularly, the aim of this study was to evaluate the association of anxiety with familiarity, a deficient form of recognition which consists only in the identification of the item without retrieval of contextual information. Two groups of 17 participants with low and high anxiety levels performed an experimental task of visual recognition memory, using neutral, positive, and negative pictures. The experiment had two test phases, with a 24-hour interval, to evaluate possible effects of consolidation. The pattern of recognition was measured, behaviorally (through an independent Remember/Know paradigm) and through event-related potentials (ERP). Participants with higher levels of anxiety developed a bias in recognition of arousing stimuli (positive and negative) compared with the control group. This bias was observed behaviorally through an increase of familiarity-based recognition, and was associated with a positive modulation of a right parietal late positive component (LPC) at approximately 600 ms of latency. Participants with higher levels of anxiety are capable of recognizing arousing stimuli but lack efficiency in retrieving past contextual information compared to lower level anxiety participants. A recognition bias can be the first step in cognitive distortions that generate anxiety. This is, to our knowledge, the first study to explore the association of anxiety with familiarity-based recognition, using an independent Remember/Know paradigm combined with electrophysiological data. Further studies with bigger samples and more recording channels are needed to confirm the electrophysiological findings.

Negative expectations influence behavioral and ERP responses in the subsequent recognition of expectancy-incongruent neutral events

Previous studies have shown that expectancy incongruence in emotional stimuli influences the encoding (i.e., the first stage of memory processing) of the stimuli. However, it is unknown about whether expectancy incongruence influences later stages of memory processing, such as recognition. To this end, expectancy cues were presented prior to emotional pictures. Most often, the cues accurately indicated the emotional consequences of the pictures, but in some cases the consequence was incongruent with the expectations, and a picture from another emotional category was presented. Afterward, participants completed an unexpected recognition task in which old and novel pictures were not preceded by expectancy cues. The results showed that, in the encoding phase, expectancy incongruence reduced response accuracy when categorizing pictorial emotions, and the effect was smaller for neutral pictures than for negative pictures. ERP results showed stronger and weaker responses to expectancy incongruent pictures compared to congruent pictures in time ranges related to the encoding-related early and middle late positive potential (LPP), respectively. In the subsequent recognition phase, d' scores were higher for incongruent neutral pictures than for congruent ones. Expectancy incongruence enlarged the P2 response but reduced the recognition-related early LPP response for neutral pictures. However, effects of expectancy incongruence were not seen for negative pictures. Therefore, the findings in the present study indicate that negative expectations influence the later recognition of expectancy incongruent neutral events, whereas negative events are more resistant to the effects of expectation incongruence.

Contextual effects of angry vocal expressions on the encoding and recognition of emotional faces: An event-related potential (ERP) study

It has been shown that stimulus memory (e.g., encoding and recognition) is influenced by emotion. In terms of face memory, event-related potential (ERP) studies have shown that the encoding of emotional faces is influenced by the emotion of concomitant context, when contextual stimuli were input from a visual modality. Behavioral studies also investigated the effect of contextual emotion on subsequent recognition of neutral faces. However, there might be no studies ever investigating the context effect on face encoding and recognition, when contextual stimuli were input from other sensory modalities (e.g., an auditory modality). Additionally, it may be unknown about the neural mechanisms underlying context effects on recognition of emotional faces. Therefore, the present study aimed to use vocal expressions as contexts to investigate whether contextual emotion influences ERP responses during face encoding and recognition. To this end, participants in the present study were asked to memorize angry and neutral faces. The faces were presented concomitant with either angry or neutral vocal expressions. Subsequently, participants were asked to perform an old/new recognition task, in which only faces were presented. In the encoding phase, ERP results showed that compared to neutral vocal expression, angry vocal expressions led to smaller P1 and N170 responses to both angry and neutral faces. For angry faces, however, late positive potential (LPP) responses were increased in the angry voice condition. In the later recognition phase, N170 responses were larger for neutral-encoded faces that had been presented with angry compared to neutral vocal expressions. Preceding angry vocal expression increased FN400 and LPP responses to both neutral-encoded and angry-encoded faces, when the faces showed the encoded expression. Therefore, the present study indicates that contextual emotion with regard to vocal expression influences neural responses during face encoding and subsequent recognition.

