Hemodynamic correlates of emotion regulation in frontal lobe epilepsy patients and healthy participants.

The ability to regulate emotions is indispensable for maintaining psychological health. It heavily relies on frontal lobe functions which are disrupted in frontal lobe epilepsy. Accordingly, emotional dysregulation and use of maladaptive emotion regulation strategies have been reported in frontal lobe epilepsy patients. Therefore, it is of clinical and scientific interest to investigate emotion regulation in frontal lobe epilepsy. We studied neural correlates of upregulating and downregulating emotions toward aversive pictures through reappraisal in 18 frontal lobe epilepsy patients and 17 healthy controls using functional magnetic resonance imaging. Patients tended to report more difficulties with impulse control than controls. On the neural level, patients had diminished activity during upregulation in distributed left-sided regions, including ventrolateral and dorsomedial prefrontal cortex, angular gyrus and anterior temporal gyrus. Patients also showed less activity than controls in the left precuneus for upregulation compared to downregulation. Unlike controls, they displayed no task-related activity changes in the left amygdala, whereas the right amygdala showed task-related modulations in both groups. Upregulation-related activity changes in the left inferior frontal gyrus, insula, orbitofrontal cortex, anterior and posterior cingulate cortex, and precuneus were correlated with questionnaire data on habitual emotion regulation. Our results show that structural or functional impairments in the frontal lobes disrupt neural mechanisms underlying emotion regulation through reappraisal throughout the brain, including posterior regions involved in semantic control. Findings on the amygdala as a major target of emotion regulation are in line with the view that specifically the left amygdala is connected with semantic processing networks.

Effects of left and right medial temporal lobe resections on hemodynamic correlates of negative and neutral scene processing.

Enhanced visual cortex activation by negative compared to neutral stimuli is often attributed to modulating feedback from the amygdala, but evidence from lesion studies is scarce, particularly regarding differential effects of left and right amygdala lesions. Therefore, we compared visual cortex activation by negative and neutral complex scenes in an event-related fMRI study between 40 patients with unilateral temporal lobe resection (TLR; 19 left [lTLR], 21 right [rTLR]), including the amygdala, and 20 healthy controls. We found preserved hemodynamic emotion modulation of visual cortex in rTLR patients and only subtle reductions in lTLR patients. In contrast, rTLR patients showed a significant decrease in visual cortex activation irrespective of picture content. In line with this, healthy controls showed small emotional modulation of the left amygdala only, while their right amygdala was activated equally by negative and neutral pictures. Correlations of activation in amygdala and visual cortex were observed for both negative and neutral pictures in the controls. In both patient groups, this relationship was attenuated ipsilateral to the TLR. Our results support the notion of reentrant mechanisms between amygdala and visual cortex and suggest laterality differences in their emotion-specificity. While right medial temporal lobe structures including the amygdala seem to influence visual processing in general, the left medial temporal lobe appears to contribute specifically to emotion processing. Still, effects of left TLR on visual emotion processing were relatively subtle. Therefore, hemodynamic correlates of visual emotion processing are likely supported by a distributed cerebral network, challenging an amygdalocentric view of emotion processing.

Negative content enhances stimulus-specific cerebral activity during free viewing of pictures, faces, and words.

Negative visual stimuli have been found to elicit stronger brain activation than do neutral stimuli. Such emotion effects have been shown for pictures, faces, and words alike, but the literature suggests stimulus-specific differences regarding locus and lateralization of the activity. In the current functional magnetic resonance imaging study, we directly compared brain responses to passively viewed negative and neutral pictures of complex scenes, faces, and words (nouns) in 43 healthy participants (21 males) varying in age and demographic background. Both negative pictures and faces activated the extrastriate visual cortices of both hemispheres more strongly than neutral ones, but effects were larger and extended more dorsally for pictures, whereas negative faces additionally activated the superior temporal sulci. Negative words differentially activated typical higher-level language processing areas such as the left inferior frontal and angular gyrus. There were small emotion effects in the amygdala for faces and words, which were both lateralized to the left hemisphere. Although pictures elicited overall the strongest amygdala activity, amygdala response to negative pictures was not significantly stronger than to neutral ones. Across stimulus types, emotion effects converged in the left anterior insula. No gender effects were apparent, but age had a small, stimulus-specific impact on emotion processing. Our study specifies similarities and differences in effects of negative emotional content on the processing of different types of stimuli, indicating that brain response to negative stimuli is specifically enhanced in areas involved in processing of the respective stimulus type in general and converges across stimuli in the left anterior insula.

