Friday, June 30, 2006

ARTICLE UPDATE - Intentional modulation of emotional responding to unpleasant pictures: An ERP study.

Moser JS, Hajcak G, Bukay E, Simons RF.

Psychophysiology, 43, 292-296.

Intentionally altering responses to unpleasant stimuli affects physiological and hemodynamic activity associated with emotional and cognitive processing. In the present experiment, we measured the late-positive potential (LPP) of the visually evoked event-related brain potential to examine the effects of intentional emotion modulation on electrophysiological correlates of emotional and cognitive processing. Seventeen participants received instructions to view, suppress, and enhance emotional responses to unpleasant stimuli. Results revealed significantly decreased electrophysiological activity during suppression of emotional responses beginning around 250 ms poststimulus and lasting several hundred milliseconds. These data suggest that ERPs are sensitive to emotion modulation/regulation processes.

Wednesday, June 28, 2006

ARTICLE UPDATE - Event-related brain potential correlates of emotional face processing

Martin Eimer and Amanda Holmes

Neuropsychologia, in press

Results from recent event-related brain potential (ERP) studies investigating brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180 ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250 ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical brain circuits.

ARTICLE UPDATE - Are you always on my mind? A review of how face perception and attention interact

Romina Palermo and Gillian Rhodes

Neuropsychologia, in press,

In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are “automatic”, in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces and facial expressions. Evidence from behavioral, neuropsychological, neuroimaging and psychophysiological studies from humans and single-unit recordings from primates is examined and the neural systems involved in processing faces, emotion and attention are highlighted. Avenues for further research are identified.

Friday, June 16, 2006

ARTICLE UPDATE - The influence of nonremembered affective associations on preference.

Ghuman AS, Bar M.

Emotion, 6, 215-223.

An important influence on our preference toward a specific object is its associations with affective information. Here, the authors concentrate on the role of memory on shaping such preferences. Specifically, the authors used a multistage behavioral paradigm that fostered associations between neutral shapes and affective images. Participants that explicitly remembered these affective associations preferred neutral shapes associated with positive images. Counterintuitively, participants who could not explicitly remember the associations preferred neutral shapes that were associated with negative images. Generally, the difference in preference between participants who could and could not remember the affective associations demonstrates a critical link between memory and preference formation. The authors propose that the preference for negatively associated items is a manifestation of a mechanism that produces an inherent incentive for rapidly assessing potentially threatening aspects in the environment.

ARTICLE UPDATE - Rapid picture presentation and affective engagement.

Smith JC, Low A, Bradley MM, Lang PJ.

Emotion, 6, 208-214.

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

ARTICLE UPDATE - Spontaneous retrieval of affective person knowledge in face perception.

Todorov A, Gobbini MI, Evans KK, Haxby JV.

Neuropsychologia, in press

In a functional magnetic resonance imaging experiment, we explored whether affective person knowledge based on memories formed from minimal information is spontaneously retrieved in face perception. In the first stage of the experiment, participants were presented with 120 unfamiliar faces. Each face was presented with a description of one of four types of behaviors: aggressive, disgusting, neutral, and nice. In the second stage, participants were scanned while engaged in a one-back recognition task in which they saw the faces that were associated with behaviors and 30 novel faces. Although this task is a simple perceptual task that neither demands person evaluation nor retrieval of person knowledge, neural responses to faces differed as a function of the behaviors. Faces associated with behaviors evoked stronger activity than did novel faces in regions implicated in social cognition-anterior paracingulate cortex and superior temporal sulcus. Explicit memory for the behaviors enhanced the neural response in these regions. Faces associated with disgusting behaviors evoked stronger activity in left anterior insula than did faces associated with aggressive behaviors. This effect was equally strong for faces associated with explicitly recalled behaviors and faces associated with non-recalled behaviors. The findings suggest that affective person knowledge acquired from minimal information is spontaneously retrieved in face perception, engaging neural systems for analysis of social cognition and emotions.

ARTICLE UPDATE - Human and computer recognition of facial expressions of emotion.

Susskind JM, Littlewort G, Bartlett MS, Movellan J, Anderson AK.