Cortical Excitability Dynamics During Fear Processing

Background:

Little is known about the modulation of cortical excitability in the prefrontal cortex during fear processing in humans. Here, we aimed to transiently modulate and test the cortical excitability during fear processing using transcranial magnetic stimulation (TMS) and brain oscillations in theta and alpha frequency bands with electroencephalography (EEG).

Methods:

We conducted two separate experiments (no-TMS and TMS). In the no-TMS experiment, EEG recordings were performed during the instructed fear paradigm in which a visual cue (CS+) was paired with an aversive unconditioned stimulus (electric shock), while the other visual cue was unpaired (CS-). In the TMS experiment, in addition the TMS was applied on the right dorsomedial prefrontal cortex (dmPFC). The participants also underwent structural MRI (magnetic resonance imaging) scanning and were assigned pseudo-randomly to both experiments, such that age and gender were matched. The cortical excitability was evaluated by time-frequency analysis and functional connectivity with weighted phase lag index (WPLI). We further linked the excitability patterns with markers of stress coping capability.

Results:

After visual cue onset, we found increased theta power in the frontal lobe and decreased alpha power in the occipital lobe during CS+ relative to CS- trials. TMS of dmPFC increased theta power in the frontal lobe and reduced alpha power in the occipital lobe during CS+. The TMS pulse increased the information flow from the sensorimotor region to the prefrontal and occipital regions in the theta and alpha bands, respectively during CS+ compared to CS-. Pre-stimulation frontal theta power (0.75–1 s) predicted the magnitude of frontal theta power changes after stimulation (1–1.25 s). Finally, the increased frontal theta power during CS+ compared to CS- was positively correlated with stress coping behavior.

Conclusion:

Our results show that TMS over dmPFC transiently modulated the regional cortical excitability and the fronto-occipital information flows during fear processing, while the pre-stimulation frontal theta power determined the strength of achieved effects. The frontal theta power may serve as a biomarker for fear processing and stress-coping responses in individuals and could be clinically tested in mental disorders.

Sympathetic responding to unconditioned stimuli predicts subsequent threat expectancy, orienting, and visuocortical bias in human aversive Pavlovian conditioning

Threat expectancy is the ability to predict an aversive outcome. What is not known is the influence of initial threat responding on the acquisition of verbal, attentional and perceptual biases towards conditioned threat cues. This study evaluated the extent to which initial unconditioned stimulus (UCS) responding was related to trial-by-trial self-reported expectancy, sensory processing (visuocortical EEG) and orienting (heart rate deceleration) to threat cues during extinction learning. Participants (n = 38) viewed oriented Gabor gratings, associated with the presence (CS+) or absence (CS-) of a 96 dB white noise (UCS), flickering at 12 Hz to elicit steady state visually evoked potentials (ssVEPs). Multivariate multiple regression revealed greater initial UCS skin conductance responding to predict extinction responding: enhanced visuocortical discrimination, greater heart rate deceleration to CS+, and greater threat expectancy endorsements. These results suggest that the motivational intensity of initial threat reactivity (sympathetic UCS responding) drives learning-induced defensive dispositions across multiple response systems.

Event-related potentials to threat of predictable and unpredictable shock

Cognitive affective neuroscience tasks that are straightforward to administer, measure key constructs of interest, and can be used in different lab settings and with multiple psychophysiological methods can lead to a more complete understanding of experimental effects. The no-threat, predictable threat, unpredictable threat (NPU-threat) task assesses constructs of interest to both clinical and basic affective science literatures, is relatively brief to administer, and has been used across labs with a number of different measurements (e.g., startle eyeblink, fMRI, corrugator response, subjective ratings). ERPs provide another means of assessing neurobiological reactivity during the NPU-threat task, but to date such measures have been underutilized. That is, no study has yet evaluated cue-elicited ERPs in the NPU-threat task. Here, cue-elicited ERPs were assessed in 78 participants who completed a version of the NPU-threat task previously shown to reliably moderate startle eyeblink amplitudes. Results showed larger P2 amplitudes for unpredictable versus predictable trials, increased P3s and late positive potentials for threatening versus no-threat trials, as well as larger stimulus preceding negativities for threatening versus no-threat trials (driven primarily by predictable threat cues). In line with prior work, we observed enhanced startle eyeblink for threatening versus no-threat trials and for unpredictable compared to predictable threat interstimulus intervals. In addition, the probe-elicited P3 was suppressed for predictable and unpredictable compared to no-threat trials. Therefore, cue-elicited ERPs, which can be recorded alongside other measures in the NPU-threat task (e.g., startle), may provide useful indices of temporally distinct stages of predictable and unpredictable threat processing.

