Electro-cortical correlates of multisensory integration using ecologically valid emotional stimuli: Differential effects for fear and disgust

The impact of degraded vision on emotional perception of audiovisual stimuli: An event-related potential study

Emotion recognition will be challenged for individuals when visual signals are degraded in real-life scenarios. Recently, researchers have conducted many studies on the distinct neural activity between clear and degraded audiovisual stimuli. These findings addressed the "how" question, but the precise stage of the distinct activity that occurred remains unknown. Therefore, it is crucial to use event-related potential (ERP) to explore the "when" question, just the time course of the neural activity of degraded audiovisual stimuli. In the present research, we established two conditions: clear auditory + degraded visual (AcVd) and clear auditory + clear visual (AcVc) multisensory conditions. We enlisted 31 participants to evaluate the emotional valence of audiovisual stimuli. The resulting data were analyzed using ERP in time domains and Microstate analysis. Current results suggest that degraded vision impairs the early-stage processing of audiovisual stimuli, with the superior parietal lobule (SPL) regulating audiovisual processing in a top-down fashion. Additionally, our findings indicate that negative and positive stimuli elicit greater EPN compared to neutral stimuli, pointing towards a subjective motivation-related attentional regulation. To sum up, in the early stage of emotional audiovisual processing, the degraded visual signal affected the perception of the physical attributes of audiovisual stimuli and had a further influence on emotion extraction processing, leading to the different regulation of top-down attention resources in the later stage.

Multisensory integration deficits in Schizophrenia and Autism evidenced in behaviour but not event related potentials

The process of integrating information from different sensory channels, known as multisensory integration (MSI) was assessed in two disorders, Autism Spectrum Disorder (ASD) and Schizophrenia (SCZ). 32 healthy controls (HC), 35 SCZ patients, and 23 ASD patients performed an audiovisual (AV) synchronous target detection task while reaction time (RT) and scalp recorded electrophysiological (EEG) activity were measured. MSI in the AV condition resulted in faster and less variable RTs compared to the unimodal conditions. Using our novel bootstrap method, MSI gain was observed in 78 % of HC, 26 % of ASD, and 48 % of SCZ patients. At the neural level, MSI in the AV condition resulted in larger amplitude of sensory evoked responses and cognitive P3 response compared to the corresponding unimodal conditions. These neural effects of MSI were not related to the behavioural MSI gain identified at the individual level and could not explain the deficits in behavioural MSI of patient groups. In conclusion, a robust MSI gain deficit in RT was observed in both patient groups that was not reflected in early perceptual and cognitive electro-cortical responses, suggesting that behavioural MSI deficits in ASD and SCZ may arise at late processing stages such as response selection.

Differential correlates of fear and anxiety in salience perception: A behavioral and ERP study with adolescents

Anxiety disorders are the most common psychopathologies among adolescents. Their diagnostic criteria include both fear and anxiety symptomatology, although according to the literature, we can find evidence for some distinction between these two emotions. The present study contribute to this distinction, exploring the effects of trait fear and trait anxiety on behavioral and neural correlates. Thirty-two participants (aged 11-16 years) performed two experimental tasks of salient target detection, including visual stimuli that were manipulated to become salient, while reaction times and EEG were recorded. Results of both tasks revealed differential effects of trait fear and trait anxiety assessed through the Fear Survey Schedule for Children-Revised and the Youth Anxiety Measure for DSM-5 on reaction times and ERP components amplitudes. Specifically, higher symptoms from Separation Anxiety Disorder increased early neural visual processing and decreased reaction times for more salient stimuli. Also, trait fear reduced later neural visual processing of salient stimuli. These findings may provide a significant contribution to guiding psychological interventions, especially with adolescents presenting higher levels of anxiety-related symptomatology.

Aberrant neural correlates of multisensory processing of audiovisual social cues related to social anxiety: An electrophysiological study

BACKGROUND

Social anxiety disorder (SAD) is characterized by abnormal fear to social cues. Although unisensory processing to social stimuli associated with social anxiety (SA) has been well described, how multisensory processing relates to SA is still open to clarification. Using electroencephalography (EEG) measurement, we investigated the neural correlates of multisensory processing and related temporal dynamics in social anxiety disorder (SAD).

METHODS

Twenty-five SAD participants and 23 healthy control (HC) participants were presented with angry and neutral faces, voices and their combinations with congruent emotions and they completed an emotional categorization task.

RESULTS

We found that face-voice combinations facilitated auditory processing in multiple stages indicated by the acceleration of auditory N1 latency, attenuation of auditory N1 and P250 amplitudes, and decrease of theta power. In addition, bimodal inputs elicited cross-modal integrative activity which is indicated by the enhancement of visual P1, N170, and P3/LPP amplitudes and superadditive response of P1 and P3/LPP. More importantly, excessively greater integrative activity (at P3/LPP amplitude) was found in SAD participants, and this abnormal integrative activity in both early and late temporal stages was related to the larger interpretation bias of miscategorizing neutral face-voice combinations as angry.

CONCLUSION

The study revealed that neural correlates of multisensory processing was aberrant in SAD and it was related to the interpretation bias to multimodal social cues in multiple processing stages. Our findings suggest that deficit in multisensory processing might be an important factor in the psychopathology of SA.