Perceived communicative context and emotional content amplify visual word processing in the fusiform gyrus.

The personal significance of a language statement depends on its communicative context. However, this is rarely taken into account in neuroscience studies. Here, we investigate how the implied source of single word statements alters their cortical processing. Participants' brain event-related potentials were recorded in response to identical word streams consisting of positive, negative, and neutral trait adjectives stated to either represent personal trait feedback from a human or to be randomly generated by a computer. Results showed a strong impact of perceived sender. Regardless of content, the notion of receiving feedback from a human enhanced all components, starting with the P2 and encompassing early posterior negativity (EPN), P3, and the late positive potential (LPP). Moreover, negative feedback by the "human sender" elicited a larger EPN, whereas positive feedback generally induced a larger LPP. Source estimations revealed differences between "senders" in visual areas, particularly the bilateral fusiform gyri. Likewise, emotional content enhanced activity in these areas. These results specify how even implied sender identity changes the processing of single words in seemingly realistic communicative settings, amplifying their processing in the visual brain. This suggests that the concept of motivated attention extends from stimulus significance to simultaneous appraisal of contextual relevance. Finally, consistent with distinct stages of emotional processing, at least in contexts perceived as social, humans are initially alerted to negative content, but later process what is perceived as positive feedback more intensely.

MRI evidence for material-specific encoding deficits and mesial-temporal alterations in presurgical frontal lobe epilepsy patients.

OBJECTIVE: Neuroimaging studies reveal frontal lobe (FL) contributions to memory encoding. Accordingly, memory impairments are documented in frontal lobe epilepsy (FLE). Still, little is known about the structural or functional correlates of such impairments. Particularly, material specificity of functional changes in cerebral activity during memory encoding in FLE is unclear. METHODS: We compared 24 FLE patients (15 right-sided) undergoing presurgical evaluation with 30 healthy controls on a memory fMRI-paradigm of learning scenes, faces, and words followed by an out-of-scanner recognition task as well as regarding their mesial temporal lobe (mTL) volumes. We also addressed effects of FLE lateralization and performance level (normal vs. low). RESULTS: FLE patients had poorer memory performance and larger left hippocampal volumes than controls. Volume increase seemed, however, irrelevant or even dysfunctional for memory performance. Further, functional changes in FLE patients were right-sided for scenes and faces and bilateral for words. In detail, during face encoding, FLE patients had, regardless of their performance level, decreased mTL activation, while during scene and word encoding only low performing FLE patients had decreased mTL along with decreased FL activation. Intact verbal memory performance was associated with higher right frontal activation in FLE patients but not in controls. SIGNIFICANCE: Pharmacoresistant FLE has a distinct functional and structural impact on the mTL. Effects vary with the encoded material and patients' performance levels. Thus, in addition to the direct effect of the FL, memory impairment in FLE is presumably to a large part due to functional mTL changes triggered by disrupted FL networks. PLAIN LANGUAGE SUMMARY: Frontal lobe epilepsy (FLE) patients may suffer from memory impairment. Therefore, we asked patients to perform a memory task while their brain was scanned by MRI in order to investigate possible changes in brain activation during learning. FLE patients showed changes in brain activation during learning and also structural changes in the mesial temporal lobe, which is a brain region especially relevant for learning but not the origin of the seizures in FLE. We conclude that FLE leads to widespread changes that contribute to FLE patients' memory impairment.

Automated tractography of the cingulate bundle in Alzheimer's disease: a multicenter DTI study.

