Friday, August 31, 2007

ARTICLE UPDATE - Amygdala activation in affective priming: a magnetoencephalogram study.

Garolera M, Coppola R, Muñoz KE, Elvevåg B, Carver FW, Weinberger DR, Goldberg TE.

NeurReport, 18, 1449-1453

We employed magnetoencephalography (MEG) to examine amygdala activity during a linguistic affective priming task. The experimental design included positive and negative word pairs. Using synthetic aperture magnetometry in the analysis of MEG data, we identified a left amygdala power increase in the theta frequency range during priming involving negative words. We found that the amygdala displayed a time-dependent intensification in responsiveness to negative stimuli, specifically between 150 and 400 ms after target presentation. This study provides evidence for theta power changes in the amygdala and demonstrates that the analysis of brain oscillations provides a powerful tool to explore mechanisms implicated in emotional processing.

ARTICLE UPDATE - Retrieval of emotional memories.

Buchanan TW.

Psychological Bulletin, 133, 761-779

Long-term memories are influenced by the emotion experienced during learning as well as by the emotion experienced during memory retrieval. The present article reviews the literature addressing the effects of emotion on retrieval, focusing on the cognitive and neurological mechanisms that have been revealed. The reviewed research suggests that the amygdala, in combination with the hippocampus and prefrontal cortex, plays an important role in the retrieval of memories for emotional events. The neural regions necessary for online emotional processing also influence emotional memory retrieval, perhaps through the reexperience of emotion during the retrieval process.

ARTICLE UPDATE - Social learning of fear

Andreas Olsson & Elizabeth A Phelps

Nature Neuroscience, 10, 1095-1102

Research across species highlights the critical role of the amygdala in fear conditioning. However, fear conditioning, involving direct aversive experience, is only one means by which fears can be acquired. Exploiting aversive experiences of other individuals through social fear learning is less risky. Behavioral research provides important insights into the workings of social fear learning, and the neural mechanisms are beginning to be understood. We review research suggesting that an amygdala-centered model of fear conditioning can help to explain social learning of fear through observation and instruction. We also describe how observational and instructed fear is distinguished by involvement of additional neural systems implicated in social-emotional behavior, language and explicit memory, and propose a modified conditioning model to account for social fear learning. A better understanding of social fear learning promotes integration of biological principles of learning with cultural evolution.

ARTICLE UPDATE - Targeting abnormal neural circuits in mood and anxiety disorders: from the laboratory to the clinic.

Ressler KJ, Mayberg HS.

Nature Neuorscience, 10, 1116-1124

Recent decades have witnessed tremendous advances in the neuroscience of emotion, learning and memory, and in animal models for understanding depression and anxiety. This review focuses on new rationally designed psychiatric treatments derived from preclinical human and animal studies. Nonpharmacological treatments that affect disrupted emotion circuits include vagal nerve stimulation, rapid transcranial magnetic stimulation and deep brain stimulation, all borrowed from neurological interventions that attempt to target known pathological foci. Other approaches include drugs that are given in relation to specific learning events to enhance or disrupt endogenous emotional learning processes. Imaging data suggest that common regions of brain activation are targeted with pharmacological and somatic treatments as well as with the emotional learning in psychotherapy. Although many of these approaches are experimental, the rapidly developing understanding of emotional circuit regulation is likely to provide exciting and powerful future treatments for debilitating mood and anxiety disorders.

Thursday, August 23, 2007

ARTICLE UPDATE - EMuJoy: software for continuous measurement of perceived emotions in music.

Nagel F, Kopiez R, Grewe O, Altenmüller E.

Behavior Research Methods, 39, 283-290

An adequate study of emotions in music and film should be based on the real-time measurement of self-reported data using a continuous-response method. The recording system discussed in this article reflects two important aspects of such research: First, for a better comparison of results, experimental and technical standards for continuous measurement should be taken into account, and second, the recording system should be open to the inclusion of multimodal stimuli. In light of these two considerations, our article addresses four basic principles of the continuous measurement of emotions: (1) the dimensionality of the emotion space, (2) data acquisition (e.g., the synchronization of media and the self-reported data), (3) interface construction for emotional responses, and (4) the use of multiple stimulus modalities. Researcher-developed software (EMuJoy) is presented as a freeware solution for the continuous measurement of responses to different media, along with empirical data from the self-reports of 38 subjects listening to emotional music and viewing affective pictures.

ARTICLE UPDATE - Does remembering emotional items impair recall of same-emotion items?

Sison JA, Mather M.