Enhancing allocation of visual attention with emotional cues presented in two sensory modalities

Background

Responses to a visual target stimulus in an exogenous spatial cueing paradigm are usually faster if cue and target occur in the same rather than in different locations (i.e., valid vs. invalid), although perceptual conditions for cue and target processing are otherwise equivalent. This cueing validity effect can be increased by adding emotional (task-unrelated) content to the cue. In contrast, adding a secondary non-emotional sensory modality to the cue (bimodal), has not consistently yielded increased cueing effects in previous studies. Here, we examined the interplay of bimodally presented cue content (i.e., emotional vs. neutral), by using combined visual-auditory cues. Specifically, the current ERP-study investigated whether bimodal presentation of fear-related content amplifies deployment of spatial attention to the cued location.

Results

A behavioral cueing validity effect occurred selectively in trials in which both aspects of the cue (i.e., face and voice) were related to fear. Likewise, the posterior contra-ipsilateral P1-activity in valid trials was significantly larger when both cues were fear-related than in all other cue conditions. Although the P3a component appeared uniformly increased in invalidly cued trials, regardless of cue content, a positive LPC deflection, starting about 450 ms after target onset, was, again, maximal for the validity contrast in trials associated with bimodal presentation of fear-related cues.

Conclusions

Simultaneous presentation of fear-related stimulus information in the visual and auditory modality appears to increase sustained visual attention (impairing disengagement of attention from the cued location) and to affect relatively late stages of target processing.

Event-Related Potentials during Verbal Recognition of Naturalistic Neutral-to-Emotional Dynamic Facial Expressions

Event-related potentials during facial emotion recognition have been studied for more than twenty years. Nowadays, there has been a growing interest in the use of naturalistic stimuli. This research was aimed, therefore, at studying event-related potentials (ERP) during recognition of dynamic facial neutral-to-emotional expressions, more ecologically valid than static faces. We recorded the ERP of 112 participants who watched 144 dynamic morphs depicting a gradual change from a neutral expression to a basic emotional expression (anger, disgust, fear, happiness, sadness and surprise) and labelled those emotions verbally. We revealed some typical ERP, like N170, P2, EPN and LPP. Participants with lower accuracy exhibited a larger posterior P2. Participants with faster correct responses exhibited a larger amplitude of P2 and LPP. We also conducted a classification analysis that yielded the accuracy of 76% for prediction of participants who recognise emotions quickly on the basis of the amplitude of posterior P2 and LPP. These results extend data from previous research about the electroencephalographic correlates of facial emotion recognition.

Sound gaps boost emotional audiovisual integration independent of attention: Evidence from an ERP study

The emotion discrimination paradigm was adopted to study the effect of interrupted sound on visual emotional processing under different attentional states. There were two experiments: Experiment 1: judging facial expressions (explicit task), Experiment 2: judging the position of a bar (implicit task). In Experiment 1, ERP results showed that there was a sound gap accelerating the effect of P1 present only under neutral faces. In Experiment 2, the accelerating effect (P1) existed regardless of the emotional condition. Combining two experiments, P1 findings suggest that sound gap enhances bottom-up attention. The N170 and late positive component (LPC) were found to be regulated by emotion face in both experiments, with fear over the neutral. Comparing the two experiments, the explicit task induced a larger LPC than the implicit task. Overall, sound gaps boosted the audiovisual integration by bottom-up attention in early integration, while cognitive expectations led to top-down attention in late stages.

The Modulation of Exogenous Attention on Emotional Audiovisual Integration

Although emotional audiovisual integration has been investigated previously, whether emotional audiovisual integration is affected by the spatial allocation of visual attention is currently unknown. To examine this question, a variant of the exogenous spatial cueing paradigm was adopted, in which stimuli varying by facial expressions and nonverbal affective prosody were used to express six basic emotions (happiness, anger, disgust, sadness, fear, surprise) via a visual, an auditory, or an audiovisual modality. The emotional stimuli were preceded by an unpredictive cue that was used to attract participants' visual attention. The results showed significantly higher accuracy and quicker response times in response to bimodal audiovisual stimuli than to unimodal visual or auditory stimuli for emotional perception under both valid and invalid cue conditions. The auditory facilitation effect was stronger than the visual facilitation effect under exogenous attention for the six emotions tested. Larger auditory enhancement was induced when the target was presented at the expected location than at the unexpected location. For emotional perception, happiness shared the biggest auditory enhancement among all six emotions. However, the influence of exogenous cueing effect on emotional perception seemed to be absent.

Late attentional processes potentially compensate for early perceptual multisensory integration deficits in children with autism: evidence from evoked potentials

Sensory processing deficits and altered long-range connectivity putatively underlie Multisensory Integration (MSI) deficits in Autism Spectrum Disorder (ASD). The present study set out to investigate non-social MSI stimuli and their electrophysiological correlates in young neurotypical adolescents and adolescents with ASD. We report robust MSI effects at behavioural and electrophysiological levels. Both groups demonstrated normal behavioural MSI. However, at the neurophysiological level, the ASD group showed less MSI-related reduction of the visual P100 latency, greater MSI-related slowing of the auditory P200 and an overall temporally delayed and spatially constrained onset of MSI. Given the task design and patient sample, and the age of our participants, we argue that electro-cortical indices of MSI deficits in ASD: (a) can be detected in early-adolescent ASD, (b) occur at early stages of perceptual processing, (c) can possibly be compensated by later attentional processes, (d) thus leading to normal MSI at the behavioural level.