Recognition memory advantage for negative emotional words has an early expiry date: Evidence from brain oscillations and ERPs

Evidence from prior studies has shown an advantage in recognition memory for emotional compared to neutral words. Whether this advantage is short-lived or rather extends over longer periods, as well as whether the effect depends on words' valence (i.e., positive or negative), remains unknown. In the present ERP/EEG study, we investigated this issue by manipulating the lag distance (LAG-2, LAG-8 and LAG-16) between the presentation of old and new words in an online recognition memory task. LAG differences were observed at behavior, ERPs and in the theta frequency band. In line with previous studies, negative words were associated with faster reaction times, higher hit rates and increased amplitude in a positive ERP component between 386 and 564 ms compared to positive and neutral words. Remarkably, the interaction of LAG by EMOTION revealed that negative words were associated with better performance and larger ERPs amplitudes only at LAG-2. Also in the LAG-2 condition, emotional words (i.e., positive and negative words) induced a stronger desynchronization in the beta band between 386 and 542 ms compared to neutral words. These early enhanced memory effects for emotional words are discussed in terms of the Negative Emotional Valence Enhances Recapitulation (NEVER) model and the mobilization-minimization hypothesis.

Our evolved unique pleasure circuit makes humans different from apes: Reconsideration of data derived from animal studies

The brain regions tied to pleasure can be triggered by engaging in sex, eating tasty food, watching a movie, accomplishments at school and athletics, consuming drugs, and noble efforts to help the community, the country, and the world. It is noteworthy that research suggests that the latter type of satisfaction, supporting the community, may result in the most substantial positive effects on our immune system. However, these pathways for these effects are not understood. Berridge and Kringelbach have suggested that pleasure is mediated by well-developed mesocorticolimbic circuitry and serves adaptive functions. In affective disorders, anhedonia (lack of pleasure) or dysphoria (negative affect) can result from a breakdown of that hedonic system. Most importantly, human neuroimaging investigations indicate that surprisingly similar circuitry is activated by quite diverse pleasures, suggesting a common neural pathway shared by all rewarding stimuli and behaviors.

Over many years the controversy of dopamine involvement in pleasure/reward has led to confusion in terms, such as trying to separate motivation from pure pleasure (i.e., wanting versus liking). We take the position that animal studies cannot provide real clinical information that is described by self-reports in humans. On November 23^rd, 2017, evidence for our concerns was revealed. A brain system involved in everything from addiction to autism appears to have evolved differently in humans than in apes, as reported by a large research team in the journal Science. To reiterate, the new findings by Sousa et al., also suggest the importance of not over-relying on rodent and even non-human primate studies. Extrapolations, when it comes to the concept of pleasure, dopamine, and reinforcement, are not supported by these data. Human experience and study are now much more critical and important. Extrapolations from non-humans to humans may be more fiction than fact. While this statement is bold it should not at all suggest that animal date is unimportant, that is not the case. It is extremely valuable in many aspects and we must encourage the development of animal models for disease. However, we must be cautious in our interpretation of results without leaping to conclusions that may be explained by follow-up human experiments and subsequent data.

We are further proposing that in terms of overcoming a never –ending battle related to the current drug epidemic, the scientific community should realize that disturbing dopamine homeostasis by taking drugs or having a system compromised by genes or other epigenetic experiences, should be treated by alternative therapeutic modalities, expressed in this article as a realistic key goal. Application of genetic addiction risk (GARS™) testing and pro-dopamine regulation (KB220) should be considered along with other promising technologies including cognitive behavioral therapy, mind fullness, brain spotting and trauma therapy. Basic scientists have worked very hard to dis-entangle pleasure from incentive salience and learning signals in brain reward circuitry, but this work may be limited to animal models and rodents. A different consideration regarding the human reward systems is required.