PURPOSE: To evaluate the feasibility of multicenter tractography of the cingulate bundle (CB) in Alzheimer's disease (AD). MATERIALS AND METHODS: Automated deterministic tractography of the CB was applied to scans of 45 patients with probable AD and 58 healthy controls (HC) acquired with Siemens Sonata (1.5T; 60 gradients), Trio (3T; 61 gradients), and Avanto (1.5T; 30 gradients). Diagnosis and center effects on the tracking indices fractional anisotropy (FA), mean diffusivity (MD), track density, and volume were estimated with analysis of variance. RESULTS: The multicenter coefficients of variance (CVs) in HC and AD patients were 7% and 7% for FA, 10% and 8% for MD, 18% and 20% for density, and 21% and 21% for volume. Multicenter and single-center CVs were within a similar range. Significant center effects declined in the order MD > FA > density > volume. After adjustment for center and age, the AD group showed significantly higher MD (P < 0.001) and lower FA (P < 0.05) as compared with the HC group. CONCLUSION: Despite strong center effects, we detected significantly altered microstructural integrity of the CB in AD patients. Diffusion-tensor imaging indices of the CB as obtained by automated tractography might qualify as a biologically sustained surrogate marker for diagnostic and monitoring purposes in multicenter AD trials.

Intra- and inter-cortical motor excitability in Alzheimer's disease.

Transcranial magnetic stimulation (TMS) provides evidence for facilitatory and inhibitory motor dysfunctions in Alzheimer's disease (AD). The corpus callosum (CC) is affected in AD already at early stages consistent with the hypothesis that AD patients exhibit alterations in transcallosally mediated motor inhibition (ipsilateral silent period, iSP). Therefore, here we aimed at investigating the integrity not only of intra-, but also of inter-hemispheric mechanisms of cortical motor excitability in AD. We determined the iSP, the resting motor threshold (RMT), and the amplitude of motor evoked potentials (MEP) in 19 AD patients and 19 healthy controls using single-pulse TMS. Furthermore, we used paired-pulse TMS to study the intra-cortical inhibition (ICI) and intra-cortical facilitation (ICF). All subjects underwent comprehensive neuropsychologic, clinical, and laboratory testing, and neuroimaging to exclude significant co-morbidity. In AD patients, the RMT was significantly reduced (Oneway-ANOVA). An analysis of covariance (ANCOVA) revealed a strong group specific interaction of the inhibitory interstimulus intervals (p = 0.005) with a reduced ICI in AD. Furthermore, we found a significantly prolonged iSP-latency (p = 0.003) in AD compared to controls, whereas the iSP-duration was not different. The iSP-latency correlated significantly with the ICI (ANCOVA) (p = 0.02). The ICF did not differ significantly between groups. Our data suggest comprehensive but still subclinical dysfunctions of motor cortical inhibition in mild to moderate clinical stages of AD with strong interactions of intra- and inter-hemispheric inhibitory phenomena. Future studies are needed to show the potential prognostic relevance of these findings for the further course of the disease.

Face processing and efficient recognition of facial expressions are impaired following right but not left anteromedial temporal lobe resections: Behavioral and fMRI evidence.

Anteromedial temporal lobe structures seem to support processing of faces and facial expressions. However, differential effects of unilateral left or right temporal lobe resections (TLR) on face processing, recognition of facial expressions, and on BOLD response to faces in intact brain areas are not yet fully understood. Therefore, we compared 39 patients with unilateral TLR (18 left, 21 right) and 20 healthy controls regarding recognition of facial identity and emotional facial expressions as well as BOLD response to fearful and neutral faces. We found impaired recognition of facial identity following right TLR, which was paralleled by reduced BOLD response to faces irrespective of expression in the right fusiform and lingual gyrus in postsurgical fMRI. Right TLR patients also exhibited subtle impairments of emotion recognition as they needed higher intensity of facial expressions for correct responses in a morphing task. Accuracy of emotion recognition and subjective appraisals of facial expressions did not differ between groups. There was no specific reduction of BOLD response to fearful versus neutral faces in either patient group. Our results underline the specific role of the right anteromedial temporal lobe in processing of faces and facial expressions by showing changes in face processing following right TLR in behavioral as well as imaging data.

Whole-brain functional correlates of memory formation in mesial temporal lobe epilepsy.

