Class II correction with magnets and superelastic coils followed by straight-wire mechanotherapy. Occlusal changes during and after dental therapy

We investigated facial recognition memory (for previously unfamiliar faces) and facial expression perception with functional magnetic resonance imaging (fMRI). Eight healthy, right-handed volunteers participated. For the facial recognition task, subjects made a decision as to the familiarity of each of 50 faces (25 previously viewed; 25 novel). We detected signal increase in the right middle temporal gyrus and left prefrontal cortex during presentation of familiar faces, and in several brain regions, including bilateral posterior cingulate gyri, bilateral insulae and right middle occipital cortex during presentation of unfamiliar faces. Standard facial expressions of emotion were used as stimuli in two further tasks of facial expression perception. In the first task, subjects were presented with alternating happy and neutral faces; in the second task, subjects were presented with alternating sad and neutral faces. During presentation of happy facial expressions, we detected a signal increase predominantly in the left anterior cingulate gyrus, bilateral posterior cingulate gyri, medial frontal cortex and right supramarginal gyrus, brain regions previously implicated in visuospatial and emotion processing tasks. No brain regions showed increased signal intensity during presentation of sad facial expressions. These results provide evidence for a distinction between the neural correlates of facial recognition memory and perception of facial expression but, whilst highlighting the role of limbic structures in perception of happy facial expressions, do not allow the mapping of a distinct neural substrate for perception of sad facial expressions.     

The combined effect of gaze direction and facial expression on cueing spatial attention.

Empirical evidence shows an effect of gaze direction on cueing spatial attention, regardless of the emotional expression shown by a face, whereas a combined effect of gaze direction and facial expression has been observed on individuals' evaluative judgments. In 2 experiments, the authors investigated whether gaze direction and facial expression affect spatial attention depending upon the presence of an evaluative goal. Disgusted, fearful, happy, or neutral faces gazing left or right were followed by positive or negative target words presented either at the spatial location looked at by the face or at the opposite spatial location. Participants responded to target words based on affective valence (i.e., positive/negative) in Experiment 1 and on letter case (lowercase/uppercase) in Experiment 2. Results showed that participants responded much faster to targets presented at the spatial location looked at by disgusted or fearful faces but only in Experiment 1, when an evaluative task was used. The present findings clearly show that negative facial expressions enhance the attentional shifts due to eye-gaze direction, provided that there was an explicit evaluative goal present. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in valence modulation of face-selective m170 response.

Magnetoencephalography was used to examine the effect of individual differences on the temporal dynamics of emotional face processing by grouping subjects based on their ability to detect masked valence-laden stimuli. Receiver operating characteristic curves and a nonparametric sensitivity measure were used to categorize subjects into those that could and could not reliably detect briefly presented fearful faces that were backward-masked by neutral faces. Results showed that, in a cluster of face-responsive sensors, the strength of the M170 response was modulated by valence only when subjects could reliably detect the masked fearful faces. Source localization of the M170 peak using synthetic aperture magnetometry identified sources in face processing areas such as right middle occipital gyrus and left fusiform gyrus that showed the valence effect for those target durations at which subjects were sensitive to the fearful stimulus. Subjects who were better able to detect fearful faces also showed higher trait anxiety levels. These results suggest that individual differences between subjects, such as trait anxiety levels and sensitivity to fearful stimuli, may be an important factor to consider when studying emotion processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does it matter where we meet? The role of emotional context in evaluative first impressions.

We investigated how emotionality of visual background context influenced perceptual ratings of faces. In two experiments participants rated how positive or negative a face, with a neutral expression (Experiment 1), or unambiguous emotional expression (happy/angry; Experiment 2), appeared when viewed overlaid onto positive, negative, or neutral background context scenes. Faces viewed in a positive context were rated as appearing more positive than when in a neutral or negative context, and faces in negative contexts were rated more negative than when in a positive or neutral context, regardless of the emotional expression portrayed. Notably, congruency of valence in face expression and background context significantly influenced face ratings. These findings suggest that human judgements of faces are relative, and significantly influenced by contextual factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Left hemisphere specialization for response to positive emotional expressions: A divided output methodology.

An extensive literature credits the right hemisphere with dominance for processing emotion. Conflicting literature finds left hemisphere dominance for positive emotions. This conflict may be resolved by attending to processing stage. A divided output (bimanual) reaction time paradigm in which response hand was varied for emotion (angry; happy) in Experiments 1 and 2 and for gender (male; female) in Experiment 3 focused on response to emotion rather than perception. In Experiments 1 and 2, reaction time was shorter when right-hand responses indicated a happy face and left-hand responses an angry face, as compared to reversed assignment. This dissociation did not obtain with incidental emotion (Experiment 3). Results support the view that response preparation to positive emotional stimuli is left lateralized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Updating positive and negative stimuli in working memory in depression.