Neuropsychologia, in press

Neuropsychological and neuroimaging evidence suggests that the human brain contains facial expression recognition detectors specialized for specific discrete emotions. However, some human behavioral data suggest that humans recognize expressions as similar and not discrete entities. This latter observation has been taken to indicate that internal representations of facial expressions may be best characterized as varying along continuous underlying dimensions. To examine the potential compatibility of these two views, the present study compared human and support vector machine (SVM) facial expression recognition performance. Separate SVMs were trained to develop fully automatic optimal recognition of one of six basic emotional expressions in real-time with no explicit training on expression similarity. Performance revealed high recognition accuracy for expression prototypes. Without explicit training of similarity detection, magnitude of activation across each emotion-specific SVM captured human judgments of expression similarity. This evidence suggests that combinations of expert classifiers from separate internal neural representations result in similarity judgments between expressions, supporting the appearance of a continuous underlying dimensionality. Further, these data suggest similarity in expression meaning is supported by superficial similarities in expression appearance.

Monday, June 12, 2006

ARTICLE UPDATE - Semantic Processing Precedes Affect Retrieval: The Neurological Case for Cognitive Primacy in Visual Processing

Justin Storbeck, Michael D. Robinson and Mark E. McCourt

Review of General Psychology, 10, 41-55.

According to the affective primacy hypothesis, visual stimuli can be evaluated prior to and independent of object identification and semantic analysis (Zajonc, 1980, 2000). Our review concludes that the affective primacy hypothesis is, from the available evidence, not likely correct. Although people can react to objects that they cannot consciously identify, such affective reactions are dependent upon prior semantic analysis within the visual cortex. The authors propose that the features of objects must first be integrated, and then the objects themselves must be categorized and identified, all prior to affective analysis. Additionally, the authors offer a preliminary neurological analysis of the mere exposure and affective priming effects that is consistent with the claim that semantic analysis is needed to elicit these effects. In sum, the authors conclude that the brain must know what something is in order to know whether it is good or bad.

Saturday, June 10, 2006

ARTICLE UPDATE - Functional neuroimaging of emotional learning and autonomic reactions

Martin Peper, Martin Herpers, Joachim Spreer, Jürgen Hennig and Josef Zentner

Journal of Psysiology - Paris, in press

This article provides a selective overview of the functional neuroimaging literature with an emphasis on emotional activation processes. Emotions are fast and flexible response systems that provide basic tendencies for adaptive action. From the range of involved component functions, we first discuss selected automatic mechanisms that control basic adaptational changes. Second, we illustrate how neuroimaging work has contributed to the mapping of the network components associated with basic emotion families (fear, anger, disgust, happiness), and secondary dimensional concepts that organise the meaning space for subjective experience and verbal labels (emotional valence, activity/intensity, approach/withdrawal, etc.). Third, results and methodological difficulties are discussed in view of own neuroimaging experiments that investigated the component functions involved in emotional learning. The amygdala, prefrontal cortex, and striatum form a network of reciprocal connections that show topographically distinct patterns of activity as a correlate of up and down regulation processes during an emotional episode. Emotional modulations of other brain systems have attracted recent research interests. Emotional neuroimaging calls for more representative designs that highlight the modulatory influences of regulation strategies and socio-cultural factors responsible for inhibitory control and extinction. We conclude by emphasising the relevance of the temporal process dynamics of emotional activations that may provide improved prediction of individual differences in emotionality.

Friday, June 09, 2006

ARTICLE UPDATE - Fear Recognition Ability Predicts Differences in Social Cognitive and Neural Functioning in Men

Ben Corden, Hugo D. Critchley, David Skuse and Raymond J. Dolan

Journal of Cognitive Neuroscience, 18, 889-897.