The mesial temporal lobe is a key region for episodic memory. Accordingly, memory impairment is frequent in patients with mesial temporal lobe epilepsy. However, the functional relevance of potentially epilepsy-induced reorganisation for memory formation is still not entirely clear. Therefore, we investigated whole-brain functional correlates of verbal and non-verbal memory encoding and subsequent memory formation in 56 (25 right sided) mesial temporal lobe epilepsy patients and 21 controls. We applied an fMRI task of learning scenes, faces, and words followed by an out-of-scanner recognition test. During encoding of faces and scenes left and right mesial temporal lobe epilepsy patients had consistently reduced activation in the epileptogenic mesial temporal lobe compared with controls. Activation increases in patients were apparent in extra-temporal regions, partly associated with subsequent memory formation (left frontal regions and basal ganglia), and patients had less deactivation in regions often linked to the default mode and auditory networks. The more specific subsequent memory contrast indicated only marginal group differences. Correlating patients' encoding activation with memory performance both within the paradigm and with independent clinical measures demonstrated predominantly increased contralateral mesio-temporal activation supporting intact memory performance. In left temporal lobe epilepsy patients, left frontal activation was also correlated with better verbal memory performance. Taken together, our findings hint towards minor extra-temporal plasticity in mesial temporal lobe epilepsy patients, which is in line with pre-surgical impairment and post-surgical memory decline in many patients. Further, data underscore the importance of particularly the contralateral mesial temporal lobe itself, to maintain intact memory performance.

Practice effects in healthy adults: a longitudinal study on frequent repetitive cognitive testing.

BACKGROUND: Cognitive deterioration is a core symptom of many neuropsychiatric disorders and target of increasing significance for novel treatment strategies. Hence, its reliable capture in long-term follow-up studies is prerequisite for recording the natural course of diseases and for estimating potential benefits of therapeutic interventions. Since repeated neuropsychological testing is required for respective longitudinal study designs, occurrence, time pattern and magnitude of practice effects on cognition have to be understood first under healthy good-performance conditions to enable design optimization and result interpretation in disease trials. METHODS: Healthy adults (N = 36; 47.3 ± 12.0 years; mean IQ 127.0 ± 14.1; 58% males) completed 7 testing sessions, distributed asymmetrically from high to low frequency, over 1 year (baseline, weeks 2-3, 6, 9, months 3, 6, 12). The neuropsychological test battery covered 6 major cognitive domains by several well-established tests each. RESULTS: Most tests exhibited a similar pattern upon repetition: (1) Clinically relevant practice effects during high-frequency testing until month 3 (Cohen's d 0.36-1.19), most pronounced early on, and (2) a performance plateau thereafter upon low-frequency testing. Few tests were non-susceptible to practice or limited by ceiling effects. Influence of confounding variables (age, IQ, personality) was minor. CONCLUSIONS: Practice effects are prominent particularly in the early phase of high-frequency repetitive cognitive testing of healthy well-performing subjects. An optimal combination and timing of tests, as extractable from this study, will aid in controlling their impact. Moreover, normative data for serial testing may now be collected to assess normal learning curves as important comparative readout of pathological cognitive processes.

Recombinant human erythropoietin in the treatment of acute ischemic stroke.

BACKGROUND AND PURPOSE: Numerous preclinical findings and a clinical pilot study suggest that recombinant human erythropoietin (EPO) provides neuroprotection that may be beneficial for the treatment of patients with ischemic stroke. Although EPO has been considered to be a safe and well-tolerated drug over 2 decades, recent studies have identified increased thromboembolic complications and/or mortality risks on EPO administration to patients with cancer or chronic kidney disease. Accordingly, the double-blind, placebo-controlled, randomized German Multicenter EPO Stroke Trial (Phase II/III; ClinicalTrials.gov Identifier: NCT00604630) was designed to evaluate efficacy and safety of EPO in stroke. METHODS: This clinical trial enrolled 522 patients with acute ischemic stroke in the middle cerebral artery territory (intent-to-treat population) with 460 patients treated as planned (per-protocol population). Within 6 hours of symptom onset, at 24 and 48 hours, EPO was infused intravenously (40,000 IU each). Systemic thrombolysis with recombinant tissue plasminogen activator was allowed and stratified for. RESULTS: Unexpectedly, a very high number of patients received recombinant tissue plasminogen activator (63.4%). On analysis of total intent-to-treat and per-protocol populations, neither primary outcome Barthel Index on Day 90 (P=0.45) nor any of the other outcome parameters showed favorable effects of EPO. There was an overall death rate of 16.4% (n=42 of 256) in the EPO and 9.0% (n=24 of 266) in the placebo group (OR, 1.98; 95% CI, 1.16 to 3.38; P=0.01) without any particular mechanism of death unexpected after stroke. CONCLUSIONS: Based on analysis of total intent-to-treat and per-protocol populations only, this is a negative trial that also raises safety concerns, particularly in patients receiving systemic thrombolysis.

