Traitement cérébral de sons émotionnels : une perspective électrophysiologique

Des sons émotionnels furent présentés comme stimuli cibles lors d'une tâche auditive de type oddball. Les effets acoustiques furent départagés des effets émotionnels à l'aide d'une tâche contrôle similaire utilisant une version brouillée des sons originaux et dépourvue de propriétés émotionnelles. Les résultats du oddball émotionnel qui ont différé du oddball contrôle ont montré des effets de valence inversés dans les composantes électrophysiologiques P2 et P300; la valence négative ayant une amplitude plus grande dans la fenêtre de 130-270ms mais moins intense autour de 290-460ms, lorsque comparée aux valences positives et neutres. Les résultats P2 peuvent être interprétés comme une mobilisation attentionnelle précoce privilégiant les stimuli potentiellement dangereux, tandis que les résultats de la P300 pourrait indiquer une évaluation moins détaillée de ces stimuli.

An ERP study of major-minor classification in melodies

COMPOSERS COMMONLY USE MAJOR OR MINOR SCALES to create different moods in music.Nonmusicians show poor discrimination and classification of this musical dimension; however, they can perform these tasks if the decision is phrased as happy vs. sad.We created pairs of melodies identical except for mode; the first major or minor third or sixth was the critical note that distinguished major from minor mode. Musicians and nonmusicians judged each melody as major vs. minor or happy vs. sad.We collected ERP waveforms, triggered to the onset of the critical note. Musicians showed a late positive component (P3) to the critical note only for the minor melodies, and in both tasks.Nonmusicians could adequately classify the melodies as happy or sad but showed little evidence of processing the critical information. Major appears to be the default mode in music, and musicians and nonmusicians apparently process mode differently.

Event-relating to potential dementia. Semantic processing in the course of healthy and pathological aging

While most healthy elderly are able to manage their everyday activities, studies showed that there are both stable and declining abilities during healthy aging. For example, there is evidence that semantic memory processes which involve controlled retrieval mechanism decrease, whereas the automatic functioning of the semantic network remains intact. In contrast, patients with Alzheimer’s disease (AD) suffer from episodic and semantic memory impairments aggravating their daily functioning. In AD, severe episodic as well as semantic memory deficits are observable. While the hallmark symptom of episodic memory decline in AD is well investigated, the underlying mechanisms of semantic memory deterioration remain unclear. By disentangling the semantic memory impairments in AD, the present thesis aimed to improve early diagnosis and to find a biomarker for dementia. To this end, a study on healthy aging and a study with dementia patients were conducted investigating automatic and controlled semantic word retrieval. Besides the inclusion of AD patients, a group of participants diagnosed with semantic dementia (SD) – showing isolated semantic memory loss – was assessed. Automatic and controlled semantic word retrieval was measured with standard neuropsychological tests and by means of event-related potentials (ERP) recorded during the performance of a semantic priming (SP) paradigm. Special focus was directed to the N400 or N400-LPC (late positive component) complex, an ERP that is sensitive to the semantic word retrieval. In both studies, data driven topographical analyses were applied. Furthermore, in the patient study, the combination of the individual baseline cerebral blood flow (CBF) with the N400 topography of each participant was employed in order to relate altered functional electrophysiology to the pathophysiology of dementia. Results of the aging study revealed that the automatic semantic word retrieval remains stable during healthy aging, the N400-LPC complex showed a comparable topography in contrast to the young participants. Both patient groups showed automatic SP to some extent, but strikingly the ERP topographies were altered compared to healthy controls. Most importantly, the N400 was identified as a putative marker for dementia. In particular, the degree of the topographical N400 similarity was demonstrated to separate healthy elderly from demented patients. Furthermore, the marker was significantly related to baseline CBF reduction in brain areas relevant for semantic word retrieval. Summing up, the first major finding of the present thesis was that all groups showed semantic priming, but that the N400 topography differed significantly between healthy and demented elderly. The second major contribution was the identification of the N400 similarity as a putative marker for dementia. To conclude, the present thesis added evidence of preserved automatic processing during healthy aging. Moreover, a possible marker which might contribute to an improved diagnosis and lead consequently to a more effective treatment of dementia was presented and has to be further developed.

