How does the brain mediate interpretation of incongruent auditory emotions? The neural response to prosody in the presence of conflicting lexico‐semantic cues

We frequently encounter conflicting emotion cues. This study examined how the neural response to emotional prosody differed in the presence of congruent and incongruent lexico-semantic cues. Two hypotheses were assessed: (i) decoding emotional prosody with conflicting lexico-semantic cues would activate brain regions associated with cognitive conflict (anterior cingulate and dorsolateral prefrontal cortex) or (ii) the increased attentional load of incongruent cues would modulate the activity of regions that decode emotional prosody (right lateral temporal cortex). While the participants indicated the emotion conveyed by prosody, functional magnetic resonance imaging data were acquired on a 3T scanner using blood oxygenation level-dependent contrast. Using SPM5, the response to congruent cues was contrasted with that to emotional prosody alone, as was the response to incongruent lexico-semantic cues (for the 'cognitive conflict' hypothesis). The right lateral temporal lobe region of interest analyses examined modulation of activity in this brain region between these two contrasts (for the 'prosody cortex' hypothesis). Dorsolateral prefrontal and anterior cingulate cortex activity was not observed, and neither was attentional modulation of activity in right lateral temporal cortex activity. However, decoding emotional prosody with incongruent lexico-semantic cues was strongly associated with left inferior frontal gyrus activity. This specialist form of conflict is therefore not processed by the brain using the same neural resources as non-affective cognitive conflict and neither can it be handled by associated sensory cortex alone. The recruitment of inferior frontal cortex may indicate increased semantic processing demands but other contributory functions of this region should be explored.     

Comprehension of emotional prosody following unilateral hemispheric lesions: processing defect versus distraction defect

Two studies were conducted in order to determine whether the poor performance of RHD patients on emotional prosody tasks could be attributed to a defect in perceiving/categorizing emotional prosody (processing defect) or to a problem in being distracted by the semantic content of affectively intoned sentences (distraction defect). In one study, patients with RHD, LHD or NHD listened to affectively intoned sentences in which the semantic content was congruent or incongruent with the emotional prosody. In a second study, the patients listened to affectively intoned sentences that had been speech filtered or unfiltered. Findings from these studies indicate that both processing and distraction defects are present in RHD patients.     

Impaired processing of affective prosody in Korsakoff's syndrome

In order to further characterize reported deficits in affect perception in alcoholic Korsakoff patients, selected prosody subtests from the Tübingen Affect Battery were administered to seven Korsakoff patients and seven normal control participants. Results indicated that both linguistic and affective prosody discrimination were intact in Korsakoff patients. As well, affective prosody identification was unimpaired when the semantic content of the sentence was emotionally congruent with affective prosody. In contrast, affective prosody identification was significantly impaired when the semantic content was either neutral or incongruent with prosody. These results suggest that Korsakoff patients are impaired in interpreting the meaning of affective prosody in the absence of semantic cues as to the emotional content of sentences.     

ERP evidence for a sex-specific Stroop effect in emotional speech

The present study investigated the interaction of emotional prosody and word valence during emotional comprehension in men and women. In a prosody-word interference task, participants listened to positive, neutral, and negative words that were spoken with a happy, neutral, and angry prosody. Participants were asked to rate word valence while ignoring emotional prosody, or vice versa. Congruent stimuli were responded faster and more accurately as compared to incongruent emotional stimuli. This behavioral effect was more salient for the word valence task than for the prosodic task and was comparable between men and women. The event-related potentials (ERPs) revealed a smaller N400 amplitude for congruent as compared to emotionally incongruent stimuli. This ERP effect, however, was significant only for the word valence judgment and only for female listeners. The present data suggest that the word valence judgment was more difficult and more easily influenced by task-irrelevant emotional information than the prosodic task in both men and women. Furthermore, although emotional prosody and word valence may have a similar influence on an emotional judgment in both sexes, ERPs indicate sex differences in the underlying processing. Women, but not men, show an interaction between prosody and word valence during a semantic processing stage.     