Locus Coeruleus Activity Strengthens Prioritized Memories Under Arousal

Recent models posit that bursts of locus ceruleus (LC) activity amplify neural gain such that limited attention and encoding resources focus even more on prioritized mental representations under arousal. Here, we tested this hypothesis in human males and females using fMRI, neuromelanin MRI, and pupil dilation, a biomarker of arousal and LC activity. During scanning, participants performed a monetary incentive encoding task in which threat of punishment motivated them to prioritize encoding of scene images over superimposed objects. Threat of punishment elicited arousal and selectively enhanced memory for goal-relevant scenes. Furthermore, trial-level pupil dilations predicted better scene memory under threat, but were not related to object memory outcomes. fMRI analyses revealed that greater threat-evoked pupil dilations were positively associated with greater scene encoding activity in LC and parahippocampal cortex, a region specialized to process scene information. Across participants, this pattern of LC engagement for goal-relevant encoding was correlated with neuromelanin signal intensity, providing the first evidence that LC structure relates to its activation pattern during cognitive processing. Threat also reduced dynamic functional connectivity between high-priority (parahippocampal place area) and lower-priority (lateral occipital cortex) category-selective visual cortex in ways that predicted increased memory selectivity. Together, these findings support the idea that, under arousal, LC activity selectively strengthens prioritized memory representations by modulating local and functional network-level patterns of information processing.SIGNIFICANCE STATEMENT Adaptive behavior relies on the ability to select and store important information amid distraction. Prioritizing encoding of task-relevant inputs is especially critical in threatening or arousing situations, when forming these memories is essential for avoiding danger in the future. However, little is known about the arousal mechanisms that support such memory selectivity. Using fMRI, neuromelanin MRI, and pupil measures, we demonstrate that locus ceruleus (LC) activity amplifies neural gain such that limited encoding resources focus even more on prioritized mental representations under arousal. For the first time, we also show that LC structure relates to its involvement in threat-related encoding processes. These results shed new light on the brain mechanisms by which we process important information when it is most needed.

Emerging Directions in Emotional Episodic Memory

Building upon the existing literature on emotional memory, the present review examines emerging evidence from brain imaging investigations regarding four research directions: (1) Social Emotional Memory, (2) The Role of Emotion Regulation in the Impact of Emotion on Memory, (3) The Impact of Emotion on Associative or Relational Memory, and (4) The Role of Individual Differences in Emotional Memory. Across these four domains, available evidence demonstrates that emotion- and memory-related medial temporal lobe brain regions (amygdala and hippocampus, respectively), together with prefrontal cortical regions, play a pivotal role during both encoding and retrieval of emotional episodic memories. This evidence sheds light on the neural mechanisms of emotional memories in healthy functioning, and has important implications for understanding clinical conditions that are associated with negative affective biases in encoding and retrieving emotional memories.

Dread of uncertain pain: An event-related potential study

Humans experience more stress about uncertain situations than certain situations. However, the neural mechanism underlying the uncertainty of a negative stimulus has not been determined. In the present study, event-related potential was recorded to examine neural responses during the dread of unpredictable pain. We used a cueing paradigm in which predictable cues were always followed by electric shocks, unpredictable cues by electric shocks at a 50/50 ratio and safe cues by no electric shock. Visual analogue scales following electric shocks were presented to quantify subjective anxiety levels. The behavioral results showed that unpredictable cues evoked high-level anxiety compared with predictable cues in both painful and unpainful stimulation conditions. More importantly, the ERPs results revealed that unpredictable cues elicited a larger P200 at parietal sites than predictable cues. In addition, unpredictable cues evoked larger P200 compared with safe cues at frontal electrodes and compared with predictable cues at parietal electrodes. In addition, larger P3b and LPP were observed during perception of safe cues compared with predictable cues at frontal and central electrodes. The similar P3b effect was also revealed in the left sites. The present study underlined that the uncertain dread of pain was associated with threat appraisal process in pain system. These findings on early event-related potentials were significant for a neural marker and development of therapeutic interventions.

