Implicit Affective Rivalry: A Behavioral and fMRI Study Combining Olfactory and Auditory Stimulation

Distinct neural bases of visual art- and music-induced aesthetic experiences

Aesthetic experiences are characterized by a conscious, emotionally and hedonically rewarding perceptions of a stimulus's aesthetic qualities and are thought to arise from a unique combination of cognitive and affective processes. To pinpoint neural correlates of aesthetic experiences, in the present study, we performed a series of meta-analyses based on the existing functional Magnetic Resonance Imaging (fMRI) studies of art appreciation in visual art (34 experiments, 692 participants) and music (34 experiments, 718 participants). The Activation Likelihood Estimation (ALE) analyses showed that the frontal pole (FP), ventromedial prefrontal cortex (vmPFC), and inferior frontal gyrus (IFG) were commonly activated in visual-art-induced aesthetic experiences, whilst bilateral superior temporal gyrus (STG) and striatal areas were commonly activated in music appreciation. Additionally, task-independent Resting-state Functional Connectivity (RSFC), task-dependent Meta-analytical Connectivity Modelling (MACM) analyses, as well as Activation Network Modeling (ANM) further showed that visual art and music engaged quite distinct brain networks. Our findings support the domain-specific view of aesthetic appreciation and challenge the notion that there is a general "common neural currency" for aesthetic experiences across domains.

Stress-induced overeating behaviors explained from a (transitory) relief-learning perspective

People use various behaviors to cope with stressful events. These behaviors are mostly adaptive, as they allow a successful release of stress without impacting other aspects of life: How nice is it to have a break with a few spoons of that favorite ice cream during a hectic working day? However, when excessive consumption of high-sugar/salt ultra-processed food becomes the gateway to find relief from stress, eating loses this adaptive function and may escalate to binge eating, lead to obesity, and other medical conditions linked to overweight. Several etiological models attempt to explain stress-induced eating and excessive overeating behaviors characterizing these clinical conditions. The popular Emotional Eating Theory proposes that stress-related (over-)eating, a major predictor of obesity and diagnosed binge eating disorders, develops based on negative reinforcement learning since food consumption regulates the negative affective state associated with stressful circumstances. Differently, the prominent Incentive Sensitization Theory explains overeating, binge eating disorders (including bulimia), and obesity in terms of excessive amplification of reward 'wanting', which is thought to emerge from overexposure to obesogenic (food)cues. The several studies oriented by these theories have paved the way to better understand stress-related (over-)eating and its clinical excesses. However, a deep mechanistic understanding of how and why stress-induced (over-)eating can escalate till clinical forms of overeating remain elusive. A well-funded connection of the mechanisms proposed by the Emotional Eating Theory and the Incentive Sensitization Theory might address this etiological open question. To avoid erroneous arguments, it is however essential to first address the internal theoretical and methodological shortcomings of each theory and connected studies. These shortcomings stem from conceptual fallacies and poorly implemented designs, which might partially explain the 'high variability and low replicability' problem of empirical findings. Next, the formulation of a new integrative model could provide fresh insight into the deep learning and biological mechanisms of this escalation. A successful formalization of this model could then create the much-needed impact in clinical and preventive research since excessive overeating is a behavior hard to change once established. In this opinion paper, I propose to apply recent insights we gathered on the role of relief from the field of safety learning to stress (over-)eating. I will present a new relief-based model that, as a starting point, has the potential to connect the Emotional Eating Theory with the Incentive Sensitization Theory, setting the base for more integrative science.

Influence of Multimodal Emotional Stimulations on Brain Activity: An Electroencephalographic Study

This study aimed to reveal the influence of emotional valence and sensory modality on neural activity in response to multimodal emotional stimuli using scalp EEG. In this study, 20 healthy participants completed the emotional multimodal stimulation experiment for three stimulus modalities (audio, visual, and audio-visual), all of which are from the same video source with two emotional components (pleasure or unpleasure), and EEG data were collected using six experimental conditions and one resting state. We analyzed power spectral density (PSD) and event-related potential (ERP) components in response to multimodal emotional stimuli, for spectral and temporal analysis. PSD results showed that the single modality (audio only/visual only) emotional stimulation PSD differed from multi-modality (audio-visual) in a wide brain and band range due to the changes in modality and not from the changes in emotional degree. The most pronounced N200-to-P300 potential shifts occurred in monomodal rather than multimodal emotional stimulations. This study suggests that emotional saliency and sensory processing efficiency perform a significant role in shaping neural activity during multimodal emotional stimulation, with the sensory modality being more influential in PSD. These findings contribute to our understanding of the neural mechanisms involved in multimodal emotional stimulation.