The determiner congruency effect in language production investigated with functional MRI

In language production, naming a picture with a gender-marked determiner phrase is faster in the presence of a distractor noun with the same grammatical gender (congruent condition) as compared with a different grammatical gender (incongruent condition). We investigated the neural correlates of this determiner congruency effect in German with functional magnetic resonance imaging (fMRI). Participants named pictures of real objects with determiner phrases (e.g. "der Tisch"-the table) in the presence of a gender-congruent or gender-incongruent distractor noun. Different comparisons allow the following functional segregation within the prefrontal cortex. First, the comparison between picture naming versus rest revealed a steeper slope of the haemodynamic response function (HRF) in the gender-congruent than the gender-incongruent condition in the left BA 44, suggesting the involvement of BA 44 in determiner selection. HRF amplitude differences between the congruent and the incongruent condition were observed outside the language network in the right fronto-median wall (congruent > incongruent), and in the left premotor cortex, middle frontal gyrus, cerebellum, and inferior parietal lobe (incongruent > congruent). The latter regions are known to be involved in the processing of incongruence and conflict in general. The data thus reveal the involvement of the left BA 44 in the selection of determiners for language production.     

Mediotemporal contributions to semantic processing: fMRI evidence from ambiguity processing during semantic context verification

The medial temporal lobe (MTL) is well known to be crucial for various types of memory; however, controversy remains as to which of its substructures contribute to semantic processing and, if so, to what extent. The current study addresses the issue of MTL contributions to semantic processing during lexico-semantic ambiguity processing by using functional magnetic resonance imaging (fMRI) in combination with a context verification task (CVT). The CVT required decisions on the semantic fit of congruent and incongruent target words to the overall meaning of preceding sentential contexts with and without semantic ambiguity. In two of the four experimental conditions (congruent homographic, incongruent homographic), target decisions were critically dependent on the successful processing of prior sentence-final lexico-semantic ambiguity. Semantic context verification per se evidenced bilateral activations of the hippocampus that were part of a functional network including inferior prefrontal and superior parietal cortices. Commonalities in activation differences pertaining to the specific cognitive component of lexico-semantic ambiguity processing were found in a left temporal lobe network that comprised activation foci in the temporal pole, the parahippocampal and fusiform gyri. The present results suggest that the hippocampus may well contribute to semantic processing, namely by a mnemonic function that serves to link the target meaning representation with the meaning of a prior sentence context. Contrary to previous reports from human lesion studies, the present findings further suggest, that the specific cognitive component of lexico-semantic ambiguity processing is neither dependent on the hippocampus nor exclusively subserved by the temporal pole, but also recruits an associative semantic memory function from the parahippocampal gyrus as well as a more general (bottom-up) semantic function from the fusiform gyrus.     

Hemispheric specialisation in processing prosodic structures: Revisited

Background : Research addressing prosodic deficits in brain-damaged populations has concentrated on the specialised capabilities of the right and the left cerebral hemispheres in processing the global characteristics of prosody. This focus has been of interest in that the fundamental frequency (F0), duration and intensity acoustic characteristics within a prosodic structure can convey different linguistic and nonlinguistic information. Much of the research investigating this interesting phenomenon has produced conflicting results. As such, different theories have been proposed in an attempt to provide plausible explanations of the conflicting findings regarding hemispheric specialisation in processing prosodic structures. Aims : The purpose of this study was to examine one of the theories, the functional lateralisation theory, through four experiments that altered the linguistic and nonlinguistic functions across a range of prosodic structures. Methods & Procedures : Three groups of subjects participated in each of the four experiments: (1) eight subjects with LHD, (2) eight subjects with RHD, and (3) eight control subjects. The first experiment addressed the extent to which the processing of lexical stress differences would be lateralised to the left or right hemisphere by requiring listeners to determine the meanings and grammatical assignments of two-syllable words conveyed through stressed or unstressed syllables. In another linguistic condition, the second experiment placed demands on syntactic parsing operations by requiring listeners to parse syntactically ambiguous sentences which were disambiguated through the perception of prosodic boundaries located at syntactic junctures. A third linguistic condition required listeners to determine the categorical assignment of a speaker's intention of making a statement or asking a question conveyed through the prosodic structures. The fourth experiment was designed to determine hemispheric lateralisation in processing nonlinguistic prosodic structures. In this experiment, listeners were required to determine the emotional state of a speaker conveyed through the prosodic structures in sentences that contained semantic information which was either congruent or incongruent with the emotional content of the prosodic structures. Results : When subjects were asked to identify lexical stress differences (Experiment 1), syntactically ambiguous sentences (Experiment 2), and questions and statements (Experiment 3) conveyed through prosody, the LHD group demonstrated a significantly poorer performance than the control and RHD groups. When asked to identify emotions conveyed through prosody (Experiment 4), the RHD group demonstrated a significantly poorer performance than the control and LHD groups. Conclusion : These findings support the functional lateralisation theory that proposes a left hemisphere dominance for processing linguistic prosodic structures and a right hemisphere dominance for processing nonlinguistic prosodic structures.     