Psychonomic Bulletin & Review, 14, 282-287

In the part-set cuing effect, cuing a subset of previously studied items impairs recall of the remaining noncued items. This experiment reveals that cuing participants with previously-studied emotional pictures (e.g., fear-evoking pictures of people) can impair recall of pictures involving the same emotion but different content (e.g., fear-evoking pictures of animals). This indicates that new events can be organized in memory using emotion as a grouping function to create associations. However, whether new information is organized in memory along emotional or nonemotional lines appears to be a flexible process that depends on people's current focus. Mentioning in the instructions that the pictures were either amusement- or fear-related led to memory impairment for pictures with the same emotion as cued pictures, whereas mentioning that the pictures depicted either animals or people led to memory impairment for pictures with the same type of actor.

ARTICLE UPDATE - Multidimensional normative ratings for the International Affective Picture System.

Libkuman TM, Otani H, Kern R, Viger SG, Novak N.

Behavior Research Methods, 39, 326-334

The purpose of the present investigation was to replicate and extend the International Affective Picture System norms (Ito, Cacioppo, & Lang, 1998; Lang, Bradley, & Cuthbert, 1999). These norms were developed to provide researchers with photographic slides that varied in emotional evocation, especially arousal and valence. In addition to collecting rating data on the dimensions of arousal and valence, we collected data on the dimensions of consequentiality, meaningfulness, familiarity, distinctiveness, and memorability. Furthermore, we collected ratings on the primary emotions of happiness, surprise, sadness, anger, disgust, and fear. A total of 1,302 participants were tested in small groups. The participants in each group rated a subset of 18 slides on 14 dimensions. Ratings were obtained on 703 slides. The means and standard deviations for all of the ratings are provided. We found our valence ratings to be similar to the previous norms. In contrast, our participants were more likely to rate the slides as less arousing than in the previous norms. The mean ratings on the remaining 12 dimensions were all below the midpoint of the 9-point Likert scale. However, sufficient variability in ratings across the slides indicates that selecting slides on the basis of these variables is feasible. Overall, the present ratings should allow investigators to use these norms for research purposes, especially in research dealing with the interrelationships among emotion and cognition. The means and standard deviations for emotions may be downloaded as an Excel spreadsheet from www.psychonomic.org/archive.

ARTICLE UPDATE - How emotions inform judgment and regulate thought

Clore GL, Huntsinger JR.

Trends in Cognitive Sciences, in press

Being happy or sad influences the content and style of thought. One explanation is that affect serves as information about the value of whatever comes to mind. Thus, when a person makes evaluative judgments or engages in a task, positive affect can enhance evaluations and empower potential responses. Rather than affect itself, the information conveyed by affect is crucial. Tests of the hypothesis find that affective influences can be made to disappear by changing the source to which the affect is attributed. In tasks, positive affect validates and negative affect invalidates accessible cognitions, leading to relational processing and item-specific processing, respectively. Positive affect is found to promote, and negative affect to inhibit, many textbook phenomena from cognitive psychology.

Monday, August 13, 2007

Recruiting participants

If you're around Leeds or York area, you're more than welcome to take part in my EEG experiment. Please go to this website for more detail.

ARTICLE UPDATE - Formalisation of Damasio's theory of emotion, feeling and core consciousness.

Bosse T, Jonker CM, Treur J.

Consciousness and Cognition, in press

This paper contributes an analysis and formalisation of Damasio's theory on core consciousness. Three important concepts in this theory are 'emotion', 'feeling' and 'feeling a feeling' (or core consciousness). In particular, a simulation model is described of the dynamics of basic mechanisms leading via emotion and feeling to core consciousness, and dynamic properties are formally specified that hold for these dynamics at a more global level. These properties have been automatically checked for the simulation model. Moreover, a formal analysis is made of relevant notions of representation used by Damasio. As part of this analysis, specifications of representation relations have been verified and confirmed against the simulation model.

ARTICLE UPDATE - Pleasantness bias in flashbulb memories: positive and negative flashbulb memories of the fall of the Berlin Wall among East and West

Bohn A, Berntsen D.

Memory & Cognition, 35, 565-577

Flashbulb memories for the fall of the Berlin Wall were examined among 103 East and West Germans who considered the event as either highly positive or highly negative. The participants in the positive group rated their memories higher on measures of reliving and sensory imagery, whereas their memory for facts was less accurate than that of the participants in the negative group. The participants in the negative group had higher ratings on amount of consequences but had talked less about the event and considered it less central to their personal and national identity than did the participants in the positive group. In both groups, rehearsal and the centrality of the memory to the person's identity and life story correlated positively with memory qualities. The results suggest that positive and negative emotions have different effects on the processing and long-term retention of flashbulb memories.