Brain activity evidence for recognition without recollection after early hippocampal damage

Amnesic patients with early and seemingly isolated hippocampal injury show relatively normal recognition memory scores. The cognitive profile of these patients raises the possibility that this recognition performance is maintained mainly by stimulus familiarity in the absence of recollection of contextual information. Here we report electrophysiological data on the status of recognition memory in one of the patients, Jon. Jon's recognition of studied words lacks the event-related potential (ERP) index of recollection, viz., an increase in the late positive component (500–700 ms), under conditions that elicit it reliably in normal subjects. On the other hand, a decrease of the ERP amplitude between 300 and 500 ms, also reliably found in normal subjects, is well preserved. This so-called N400 effect has been linked to stimulus familiarity in previous ERP studies of recognition memory. In Jon, this link is supported by the finding that his recognized and unrecognized studied words evoked topographically distinct ERP effects in the N400 time window. These data suggest that recollection is more dependent on the hippocampal formation than is familiarity, consistent with the view that the hippocampal formation plays a special role in episodic memory, for which recollection is so critical.

Electro-cortical implicit race bias does not vary with participants' race or sex

Earlier research found evidence for electro-cortical race bias towards black target faces in white American participants irrespective of the task relevance of race. The present study investigated whether an implicit race bias generalizes across cultural contexts and racial in- and out-groups. An Australian sample of 56 Chinese and Caucasian males and females completed four oddball tasks that required sex judgements for pictures of male and female Chinese and Caucasian posers. The nature of the background (across task) and of the deviant stimuli (within task) was fully counterbalanced. Event-related potentials (ERPs) to deviant stimuli recorded from three midline sites were quantified in terms of mean amplitude for four components: N1, P2, N2 and a late positive complex (LPC; 350–700 ms). Deviants that differed from the backgrounds in sex or race elicited enhanced LPC activity. These differences were not modulated by participant race or sex. The current results replicate earlier reports of effects of poser race relative to background race on the LPC component of the ERP waveform. In addition, they indicate that an implicit race bias occurs regardless of participant's or poser's race and is not confined to a particular cultural context.

听觉想象的大脑表征

As a species of internal representation, how is mental imagery organized in the brain? There are two issues related to this question: the time course and the nature of mental imagery. On the nature of mental imagery, today's imagery debate is influenced by two opposing theories: (1) Pylyshyn’s propositional theory and (2) Kosslyn’s depictive representation theory. Behavioural studies indicated that imagery encodes properties of the physical world, such as the spacial and size information of the visual world. Neuroimaging and neuropsychological data indicated that sensory cortex; especially the primary sensory cortex, is involved in imagery. In visual modality, neuroimaging data further indicated that during visual imagery, spatial information is mapped in the primary visual, providing strong evidences for depictive theory. In the auditory modality, behavioural studies also indicated that auditory imagery represents loudness and pitch of sound; this kind of neuroimaging evidence, however, is absent. The aim of the present study was to investigate the time course of auditory imagery processing, and to provide the neuroimaging evidence that imaginal auditory representations encode loudness and pitch information, using the ERP method and a cue-imagery (S1)-S2 paradigm. The results revealed that imagery effects started with an enhancement of the P2, probably indexing the top-down allocation of attention to the imagery task; and continued into a more positive-going late positive potentials (LPC), probably reflecting the formation of auditory imagery. The amplitude of this LPC was inversely related to the pitch of the imagined sound, but directly related to the loudness of the imagined sound, which were consistent with auditory perception related N1 component, providing evidences that auditory imagery encodes pitch and loudness information. When the S2 showed difference in pitch of loudness from the previously imagined S1, the behavioral performance were significantly worse and accordingly a conflict related N2 was elicited; and the high conflict elicited greater N2 amplitude than low conflict condition, providing further evidences that imagery is analog of perception and can encode pitch and loudness information. The present study suggests that imagery starts with an mechanism of top-down allocation of attention to the imagery task; and continuing into the step of imagery formation during which the physical features of the imagined stimulus can be encoded, providing supports to Kosslyn’s depictive representation theory.