By testing the facial fear-recognition ability of 341 men in the general population, we show that 8.8% have deficits akin to those seen with acquired amygdala damage. Using psychological tests and functional magnetic resonance imaging (fMRI) we tested the hypothesis that poor fear recognition would predict deficits in other domains of social cognition and, in response to socially relevant stimuli, abnormal activation in brain regions that putatively reflect engagement of the "social brain." On tests of "theory of mind" ability, 25 "low fear scorers" (LFS) performed significantly worse than 25 age- and IQ-matched "normal (good) fear scorers" (NFS). In fMRI, we compared evoked activity during a gender judgement task to neutral faces portraying different head and eye gaze orientations in 12 NFS and 12 LFS subjects. Despite identical between-group accuracy in gender discrimination, LFS demonstrated significantly reduced activation in amygdala, fusiform gyrus, and anterior superior temporal cortices when viewing faces with direct versus averted gaze. In a functional connectivity analysis, NFS show enhanced connectivity between the amygdala and anterior temporal cortex in the context of direct gaze; this enhanced coupling is absent in LFS. We suggest that important individual differences in social cognitive skills are expressed within the healthy male population, which appear to have a basis in a compromised neural system that underpins social information processing.

ARTICLE UPDATE - Orbitofrontal Cortex and Social Behavior: Integrating Self-monitoring and Emotion–Cognition Interactions

Jennifer S. Beer, Oliver P. John, Donatella Scabini and Robert T. Knight

Journal of Cognitive Neuroscience, 18, 871-879.

The role of the orbitofrontal cortex in social behavior remains a puzzle. Various theories of the social functions of the orbitofrontal cortex focus on the role of this area in either emotional processing or its involvement in online monitoring of behavior (i.e., self-monitoring). The present research attempts to integrate these two theories by examining whether improving the self-monitoring of patients with orbitofrontal damage is associated with the generation of emotions needed to guide interpersonal behavior. Patients with orbitofrontal damage, patients with lateral prefrontal damage, and healthy controls took part in an interpersonal task. After completing the task, participants' self-monitoring was increased by showing them a videotape of their task performance. In comparison to healthy controls and patients with lateral prefrontal damage, orbitofrontal damage was associated with objectively inappropriate social behavior. Although patients with orbitofrontal damage were aware of social norms of intimacy, they were unaware that their task performance violated these norms. The embarrassment typically associated with inappropriate social behavior was elicited in these patients only after their self-monitoring increased from viewing their videotaped performance. These findings suggest that damage to the orbitofrontal cortex impairs self-insight that may preclude the generation of helpful emotional information. The results highlight the role of the orbitofrontal cortex in the interplay of self-monitoring and emotional processing and suggest avenues for neurorehabilitation of patients with social deficits subsequent to orbitofrontal damage.

ARTICLE UPDATE - Neural systems connecting interoceptive awareness and feelings.

Pollatos O, Gramann K, Schandry R.

Human Brain Mapping, in press

In many theories of emotions the representations of bodily responses play an important role for subjective feelings. We tested the hypothesis that the perception of bodily states is positively related to the experienced intensity of feelings as well as to the activity of first-order and second-order brain structures involved in the processing of feelings. Using a heartbeat perception task, subjects were separated into groups with either high or poor interoceptive awareness. During emotional picture presentation we measured high-density EEG and used spatiotemporal current density reconstruction to identify regions involved in both interoceptive awareness and emotion processing. We observed a positive relation between interoceptive awareness and the experienced intensity of emotions. Furthermore, the P300 amplitudes to pleasant and unpleasant pictures were enhanced for subjects with high interoceptive awareness. The source reconstruction revealed that interoceptive awareness is related to an enhanced activation in both first-order structures (insula, somatosensory cortices) and second-order structures (anterior cingulate, prefrontal cortices). We conclude that the perception of bodily states is a crucial determinant for the processing and the subjective experience of feelings.

ARTICLE UPDATE - Hemispheric asymmetries for the conscious and unconscious perception of emotional words

Smith SD, Bulman-Fleming MB.

Laterality, 11, 304-330.

The current research examines the interactions between hemispheric asymmetries for visual perception and emotion. In a series of four experiments, participants completed tasks measuring both conscious and unconscious perception of linguistic stimuli. In these studies, stimulus-presentation parameters (brief exposure duration vs masking) and the emotional valence of the test stimuli (negative vs positive) were manipulated in order to create studies in which the visual and emotional asymmetries were congruent (favoured the same hemispheres) or were incongruent (favoured opposing hemispheres). The results demonstrated that negative emotional stimuli led to a right-hemisphere advantage for conscious perception only when stimuli were shown for brief exposures (17 ms). Positive emotional words did not elicit hemispheric asymmetries. The results are discussed in terms of their relevance for theories of emotional lateralisation.