Progress in Brain Research, volume 156, 2006

Lang, P. J. & Davis, M. (2006). Emotion, motivation, and the brain: reflex foundations in animal and human research. Prog.Brain Res., 156, 3-29.
Notes: NIMH Center for the Study of Emotion and Attention, Department of Clinical and Health Psychology, University of Florida, FL 32610-0165, USA.
This review will focus on a motivational circuit in the brain, centered on the amygdala, that underlies human emotion. This neural circuitry of appetitive/approach and defensive/avoidance was laid down early in our evolutionary history in primitive cortex, sub-cortex, and mid-brain, to mediate behaviors basic to the survival of individuals and the propagation of genes to coming generations. Thus, events associated with appetitive rewards, or that threaten danger or pain, engage attention and prompt information gathering more so than other input. Motive cues also occasion metabolic arousal, anticipatory responses, and mobilize the organism to prepare for action. Findings are presented from research with animals, elucidating these psychophysiological (e.g., cardiovascular, neuro-humoral) and behavioral (e.g., startle potentiation, "freezing") patterns in emotion, and defining their mediating brain circuits. Parallel results are described from experiments with humans, showing similar activation patterns in brain and body in response to emotion cues, co-varying with participants' reports of affective valence and increasing emotional arousal

Schupp, H. T., Flaisch, T., Stockburger, J., & Junghofer, M. (2006). Emotion and attention: event-related brain potential studies. Prog.Brain Res., 156, 31-51.
Notes: Department of Psychology, University of Konstanz, Konstanz, and Institute for Biomagnetism and Biosignalanalysis, Munster University Hospital, Germany.
Emotional pictures guide selective visual attention. A series of event-related brain potential (ERP) studies is reviewed demonstrating the consistent and robust modulation of specific ERP components by emotional images. Specifically, pictures depicting natural pleasant and unpleasant scenes are associated with an increased early posterior negativity, late positive potential, and sustained positive slow wave compared with neutral contents. These modulations are considered to index different stages of stimulus processing including perceptual encoding, stimulus representation in working memory, and elaborate stimulus evaluation. Furthermore, the review includes a discussion of studies exploring the interaction of motivated attention with passive and active forms of attentional control. Recent research is reviewed exploring the selective processing of emotional cues as a function of stimulus novelty, emotional prime pictures, learned stimulus significance, and in the context of explicit attention tasks. It is concluded that ERP measures are useful to assess the emotion-attention interface at the level of distinct processing stages. Results are discussed within the context of two-stage models of stimulus perception brought out by studies of attention, orienting, and learning

Codispoti, M., Ferrari, V., De Cesarei, A., & Cardinale, R. (2006). Implicit and explicit categorization of natural scenes. Prog.Brain Res., 156, 53-65.
Notes: Department of Psychology, University of Bologna, Viale Berti Pichat, 5-40127 Bologna, Italy.
Event-related potential (ERP) studies have consistently found that emotionally arousing (pleasant and unpleasant) pictures elicit a larger late positive potential (LPP) than neutral pictures in a window from 400 to 800 ms after picture onset. In addition, an early ERP component has been reported to vary with emotional arousal in a window from about 150 to 300 ms with affective, compared to neutral stimuli, prompting significantly less positivity over occipito-temporal sites. Similar early and late ERP components have been found in explicit categorization tasks, suggesting that selective attention to target features results in similar cortical changes. Several studies have shown that the affective modulation of the LPP persisted even when the same pictures are repeated several times, when they are presented as distractors, or when participants are engaged in a competing task. These results indicate that categorization of affective stimuli is an obligatory process. On the other hand, perceptual factors (e.g., stimulus size) seem to affect the early ERP component but not the affective modulation of the LPP. Although early and late ERP components vary with stimulus relevance, given that they are differentially affected by stimulus and task manipulations, they appear to index different facets of picture processing