The presence of a culturally similar or dissimilar social partner affects neural responses to emotional stimuli

Background: Emotional responding is sensitive to social context; however, little emphasis has been placed on the mechanisms by which social context effects changes in emotional responding.

Objective: We aimed to investigate the effects of social context on neural responses to emotional stimuli to inform on the mechanisms underpinning context-linked changes in emotional responding.

Design: We measured event-related potential (ERP) components known to index specific emotion processes and self-reports of explicit emotion regulation strategies and emotional arousal. Female Chinese university students observed positive, negative, and neutral photographs, whilst alone or accompanied by a culturally similar (Chinese) or dissimilar researcher (British).

Results: There was a reduction in the positive versus neutral differential N1 amplitude (indexing attentional capture by positive stimuli) in the dissimilar relative to alone context. In this context, there was also a corresponding increase in amplitude of a frontal late positive potential (LPP) component (indexing engagement of cognitive control resources). In the similar relative to alone context, these effects on differential N1 and frontal LPP amplitudes were less pronounced, but there was an additional decrease in the amplitude of a parietal LPP component (indexing motivational relevance) in response to positive stimuli. In response to negative stimuli, the differential N1 component was increased in the similar relative to dissimilar and alone (trend) context.

Conclusion: These data suggest that neural processes engaged in response to emotional stimuli are modulated by social context. Possible mechanisms for the social-context-linked changes in attentional capture by emotional stimuli include a context-directed modulation of the focus of attention, or an altered interpretation of the emotional stimuli based on additional information proportioned by the context.

ERP and cardiovascular correlates of source memory discrimination in older and younger adults /

There is much evidence to support an age-related decline in source memory ability. However, the underlying mechanisms responsible for this decline are not well understood. The current study was carried out to determine the electrophysiological correlates of source memory discrimination in younger and older adults. Event-related potentials (ERPs) and continuous electrocardiographic (ECG) data were collected from younger (M= 21 years) and older (M= 71 years) adults during a source memory task. Older adults were more likely to make source memory errors for recently repeated, non-target words than were younger adults. Moreover, their ERP records for correct trials showed an increased amplitude in the late positive (LP) component (400-800 msec) for the most recently presented, non-target stimuli relative to the LP noted for target items. Younger adults showed an opposite pattern, with a large LP component for target items, and a much smaller LP component for the recently repeated non-target items. Computation of parasympathetic activity in the vagus nerve was performed on the ECG data (Porges, 1985). The resulting measure, vagal tone, was used as an index of physiological responsivity. The vagal tone index of physiological responsivity was negatively related to the LP amplitude for the most recently repeated, non-target words in both groups, after accounting for age effects. The ERP data support the hypothesis that the tendency to make source memory errors on the part of older adults is related to the ability to selectively control attentional processes during task performance. Furthermore, the relationship between vagal tone and ERP reactivity suggests that there is a physiological basis to the heightened reactivity measured in the LP response to recently repeated non-target items such that, under decreased physiological resources, there is an impairment in the ability to selectively inhibit bottom-up, stimulus based properties in favour of task-related goals in older adults. The inconsistency of these results with other explanatory models of source memory deficits is discussed. It is concluded that the data are consistent with a physiological reactivity model requiring inhibition of reactivity to irrelevant, but perceptually-fluent, stimuli.

Still feeling it: the time course of emotional recovery from an attentional perspective