Difficulties in the ability to update stimuli in working memory (WM) may underlie the problems with regulating emotions that lead to the development and perpetuation of mood disorders such as depression. To examine the ability to update affective material in WM, the authors had diagnosed depressed and never-disordered control participants perform an emotion 2-back task in which participants were presented with a series of happy, sad, and neutral faces and were asked to indicate whether the current face had the same (match-set) or different (break-set or no-set) emotional expression as that presented 2 faces earlier. Participants also performed a 0-back task with the same emotional stimuli to serve as a control for perceptual processing. After transforming reaction times to control for baseline group differences, depressed and nondepressed participants exhibited biases in updating emotional content that reflects the tendency to keep negative information and positive information, respectively, active in WM. Compared with controls, depressed participants were both slower to disengage from sad stimuli and faster to disengage from happy facial expressions. In contrast, nondepressed controls took longer to disengage from happy stimuli than from neutral or sad stimuli. These group differences in reaction times may reflect both protective and maladaptive biases in WM that underlie the ability to effectively regulate negative affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention to emotional faces following recovery from depression.

This study was designed to examine attentional biases in the processing of emotional faces in currently and formerly depressed participants and healthy controls. Using a dot-probe task, the authors presented faces expressing happy or sad emotions paired with emotionally neutral faces. Whereas both currently and formerly depressed participants selectively attended to the sad faces, the control participants selectively avoided the sad faces and oriented toward the happy faces, a positive bias that was not observed for either of the depressed groups. These results indicate that attentional biases in the processing of emotional faces are evident even after individuals have recovered from a depressive episode. Implications of these findings for understanding the roles of cognitive and interpersonal functioning in depression are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binocular rivalry: A window into emotional processing in aging.

Previous binocular rivalry studies with younger adults have shown that emotional stimuli dominate perception over neutral stimuli. Here we investigated the effects of age on patterns of emotional dominance during binocular rivalry. Participants performed a face/house rivalry task where the emotion of the face (happy, angry, neutral) and orientation (upright, inverted) of the face and house stimuli were varied systematically. Age differences were found with younger adults showing a general emotionality effect (happy and angry faces were more dominant than neutral faces) and older adults showing inhibition of anger (neutral faces were more dominant than angry faces) and positivity effects (happy faces were more dominant than both angry and neutral faces). Age differences in dominance patterns were reflected by slower rivalry rates for both happy and angry compared to neutral face/house pairs in younger adults, and slower rivalry rates for happy compared to both angry and neutral face/house pairs in older adults. Importantly, these patterns of emotional dominance and slower rivalry rates for emotional-face/house pairs disappeared when the stimuli were inverted. This suggests that emotional valence, and not low-level image features, were responsible for the emotional bias in both age groups. Given that binocular rivalry has a limited role for voluntary control, the findings imply that anger suppression and positivity effects in older adults may extend to more automatic tasks. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Emotion-attention interactions in recognition memory for distractor faces.

Effective filtering of distractor information has been shown to be dependent on perceptual load. Given the salience of emotional information and the presence of emotion-attention interactions, we wanted to explore the recognition memory for emotional distractors especially as a function of focused attention and distributed attention by manipulating load and the spatial spread of attention. We performed two experiments to study emotion-attention interactions by measuring recognition memory performance for distractor neutral and emotional faces. Participants performed a color discrimination task (low-load) or letter identification task (high-load) with a letter string display in Experiment 1 and a high-load letter identification task with letters presented in a circular array in Experiment 2. The stimuli were presented against a distractor face background. The recognition memory results show that happy faces were recognized better than sad faces under conditions of less focused or distributed attention. When attention is more spatially focused, sad faces were recognized better than happy faces. The study provides evidence for emotion-attention interactions in which specific emotional information like sad or happy is associated with focused or distributed attention respectively. Distractor processing with emotional information also has implications for theories of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic Priming of Different Affective Categories.

The authors investigated affective semantic priming using a lexical decision task with 4 affective categories of related word pairs: neutral, happy, fearful, and sad. Results demonstrated a striking and reliable effect of affective category on semantic priming. Neutral and happy prime-targets yielded significant semantic priming. Fearful pairs showed no or modest priming facilitation, and sad primes slowed reactions to sad targets. A further experiment established that affective primes do not have generalized facilitatory-inhibitory effects. The results are interpreted as showing that the associative mechanisms that support semantic priming for neutral words are also shared by happy valence words but not for negative valence words. This may reflect increased vigilance necessary in adverse contexts or suggest that the associative mechanisms that bind negative valence words are distinct. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inversion effect for faces in split-brain monkeys