Quantifying the Confidence in fMRI-Based Language Lateralisation Through Laterality Index Deconstruction.

In epilepsy patients, language lateralisation is an important part of the presurgical diagnostic process. Using task-based fMRI, language lateralisation can be determined by visual inspection of activity patterns or by quantifying the difference in left- and right-hemisphere activity using variations of a basic formula [(L-R)/(L+R)]. However, the values of this laterality index (LI) depend on the choice of activity thresholds and regions of interest. The diagnostic utility of the LI also depends on how its continuous values are translated into categorical decisions about a patient's language lateralisation. Here, we analysed fMRI data from 712 epilepsy patients who performed a verbal fluency task. Each fMRI data set was evaluated by a trained human rater as depicting left-sided, right-sided, or bilateral lateralisation or as being inconclusive. We used data-driven methods to define the activity thresholds and regions of interest used for LI computation and to define a classification scheme that allowed us to translate the LI values into categorical decisions. By deconstructing the LI into measures of laterality (L-R) and strength (L+R), we also modelled the relationship between activation strength and conclusiveness of a data set. In a held-out data set, predictions reached 91% correct when using only conclusive data and 82% when inconclusive data were included. Although only trained on human evaluations of fMRIs, the approach generalised to the prediction of language Wada test results, allowing for significant above-chance accuracies. Compared against different existing methods of LI-computation, our approach improved the identification and exclusion of inconclusive cases and ensured that decisions for the remaining data could be made with consistently high accuracies. We discuss how this approach can support clinicians in assessing fMRI data on a single-case level, deciding whether lateralisation can be determined with sufficient certainty or whether additional information is needed.

The hidden identity of faces: a case of lifelong prosopagnosia.

BACKGROUND: Not being able to recognize a person's face is a highly debilitating condition from which people with developmental prosopagnosia (DP) suffer their entire life. Here we describe the case of J, a 30 year old woman who reports being unable to recognize her parents, her husband, or herself in the mirror. CASE PRESENTATION: We set out to assess the severity of J's prosopagnosia using tests with unfamiliar as well as familiar faces and investigated whether impaired configural processing explains her deficit. To assess the specificity of the impairment, we tested J's performance when evaluating emotions, intentions, and the attractiveness and likability of faces. Detailed testing revealed typical brain activity patterns for faces and normal object recognition skills, and no evidence of any brain injury. However, compared to a group of matched controls, J showed severe deficits in learning new faces, and in recognizing familiar faces when only inner features were available. Her recognition of uncropped faces with blurred features was within the normal range, indicating preserved configural processing when peripheral features are available. J was also unimpaired when evaluating intentions and emotions in faces. In line with healthy controls, J rated more average faces as more attractive. However, she was the only one to rate them as less likable, indicating a preference for more distinctive and easier to recognize faces. CONCLUSIONS: Taken together, the results illustrate both the severity and the specificity of DP in a single case. While DP is a heterogeneous disorder, an inability to integrate the inner features of the face into a whole might be the best explanation for the difficulties many individuals with prosopagnosia experience.

Thought experiment: Decoding cognitive processes from the fMRI data of one individual.

Cognitive processes, such as the generation of language, can be mapped onto the brain using fMRI. These maps can in turn be used for decoding the respective processes from the brain activation patterns. Given individual variations in brain anatomy and organization, analyzes on the level of the single person are important to improve our understanding of how cognitive processes correspond to patterns of brain activity. They also allow to advance clinical applications of fMRI, because in the clinical setting making diagnoses for single cases is imperative. In the present study, we used mental imagery tasks to investigate language production, motor functions, visuo-spatial memory, face processing, and resting-state activity in a single person. Analysis methods were based on similarity metrics, including correlations between training and test data, as well as correlations with maps from the NeuroSynth meta-analysis. The goal was to make accurate predictions regarding the cognitive domain (e.g. language) and the specific content (e.g. animal names) of single 30-second blocks. Four teams used the dataset, each blinded regarding the true labels of the test data. Results showed that the similarity metrics allowed to reach the highest degrees of accuracy when predicting the cognitive domain of a block. Overall, 23 of the 25 test blocks could be correctly predicted by three of the four teams. Excluding the unspecific rest condition, up to 10 out of 20 blocks could be successfully decoded regarding their specific content. The study shows how the information contained in a single fMRI session and in each of its single blocks can allow to draw inferences about the cognitive processes an individual engaged in. Simple methods like correlations between blocks of fMRI data can serve as highly reliable approaches for cognitive decoding. We discuss the implications of our results in the context of clinical fMRI applications, with a focus on how decoding can support functional localization.

