The role of low-level image features in the affective categorization of rapidly presented scenes

The role of phase and orientation for ERP modulations of spectrum-manipulated fearful and neutral faces

Prioritized processing of fearful compared to neutral faces has been proposed to result from evolutionary adaptation of the contrast sensitivity function (CSF) to the features of emotionally relevant faces and/or vice versa. However, it is unknown whether a stimulus merely has to feature the amplitude spectrum of a fearful face to be prioritized or whether the relevant spatial frequencies have to occur with specific phases and orientations. Prioritized processing is indexed by specific increases of Event-Related Potentials (ERPs) of the EEG and occurs throughout different early processing stages, indexed by emotion-related modulations of the P1, N170, and EPN. In this pre-registered study, we manipulated phase and amplitude properties of the Fourier spectra of neutral and fearful faces to test the effect of phase coherence (PC, face vs. scramble) and orientation coherence (OC, original vs. rotational average) and their interactions with differential emotion processing. We found that differential emotion processing was not present at the level of P1 but strongly affected N170 and EPN. In both cases, intact phase coherence was required for enhanced processing of fearful faces. OC did not interact with emotion. While faces produced the typical N170 effect, we observed a reversed effect for scrambles. Additional exploratory independent component analysis (ICA) suggests that this reversal could signal a mismatch between an early "perceptual hypothesis" and feedback of configural information. In line with our expectations, fearful-neutral differences for the N170 and EPN depend on configural information, i.e., recognizable faces.

The effect of family-centered sensory and affective stimulation on comatose patients with traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

Sensory stimulation has been used in the early rehabilitation of comatose patients with traumatic brain injury, but the effect of sensory stimulation involving family members is unclear.

OBJECTIVES

To evaluate the effects of family-centered sensory and affective stimulation on comatose patients with traumatic brain injury and explore the factors that affect the outcomes.

DESIGN

A systematic review with a meta-analysis.

DATA SOURCES

Electronic databases including PubMed, Web of Science, Google Scholar, Cochrane Library, CINAHL, China National Knowledge Infrastructure, and WanFang were searched from October 2019 to May 2020.

REVIEW METHODS

Two reviewers independently assessed eligibility of potential studies and extracted data. Quality of included studies was assessed according to the evaluation criteria of Cochrane Evaluation Manual 5.1.0. Outcome measures of the meta-analysis were the Glasgow Coma Scale scores, the Western Neuro Sensory Stimulation Profile scores, awakening time, and satisfaction rate. To explore whether there was a difference in the effect between variants of the intervention, variables as subgroups were time to start intervention, type of intervention, duration of each intervention, daily frequency of intervention, days of intervention, and patient's area.

RESULT

Seventeen randomized controlled trials were included in the review and meta-analysis. Most studies were of medium quality. The improvement of the Glasgow Coma Scale score is significantly greater with the intervention implemented within 24 h compared to the intervention implemented 24 h later (mean difference 3.91, 95% confidence interval 3.44-4.38 vs. mean difference 1.90, 95% confidence interval 1.69-2.12, respectively). The results of subgroup analyses show that auditory stimulation combined with tactile stimulation and multi-sensory stimulation are associated with better outcomes than a single use of auditory stimulation. Studies from Asia report more positive outcomes than those from America (mean difference 1.94, 95% confidence interval 1.73-2.16 vs. mean difference 0.44, 95% confidence interval -0.87-1.75). And the improvement of the Glasgow Coma Scale score with the stimulation performed by family members is greater than that with the stimulation implemented by nurses (mean difference 2.17, 95% confidence interval 1.67-2.66). Besides, it is associated with better awakening time, awakening rate, and satisfaction rate compared to routine care.

CONCLUSION

Early family-centered sensory and affective stimulation is more effective than routine care and nurse-implemented sensory stimulation in improving the level of consciousness and cognition of comatose patients with traumatic brain injury, and multi-sensory stimulation is more effective than single stimulation. More studies with larger sample size and high quality in different countries are warranted.

Image Valence Modulates the Processing of Low-Resolution Affective Natural Scenes

In natural vision, noisy and distorted visual inputs often change our perceptual strategy in scene perception. However, it is unclear the extent to which the affective meaning embedded in the degraded natural scenes modulates our scene understanding and associated eye movements. In this eye-tracking experiment by presenting natural scene images with different categories and levels of emotional valence (high-positive, medium-positive, neutral/low-positive, medium-negative, and high-negative), we systematically investigated human participants' perceptual sensitivity (image valence categorization and arousal rating) and image-viewing gaze behaviour to the changes of image resolution. Our analysis revealed that reducing image resolution led to decreased valence recognition and arousal rating, decreased number of fixations in image-viewing but increased individual fixation duration, and stronger central fixation bias. Furthermore, these distortion effects were modulated by the scene valence with less deterioration impact on the valence categorization of negatively valenced scenes and on the gaze behaviour in viewing of high emotionally charged (high-positive and high-negative) scenes. It seems that our visual system shows a valence-modulated susceptibility to the image distortions in scene perception.

Global Image Properties Predict Ratings of Affective Pictures

Affective pictures are widely used in studies of human emotions. The objects or scenes shown in affective pictures play a pivotal role in eliciting particular emotions. However, affective processing can also be mediated by low-level perceptual features, such as local brightness contrast, color or the spatial frequency profile. In the present study, we asked whether image properties that reflect global image structure and image composition affect the rating of affective pictures. We focused on 13 global image properties that were previously associated with the esthetic evaluation of visual stimuli, and determined their predictive power for the ratings of five affective picture datasets (IAPS, GAPED, NAPS, DIRTI, and OASIS). First, we used an SVM-RBF classifier to predict high and low ratings for valence and arousal, respectively, and achieved a classification accuracy of 58–76% in this binary decision task. Second, a multiple linear regression analysis revealed that the individual image properties account for between 6 and 20% of the variance in the subjective ratings for valence and arousal. The predictive power of the image properties varies for the different datasets and type of ratings. Ratings tend to share similar sets of predictors if they correlate positively with each other. In conclusion, we obtained evidence from non-linear and linear analyses that affective pictures evoke emotions not only by what they show, but they also differ by how they show it. Whether the human visual system actually uses these perceptive cues for emotional processing remains to be investigated.