Emotional reactivity and the time taken to recover, particularly from negative, stressful, events, are inextricably linked, and both are crucial for maintaining well-being. It is unclear, however, to what extent emotional reactivity during stimulus onset predicts the time course of recovery after stimulus offset. To address this question, 25 participants viewed arousing (negative and positive) and neutral pictures from the International Affective Picture System (IAPS) followed by task-relevant face targets, which were to be gender categorized. Faces were presented early (400–1500 ms) or late (2400–3500 ms) after picture offset to capture the time course of recovery from emotional stimuli. Measures of reaction time (RT), as well as face-locked N170 and P3 components were taken as indicators of the impact of lingering emotion on attentional facilitation or interference. Electrophysiological effects revealed negative and positive images to facilitate face-target processing on the P3 component, regardless of temporal interval. At the individual level, increased reactivity to: (1) negative pictures, quantified as the IAPS picture-locked Late Positive Potential (LPP), predicted larger attentional interference on the face-locked P3 component to faces presented in the late time window after picture offset. (2) Positive pictures, denoted by the LPP, predicted larger facilitation on the face-locked P3 component to faces presented in the earlier time window after picture offset. These results suggest that subsequent processing is still impacted up to 3500 ms after the offset of negative pictures and 1500 ms after the offset of positive pictures for individuals reacting more strongly to these pictures, respectively. Such findings emphasize the importance of individual differences in reactivity when predicting the temporality of emotional recovery. The current experimental model provides a novel basis for future research aiming to identify profiles of adaptive and maladaptive recovery.

Brain electrical microstates in subjects with panic disorder

Brain electrical microstates represent spatial configurations of scalp recorded brain electrical activity and are considered to be the basic elements of stepwise processing of information in the brain. In the present study, the hypothesis of a temporo-limbic dysfunction in panic disorder (PD) was tested by investigating the topographic descriptors of brain microstates, in particular the one corresponding to the Late Positive Complex (LPC), an event-related potential (ERP) component with generators in these regions. ERPs were recorded in PD patients and matched healthy subjects during a target detection task, in a central (CC) and a lateral condition (LC). In the CC, a leftward shift of the LPC microstate positive centroid was observed in the patients with PD versus the healthy control subjects. In the LC, the topographic descriptor of the first microstate showed a rightward shift, while those of both the second and the fourth microstate, corresponding to the LPC, revealed a leftward shift in the PD patients versus the healthy control subjects. These findings indicate an overactivation of the right hemisphere networks involved in early visual processing and a hypoactivation of the right hemisphere circuits involved in LPC generators in PD. In line with this interpretation, the abnormal topography of the LPC microstate, observed in the CC, was associated with a worse performance on a test exploring right temporo-hippocampal functioning. Topographical abnormalities found for the LPC microstate in the LC were associated with a higher number of panic attacks, suggesting a pathogenetic role of the right temporo-hippocampal dysfunction in PD.

Late cardiac sodium current can be assessed using automated patch-clamp

The cardiac late Na (+) current is generated by a small fraction of voltage-dependent Na (+) channels that undergo a conformational change to a burst-gating mode, with repeated openings and closures during the action potential (AP) plateau. Its magnitude can be augmented by inactivation-defective mutations, myocardial ischemia, or prolonged exposure to chemical compounds leading to drug-induced (di)-long QT syndrome, and results in an increased susceptibility to cardiac arrhythmias. Using CytoPatch™ 2 automated patch-clamp equipment, we performed whole-cell recordings in HEK293 cells stably expressing human Nav1.5, and measured the late Na (+) component as average current over the last 100 ms of 300 ms depolarizing pulses to -10 mV from a holding potential of -100 mV, with a repetition frequency of 0.33 Hz. Averaged values in different steady-state experimental conditions were further corrected by the subtraction of current average during the application of tetrodotoxin (TTX) 30 μM. We show that ranolazine at 10 and 30 μM in 3 min applications reduced the late Na (+) current to 75.0 ± 2.7% (mean ± SEM, n = 17) and 58.4 ± 3.5% ( n = 18) of initial levels, respectively, while a 5 min application of veratridine 1 μM resulted in a reversible current increase to 269.1 ± 16.1% ( n = 28) of initial values. Using fluctuation analysis, we observed that ranolazine 30 μM decreased mean open probability p from 0.6 to 0.38 without modifying the number of active channels n, while veratridine 1 μM increased n 2.5-fold without changing p. In human iPSC-derived cardiomyocytes, veratridine 1 μM reversibly increased APD90 2.12 ± 0.41-fold (mean ± SEM, n = 6). This effect is attributable to inactivation removal in Nav1.5 channels, since significant inhibitory effects on hERG current were detected at higher concentrations in hERG-expressing HEK293 cells, with a 28.9 ± 6.0% inhibition (mean ± SD, n = 10) with 50 μM veratridine.