Cued uncertainty modulates later recognition of emotional pictures: An ERP study

Previous studies have shown that uncertainty about the emotional content of an upcoming event modulates event-related potentials (ERPs) during the encoding of the event, and this modulation is affected by whether there are cues (i.e., cued uncertainty) or not (i.e., uncued uncertainty) prior to the encoding of the uncertain event. Recently, we showed that uncued uncertainty affected ERPs in later recognition of the emotional event. However, it is as yet unknown how the ERP effects of recognition are modulated by cued uncertainty. To address this issue, participants were asked to view emotional (negative and neutral) pictures that were presented after cues. The cues either indicated the emotional content of the pictures (the certain condition) or not (the cued uncertain condition). Subsequently, participants had to perform an unexpected old/new task in which old and novel pictures were shown without any cues. ERP data in the old/new task showed smaller P2 amplitudes for neutral pictures in the cued uncertain condition compared to the certain condition, but this uncertainty effect was not observed for negative pictures. Additionally, P3 amplitudes were generally enlarged for pictures in the cued uncertain condition. Taken together, the present findings indicate that cued uncertainty alters later recognition of emotional events in relevance to feature processing and attention allocation.

Repetition and ERPs during emotional scene processing: A selective review

A set of studies are reviewed that investigate the effects of repetition during scene perception on event-related potentials, elucidating perceptual, memory and emotional processes. Repetition suppression was consistently found for the amplitude of early frontal N2 and posterior P2 components, which was greatly enhanced for massed, compared to distributed, repetition. Both repetition suppression and enhancement of the amplitude of a centro-parietal positive potential (LPP) were found in specific contexts. Suppression was reliably found following a massive number of repetitions of few items, whereas enhancement is found when repetitions are spaced; enhancement was apparent both during simple free viewing as well as on an explicit recognition test. Regardless of repetition, an enhanced LPP was always found for emotional, compared to neutral, scenes. Taken together, the data suggest that different effects of massed and distributed repetitions on specific ERP components index perceptual priming, habituation, and spontaneous episodic retrieval.

A pragmatic comparison of noise burst and electric shock unconditioned stimuli for fear conditioning research with many trials

Several methods that are promising for studying the neurophysiology of fear conditioning (e.g., EEG, MEG) require a high number of trials to achieve an adequate signal-to-noise ratio. While electric shock and white noise burst are among the most commonly used unconditioned stimuli (US) in conventional fear conditioning studies with few trials, it is unknown whether these stimuli are equally well suited for paradigms with many trials. Here, N = 32 participants underwent a 260-trial differential fear conditioning and extinction paradigm with a 240-trial recall test 24 h later and neutral faces as conditioned stimuli. In a between-subjects design, either white noise bursts (n = 16) or electric shocks (n = 16) served as US, and intensities were determined using the most common procedure for each US (i.e., a fixed 95 dB noise burst and a work-up procedure for electric shocks, respectively). In addition to differing US types, groups also differed in closely linked US-associated characteristics (e.g., calibration methods, stimulus intensities, timing). Subjective ratings (arousal/valence), skin conductance, and evoked heart period changes (i.e., fear bradycardia) indicated more reliable, extinction-resistant, and stable conditioning in the white noise burst versus electric shock group. In fear conditioning experiments where many trials are presented, white noise burst should serve as US.

From Positivity to Negativity Bias: Ambiguity Affects the Neurophysiological Signatures of Feedback Processing

Previous studies on the neurophysiological underpinnings of feedback processing almost exclusively used low-ambiguity feedback, which does not fully address the diversity of situations in everyday life. We therefore used a pseudo trial-and-error learning task to investigate ERPs of low- versus high-ambiguity feedback. Twenty-eight participants tried to deduce the rule governing visual feedback to their button presses in response to visual stimuli. In the blocked condition, the same two feedback words were presented across several consecutive trials, whereas in the random condition feedback was randomly drawn on each trial from sets of five positive and five negative words. The feedback-related negativity (FRN-D), a frontocentral ERP difference between negative and positive feedback, was significantly larger in the blocked condition, whereas the centroparietal late positive complex indicating controlled attention was enhanced for negative feedback irrespective of condition. Moreover, FRN-D in the blocked condition was due to increased reward positivity (Rew-P) for positive feedback, rather than increased (raw) FRN for negative feedback. Our findings strongly support recent lines of evidence that the FRN-D, one of the most widely studied signatures of reinforcement learning in the human brain, critically depends on feedback discriminability and is primarily driven by the Rew-P. A novel finding concerned larger frontocentral P2 for negative feedback in the random but not the blocked condition. Although Rew-P points to a positivity bias in feedback processing under conditions of low feedback ambiguity, P2 suggests a specific adaptation of information processing in case of highly ambiguous feedback, involving an early negativity bias. Generalizability of the P2 findings was demonstrated in a second experiment using explicit valence categorization of highly emotional positive and negative adjectives.