Pourtois, G. & Vuilleumier, P. (2006). Dynamics of emotional effects on spatial attention in the human visual cortex. Prog.Brain Res., 156, 67-91.
Notes: Neurology & Imaging of Cognition, Clinic of Neurology, University Hospital & Department of Neurosciences, University Medical Center, University of Geneva, Switzerland.
An efficient detection of threat is crucial for survival and requires an appropriate allocation of attentional resources toward the location of potential danger. Recent neuroimaging studies have begun to uncover the brain machinery underlying the reflexive prioritization of spatial attention to locations of threat-related stimuli. Here, we review functional brain imaging experiments using event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI) in a dot-probe paradigm with emotional face cues, in which we investigated the spatio-temporal dynamics of attentional orienting to a visual target when the latter is preceded by either a fearful or happy face, at the same (valid) location or at a different (invalid) location in visual periphery. ERP results indicate that fearful faces can bias spatial attention toward threat-related location, and enhance the amplitude of the early exogenous visual P1 activity generated within the extrastriate cortex in response to a target following a valid rather than invalid fearful face. Furthermore, this gain control mechanism in extrastriate cortex (at 130-150 ms) is preceded by an earlier modulation of activity in posterior parietal regions (at 40-80 ms) that may provide a critical source of top-down signals on visual cortex. Happy faces produced no modulation of ERPs in extrastriate and parietal cortex. fMRI data also show increased responses in the occipital visual cortex for valid relative to invalid targets following fearful faces, but in addition reveal significant decreases in intraparietal cortex and increases in orbitofrontal cortex when targets are preceded by an invalid fearful face, suggesting that negative emotional stimuli may not only draw but also hold spatial attention more strongly than neutral or positive stimuli. These data confirm that threat may act as a powerful exogenous cue and trigger reflexive shifts in spatial attention toward its location, through a rapid temporal sequence of neural events in parietal and temporo-occipital areas, with dissociable neural substrates for engagement benefits in attention affecting activity in extrastriate occipital areas and increased disengagement costs affecting intraparietal cortex. These brain-imaging results reveal how emotional signals related to threat can play an important role in modulating spatial attention to afford flexible perception and action

Sabatinelli, D., Lang, P. J., Bradley, M. M., & Flaisch, T. (2006). The neural basis of narrative imagery: emotion and action. Prog.Brain Res., 156, 93-103.
Notes: NIMH Center for the Study of Emotion and Attention, University of Florida, PO Box 100165 HSC, Gainesville, FL 32608, USA.
It has been proposed that narrative emotional imagery activates an associative network of stimulus, semantic, and response (procedural) information. In previous research, predicted response components have been demonstrated through psychophysiological methods in peripheral nervous system. Here we investigate central nervous system concomitants of pleasant, neutral, and unpleasant narrative imagery with functional magnetic resonance imaging. Subjects were presented with brief narrative scripts over headphones, and then imagined themselves engaged in the described events. During script perception, auditory association cortex showed enhanced activation during affectively arousing (pleasant and unpleasant), relative to neutral imagery. Structures involved in language processing (left middle frontal gyrus) and spatial navigation (retrosplenium) were also active during script presentation. At the onset of narrative imagery, supplementary motor area, lateral cerebellum, and left inferior frontal gyrus were initiated, showing enhanced signal change during affectively arousing (pleasant and unpleasant), relative to neutral scripts. These data are consistent with a bioinformational model of emotion that considers response mobilization as the measurable output of narrative imagery

Wiens, S. (2006). Subliminal emotion perception in brain imaging: findings, issues, and recommendations. Prog.Brain Res., 156, 105-121.
Notes: Department of Psychology, Stockholm University, Frescati Hagvag, 106 91 Stockholm, Sweden.
Many theories of emotion propose that emotional input is processed preferentially due to its relevance for the organism. Further, because consciousness has limited capacity, these considerations imply that emotional input ought to be processed even if participants are perceptually unaware of the input (subliminal perception). Although brain imaging has studied effects of unattended, suppressed (in binocular rivalry), and visually masked emotional pictures, conclusions regarding subliminal perception have been mixed. The reason is that subliminal perception demands a concept of an awareness threshold or limen, but there is no agreement on how to define and measure this threshold. Although different threshold concepts can be identified in psychophysics (signal detection theory), none maps directly onto perceptual awareness. Whereas it may be tempting to equate unawareness with the complete absence of objective discrimination ability (d'=0), this approach is incompatible with lessons from blindsight and denies the subjective nature of consciousness. This review argues that perceptual awareness is better viewed as a continuum of sensory states than a binary state. When levels of awareness are characterized carefully in terms of objective discrimination and subjective experience, findings can be informative regarding the relative independence of effects from awareness and the potentially moderating role of awareness in processing emotional input. Thus, because the issue of a threshold concept may never be resolved completely, the emphasis is to not prove subliminal perception but to compare effects at various levels of awareness