The Rivers Avon & Erme SAP Consultation Document

This is the Rivers Avon & Erme Salmon Action Plan Consultation document produced by the Environment Agency in 2003. This document is part of a national initiative to produce action plans for the management of all the main salmon rivers of England and Wales by 2003. The aim of this plan is (i) to assess the status of the salmon stocks and fisheries of the rivers Avon and Erme - including the use of Conservation Limits as part of this process, (ii) to identify factors which may limiting stock and fishery performance and (iii) to propose remedial measures address these factors. The report pays attention on the external consultation of the Rivers Avon & Erme Salmon Action Plan (SAP). While the stocks of both rivers have exceeded their respective conservation limits occasionally in individual years, only the Erme has achieved a period of statistical compliance since 1993. It is possible that this situation is largely normal, due to the steep nature of the rivers, obstructions to migration and dependence on suitable flow conditions occurring at the right time of year. The decline of the spring-running component of the stocks has left the populations dependent on autumn flows for the success of the late running component. Actions required to improve compliance with Conservation Limits are proposed and prioritised. The urgent actions relate to the need to improve the consistency with which adequate numbers of salmon reach and utilise fully all the accessible areas of the river systems. This document is intended to be dynamic, with opportunities for review occurring at regular intervals. For example, as the science of fisheries management improves, particularly in the setting of Conservation Limits, so the targets may be altered to reflect any improved methodology.

负性情绪对分泌型免疫球蛋白A的影响以及事件相关电位的关联变化

Although the influence of emotional states on immune function has been generally recognized, researches on the effects of negative emotion on individual SIgA levels have reported mixed findings. Our study aimed to elucidate the relationship between changes in EEG activity and cognitive and psychological mechanisms to the immune changes induced by negative emotion. In experiment one, we investigated how the negative emotional arousal that was induced by watching a number of unpleasant pictures altered the concentration of secretory immunoglobulin A (SIgA). Although our results found discrepancies in the changing tendency of SIgA concentration among participants (some participants’ SIgA decreased after watching unpleasant pictures, whereas others increased), further analysis revealed a coherency among the changing of SIgA concentration, participants’ general coping styles and their actual emotion regulation strategies in perceiving unpleasant pictures, and the event-related potentials (ERPs) associated with the watching of unpleasant pictures. The participants whose SIgA increased after watching unpleasant pictures (the increasers) had higher positive coping scores in the Trait Coping Styles Questionnaire (TCSQ) than those whose SIgA decreased (the decreasers). Also, relative to the decreasers, the increasers tended to use more emotion regulation strategies especially when the presented pictures were extremely negative and exhibited a reverse dissociation pattern between the extremely negative pictures and the moderately negative ones in the amplitude of late positive potential (LPP) that was related to the cognitive evaluation of stimuli’s meaning. On this basis, Event-related potentials were recorded first while participants passively viewed unpleasant pictures, and then during an emotion regulation block in which participants were instructed to reappraise unpleasant pictures in the experiment two. We also collected the immune index before and after the passive viewing block and the emotion regulation block. Our study proved that participants felt a less intense emotional response to unpleasant pictures that followed a reappraisal instruction. The decreasing emotional responding to unpleasant pictures decreased the amplitude of the LPP. But larger N2 was induced in the emotion regulation block, because the participants needed to obtained more attentional resources to detect and integrate more stimulus features to use the cognitive reappraisal strategy effectively. The present study has important theoretic and practical significance. For the theoretic significance, our study elucidated the relationship between changes in EEG activity and cognitive and psychological mechanisms to the immune changes induced by negative emotion by using the technologies of ERP, experimental interview and psychological measurement. Meanwhile, our study also provided an explanation for the different changing tendencies of SIgA induced by negative emotions, and it plays an important role in further studying the cognitive neural mechanisms of immune level in response to emotion. As to the practical significance, our study suggests that individuals who use active emotion regulation in the face of negative emotion stimuli may experience significantly increases in immune system function, subsequently lowering the possibility of infection.