The contribution of semantic memory to the recognition of basic emotions and emotional valence: Evidence from the semantic variant of primary progressive aphasia

ABSTRACT

There is compelling evidence that semantic memory is involved in emotion recognition. However, its contribution to the recognition of emotional valence and basic emotions remains unclear. We compared the performance of 10 participants with the semantic variant of primary progressive aphasia (svPPA), a clinical model of semantic memory impairment, to that of 33 healthy participants using three experimental tasks assessing the recognition of: 1) emotional valence conveyed by photographic scenes, 2) basic emotions conveyed by facial expressions, and 3) basic emotions conveyed by prosody sounds. Individuals with svPPA showed significant deficits in the recognition of emotional valence and basic emotions (except happiness and surprise conveyed by facial expressions). However, the performance of the two groups was comparable when the performance on tests assessing semantic memory was added as a covariate in the analyses. Altogether, these results suggest that semantic memory contributes to the recognition of emotional valence and basic emotions. By examining the recognition of emotional valence and basic emotions in individuals with selective semantic memory loss, our results contribute to the refinement of current theories on the role of semantic memory in emotion recognition.     

Syntactic and semantic modulation of neural activity during auditory sentence comprehension

In previous functional neuroimaging studies, left anterior temporal and temporal-parietal areas responded more strongly to sentences than to randomly ordered lists of words. The smaller response for word lists could be explained by either (1) less activation of syntactic processes due to the absence of syntactic structure in the random word lists or (2) less activation of semantic processes resulting from failure to combine the content words into a global meaning. To test these two explanations, we conducted a functional magnetic resonance imaging study in which word order and combinatorial word meaning were independently manipulated during auditory comprehension. Subjects heard six different stimuli: normal sentences, semantically incongruent sentences in which content words were randomly replaced with other content words, pseudoword sentences, and versions of these three sentence types in which word order was randomized to remove syntactic structure. Effects of syntactic structure (greater activation to sentences than to word lists) were observed in the left anterior superior temporal sulcus and left angular gyrus. Semantic effects (greater activation to semantically congruent stimuli than either incongruent or pseudoword stimuli) were seen in widespread, bilateral temporal lobe areas and the angular gyrus. Of the two regions that responded to syntactic structure, the angular gyrus showed a greater response to semantic structure, suggesting that reduced activation for word lists in this area is related to a disruption in semantic processing. The anterior temporal lobe, on the other hand, was relatively insensitive to manipulations of semantic structure, suggesting that syntactic information plays a greater role in driving activation in this area.     

Effects of Prosodic and Semantic Cues on Facial Emotion Recognition in Relation to Autism-Like Traits

The current study investigated whether those with higher levels of autism-like traits process emotional information from speech differently to those with lower levels of autism-like traits. Neurotypical adults completed the autism-spectrum quotient and an emotional priming task. Vocal primes with varied emotional prosody, semantics, or a combination, preceded emotional target faces. Prime-target pairs were congruent or incongruent in their emotional content. Overall, congruency effects were found for combined prosody-semantic primes, however no congruency effects were found for semantic or prosodic primes alone. Further, those with higher levels of autism-like traits were not influenced by the prime stimuli. These results suggest that failure to integrate emotional information across modalities may be characteristic of the broader autism phenotype.     