Inverting facial stimuli disrupts recognition in human subjects more severely than does inversion of other objects normally seen upright. Furthermore, this disruption affects mechanisms in the right hemisphere, which is the hemisphere preeminent for face processing, more than mechanisms in the left. To determine the extent of these effects in monkeys we retrained each hemisphere of 20 split-brain rhesus monkeys on eight upright facial discriminations they had previously learned. As a group, the monkeys again performed better with the right hemisphere than with the left in remembering these problems, confirming the right hemispheric advantage previously found. As soon as a particular discrimination was relearned to criterion with one hemisphere, the same discrimination was presented inverted. The monkeys learned the inverted facial discriminations with each hemisphere but as a group no longer showed a right hemispheric advantage. Thus, the monkeys, like people, show a greater inversion effect for faces with the right hemisphere than with the left. This result indicates that monkeys normally process faces configurally using holistic mechanisms in the right hemisphere but, when required by the nature of the stimuli, can utilize piecemeal processing of specific features with either hemisphere.     

Judging approachability on the face of it: The influence of face and body expressions on the perception of approachability.

The aim of the current study was to examine how emotional expressions displayed by the face and body influence the decision to approach or avoid another individual. In Experiment 1, we examined approachability judgments provided to faces and bodies presented in isolation that were displaying angry, happy, and neutral expressions. Results revealed that angry expressions were associated with the most negative approachability ratings, for both faces and bodies. The effect of happy expressions was shown to differ for faces and bodies, with happy faces judged more approachable than neutral faces, whereas neutral bodies were considered more approachable than happy bodies. In Experiment 2, we sought to examine how we integrate emotional expressions depicted in the face and body when judging the approachability of face-body composite images. Our results revealed that approachability judgments given to face-body composites were driven largely by the facial expression. In Experiment 3, we then aimed to determine how the categorization of body expression is affected by facial expressions. This experiment revealed that body expressions were less accurately recognized when the accompanying facial expression was incongruent than when neutral. These findings suggest that the meaning extracted from a body expression is critically dependent on the valence of the associated facial expression. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Hemispheric asymmetry for emotional stimuli detected with fMRI

Current brain models of emotion processing hypothesize that positive (or approach-related) emotions are lateralized towards the left hemisphere, whereas negative (or withdrawal-related) emotions are lateralized towards the right hemisphere. Brain imaging studies, however, have so far failed to document such hemispheric lateralization. In a functional magnetic resonance imaging (fMRI) study, 14 female subjects viewed alternating blocks of emotionally valenced positive and negative pictures. When the experience of valence was equated for arousal, overall brain reactivity was lateralized towards the left hemisphere for positive pictures and towards the right hemisphere for negative pictures. This study provides direct support for the valence hypothesis, under conditions of equivalent arousal, by means of functional brain imaging.     

No evidence of hemispheric facilitation following the induction of negative and positive affect

A dichotomy is thought to exist between the hemispheres whereby the right hemisphere is specialized for the processing of negative emotions and the left hemisphere is specialized for positive emotions. Van Strien and Morpurgo (Neuropsychologia, 1992, 30, 845-848) demonstrated that the activation of negative and positive emotional states resulted in the allocation of attentional resources to the contralateral hemispace. In the present experiment we sought to replicate this effect and improve upon certain methodological features of the experiment. The effect of positive and negative emotions on performance in the left and right visual fields was investigated in 30 dextral students. Positive and negative emotional states were generated by presenting subjects with an emotive word prior to each trial and subsequently requiring them to use that word within a sentence. Performance within the left and right fields was measured using a gap detection task which was neutral in relation to functional asymmetry. No evidence of right or left visual field facilitation was found for the positive or negative conditions, respectively. These results are not interpreted as a refutation of hemispheric specialization for emotional valence. Instead, they are seen to highlight the frailty of hemispheric facilitation effects.     

When side matters: Hemispheric processing and the visual specificity of emotional memories.

Previous studies have shown that the right hemisphere processes the visual details of objects and the emotionality of information. These two roles of the right hemisphere have not been examined concurrently. In the present study, the authors examined whether right hemisphere processing would lead to particularly good memory for the visual details of emotional stimuli. Participants viewed positive, negative, and neutral objects, displayed to the left or right of a fixation cross. Later, participants performed a recognition task in which they evaluated whether items were "same" (same visual details), "similar" (same verbal label, different visual details), or "new" (unrelated) in comparison with the studied objects. Participants remembered the visual details of negative items well, and this advantage in memory specificity was particularly pronounced when the items had been presented directly to the right hemisphere (i.e., to the left of the fixation cross). These results suggest that there is an episodic memory benefit conveyed when negative items are presented directly to the right hemisphere, likely because of the specialization of the right hemisphere for processing both visual detail and negatively valenced emotional information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of emotional faces: Salient physical features guide effective visual search.