Anticipation of Negative Pictures Enhances the P2 and P3 in Their Later Recognition

Anticipation of emotional pictures has been found to be relevant to the encoding of the pictures as well as their later recognition performance. However, it is as yet unknown whether anticipation modulates neural activity in the later recognition of emotional pictures. To address this issue, participants in the present study were asked to view emotional (negative or neutral) pictures. The picture was preceded by a cue which indicated the emotional content of the picture in half of the trials (the anticipated condition) and without any cues in the other half (the unanticipated condition). Subsequently, participants had to perform an unexpected old/new recognition task in which old and novel pictures were presented without any preceding cues. Electroencephalography data was recorded during the recognition phase. Event-related potential results showed that for negative pictures, P2 and P3 amplitudes were larger in the anticipated as compared to the unanticipated condition; whereas this anticipation effect was not shown for neutral pictures. The present findings suggest that anticipation of negative pictures may enhance neural activity in their later recognition.

Anchors as Semantic Primes in Value Construction: An EEG Study of the Anchoring Effect

Previous research regarding anchoring effects has demonstrated that human judgments are often assimilated to irrelevant information. Studies have demonstrated that anchors influence the economic valuation of various products and experiences; however, the cognitive explanations of this effect remain controversial, and its neural mechanisms have rarely been explored. In the current study, we conducted an electroencephalography (EEG) experiment to investigate the anchoring effect on willingness to accept (WTA) for an aversive hedonic experience and the role of anchors in this judgment heuristic. The behavioral results demonstrated that random numbers affect participants' WTA for listening to pieces of noise. The participants asked for higher pay after comparing their WTA with higher numbers. The EEG results indicated that anchors also influenced the neural underpinnings of the valuation process. Specifically, when a higher anchor number was drawn, larger P2 and late positive potential amplitudes were elicited, reflecting the anticipation of more intensive pain from the subsequent noise. Moreover, higher anchors induced a stronger theta band power increase compared with lower anchors when subjects listened to the noises, indicating that the participants felt more unpleasant during the actual experience of the noise. The levels of unpleasantness during both anticipation and experience were consistent with the semantic information implied by the anchors. Therefore, these data suggest that a semantic priming process underlies the anchoring effect in WTA. This study provides proof for the robustness of the anchoring effect and neural evidence of the semantic priming model. Our findings indicate that activated contextual information, even seemingly irrelevant, can be embedded in the construction of economic value in the brain.

Neural mechanisms of placebo anxiolysis

The beneficial effects of placebo treatments on fear and anxiety (placebo anxiolysis) are well known from clinical practice, and there is strong evidence indicating a contribution of treatment expectations to the efficacy of anxiolytic drugs. Although clinically highly relevant, the neural mechanisms underlying placebo anxiolysis are poorly understood. In two studies in humans, we tested whether the administration of an inactive treatment along with verbal suggestions of anxiolysis can attenuate experimentally induced states of phasic fear and/or sustained anxiety. Phasic fear is the response to a well defined threat and includes attentional focusing on the source of threat and concomitant phasic increases of autonomic arousal, whereas in sustained states of anxiety potential and unclear danger requires vigilant scanning of the environment and elevated tonic arousal levels. Our placebo manipulation consistently reduced vigilance measured in terms of undifferentiated reactivity to salient cues (indexed by subjective ratings, skin conductance responses and EEG event-related potentials) and tonic arousal [indexed by cue-unrelated skin conductance levels and enhanced EEG alpha (8-12 Hz) activity], indicating a downregulation of sustained anxiety rather than phasic fear. We also observed a placebo-dependent sustained increase of frontal midline EEG theta (4-7 Hz) power and frontoposterior theta coupling, suggesting the recruitment of frontally based cognitive control functions. Our results thus support the crucial role of treatment expectations in placebo anxiolysis and provide insight into the underlying neural mechanisms.