Junghofer, M., Peyk, P., Flaisch, T., & Schupp, H. T. (2006). Neuroimaging methods in affective neuroscience: selected methodological issues. Prog.Brain Res., 156, 123-143.
Notes: Institute for Biosignalanalysis and Biomagnetism, University of Munster, Munster, Germany.
A current goal of affective neuroscience is to reveal the relationship between emotion and dynamic brain activity in specific neural circuits. In humans, noninvasive neuroimaging measures are of primary interest in this endeavor. However, methodological issues, unique to each neuroimaging method, have important implications for the design of studies, interpretation of findings, and comparison across studies. With regard to event-related brain potentials, we discuss the need for dense sensor arrays to achieve reference-independent characterization of field potentials and improved estimate of cortical brain sources. Furthermore, limitations and caveats regarding sparse sensor sampling are discussed. With regard to event-related magnetic field (ERF) recordings, we outline a method to achieve magnetoencephalography (MEG) sensor standardization, which improves effects' sizes in typical neuroscientific investigations, avoids the finding of ghost effects, and facilitates comparison of MEG waveforms across studies. Focusing on functional magnetic resonance imaging (fMRI), we question the unjustified application of proportional global signal scaling in emotion research, which can greatly distort statistical findings in key structures implicated in emotional processing and possibly contributing to conflicting results in affective neuroscience fMRI studies, in particular with respect to limbic and paralimbic structures. Finally, a distributed EEG/MEG source analysis with statistical parametric mapping is outlined providing a common software platform for hemodynamic and electromagnetic neuroimaging measures. Taken together, to achieve consistent and replicable patterns of the relationship between emotion and neuroimaging measures, methodological aspects associated with the various neuroimaging techniques may be of similar importance as the definition of emotional cues and task context used to study emotion

Kissler, J., Assadollahi, R., & Herbert, C. (2006). Emotional and semantic networks in visual word processing: insights from ERP studies. Prog.Brain Res., 156, 147-183.
Notes: Department of Psychology, University of Konstanz, P. O. Box D25, D-78457 Konstanz, Germany.
The event-related brain potential (ERP) literature concerning the impact of emotional content on visual word processing is reviewed and related to general knowledge on semantics in word processing: emotional connotation can enhance cortical responses at all stages of visual word processing following the assembly of visual word form (up to 200 ms), such as semantic access (around 200 ms), allocation of attentional resources (around 300 ms), contextual analysis (around 400 ms), and sustained processing and memory encoding (around 500 ms). Even earlier effects have occasionally been reported with subliminal or perceptual threshold presentation, particularly in clinical populations. Here, the underlying mechanisms are likely to diverge from the ones operational in standard natural reading. The variability in timing of the effects can be accounted for by dynamically changing lexical representations that can be activated as required by the subjects' motivational state, the task at hand, and additional contextual factors. Throughout, subcortical structures such as the amygdala are likely to contribute these enhancements. Further research will establish whether or when emotional arousal, valence, or additional emotional properties drive the observed effects and how experimental factors interact with these. Meticulous control of other word properties known to affect ERPs in visual word processing, such as word class, length, frequency, and concreteness and the use of more standardized EEG procedures is vital. Mapping the interplay between cortical and subcortical mechanisms that give rise to amplified cortical responses to emotional words will be of highest priority for future research

Fischler, I. & Bradley, M. (2006). Event-related potential studies of language and emotion: words, phrases, and task effects. Prog.Brain Res., 156, 185-203.
Notes: Psychology Department, PO Box 112250, University of Florida, Gainesville, FL 32611, USA.
This chapter reviews research that focuses on the effects of emotionality of single words, and of simple phrases, on event-related brain potentials when these are presented visually in various tasks. In these studies, presentation of emotionally evocative language material has consistently elicited a late (c. 300-600 ms post-onset) positive-going, largely frontal-central shift in the event-related potentials (ERPs), relative to neutral materials. Overall, affectively pleasant and unpleasant words or phrases are quite similar in their neuroelectric profiles and rarely differ substantively. This emotionality effect is enhanced in both amplitude and latency when emotional content is task relevant, but is also reliably observed when the task involves other semantically engaging tasks. On the other hand, it can be attenuated or eliminated when the task does not involve semantic evaluation (e.g., lexical decisions to words or orthographic judgments to the spelling patterns) or when comprehension of phrases requires integration of the connotative meaning of several words (e.g., compare dead puppy and dead tyrant). Taken together, these studies suggest that the emotionality of written language has a rapid and robust impact on ERPs, which can be modulated by specific task demands as well as the linguistic context in which the affective stimulus occurs