Localizing the human brain response to olfactory stimulation: A meta-analytic approach

The human sense of smell and the ability to detect and distinguish odors allows for the extraction of valuable information from the environment, thereby driving human behavior. Not only can the sense of smell help to monitor the safety of inhaled air, but it can also help to evaluate the edibility of food. Therefore, in an effort to further our understanding of the human sense of smell, the aim of this meta-analysis was to provide the scientific community with activation probability maps of the functional anatomy of the olfactory system, in addition to separate activation maps for specific odor categories (pleasant, food, and aversive odors). The activation likelihood estimation (ALE) method was utilized to quantify all relevant and available data to perform a formal statistical analysis on the inter-study concordance of various odor categories. A total of 81 studies (108 contrasts, 1053 foci) fulfilled our inclusion criteria. Significant ALE peaks were observed in all odor categories in brain areas typically associated with the functional neuroanatomy of olfaction including the piriform cortex, amygdala, insula, and orbitofrontal cortex, amongst others. Additional contrast analyses indicate clear differences in neural activation patterns between odor categories.

The Power of Odor Persuasion: The Incorporation of Olfactory Cues in Virtual Environments for Personalized Relaxation

Olfaction is the most ancient sense and is directly connected with emotional areas in the brain. It gives rise to perception linked to emotion both in everyday life and in memory-recall activities. Despite its emotional primacy in perception and its role in sampling the real physical world, olfaction is rarely used in clinical psychological settings because it relies on stimuli that are difficult to deliver. However, recent developments in virtual-reality tools are creating novel possibilities for the engagement of the sense of smell in this field. In this article, we present the relevant features of olfaction for relaxation purposes and then discuss possible future applications of involving olfaction in virtual-reality interventions for relaxation. We also discuss clinical applications, the potential of new tools, and current obstacles and limitations.

A short-term musical training affects implicit emotion regulation only in behaviour but not in brain activity

Background

In everyday life, negative emotions can be implicitly regulated by positive stimuli, without any conscious cognitive engagement; however, the effects of such implicit regulation on mood and related neuro-mechanisms, remain poorly investigated in literature. Yet, improving implicit emotional regulation could reduce psychological burden and therefore be clinically relevant for treating psychiatric disorders with strong affective symptomatology.

Results

Music training reduced the negative emotional state elicited by negative odours. However, such change was not reflected at the brain level.

Conclusions

In a context of affective rivalry a musical training enhances implicit regulatory processes. Our findings offer a first base for future studies on implicit emotion regulation in clinical populations.

A coordinate-based meta-analysis of music-evoked emotions

Since the publication of the first neuroscience study investigating emotion with music about two decades ago, the number of functional neuroimaging studies published on this topic has increased each year. This research interest is in part due to the ubiquity of music across cultures, and to music's power to evoke a diverse range of intensely felt emotions. To support a better understanding of the brain correlates of music-evoked emotions this article reports a coordinate-based meta-analysis of neuroimaging studies (n = 47 studies with n = 944 subjects). The studies employed a range of diverse experimental approaches (e.g., using music to evoke joy, sadness, fear, tension, frissons, surprise, unpleasantness, or feelings of beauty). The results of an activation likelihood estimation (ALE) indicate large clusters in a range of structures, including amygdala, anterior hippocampus, auditory cortex, and numerous structures of the reward network (ventral and dorsal striatum, anterior cingulate cortex, orbitofrontal cortex, secondary somatosensory cortex). The results underline the rewarding nature of music, the role of the auditory cortex as an emotional hub, and the role of the hippocampus in attachment-related emotions and social bonding.