Anticipation of electric shocks modulates low beta power and event-related fields during memory encoding

In humans, the temporal and oscillatory dynamics of pain anticipation and its effects on long-term memory are largely unknown. Here, we investigated this open question by using a previously established behavioral paradigm in combination with magnetoencephalography (MEG). Healthy human subjects encoded a series of scene images, which was combined with cues predicting an aversive electric shock with different probabilities (0.2, 0.5 or 0.8). After encoding, memory for the studied images was tested using a remember/know recognition task. Behaviorally, pain anticipation did not modulate recollection-based recognition memory per se, but interacted with the perceived unpleasantness of the electric shock [visual analogue scale rating from 1 (not unpleasant) to 10 (highly unpleasant)]. More precisely, the relationship between pain anticipation and recollection followed an inverted u-shaped function the more unpleasant the shocks were rated by a subject. At the physiological level, this quadratic effect was mimicked in the event-related magnetic fields associated with successful memory formation ('DM-effect') ∼450ms after image onset at left frontal sensors. Importantly, across all subjects, shock anticipation modulated oscillatory power in the low beta frequency range (13-20Hz) in a linear fashion at left temporal sensors. Taken together, our findings indicate that beta oscillations provide a generic mechanism underlying pain anticipation; the effect on subsequent long-term memory, on the other hand, is much more variable and depends on the level of individual pain perception. As such, our findings give new and important insights into how aversive motivational states can drive memory formation.

Sustained attention in context conditioning: Evidence from steady-state VEPs

In classical fear conditioning an aversive event is paired repeatedly with a predictive stimulus, which later elicits fear. Repeated presentation of an aversive event in the absence of a predictive cue however may induce anxiety, and the context may gain a threatening value. As such conditioned anxiety can be considered a sustained reaction compared to phasic fear, it would be interesting to track continuous cortical responses during context conditioning. The present study realized a differential context conditioning paradigm and assessed sustained cortical activations to the threatening and the safe context and how neutral cues are processed within both contexts. Two pictures of different office rooms presented for 20s served as contexts. One room became associated with an unpleasant noise that was presented unpredictably (CTX+) while the other office (CTX-) was never associated with this unpleasant noise. After acquisition, a social agent or an object was presented as a distractor in both contexts. Cortical activations in response to contexts and distractors were assessed separately by steady-state visually evoked potentials (ssVEPs) using frequency tagging. Results revealed enhanced ssVEP-amplitudes for CTX+ compared to CTX- in a lateral occipital cluster during acquisition. Similarly, CTX+ elicited higher ssVEP-amplitudes during the test phase, and these context conditioning effects were not reduced by the simultaneous presentation of novel distractors. These results indicate that context conditioning was successfully implemented and that the anxiety context received facilitated cortical processing across the whole viewing time. We conclude that threatening contexts capture attention over a longer period of time, and are immune to distraction by new objects.

Spatio-temporal dynamics of kind versus hostile intentions in the human brain: An electrical neuroimaging study

Neuroscience research suggests that inferring neutral intentions of other people recruits a specific brain network within the inferior fronto-parietal action observation network as well as a putative social network including brain areas subserving theory of mind, such as the posterior superior temporal sulcus (pSTS), the temporo-parietal junction (TPJ), and also the anterior cingulate cortex (ACC). Recent studies on harmful intentions have refined this network by showing the specific involvement of the ACC, amygdala, and ventromedial prefrontal cortex (vmPFC) in early stages (within 200 ms) of information processing. However, the functional dynamics for kind intentions within and among these networks remains unclear. To address this question, we measured electrical brain activity from 18 healthy adult participants while they were performing an intention inference task with three different types of intentions: kind, hostile and non-interactive. Electrophysiological results revealed that kind intentions were characterized by significantly larger peak amplitudes of N2 over the frontal sites than those for hostile and non-interactive intentions. On the other hand, there were no significant differences between hostile and non-interactive intentions at N2. The source analysis suggested that the vicinity of the left cingulate gyrus contributed to the N2 effect by subtracting the kindness condition from the non-interactive condition within 250-350 ms. At a later stage (i.e., during the 270-500 ms epoch), the peak amplitude of the P3 over the parietal sites and the right hemisphere was significantly larger for hostile intentions compared to the kind and non-interactive intentions. No significant differences were observed at P3 between kind and non-interactive intentions. The source analysis showed that the vicinity of the left anterior cingulate cortex contributed to the P3 effect by subtracting the hostility condition from the non-interactive condition within 450-550 ms. The present study provides preliminary evidence of the spatio-temporal dynamics sustaining the dissociation between the understandings of different types of social intentions.

