Neural patterns associated with mixed valence feelings differ in consistency and predictability throughout the brain.

Mixed feelings, the simultaneous presence of feelings with positive and negative valence, remain an understudied topic. They pose a specific set of challenges due to individual variation, and their investigation requires analtyic approaches focusing on individually self-reported states. We used functional magnetic resonance imaging (fMRI) to scan 27 subjects watching an animated short film chosen to induce bittersweet mixed feelings. The same subjects labeled when they had experienced positive, negative, and mixed feelings. Using hidden-Markov models, we found that various brain regions could predict the onsets of new feeling states as determined by self-report. The ability of the models to identify these transitions suggests that these states may exhibit unique and consistent neural signatures. We next used the subjects' self-reports to evaluate the spatiotemporal consistency of neural patterns for positive, negative, and mixed states. The insula had unique and consistent neural signatures for univalent states, but not for mixed valence states. The anterior cingulate and ventral medial prefrontal cortex had consistent neural signatures for both univalent and mixed states. This study is the first to demonstrate that subjectively reported changes in feelings induced by naturalistic stimuli can be predicted from fMRI and the first to show direct evidence for a neurally consistent representation of mixed feelings.

Homeostatic Feelings and the Emergence of Consciousness.

In this article, we summarize our views on the problem of consciousness and outline the current version of a novel hypothesis for how conscious minds can be generated in mammalian organisms. We propose that a mind can be considered conscious when three processes are in place: the first is a continuous generation of interoceptive feelings, which results in experiencing of the organism's internal operations; the second is the equally continuous production of images, generated according to the organism's sensory perspective relative to its surround; the third combines feeling/experience and perspective resulting in a process of subjectivity relative to the image contents. We also propose a biological basis for these three components: the peripheral and central physiology of interoception and exteroception help explain the implementation of the first two components, whereas the third depends on central nervous system integration, at multiple levels, from spinal cord, brainstem, and diencephalic nuclei, to selected regions of the mesial cerebral cortices.

Hanna and Antonio Damasio.

Hanna and Antonio Damasio work at the intersection between neuroscience, neurology, philosophy, and psychology. They discuss the value of single case studies for neuroscience, consciousness research and the limits of AI, and the fascinating relationship between creativity and the brain.

Preventing antisocial robots: A pathway to artificial empathy.

Given the accelerating powers of artificial intelligence (AI), we must equip artificial agents and robots with empathy to prevent harmful and irreversible decisions. Current approaches to artificial empathy focus on its cognitive or performative processes, overlooking affect, and thus promote sociopathic behaviors. Artificially vulnerable, fully empathic AI is necessary to prevent sociopathic robots and protect human welfare.

Feelings Are the Source of Consciousness.

In this view, we address the problem of consciousness, and although we focus on its human presentation, we note that the phenomenon is present in numerous nonhuman species and use findings from a variety of animal studies to explain our hypothesis for how consciousness is made. Consciousness occurs when mind contents, such as perceptions and thoughts, are spontaneously identified as belonging to a specific organism/owner. Conscious minds are said to have a self that experiences mental events. We hypothesize that the automatic identification that associates minds and organisms is provided by a continuous flow of homeostatic feelings. Those feelings arise from the uninterrupted process of life regulation and correspond to both salient physiological fluctuations such as hunger, pain, well-being, or malaise, as well as to states closer to metabolic equilibrium and best described as feelings of life/existence, such as breathing or body temperature. We also hypothesize that homeostatic feelings were the inaugural phenomena of consciousness in biological evolution and venture that they were selected because the information they provided regarding the current state of life regulation conferred extraordinary advantages to the organisms so endowed. The "knowledge" carried by conscious homeostatic feelings provided "overt" guidance for life regulation, an advance over the covert regulation present in nonconscious organisms. Finally, we outline a mechanism for the generation of feelings based on a two-way interaction between interoceptive components of the nervous system and a particular set of nonneural components of the organism's interior, namely, viscera and circulating chemical molecules involved in their operations. Feelings emerge from this interaction as continuous and hybrid phenomena, related simultaneously to two series of events. The first is best described by the terms neural/representational/and mental and the second by the terms nonneural/visceral/and chemical. We note that this account offers a solution for the mind-body problem: homeostatic feelings constitute the "mental" version of bodily processes.

Perspective-taking is associated with increased discriminability of affective states in the ventromedial prefrontal cortex.