Jackson, M. A. & Crosson, B. (2006). Emotional connotation of words: role of emotion in distributed semantic systems. Prog.Brain Res., 156, 205-216.
Notes: Nemours Children's Clinic, Neurology Division, 807 Children's Way, Jacksonville, FL 32207, USA.
One current doctrine regarding lexical-semantic functions asserts separate input and output lexicons with access to a central semantic core. In other words, processes related to word form have separate representations for input (comprehension) vs. output (expression), while processes related to meaning are not split along the input-output dimension. Recent evidence from our laboratory suggests that semantic processes related to emotional connotation may be an exception to this rule. The ability to distinguish among different emotional connotations may be linked distinctly both to attention systems that select specific sensory input for further processing and to intention systems that select specific actions for output. In particular, the neuroanatomic substrates for emotional connotation on the input side of the equation appear to differ from the substrates on the output side of the equation. Implications for semantic processing of emotional connotation and its relationship to attention and motivation systems are discussed

Keil, A. (2006). Macroscopic brain dynamics during verbal and pictorial processing of affective stimuli. Prog.Brain Res., 156, 217-232.
Notes: Department of Psychology, University of Konstanz, PO Box D23, D-78457 Konstanz, Germany.
Emotions can be viewed as action dispositions, preparing an individual to act efficiently and successfully in situations of behavioral relevance. To initiate optimized behavior, it is essential to accurately process the perceptual elements indicative of emotional relevance. The present chapter discusses effects of affective content on neural and behavioral parameters of perception, across different information channels. Electrocortical data are presented from studies examining affective perception with pictures and words in different task contexts. As a main result, these data suggest that sensory facilitation has an important role in affective processing. Affective pictures appear to facilitate perception as a function of emotional arousal at multiple levels of visual analysis. If the discrimination between affectively arousing vs. nonarousing content relies on fine-grained differences, amplification of the cortical representation may occur as early as 60-90 ms after stimulus onset. Affectively arousing information as conveyed via visual verbal channels was not subject to such very early enhancement. However, electrocortical indices of lexical access and/or activation of semantic networks showed that affectively arousing content may enhance the formation of semantic representations during word encoding. It can be concluded that affective arousal is associated with activation of widespread networks, which act to optimize sensory processing. On the basis of prioritized sensory analysis for affectively relevant stimuli, subsequent steps such as working memory, motor preparation, and action may be adjusted to meet the adaptive requirements of the situation perceived

Grandjean, D., Banziger, T., & Scherer, K. R. (2006). Intonation as an interface between language and affect. Prog.Brain Res., 156, 235-247.
Notes: Swiss Center for Affective Sciences, University of Geneva, 7 rue des Battoirs, 1205 Geneva, Switzerland.
The vocal expression of human emotions is embedded within language and the study of intonation has to take into account two interacting levels of information--emotional and semantic meaning. In addition to the discussion of this dual coding system, an extension of Brunswik's lens model is proposed. This model includes the influences of conventions, norms, and display rules (pull effects) and psychobiological mechanisms (push effects) on emotional vocalizations produced by the speaker (encoding) and the reciprocal influences of these two aspects on attributions made by the listener (decoding), allowing the dissociation and systematic study of the production and perception of intonation. Three empirical studies are described as examples of possibilities of dissociating these different phenomena at the behavioral and neurological levels in the study of intonation

Wildgruber, D., Ackermann, H., Kreifelts, B., & Ethofer, T. (2006). Cerebral processing of linguistic and emotional prosody: fMRI studies. Prog.Brain Res., 156, 249-268.
Notes: Department of Psychiatry, University of Tubingen, Osianderstr. 24, 72076 Tubingen, Germany.
During acoustic communication in humans, information about a speaker's emotional state is predominantly conveyed by modulation of the tone of voice (emotional or affective prosody). Based on lesion data, a right hemisphere superiority for cerebral processing of emotional prosody has been assumed. However, the available clinical studies do not yet provide a coherent picture with respect to interhemispheric lateralization effects of prosody recognition and intrahemispheric localization of the respective brain regions. To further delineate the cerebral network engaged in the perception of emotional tone, a series of experiments was carried out based upon functional magnetic resonance imaging (fMRI). The findings obtained from these investigations allow for the separation of three successive processing stages during recognition of emotional prosody: (1) extraction of suprasegmental acoustic information predominantly subserved by right-sided primary and higher order acoustic regions; (2) representation of meaningful suprasegmental acoustic sequences within posterior aspects of the right superior temporal sulcus; (3) explicit evaluation of emotional prosody at the level of the bilateral inferior frontal cortex. Moreover, implicit processing of affective intonation seems to be bound to subcortical regions mediating automatic induction of specific emotional reactions such as activation of the amygdala in response to fearful stimuli. As concerns lower level processing of the underlying suprasegmental acoustic cues, linguistic and emotional prosody seem to share the same right hemisphere neural resources. Explicit judgment of linguistic aspects of speech prosody, however, appears to be linked to left-sided language areas whereas bilateral orbitofrontal cortex has been found involved in explicit evaluation of emotional prosody. These differences in hemispheric lateralization effects might explain that specific impairments in nonverbal emotional communication subsequent to focal brain lesions are relatively rare clinical observations as compared to the more frequent aphasic disorders