Hemispheric dominance for emotions, empathy and social behaviour: evidence from right and left handers with frontotemporal dementia

Although evidence from primates suggests an important role for the anterior temporal cortex in social behaviour, human research has to date concentrated almost solely on the orbitofrontal cortex and amygdala. By describing four cases of the temporal variant of frontotemporal dementia we show how this degenerative condition provides an excellent model for investigating the role of the anterior temporal lobe, especially the right, in emotions, empathy and social behaviour. Assessments of semantic memory, processing of emotional facial expression and emotional prosody were made, empathy was measured, and facial expressions of emotion were coded. Of the two right handers described, one subject with predominantly left temporal lobe atrophy had severe semantic impairment but normal performance on all emotional tasks. In contrast, the subject with right temporal lobe atrophy showed severely impaired recognition of emotion from faces and voices that was not due to semantic or perceptual difficulties. Empathy was lost, interpersonal skills were severely affected and facial expression of emotion was characterized by a fixed expression that was unresponsive to situations. Additionally, two left handers with right temporal lobe atrophy are described. One demonstrated the same pattern of hemispheric lateralization as the right handers and had emotional impairment. The other left hander showed the opposite pattern of deficits, suggesting a novel presentation of anomalous dominance with reversed hemispheric specialization of semantic memory and emotional processing.     

汉语单字词音、义加工的脑激活模式

目的：研究汉字音、义加工的脑机制。方法：采用汉字单字词为实验材料，通过功能磁共振成像扫描执行语音和语义两种认知任务的脑区。结果：语音任务激活的脑区有，左侧顶叶下部和颞上回(BA 40／39／22，BA：Brodmann Area，即布鲁德曼分区，下同)，左侧枕中回(BA18／19)，右侧枕下回(BA18／19)，以及左中央前回(BA6)。语义任务激活的脑区有，左侧顶叶下部(BA40／39)和左侧颞上回(BA22)，左侧额下回(BA10／47)，右侧额中回和额上回(BA10／11)，以及左侧额中回(BA11)。语义任务减去语音任务激活的脑区有，左侧额下回(BA47)，左侧海马(BA36)和右侧海马旁回(BA36)。语音任务减去语义任务没有发现任何脑区的显著激活。结论：在语义任务中与语音有关的脑区得到激活；而在语音任务中与语义有关的脑区没有激活。     

First-pass selectivity for semantic categories in human anteroventral temporal lobe

How the brain encodes the semantic concepts represented by words is a fundamental question in cognitive neuroscience. Hemodynamic neuroimaging studies have robustly shown that different areas of posteroventral temporal lobe are selectively activated by images of animals versus manmade objects. Selective responses in these areas to words representing animals versus objects are sometimes also seen, but they are task-dependent, suggesting that posteroventral temporal cortex may encode visual categories, while more anterior areas encode semantic categories. Here, using the spatiotemporal resolution provided by intracranial macroelectrode and microelectrode arrays, we report category-selective responses to words representing animals and objects in human anteroventral temporal areas including inferotemporal, perirhinal, and entorhinal cortices. This selectivity generalizes across tasks and sensory modalities, suggesting that it represents abstract lexicosemantic categories. Significant category-specific responses are found in measures sensitive to synaptic activity (local field potentials, high gamma power, current sources and sinks) and unit-firing (multiunit and single-unit activity). Category-selective responses can occur at short latency (as early as 130 ms) in middle cortical layers and thus are extracted in the first pass of activity through the anteroventral temporal lobe. This activation may provide input to posterior areas for iconic representations when required by the task, as well as to the hippocampal formation for categorical encoding and retrieval of memories, and to the amygdala for emotional associations. More generally, these results support models in which the anteroventral temporal lobe plays a primary role in the semantic representation of words.     