Recent work using multivariate-pattern analysis (MVPA) on functional magnetic resonance imaging (fMRI) data has found that distinct affective states produce correspondingly distinct patterns of neural activity in the cerebral cortex. However, it is unclear whether individual differences in the distinctiveness of neural patterns evoked by affective stimuli underlie empathic abilities such as perspective-taking (PT). Accordingly, we examined whether we could predict PT tendency from the classification of blood-oxygen-level-dependent (BOLD) fMRI activation patterns while participants (n = 57) imagined themselves in affectively charged scenarios. We used an MVPA searchlight analysis to map where in the brain activity patterns permitted the classification of four affective states: happiness, sadness, fear and disgust. Classification accuracy was significantly above chance levels in most of the prefrontal cortex and in the posterior medial cortices. Furthermore, participants' self-reported PT was positively associated with classification accuracy in the ventromedial prefrontal cortex and insula. This finding has implications for understanding affective processing in the prefrontal cortex and for interpreting the cognitive significance of classifiable affective brain states. Our multivariate approach suggests that PT ability may rely on the grain of internally simulated affective representations rather than simply the global strength.

Interoception and the origin of feelings: A new synthesis.

Feelings are conscious mental events that represent body states as they undergo homeostatic regulation. Feelings depend on the interoceptive nervous system (INS), a collection of peripheral and central pathways, nuclei and cortical regions which continuously sense chemical and anatomical changes in the organism. How such humoral and neural signals come to generate conscious mental states has been a major scientific question. The answer proposed here invokes (1) several distinctive and poorly known physiological features of the INS; and (2) a unique interaction between the body (the 'object' of interoception) and the central nervous system (which generates the 'subject' of interoception). The atypical traits of the INS and the direct interactions between neural and non-neural physiological compartments of the organism, neither of which is present in exteroceptive systems, plausibly explain the qualitative and subjective aspects of feelings, thus accounting for their conscious nature.

Seeing objects improves our hearing of the sounds they make.

It has been established that lip reading improves the perception of auditory speech. But does seeing objects themselves help us hear better the sounds they make? Here we report a series of psychophysical experiments in humans showing that the visual enhancement of auditory sensitivity is not confined to speech. We further show that the crossmodal enhancement was associated with the conscious visualization of the stimulus: we can better hear the sounds an object makes when we are conscious of seeing that object. Our work extends an intriguing crossmodal effect, previously circumscribed to speech, to a wider domain of real-world objects, and suggests that consciousness contributes to this effect.

Bittersweet: The Neuroscience of Ambivalent Affect.

Ambivalent affective states, such as bittersweetness, nostalgia, and longing, which are felt as having both positive and negative aspects, are an important component of human experience but have received little attention. The most influential theoretical frameworks in affective neuroscience focus largely on univalenced states. As a result, it is not known whether ambivalent affect corresponds to a simultaneously positive and negative valenced state or whether it results from a rapid vacillation between positive and negative states. Here we hypothesize that ambivalent affect involves both mechanisms, that is, rapid vacillation and simultaneity of positive and negative affect, albeit at different neurobiological levels. Rapidly vacillating univalent emotions could give rise to an ambivalent feeling, a mechanism that depends on brainstem nuclei that facilitate rapid action programs of emotional behavior while inhibiting opposing behaviors. This reciprocal inhibition prevents organisms from simultaneously implementing responses to conflicting emotions but also allows for rapid switching between emotions triggered by counterfactual thinking and rapid reappraisal of situations. We propose that as these transitions occur and respective interoceptive information reaches the insular cortex, further processing of this "emotional moment" would allow separate emotional events to be experienced as one "mixed" and integrated feeling.

Dynamic intersubject neural synchronization reflects affective responses to sad music.

Psychological theories of emotion often highlight the dynamic quality of the affective experience, yet neuroimaging studies of affect have traditionally relied on static stimuli that lack ecological validity. Consequently, the brain regions that represent emotions and feelings as they unfold remain unclear. Recently, dynamic, model-free analytical techniques have been employed with naturalistic stimuli to better capture time-varying patterns of activity in the brain; yet, few studies have focused on relating these patterns to changes in subjective feelings. Here, we address this gap, using intersubject correlation and phase synchronization to assess how stimulus-driven changes in brain activity and connectivity are related to two aspects of emotional experience: emotional intensity and enjoyment. During fMRI scanning, healthy volunteers listened to a full-length piece of music selected to induce sadness. After scanning, participants listened to the piece twice while simultaneously rating the intensity of felt sadness or felt enjoyment. Activity in the auditory cortex, insula, and inferior frontal gyrus was significantly synchronized across participants. Synchronization in auditory, visual, and prefrontal regions was significantly greater in participants with higher measures of a subscale of trait empathy related to feeling emotions in response to music. When assessed dynamically, continuous enjoyment ratings positively predicted a moment-to-moment measure of intersubject synchronization in auditory, default mode, and striatal networks, as well as the orbitofrontal cortex, whereas sadness predicted intersubject synchronization in limbic and striatal networks. The results suggest that stimulus-driven patterns of neural communication in emotional processing and high-level cortical regions carry meaningful information with regards to our feeling in response to a naturalistic stimulus.

A Role for The P2Y1 Receptor in Nonsynaptic Cross-depolarization in the Rat Dorsal Root Ganglia.