Pihan, H. (2006). Affective and linguistic processing of speech prosody: DC potential studies. Prog.Brain Res., 156, 269-284.
Notes: Department of Neurology, Schulthness Klinik, 8008 Zurich, and Department of Neurology, Inselspital, University of Bern, 3010 Bern, Switzerland.
Speech melody or prosody subserves linguistic, emotional, and pragmatic functions in speech communication. Prosodic perception is based on the decoding of acoustic cues with a predominant function of frequency-related information perceived as speaker's pitch. Evaluation of prosodic meaning is a cognitive function implemented in cortical and subcortical networks that generate continuously updated affective or linguistic speaker impressions. Various brain-imaging methods allow delineation of neural structures involved in prosody processing. In contrast to functional magnetic resonance imaging techniques, DC (direct current, slow) components of the EEG directly measure cortical activation without temporal delay. Activation patterns obtained with this method are highly task specific and intraindividually reproducible. Studies presented here investigated the topography of prosodic stimulus processing in dependence on acoustic stimulus structure and linguistic or affective task demands, respectively. Data obtained from measuring DC potentials demonstrated that the right hemisphere has a predominant role in processing emotions from the tone of voice, irrespective of emotional valence. However, right hemisphere involvement is modulated by diverse speech and language-related conditions that are associated with a left hemisphere participation in prosody processing. The degree of left hemisphere involvement depends on several factors such as (i) articulatory demands on the perceiver of prosody (possibly, also the poser), (ii) a relative left hemisphere specialization in processing temporal cues mediating prosodic meaning, and (iii) the propensity of prosody to act on the segment level in order to modulate word or sentence meaning. The specific role of top-down effects in terms of either linguistically or affectively oriented attention on lateralization of stimulus processing is not clear and requires further investigations

Kotz, S. A., Meyer, M., & Paulmann, S. (2006). Lateralization of emotional prosody in the brain: an overview and synopsis on the impact of study design. Prog.Brain Res., 156, 285-294.
Notes: Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1a, 04103 Leipzig, Germany.
Recently, research on the lateralization of linguistic and nonlinguistic (emotional) prosody has experienced a revival. However, both neuroimaging and patient evidence do not draw a coherent picture substantiating right-hemispheric lateralization of prosody and emotional prosody in particular. The current overview summarizes positions and data on the lateralization of emotion and emotional prosodic processing in the brain and proposes that: (1) the realization of emotional prosodic processing in the brain is based on differentially lateralized subprocesses and (2) methodological factors can influence the lateralization of emotional prosody in neuroimaging investigations. Latter evidence reveals that emotional valence effects are strongly right lateralized in studies using compact blocked presentation of emotional stimuli. In contrast, data obtained from event-related studies are indicative of bilateral or left-accented lateralization of emotional prosodic valence. These findings suggest a strong interaction between language and emotional prosodic processing

Dietrich, S., Ackermann, H., Szameitat, D. P., & Alter, K. (2006). Psychoacoustic studies on the processing of vocal interjections: how to disentangle lexical and prosodic information? Prog.Brain Res., 156, 295-302.
Notes: Max-Planck-Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1a, 04103 Leipzig, Germany.
Both intonation (affective prosody) and lexical meaning of verbal utterances participate in the vocal expression of a speaker's emotional state, an important aspect of human communication. However, it is still a matter of debate how the information of these two 'channels' is integrated during speech perception. In order to further analyze the impact of affective prosody on lexical access, so-called interjections, i.e., short verbal emotional utterances, were investigated. The results of a series of psychoacoustic studies indicate the processing of emotional interjections to be mediated by a divided cognitive mechanism encompassing both lexical access and the encoding of prosodic data. Emotional interjections could be separated into elements with high- or low-lexical content. As concerns the former items, both prosodic and propositional cues have a significant influence upon recognition rates, whereas the processing of the low-lexical cognates rather solely depends upon prosodic information. Incongruencies between lexical and prosodic data structures compromise stimulus identification. Thus, the analysis of utterances characterized by a dissociation of the prosodic and lexical dimension revealed prosody to exert a stronger impact upon listeners' judgments than lexicality. Taken together, these findings indicate that both propositional and prosodic speech components closely interact during speech perception