APOE ɛ4 constrains engagement of encoding‐related compensatory networks in amnestic mild cognitive impairment

People with amnestic mild cognitive impairment (aMCI), compared to healthy older adults (HO), benefit less from semantic congruent cues during episodic encoding. The presence of the apolipoprotein E (APOE) ?4 makes this congruency benefit smaller, but the neural correlates of this deficit are unknown. Here, we estimated the source generators of EEG oscillatory activity associated with successful encoding of face‐location associations preceded by semantically congruent and incongruent cues in HO (N = 26) and aMCI subjects (N = 34), 16 of which were ?4 carriers (?4⁺) and 18 ?4 noncarriers (?4^?). Source estimation was performed in those spectrotemporal windows where the power of low‐alpha, high‐alpha, and beta oscillatory activity differed either between congruent and incongruent faces or between groups. Differences in high‐alpha and beta‐oscillatory dynamics indicated that aMCI ?4⁺ are unable to activate lateral regions of the temporal lobe involved in associative memory and congruency benefit in HO. Interestingly, and regardless of APOE genotype, aMCI activated additional regions relative to HO, through alpha oscillations. However, only activation in a distributed fronto‐temporo‐parietal network in ?4 noncarriers was paralleled by enhanced memory. On the contrary, the redundant prefrontal activation shown by aMCI ?4⁺ did not prevent performance from decreasing. These results indicate that the effect of aMCI‐related degeneracy on functional networks is constrained by the presence of APOE ?4. Whereas individuals with aMCI ?4^? activate attentional, perceptual and semantic compensatory networks, aMCI ?4⁺ show reduced processing efficiency and capacity. © 2015 Wiley Periodicals, Inc.     

Abnormalities in the processing of emotional prosody from single words in schizophrenia

BackgroundAbnormalities in emotional prosody processing have been consistently reported in schizophrenia and are related to poor social outcomes. However, the role of stimulus complexity in abnormal emotional prosody processing is still unclear.MethodWe recorded event-related potentials in 16 patients with chronic schizophrenia and 16 healthy controls to investigate: 1) the temporal course of emotional prosody processing; and 2) the relative contribution of prosodic and semantic cues in emotional prosody processing. Stimuli were prosodic single words presented in two conditions: with intelligible (semantic content condition—SCC) and unintelligible semantic content (pure prosody condition—PPC).ResultsRelative to healthy controls, schizophrenia patients showed reduced P50 for happy PPC words, and reduced N100 for both neutral and emotional SCC words and for neutral PPC stimuli. Also, increased P200 was observed in schizophrenia for happy prosody in SCC only. Behavioral results revealed higher error rates in schizophrenia for angry prosody in SCC and for happy prosody in PPC.ConclusionsTogether, these data further demonstrate the interactions between abnormal sensory processes and higher-order processes in bringing about emotional prosody processing dysfunction in schizophrenia. They further suggest that impaired emotional prosody processing is dependent on stimulus complexity.     

Fronto-temporal interactions during overt verbal initiation and suppression

The Hayling Sentence Completion Task (HSCT) is known to activate left hemisphere frontal and temporal language regions. However, the effective connectivity between frontal and temporal language regions associated with the task has yet to be examined. The aims of the study were to examine activation and effective connectivity during the HSCT using a functional magnetic resonance imaging (fMRI) paradigm in which participants made overt verbal responses. We predicted that producing an incongruent response (response suppression), compared to a congruent one (response initiation), would be associated with greater activation in the left prefrontal cortex and an increase in the effective connectivity between temporal and frontal regions. Fifteen participants were scanned while completing 80 sentence stems. The congruency and constraint of sentences varied across trials. Dynamic Causal Modeling (DCM) and Bayesian Model Selection (BMS) were used to compare a set of alternative DCMs of fronto-temporal connectivity. The HSCT activated regions in the left temporal and prefrontal cortices, and the cuneus. Response suppression was associated with greater activation in the left middle and orbital frontal gyri and the bilateral precuneus than response initiation. Left middle temporal and frontal regions identified by the conventional fMRI analyses were entered into the DCM analysis. Using a systematic BMS procedure, the optimal DCM showed that the connection from the left middle temporal gyrus, which was driven by verbal stimuli per se, was significantly increased in strength during response suppression compared to initiation. Greater effective connectivity between left temporal and prefrontal regions during response suppression may reflect the transfer of information from posterior temporal regions where semantic and lexical information is stored to prefrontal regions where it is manipulated in preparation for an appropriate response.     