Locus coeruleus neuromodulation of memories encoded during negative or unexpected action outcomes

When people experience surprising or sub-optimal performance outcomes, an increase in autonomic arousal helps allocate cognitive resources to adjust behavior accordingly. The locus-coeruleus-norepinephrine (LC-NE) system regulates a central orienting response to behaviorally relevant events, and might therefore signal the need to attend to and learn from performance feedback. Memories of such events also rely on elevated NE, suggesting that LC activity not only responds to salient performance outcomes but also strengthens memory for stimuli associated with their occurrence. In the present study, we used a monetary incentive delay paradigm to determine whether LC functional connectivity during reaction time feedback relates to trial-by-trial memory of preceding photo-objects. We used one psychophysiological interaction (PPI) analysis to examine patterns of LC functional connectivity that were associated with subsequent memory for picture trials in which negative or positive feedback was given, and a second PPI analysis to investigate whether successfully encoded objects from trials with uncertain outcomes were related to distinct patterns of LC functional connectivity across the brain. The PPI results revealed that successfully encoded negative feedback trials (i.e., responses exceeding the response deadline) were uniquely associated with enhanced functional coupling between the LC and left anterior insula. Furthermore, successful memory for objects in low reaction time certainty trials (i.e., responses closest to the response deadline) were linked to positive LC functional coupling with left dorsolateral prefrontal cortex. These findings suggest that noradrenergic influences help facilitate memory encoding during outcome processing via dynamic interactions with regions that process negative or unexpected feedback.

Encoding and reinstatement of threat: recognition potentials

On a recognition test, stimuli originally encoded in the context of shock threat show an enhanced late parietal positivity during later recognition compared to stimuli encoded during safety, particularly for emotionally arousing stimuli. The present study investigated whether this ERP old/new effect is further influenced when a threat context is reinstated during the recognition test. ERPs were measured in a yes-no recognition test for words rated high or low in emotional arousal that were encoded and recognized in the context of cues that signaled threat of shock or safety. Correct recognition of words encoded under threat, irrespective of reinstatement, was associated with an enhanced old-new ERP difference (500-700ms; centro-parietal), and this difference was only reliable for emotionally arousing words. Taken together, the data suggest that information processed in a stressful context are associated with better recollection on later recognition, an effect that was not modulated by reinstating the stressful context at retrieval.

The impact of anxiety upon cognition: perspectives from human threat of shock studies

Anxiety disorders constitute a sizeable worldwide health burden with profound social and economic consequences. The symptoms are wide-ranging; from hyperarousal to difficulties with concentrating. This latter effect falls under the broad category of altered cognitive performance which is the focus of this review. Specifically, we examine the interaction between anxiety and cognition focusing on the translational threat of unpredictable shock paradigm; a method previously used to characterize emotional responses and defensive mechanisms that is now emerging as valuable tool for examining the interaction between anxiety and cognition. In particular, we compare the impact of threat of shock on cognition in humans to that of pathological anxiety disorders. We highlight that both threat of shock and anxiety disorders promote mechanisms associated with harm avoidance across multiple levels of cognition (from perception to attention to learning and executive function)-a "hot" cognitive function which can be both adaptive and maladaptive depending upon the circumstances. This mechanism comes at a cost to other functions such as working memory, but leaves some functions, such as planning, unperturbed. We also highlight a number of cognitive effects that differ across anxiety disorders and threat of shock. These discrepant effects are largely seen in "cold" cognitive functions involving control mechanisms and may reveal boundaries between adaptive (e.g., response to threat) and maladaptive (e.g., pathological) anxiety. We conclude by raising a number of unresolved questions regarding the role of anxiety in cognition that may provide fruitful avenues for future research.