Tuesday, August 07, 2007

ARTICLE UPDATE - The shape of threat: Simple geometric forms evoke rapid and sustained capture of attention.

Larson, Christine L.; Aronoff, Joel; Stearns, Jeffrey J.

Emotion, 7, 526-534

Previous work has indicated that simple geometric shapes underlying facial expressions are capable of conveying emotional meaning. Specifically, a series of studies found that a simple shape, a downward-pointing "V," which is similar to the geometric configuration of the face in angry expressions, is perceived as threatening. A parallel line of research has determined that threatening stimuli more readily capture attention. In five experiments, the authors sought to determine whether this preferential processing was also present for the simple geometric form of a downward-pointing "V." Using a visual search paradigm, across these experiments the authors found that, when embedded in a field of other shapes, downward-pointing V's were detected faster and, in some cases, more accurately than identical shapes pointing upward. These findings indicate that the meaning of threat can be conveyed rapidly with minimal stimulus detail. In addition, in some cases, during trials of homogeneous fields of stimuli, fields of downward-pointing V's led to slower response times, suggesting that this shape's ability to capture attention may also extend to difficulty in disengaging attention as well.

ARTICLE UPDATE - Here is looking at you: Emotional faces predominate in binocular rivalry.

Alpers, Georg W.; Gerdes, Antje B. M.

Emotion, 7, 495-506

Two incompatible pictures compete for perceptual dominance when they are presented to one eye each. This so-called binocular rivalry results in an alternation of dominant and suppressed percepts. In accordance with current theories of emotion processing, the authors' previous research has suggested that emotionally arousing pictures predominate in this perceptual process. Three experiments were run with pictures of emotional facial expressions that are known to induce emotions while being well controlled in terms of physical characteristics. In Experiment 1, photographs of emotional and neutral facial expressions were presented of the same actor to minimize physical differences. In Experiment 2, schematic emotional expressions were presented to further eliminate low-level differences. In Experiment 3, a probe-detection task was conducted to control for possible response-biases. Together, these data clearly demonstrate that emotional facial expressions predominate over neutral expressions; they are more often the first percept and they are perceived for longer durations. This is not caused by physical stimulus properties or by response-biases. This novel approach supports that emotionally significant visual stimuli are preferentially perceived.

ARTICLE UPDATE - Anxiety and sensitivity to gaze direction in emotionally expressive faces.

Fox, Elaine; Mathews, Andrew; Calder, Andrew J.; Yiend, Jenny

Emotion, 7, 478-486

This study investigated the role of neutral, happy, fearful, and angry facial expressions in enhancing orienting to the direction of eye gaze. Photographs of faces with either direct or averted gaze were presented. A target letter (T or L) appeared unpredictably to the left or the right of the face, either 300 ms or 700 ms after gaze direction changed. Response times were faster in congruent conditions (i.e., when the eyes gazed toward the target) relative to incongruent conditions (when the eyes gazed away from the target letter). Facial expression did influence reaction times, but these effects were qualified by individual differences in self-reported anxiety. High trait-anxious participants showed an enhanced orienting to the eye gaze of faces with fearful expressions relative to all other expressions. In contrast, when the eyes stared straight ahead, trait anxiety was associated with slower responding when the facial expressions depicted anger. Thus, in anxiety-prone people attention is more likely to be held by an expression of anger, whereas attention is guided more potently by fearful facial expressions.

ARTICLE UPDATE - Blinded by emotion: Target misses follow attention capture by arousing distractors in RSVP.

Arnell, Karen M.; Killman, Kassandra V.; Fijavz, David

Emotion, 7, 465-477

Participants are usually able to search rapid serial visual presentation (RSVP) streams and report a single target, given that RSVP distractors do not typically deplete attention required for target identification. Here, participants performed single target search, but the target was preceded by a to-be-ignored distractor varying in valence and arousal. When the critical distractor was a sexual word, lower target accuracy was observed, particularly at short distractor-target stimulus onset asynchronies, even when participants were shown the critical distractors beforehand and told to ignore them. No reduction in target accuracy was evidenced when the critical distractor was negative, positive, threatening, or emotionally neutral. Target accuracy was predicted by participants' arousal ratings to the critical distractor words and by their memory for them, but not by their valence ratings. Memory for critical distractors mediated the relationship between arousal and target accuracy. The results provide evidence that arousing sexual words involuntarily capture attention and enter awareness at the expense of goal-driven targets, at least in the context of laboratory experiments performed by young university participants for whom sexual material might have high impact and relevance.