Processing of affective stimuli in alcoholism

Investigations of neuropsychological functioning in alcoholism have revealed executive and memory deficits which have been interpreted in the light of the "frontal lobe hypothesis" which asserts that the frontal lobes are particularly vulnerable to the toxic effects of alcohol. Inspite of the known involvement of the orbitofrontal cortex in the processing of affective stimuli, only few studies concerning affective processing in alcoholism have been conducted so far. Alcoholics and healthy controls were compared by using a comprehensive neuropsychological test battery which included the measurement of facial affect as well as affective prosody perception. Analysis revealed impairments of alcoholics with respect to naming prosody with incongruent semantic content and matching affective prosody to facial expression. Alcoholics showed deficits of affective prosody processing which became evident in ambiguous situations in which no additional cues could be used simultaneously for the interpretation of emotional prosody. These deficits could contribute to interpersonal problem solving and should thus be considered in the therapy of alcoholism.     

Supramodal representation of emotions

Supramodal representation of emotion and its neural substrates have recently attracted attention as a marker of social cognition. However, the question whether perceptual integration of facial and vocal emotions takes place in primary sensory areas, multimodal cortices, or in affective structures remains unanswered yet. Using novel computer-generated stimuli, we combined emotional faces and voices in congruent and incongruent ways and assessed functional brain data (fMRI) during an emotional classification task. Both congruent and incongruent audiovisual stimuli evoked larger responses in thalamus and superior temporal regions compared with unimodal conditions. Congruent emotions were characterized by activation in amygdala, insula, ventral posterior cingulate (vPCC), temporo-occipital, and auditory cortices; incongruent emotions activated a frontoparietal network and bilateral caudate nucleus, indicating a greater processing load in working memory and emotion-encoding areas. The vPCC alone exhibited differential reactions to congruency and incongruency for all emotion categories and can thus be considered a central structure for supramodal representation of complex emotional information. Moreover, the left amygdala reflected supramodal representation of happy stimuli. These findings document that emotional information does not merge at the perceptual audiovisual integration level in unimodal or multimodal areas, but in vPCC and amygdala.     

Brain network of semantic integration in sentence reading: Insights from independent component analysis and graph theoretical analysis

A set of cortical and sub‐cortical brain structures has been linked with sentence‐level semantic processes. However, it remains unclear how these brain regions are organized to support the semantic integration of a word into sentential context. To look into this issue, we conducted a functional magnetic resonance imaging (fMRI) study that required participants to silently read sentences with semantically congruent or incongruent endings and analyzed the network properties of the brain with two approaches, independent component analysis (ICA) and graph theoretical analysis (GTA). The GTA suggested that the whole‐brain network is topologically stable across conditions. The ICA revealed a network comprising the supplementary motor area (SMA), left inferior frontal gyrus, left middle temporal gyrus, left caudate nucleus, and left angular gyrus, which was modulated by the incongruity of sentence ending. Furthermore, the GTA specified that the connections between the left SMA and left caudate nucleus as well as that between the left caudate nucleus and right thalamus were stronger in response to incongruent vs. congruent endings. Hum Brain Mapp 35:367–376, 2014. © 2012 Wiley Periodicals, Inc.     

Neuroelectric and behavioral indices of interference control during acute cycling.

OBJECTIVE: This study examined the effects of in-task, moderate-intensity aerobic exercise on neuroelectric and behavioral indices of interference control, one component of executive control. METHODS: Forty-one participants completed a V O(2) max test to determine maximal heart rate (HR). On a separate day, event-related brain potentials and task performance were measured during the counterbalanced conditions of upright cycling at 60% of maximal HR and rest while performing congruent and incongruent trials of a flanker task. RESULTS: Exercise resulted in reduced response accuracy for incongruent trials relative to rest; an effect not found for congruent trials. Decreased N1 amplitude was observed during exercise at parietal sites and globally for N2. Exercise also resulted in increased amplitude for the P2 at frontal and central sites, and for the P3 at frontal and lateral sites. Further, longer N2 and P3 latencies were observed during exercise relative to rest. CONCLUSION: These findings suggest that the need to allocate attentional resources toward the large-scale bodily movements inherent in exercise may relate to inefficiency of neural resource allocation, resulting in decreased interference control. SIGNIFICANCE: These data indicate general and selective exercise-induced decrements in cognitive processing while performing acute aerobic exercise.