汉语句子和语篇韵律层级边界的认知加工及其ERP效应

The aim of the present study was to explore whether the CPS (Closure Positive Shift) which reflected prosodic processing will be elicited when listeners perceived different hierarchical prosodic boundaries in Chinese sentence and discourse (Quatrain). In addiction, the similarity and difference in amplitude, onset latency and scalp distribution between these CPS were investigated. The nature of the CPS and its relationship to acoustic parameters was also explored systematically. The main results and conclusions of the present study were: (1) Phonological phrase boundaries and intonational phrase boundaries in Chinese sentences both elicited the CPS; however, phonological word boundaries can't evoke it. The CPS induced by phonological phrase boundaries was earlier than the one related to intonational phrase boundaries in onset latency, and the amplitude was also somewhat lower. When the pauses in the vicinity of these two boundaries were removed, the onset latency difference disappeared while amplitude in the new conditions was also lower. This indicates that whenever listeners segment sentence into phrases, the CPS will be elicited. Besides, pause was not the decisive factor to elicit the CPS, but can modify its onset latency and amplitude effectively. (2) The different hierarchical prosodic boundaries in seven character quatrain including phonological phrase boundaries, intonational phrase boundaries and sentence pair boundaries elicited the CPS respectively. Furthermore, just like in the sentence level, onset latency of the CPS induced by the prosodic boundaries in the discourse was also influenced by the length of pause: the shorter the pause was, the earlier the onset latency. For the comparison between the CPS evoked by the same and different hierarchical prosodic boundaries, its amplitude was influenced by the extent to which prosodic representations were activated. Thus, the condition of the CPS elicitation was extended to the prosodic bounaries in discourse, and further indicated that it was influenced by acoustic parameters. (3) No matter what task the participants completed, just like word detection or rythem matching task, the CPS will be evoked. However, its amplitude was larger in the anterior region, when listeners completed the word detection task which needed more attention and higher load of working memory. The present result indicated that the elicitation of the CPS was not influenced by the task the participants completed, but different task influence its scalp distribution. (4) The final syllable of the sentence and quatrain can't elicit the CPS, but a P300-like positive component. Although the scalp distribution was similar to the CPS, it was much higher in amplitude. The present result suggested that only the prosodic boundaries reflecting not only the closure of the former prosodic unit but also integrating the later one will elicit the CPS.

大脑序列记忆信息的提取

The purpose of this study was to examine the cognitive and neural mechanism underlying the serial position effects using cognitive experiments and ERPs(the event related potentials), for 11 item lists in very short-term and the continuous-distractor paradigm with Chinese character. The results demonstrated that when the length of list was 11 Chinese character, and the presentation time, the item interval and the retention interval was 400ms, the primacy effect and recency effect belong to the associative memory and absolute memory respectively. The retrieval of the item at the primacy part depended mainly on the context cues, but the retrieval of the item at the recency part depended mainly on the memory trace. The same results was concluded in the continuous-distractor paradigm (the presentation time was 1sec, the item interval is 12sec, and the retention interval was 30sec). Cognitive results revealed the robust serial position effects in the continuous-distractor paradigm. The different retrieval process between items at the primacy part and items at the recency part of the serial position curve was found. The behavioral responses data of ERP illustrated that the responses for the prime and recent items differed neither in accuracy nor reaction time, the retrieval time for the items at the primacy part was longer than that for the items at the recency part. And the accuracy of retrieval for the primacy part item was lower than that for the recency part items. That meant the retrieval of primacy part items needed more cognitive processes. The recent items, compared with the prime items, evoked ERPs that were more positive, this enhanced positivity occurred in a positive component peaking around 360ms. And for the same retrieval direction (forward or backward), the significant positive component difference between the retrieval for prime items and the retrieval for recent items was found. But there was no significant difference between the forward and backward retrieval at both the primacy and recency part of the serial position curve. These revealed the two kind of retrieval (forward and backward) at the same part of the serial position curve belonged to the same property. These findings fit more closely with the notion of the distinct between the associative memory and the absolute memory.