ARTICLE UPDATE - Anxiety Moderates the Interplay Between Cognitive and Affective Processing

Jeremy D. Dvorak-Bertsch, John J. Curtin, Tal J. Rubinstein, Joseph P. Newman

Psychological Science, 18, 699-705

Evidence suggests that focus of attention and cognitive load may each affect emotional processing and that individual differences in anxiety moderate such effects. We examined (a) fear-potentiated startle (FPS) under threat-focused (TF), low-load/alternative-set (LL/AS), and high-load/alternative-set (HL/AS) conditions and (b) the moderating effect of trait anxiety on FPS across these conditions. As predicted, redirecting attentional focus away from threat cues and increasing cognitive load reduced FPS. However, the moderating effects of anxiety were specific to the LL/AS condition. Whereas FPS was comparable for high-anxiety and low-anxiety subjects in the TF and HL/AS conditions, FPS was significantly greater for high-anxiety than for low-anxiety subjects in the LL/AS condition. These results suggest that affective processing requires attentional resources and that exaggerated threat processing in anxious individuals relates to direction of attention rather than emotional reactivity per se.

Monday, August 06, 2007

ARTICLE UPDATE - Anxiety and the interpretation of ambiguous facial expressions: The influence of contextual cues.

Blanchette I, Richards A, Cross A.

The Quarterly Journal of Experimental Psychology, 60, 1101 - 1115

In 3 experiments, we investigate how anxiety influences interpretation of ambiguous facial expressions of emotion. Specifically, we examine whether anxiety modulates the effect of contextual cues on interpretation. Participants saw ambiguous facial expressions. Simultaneously, positive or negative contextual information appeared on the screen. Participants judged whether each expression was positive or negative. We examined the impact of verbal and visual contextual cues on participants' judgements. We used 3 different anxiety induction procedures and measured levels of trait anxiety (Experiment 2). Results showed that high state anxiety resulted in greater use of contextual information in the interpretation of the facial expressions. Trait anxiety was associated with mood-congruent effects on interpretation, but not greater use of contextual information.

ARTICLE UPDATE - Audiovisual integration of emotional signals in voice and face: An event-related fMRI study.

Kreifelts B, Ethofer T, Grodd W, Erb M, Wildgruber D.

NeuroImage, in press

In a natural environment, non-verbal emotional communication is multimodal (i.e. speech melody, facial expression) and multifaceted concerning the variety of expressed emotions. Understanding these communicative signals and integrating them into a common percept is paramount to successful social behaviour. While many previous studies have focused on the neurobiology of emotional communication in the auditory or visual modality alone, far less is known about multimodal integration of auditory and visual non-verbal emotional information. The present study investigated this process using event-related fMRI. Behavioural data revealed that audiovisual presentation of non-verbal emotional information resulted in a significant increase in correctly classified stimuli when compared with visual and auditory stimulation. This behavioural gain was paralleled by enhanced activation in bilateral posterior superior temporal gyrus (pSTG) and right thalamus, when contrasting audiovisual to auditory and visual conditions. Further, a characteristic of these brain regions, substantiating their role in the emotional integration process, is a linear relationship between the gain in classification accuracy and the strength of the BOLD response during the bimodal condition. Additionally, enhanced effective connectivity between audiovisual integration areas and associative auditory and visual cortices was observed during audiovisual stimulation, offering further insight into the neural process accomplishing multimodal integration. Finally, we were able to document an enhanced sensitivity of the putative integration sites to stimuli with emotional non-verbal content as compared to neutral stimuli.

ARTICLE UPDATE - Differential electrocortical responses to increasing intensities of fearful and happy emotional expressions.

Leppänen JM, Kauppinen P, Peltola MJ, Hietanen JK.

Brain Research, in press

Previous studies have shown differential event-related potentials (ERPs) to fearful and happy/neutral facial expressions. To investigate whether the brain systems underlying these ERP differences are sensitive to the intensity of fear and happiness, behavioral recognition accuracy and reaction times as well as ERPs were measured while observers categorized low-intensity (50%), prototypical (100%), and caricatured (150%) fearful and happy facial expressions. The speed and accuracy of emotion categorization improved with increasing levels of expression intensity, and 100% and 150% expressions were consistently classified as expressions of the intended emotions. Comparison of ERPs to 100% and 150% expressions revealed a differential pattern of ERPs to 100% and 150% fear expressions over occipital-temporal electrodes 190-290 ms post-stimulus (a negative shift in ERP activity for high-intensity fearful expressions). Similar ERP differences were not observed for 100% and 150% happy expressions, ruling out the possibility that the ERPs to high-intensity fear reflected a response to increased expression intensity per se. Together, these results suggest that differential electrocortical responses to fearful facial expressions over posterior electrodes are generated by a neural system that responds to the intensity of negative but not positive emotional expressions.