In this study, the authors investigated how salient visual features capture attention and facilitate detection of emotional facial expressions. In a visual search task, a target emotional face (happy, disgusted, fearful, angry, sad, or surprised) was presented in an array of neutral faces. Faster detection of happy and, to a lesser extent, surprised and disgusted faces was found both under upright and inverted display conditions. Inversion slowed down the detection of these faces less than that of others (fearful, angry, and sad). Accordingly, the detection advantage involves processing of featural rather than configural information. The facial features responsible for the detection advantage are located in the mouth rather than the eye region. Computationally modeled visual saliency predicted both attentional orienting and detection. Saliency was greatest for the faces (happy) and regions (mouth) that were fixated earlier and detected faster, and there was close correspondence between the onset of the modeled saliency peak and the time at which observers initially fixated the faces. The authors conclude that visual saliency of specific facial features--especially the smiling mouth--is responsible for facilitated initial orienting, which thus shortens detection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotion perception is mediated by spatial frequency content.

Spatial frequencies have been shown to play an important role in face identification, but very few studies have investigated the role of spatial frequency content in identifying different emotions. In the present study we investigated the role of spatial frequency in identifying happy and sad facial expressions. Two experiments were conducted to investigate (a) the role of specific spatial frequency content in emotion identification, and (b) hemispherical asymmetry in emotion identification. Given the links between global processing, happy emotions, and low frequencies, we hypothesized that low spatial frequencies would be important for identifying the happy expression. Correspondingly, we also hypothesized that high spatial frequencies would be important in identifying the sad expression given the links between local processing, sad emotions, and high spatial frequencies. As expected we found that the identification of happy expression was dependent on low spatial frequencies and the identification of sad expression was dependent on high spatial frequencies. There was a hemispheric asymmetry with the identification of sad expression, especially in the right hemisphere, possibly mediated by high spatial frequency content. Results indicate the importance of spatial frequency content in the identification of happy and sad emotional expressions and point to the mechanisms involved in emotion identification. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Hemispheric lateralization of perception and memory for emotional verbal stimuli in normal individuals.

The purposes of this study were to extend the literature on lateralization of perception of emotional verbal stimuli in normal individuals, including a test of both the right hemisphere and valence models, and to investigate predictions from these models regarding lateralization of memory for emotional verbal stimuli in normal individuals, an area that, to our knowledge, has not been investigated. Seventy-nine undergraduates were presented lateralized positive, negative, and neutral English words and nonwords. Participants were then asked to freely recall the presented words and, after a 20-min delay, to recognize the words. Recognition memory data provided strong support for the valence model. In addition, free-recall and perception data provided partial support for this model. The literature on the lateralization of processing emotional verbal and nonverbal material is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biased recognition of positive faces in aging and amnestic mild cognitive impairment.

We investigated age differences in biased recognition of happy, neutral, or angry faces in 4 experiments. Experiment 1 revealed increased true and false recognition for happy faces in older adults, which persisted even when changing each face’s emotional expression from study to test in Experiment 2. In Experiment 3, we examined the influence of reduced memory capacity on the positivity-induced recognition bias, which showed the absence of emotion-induced memory enhancement but a preserved recognition bias for positive faces in patients with amnestic mild cognitive impairment compared with older adults with normal memory performance. In Experiment 4, we used semantic differentials to measure the connotations of happy and angry faces. Younger and older participants regarded happy faces as more familiar than angry faces, but the older group showed a larger recognition bias for happy faces. This finding indicates that older adults use a gist-based memory strategy based on a semantic association between positive emotion and familiarity. Moreover, older adults’ judgments of valence were more positive for both angry and happy faces, supporting the hypothesis of socioemotional selectivity. We propose that the positivity-induced recognition bias might be based on fluency, which in turn is based on both positivity-oriented emotional goals and on preexisting semantic associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affect and facilitative self-control: Influence of ecological setting, cognition, and social agent.

Three components of a situation--the ecological setting, the child's cognition, and the social agent--were imbued with positive, neutral, or negative affect to determine if they were functionally related to the continued maintenance of performance at a motor task by 108 1st and 2nd graders. Maintenance of performance is discussed in terms of facilitative self-control, and theoretical linkages to cognitive self-reinforcement and distractibility-frustrative nonreward theories are proposed. The most powerful effects occurred when the affect of the ecological setting was changed: Ss who experienced a happy room (happy pictures and faces) persisted longer than those in the sad or neutral room. Also, Ss who thought about happy things persisted longer than Ss who thought about sad or neutral things, but only when the E acted happy and recently had told the S a happy story. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)