Pell, M. D. (2006). Judging emotion and attitudes from prosody following brain damage. Prog.Brain Res., 156, 303-317.
Notes: School of Communication Sciences and Disorders, McGill University, 1266 Ave. des Pins Ouest, Montreal, QC, H3G 1A8, Canada.
Research has long indicated a role for the right hemisphere in the decoding of basic emotions from speech prosody, although there are few data on how the right hemisphere is implicated in processes for understanding the emotive "attitudes" of a speaker from prosody. We describe recent clinical studies that compared how well listeners with and without focal right hemisphere damage (RHD) understand speaker attitudes such as "confidence" or "politeness," which are signaled in large part by prosodic features of an utterance. We found that RHD listeners as a group were abnormally sensitive to both the expressed confidence and expressed politeness of speakers, and that these difficulties often correlated with impairments for understanding basic emotions from prosody in many RHD individuals. Our data emphasize a central role for the right hemisphere in the ability to appreciate emotions and speaker attitudes from prosody, although the precise source of these social-pragmatic deficits may arise in different ways in the context of right hemisphere compromise

Schwaninger, A., Wallraven, C., Cunningham, D. W., & Chiller-Glaus, S. D. (2006). Processing of facial identity and expression: a psychophysical, physiological, and computational perspective. Prog.Brain Res., 156, 321-343.
Notes: Department of Bulthoff, Max Planck Institute for Biological Cybernetics, Spemannstr. 38, 72076 Tubingen, Germany.
A deeper understanding of how the brain processes visual information can be obtained by comparing results from complementary fields such as psychophysics, physiology, and computer science. In this chapter, empirical findings are reviewed with regard to the proposed mechanisms and representations for processing identity and emotion in faces. Results from psychophysics clearly show that faces are processed by analyzing component information (eyes, nose, mouth, etc.) and their spatial relationship (configural information). Results from neuroscience indicate separate neural systems for recognition of identity and facial expression. Computer science offers a deeper understanding of the required algorithms and representations, and provides computational modeling of psychological and physiological accounts. An interdisciplinary approach taking these different perspectives into account provides a promising basis for better understanding and modeling of how the human brain processes visual information for recognition of identity and emotion in faces

Ethofer, T., Pourtois, G., & Wildgruber, D. (2006). Investigating audiovisual integration of emotional signals in the human brain. Prog.Brain Res., 156, 345-361.
Notes: Section of Experimental MR of the CNS, Department of Neuroradiology, Otfried-Muller-Str. 51, University of Tubingen, 72076 Tubingen, Germany.
Humans can communicate their emotional state via facial expression and affective prosody. This chapter reviews behavioural, neuroanatomical, electrophysiological and neuroimaging studies pertaining to audiovisual integration of emotional communicative signals. Particular emphasis will be given to neuroimaging studies using positron emission tomography (PET) or functional magnetic resonance imaging (fMRI). Conjunction analyses, interaction analyses, correlation analyses between haemodynamic responses and behavioural effects and connectivity analyses have been employed to analyse neuroimaging data. There is no general agreement as to which of these approaches can be considered "optimal" to classify brain regions as multisensory. We argue that these approaches provide complementing information as they assess different aspects of multisensory integration of emotional information. Assets and drawbacks of the different analysis types are discussed and demonstrated on the basis of one fMRI data set

Adolphs, R. & Spezio, M. (2006). Role of the amygdala in processing visual social stimuli. Prog.Brain Res., 156, 363-378.
Notes: Division of the Humanities and Social Sciences, HSS 228-77, California Institute of Technology, Pasadena, CA 91125, USA.
We review the evidence implicating the amygdala as a critical component of a neural network of social cognition, drawing especially on research involving the processing of faces and other visual social stimuli. We argue that, although it is clear that social behavioral representations are not stored in the amygdala, the most parsimonious interpretation of the data is that the amygdala plays a role in guiding social behaviors on the basis of socioenvironmental context. Thus, it appears to be required for normal social cognition. We propose that the amygdala plays this role by attentionally modulating several areas of visual and somatosensory cortex that have been implicated in social cognition, and in helping to direct overt visuospatial attention in face gaze. We also hypothesize that the amygdala exerts attentional modulation of simulation in somatosensory cortices such as supramarginal gyrus and insula. Finally, we argue that the term emotion be broadened to include increased attention to bodily responses and their representation in cortex