In your face: the biased judgement of fear-anger expressions in violent offenders.

BACKGROUND: Why is it that certain violent criminals repeatedly find themselves engaged in brawls? Many inmates report having felt provoked or threatened by their victims, which might be due to a tendency to ascribe malicious intentions when faced with ambiguous social signals, termed hostile attribution bias. METHODS: The present study presented morphed fear-anger faces to prison inmates with a history of violent crimes, a history of child sexual abuse, and to matched controls form the general population. Participants performed a fear-anger decision task. Analyses compared both response frequencies and measures derived from psychophysical functions fitted to the data. In addition, a test to distinguish basic facial expressions and questionnaires for aggression, psychopathy and personality disorders were administered. RESULTS: Violent offenders present with a reliable hostile attribution bias, in that they rate ambiguous fear-anger expressions as more angry, compared to both the control population and perpetrators of child sexual abuse. Psychometric functions show a lowered threshold to detect anger in violent offenders compared to the general population. This effect is especially pronounced for male faces, correlates with self-reported aggression and presents in absence of a general emotion recognition impairment. CONCLUSIONS: The results indicate that a hostile attribution, related to individual level of aggression and pronounced for male faces, might be one mechanism mediating physical violence.

Mapping the emotional face. How individual face parts contribute to successful emotion recognition.

Which facial features allow human observers to successfully recognize expressions of emotion? While the eyes and mouth have been frequently shown to be of high importance, research on facial action units has made more precise predictions about the areas involved in displaying each emotion. The present research investigated on a fine-grained level, which physical features are most relied on when decoding facial expressions. In the experiment, individual faces expressing the basic emotions according to Ekman were hidden behind a mask of 48 tiles, which was sequentially uncovered. Participants were instructed to stop the sequence as soon as they recognized the facial expression and assign it the correct label. For each part of the face, its contribution to successful recognition was computed, allowing to visualize the importance of different face areas for each expression. Overall, observers were mostly relying on the eye and mouth regions when successfully recognizing an emotion. Furthermore, the difference in the importance of eyes and mouth allowed to group the expressions in a continuous space, ranging from sadness and fear (reliance on the eyes) to disgust and happiness (mouth). The face parts with highest diagnostic value for expression identification were typically located in areas corresponding to action units from the facial action coding system. A similarity analysis of the usefulness of different face parts for expression recognition demonstrated that faces cluster according to the emotion they express, rather than by low-level physical features. Also, expressions relying more on the eyes or mouth region were in close proximity in the constructed similarity space. These analyses help to better understand how human observers process expressions of emotion, by delineating the mapping from facial features to psychological representation.

Auditory attention enhances processing of positive and negative words in inferior and superior prefrontal cortex.

Visually presented emotional words are processed preferentially and effects of emotional content are similar to those of explicit attention deployment in that both amplify visual processing. However, auditory processing of emotional words is less well characterized and interactions between emotional content and task-induced attention have not been fully understood. Here, we investigate auditory processing of emotional words, focussing on how auditory attention to positive and negative words impacts their cerebral processing. A Functional magnetic resonance imaging (fMRI) study manipulating word valence and attention allocation was performed. Participants heard negative, positive and neutral words to which they either listened passively or attended by counting negative or positive words, respectively. Regardless of valence, active processing compared to passive listening increased activity in primary auditory cortex, left intraparietal sulcus, and right superior frontal gyrus (SFG). The attended valence elicited stronger activity in left inferior frontal gyrus (IFG) and left SFG, in line with these regions' role in semantic retrieval and evaluative processing. No evidence for valence-specific attentional modulation in auditory regions or distinct valence-specific regional activations (i.e., negative > positive or positive > negative) was obtained. Thus, allocation of auditory attention to positive and negative words can substantially increase their processing in higher-order language and evaluative brain areas without modulating early stages of auditory processing. Inferior and superior frontal brain structures mediate interactions between emotional content, attention, and working memory when prosodically neutral speech is processed.

Categorical Perception of Fear and Anger Expressions in Whole, Masked and Composite Faces.

Human observers are remarkably proficient at recognizing expressions of emotions and at readily grouping them into distinct categories. When morphing one facial expression into another, the linear changes in low-level features are insufficient to describe the changes in perception, which instead follow an s-shaped function. Important questions are, whether there are single diagnostic regions in the face that drive categorical perception for certain parings of emotion expressions, and how information in those regions interacts when presented together. We report results from two experiments with morphed fear-anger expressions, where (a) half of the face was masked or (b) composite faces made up of different expressions were presented. When isolated upper and lower halves of faces were shown, the eyes were found to be almost as diagnostic as the whole face, with the response function showing a steep category boundary. In contrast, the mouth allowed for a substantially lesser amount of accuracy and responses followed a much flatter psychometric function. When a composite face consisting of mismatched upper and lower halves was used and observers were instructed to exclusively judge either the expression of mouth or eyes, the to-be-ignored part always influenced perception of the target region. In line with experiment 1, the eye region exerted a much stronger influence on mouth judgements than vice versa. Again, categorical perception was significantly more pronounced for upper halves of faces. The present study shows that identification of fear and anger in morphed faces relies heavily on information from the upper half of the face, most likely the eye region. Categorical perception is possible when only the upper face half is present, but compromised when only the lower part is shown. Moreover, observers tend to integrate all available features of a face, even when trying to focus on only one part.

Investigating the brain basis of facial expression perception using multi-voxel pattern analysis.

Humans can readily decode emotion expressions from faces and perceive them in a categorical manner. The model by Haxby and colleagues proposes a number of different brain regions with each taking over specific roles in face processing. One key question is how these regions directly compare to one another in successfully discriminating between various emotional facial expressions. To address this issue, we compared the predictive accuracy of all key regions from the Haxby model using multi-voxel pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) data. Regions of interest were extracted using independent meta-analytical data. Participants viewed four classes of facial expressions (happy, angry, fearful and neutral) in an event-related fMRI design, while performing an orthogonal gender recognition task. Activity in all regions allowed for robust above-chance predictions. When directly comparing the regions to one another, fusiform gyrus and superior temporal sulcus (STS) showed highest accuracies. These results underscore the role of the fusiform gyrus as a key region in perception of facial expressions, alongside STS. The study suggests the need for further specification of the relative role of the various brain areas involved in the perception of facial expression. Face processing appears to rely on more interactive and functionally overlapping neural mechanisms than previously conceptualised.

It's all in your head - how anticipating evaluation affects the processing of emotional trait adjectives.

Language has an intrinsically evaluative and communicative function. Words can serve to describe emotional traits and states in others and communicate evaluations. Using electroencephalography (EEG), we investigate how the cerebral processing of emotional trait adjectives is modulated by their perceived communicative sender in anticipation of an evaluation. 16 students were videotaped while they described themselves. They were told that a stranger would evaluate their personality based on this recording by endorsing trait adjectives. In a control condition a computer program supposedly randomly selected the adjectives. Actually, both conditions were random. A larger parietal N1 was found for adjectives in the supposedly human-generated condition. This indicates that more visual attention is allocated to the presented adjectives when putatively interacting with a human. Between 400 and 700 ms a fronto-central main effect of emotion was found. Positive, and in tendency also negative adjectives, led to a larger late positive potential (LPP) compared to neutral adjectives. A centro-parietal interaction in the LPP-window was due to larger LPP amplitudes for negative compared to neutral adjectives within the 'human sender' condition. Larger LPP amplitudes are related to stimulus elaboration and memory consolidation. Participants responded more to emotional content particularly when presented in a meaningful 'human' context. This was first observed in the early posterior negativity window (210-260 ms). But the significant interaction between sender and emotion reached only trend-level on post hoc tests. Our results specify differential effects of even implied communicative partners on emotional language processing. They show that anticipating evaluation by a communicative partner alone is sufficient to increase the relevance of particularly emotional adjectives, given a seemingly realistic interactive setting.