Keysers, C. & Gazzola, V. (2006). Towards a unifying neural theory of social cognition. Prog.Brain Res., 156, 379-401.
Notes: BCN Neuro-Imaging-Centre, University Medical Center Groningen, University of Groningen, A. Deusinglaan 2, 9713AW Groningen, The Netherlands.
Humans can effortlessly understand a lot of what is going on in other peoples' minds. Understanding the neural basis of this capacity has proven quite difficult. Since the discovery of mirror neurons, a number of successful experiments have approached the question of how we understand the actions of others from the perspective of sharing their actions. Recently we have demonstrated that a similar logic may apply to understanding the emotions and sensations of others. Here, we therefore review evidence that a single mechanism (shared circuits) applies to actions, sensations and emotions: witnessing the actions, sensations and emotions of other individuals activates brain areas normally involved in performing the same actions and feeling the same sensations and emotions. We propose that these circuits, shared between the first (I do, I feel) and third person perspective (seeing her do, seeing her feel) translate the vision and sound of what other people do and feel into the language of the observers own actions and feelings. This translation could help understand the actions and feelings of others by providing intuitive insights into their inner life. We propose a mechanism for the development of shared circuits on the basis of Hebbian learning, and underline that shared circuits could integrate with more cognitive functions during social cognitions

Chakrabarti, B. & Baron-Cohen, S. (2006). Empathizing: neurocognitive developmental mechanisms and individual differences. Prog.Brain Res., 156, 403-417.
Notes: Autism Research Centre, University of Cambridge, Psychiatry Department, Douglas House, 18B Trumpington Rd, Cambridge CB2 2AH, UK.
This chapter reviews the Mindreading System model encompassing four neurocognitive mechanisms (ID, EDD, SAM, and ToMM) before reviewing the revised empathizing model encompassing two new neurocognitive mechanisms (TED and TESS). It is argued that the empathizing model is more comprehensive because it entails perception, interpretation, and affective responses to other agents. Sex differences in empathy (female advantage) are then reviewed, as a clear example of individual differences in empathy. This leads into an illustration of individual differences using the Empathy Quotient (EQ). Finally, the neuroimaging literature in relation to each of the neurocognitive mechanisms is briefly summarized and a new study is described that tests if different brain regions respond to the perception of different facial expressions of emotion, as a function of the observer's EQ

Leiberg, S. & Anders, S. (2006). The multiple facets of empathy: a survey of theory and evidence. Prog.Brain Res., 156, 419-440.
Notes: Institute of Medical Psychology and Behavioral Neurobiology, University of Tubingen, Tubingen, Germany.
Empathy is the ability to perceive and understand other people's emotions and to react appropriately. This ability is a necessary prerequisite for successful interpersonal interaction. Empathy is a multifaceted construct including low-level mechanisms like emotional contagion as well as high-level processes like perspective-taking. The ability to empathize varies between individuals and is considered a stable personality trait: some people are generally more successful in empathizing than others. In this chapter we will first present different conceptualizations of the construct of empathy, and refer to empathy-regulating processes as well as to the relationship between empathy and social behavior. Then, we will review peripheral physiological and brain imaging studies pertaining to low- and high-level empathic processes, empathy-modulating processes, and the link between empathy and social behavior. Further, we will present evidence regarding interindividual differences in these processes as an important source of information for solving the conundrum of how the comprehension of others' emotions is achieved by our brains

Hennenlotter, A. & Schroeder, U. (2006). Partly dissociable neural substrates for recognizing basic emotions: a critical review. Prog.Brain Res., 156, 443-456.
Notes: Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1A, D-04103 Leipzig, Germany.
Facial expressions are powerful non-verbal displays of emotion which signal valence information to others and constitute an important communicative element in social interaction. Six basic emotional expressions (fear, disgust, anger, surprise, happiness, and sadness) have been shown to be universal in their performance and perception. Recently, a growing number of clinical and functional imaging studies have aimed at identifying partly dissociable neural subsystems for recognizing basic emotions. Convincing results have been obtained for fearful and disgusted facial expressions only. Empirical evidence for a specialized neural representation of anger, surprise, sadness, or happiness is more limited, primarily due to lack of clinical cases with selective impairments in recognizing these emotions. In functional imaging research, the detection of dissociable neural responses requires direct comparisons of signal changes associated with the perception of different emotions, which are often not provided. Only recently has evidence been obtained that the recruitment of emotion-specific neural subsystems may be closely linked to characteristic facial features of single expressions such as the eye region for fearful faces. Investigations into the neural systems underlying the processing of such diagnostic cues for each of the six basic emotions may be helpful to further elucidate their neural representation

Sommer, M., Hajak, G., Dohnel, K., Schwerdtner, J., Meinhardt, J., & Muller, J. L. (2006). Integration of emotion and cognition in patients with psychopathy. Prog.Brain Res., 156, 457-466.
Notes: Department of Psychiatry, Psychotherapy and Psychosomatic, University of Regensburg, Universitatsstrasse 84, D-93053 Regensburg, Germany.
Psychopathy is a personality disorder associated with emotional characteristics like impulsivity, manipulativeness, affective shallowness, and absence of remorse or empathy. The impaired emotional responsiveness is considered to be the hallmark of the disorder. There are two theories that attempt to explain the emotional dysfunction and the poor socialization in psychopathy: (1) the low-fear model and (2) the inhibition of violence model. Both approaches are supported by several studies. Studies using aversive conditioning or the startle modulation underline the severe difficulties in processing negative stimuli in psychopaths. Studies that explore the processing of emotional expressions show a deficit of psychopathic individuals for processing sad or fearful facial expressions or vocal affect. In the cognitive domain, psychopaths show performance deficits in the interpretation of the motivational significance of stimuli. Studies investigating the impact of emotions on cognitive processes show that in psychopaths in contrast to healthy controls negative emotions drain no resources from a cognitive task. It is suggested that dysfunctions in the frontal cortex, especially the orbitofrontal cortex, the cingulate cortex and the amygdala are associated with the emotional and cognitive impairments

Kucharska-Pietura, K. (2006). Disordered emotional processing in schizophrenia and one-sided brain damage. Prog.Brain Res., 156, 467-479.
Notes: Whitchurch Hospital, Cardiff and Vale NHS Trust, Cardiff CF 14 7XB, UK.
The work concentrates on the problem of human emotions in healthy and pathologically changed brains, mainly in persons afflicted with schizophrenia or with organic impairments localized in one of the cerebral hemispheres. This chapter presents the state of current knowledge concerning the hemispheric lateralization of emotions among healthy people, psychiatric patients, and patients with one-sided brain lesion, on the basis of clinical observations, the results of experimental work, and the newest neuroimaging techniques. The numerous experiments and scientific methods used to assess the hemispheric lateralization of emotions and the discrepancies in their results point toward a lack of consistent theory in the field of hemispheric specialization in the regulation of emotional processes. Particular scientific interest was taken in the emotions of persons afflicted with schizophrenia, either in its early or late stages. This was inspired by the emotional behavior of schizophrenic patients on a psychiatric ward and their ability to perceive and express emotions during various stages of the schizophrenic process. In order to examine the cerebral manifestations of emotional deficits and the specialization of cerebral hemispheres for emotional processes, the author has described the emotional behavior of patients with unilateral cerebral stroke, i.e., patients with damage to the right or left cerebral hemisphere. Overall, the inferior performance of emotional tasks by right-hemisphere-damaged patients compared to other groups might support right-hemisphere superiority for affect perception despite variations in the stimuli used

Ende, G., Demirakca, T., & Tost, H. (2006). The biochemistry of dysfunctional emotions: proton MR spectroscopic findings in major depressive disorder. Prog.Brain Res., 156, 481-501.
Notes: NMR Research in Psychiatry, Central Institute of Mental Health, J5, 68159 Mannheim, Germany.
Key neural systems involved in the processing and communication of emotions are impaired in patients with major depressive disorder (MDD). Emotional and behavioral symptoms are thought to be caused by damage or dysfunction in specific areas of the brain that are responsible for directing attention, motivating behavior, and learning the significance of environmental stimuli. Functional brain studies with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) give support for functional abnormalities in MDD that are predominantly located in areas known to play an important role in the communication and processing of emotions. Disturbances in emotional processing as they are observed in MDD, if any, have very subtle morphometrical brain correlates. With proton magnetic resonance spectroscopy (1H MRS), brain metabolites can be measured noninvasively in vivo, thus furthering the understanding of the effects of changes in neurotransmitters within the brain. The current literature on 1H MRS studies in MDD is small with a large diversity of MRS methods applied, brain regions studied, and metabolite changes found. Nevertheless, there is strong evidence that changes in neurometabolite concentrations in MDD occur within brain regions, which are involved in the processing and communication of emotions that can be monitored by 1H MRS. This review summarizes the literature about biochemical changes quantified via 1H MRS in MDD patients in brain regions that play an important role for the communication and processing of emotions