Non-synaptic transmission is pervasive throughout the nervous system. It appears especially prevalent in peripheral ganglia, where non-synaptic interactions between neighboring cell bodies have been described in both physiological and pathological conditions, a phenomenon referred to as cross-depolarization (CD) and thought to play a role in sensory processing and chronic pain. CD has been proposed to be mediated by a chemical agent, but its identity has remained elusive. Here, we report that in the rat dorsal root ganglion (DRG), the P2Y1 purinergic receptor (P2RY1) plays an important role in regulating CD. The effect of P2RY1 is cell-type specific: pharmacological blockade of P2RY1 inhibited CD in A-type neurons while enhancing it in C-type neurons. In the nodose ganglion of the vagus, CD requires extracellular calcium in a large percentage of cells. In contrast, we show that in the DRG extracellular calcium appears to play no major role, pointing to a mechanistic difference between the two peripheral ganglia. Furthermore, we show that DRG glial cells also play a cell-type specific role in CD regulation. Fluorocitrate-induced glial inactivation had no effect on A-cells but enhanced CD in C-cells. These findings shed light on the mechanism of CD in the DRG and pave the way for further analysis of non-synaptic neuronal communication in sensory ganglia.

Decoding the neural signatures of emotions expressed through sound.

Effective social functioning relies in part on the ability to identify emotions from auditory stimuli and respond appropriately. Previous studies have uncovered brain regions engaged by the affective information conveyed by sound. But some of the acoustical properties of sounds that express certain emotions vary remarkably with the instrument used to produce them, for example the human voice or a violin. Do these brain regions respond in the same way to different emotions regardless of the sound source? To address this question, we had participants (N = 38, 20 females) listen to brief audio excerpts produced by the violin, clarinet, and human voice, each conveying one of three target emotions-happiness, sadness, and fear-while brain activity was measured with fMRI. We used multivoxel pattern analysis to test whether emotion-specific neural responses to the voice could predict emotion-specific neural responses to musical instruments and vice-versa. A whole-brain searchlight analysis revealed that patterns of activity within the primary and secondary auditory cortex, posterior insula, and parietal operculum were predictive of the affective content of sound both within and across instruments. Furthermore, classification accuracy within the anterior insula was correlated with behavioral measures of empathy. The findings suggest that these brain regions carry emotion-specific patterns that generalize across sounds with different acoustical properties. Also, individuals with greater empathic ability have more distinct neural patterns related to perceiving emotions. These results extend previous knowledge regarding how the human brain extracts emotional meaning from auditory stimuli and enables us to understand and connect with others effectively.

Music training and child development: a review of recent findings from a longitudinal study.

Evidence suggests that learning to play music enhances musical processing skills and benefits other cognitive abilities. Furthermore, studies of children and adults indicate that the brains of musicians and nonmusicians are different. It has not been determined, however, whether such differences result from pre-existing traits, musical training, or an interaction between the two. As part of an ongoing longitudinal study, we investigated the effects of music training on children's brain and cognitive development. The target group of children was compared with two groups of children, one involved in sports and another not enrolled in any systematic afterschool training. Two years after training, we observed that children in the music group had better performance than comparison groups in musically relevant auditory skills and showed related brain changes. For nonmusical skills, children with music training, compared with children without music or with sports training, showed stronger neural activation during a cognitive inhibition task in regions involved in response inhibition despite no differences in performance on behavioral measures of executive function. No such differences were found between music and sports groups. We conclude that music training induces brain and behavioral changes in children, and those changes are not attributable to pre-existing biological traits.

Childhood Music Training Induces Change in Micro and Macroscopic Brain Structure: Results from a Longitudinal Study.

Several studies comparing adult musicians and nonmusicians have shown that music training is associated with structural brain differences. It is not been established, however, whether such differences result from pre-existing biological traits, lengthy musical training, or an interaction of the two factors, or if comparable changes can be found in children undergoing music training. As part of an ongoing longitudinal study, we investigated the effects of music training on the developmental trajectory of children's brain structure, over two years, beginning at age 6. We compared these children with children of the same socio-economic background but either involved in sports training or not involved in any systematic after school training. We established at the onset that there were no pre-existing structural differences among the groups. Two years later we observed that children in the music group showed (1) a different rate of cortical thickness maturation between the right and left posterior superior temporal gyrus, and (2) higher fractional anisotropy in the corpus callosum, specifically in the crossing pathways connecting superior frontal, sensory, and motor segments. We conclude that music training induces macro and microstructural brain changes in school-age children, and that those changes are not attributable to pre-existing biological traits.

Decoding the neural representation of story meanings across languages.

Drawing from a common lexicon of semantic units, humans fashion narratives whose meaning transcends that of their individual utterances. However, while brain regions that represent lower-level semantic units, such as words and sentences, have been identified, questions remain about the neural representation of narrative comprehension, which involves inferring cumulative meaning. To address these questions, we exposed English, Mandarin, and Farsi native speakers to native language translations of the same stories during fMRI scanning. Using a new technique in natural language processing, we calculated the distributed representations of these stories (capturing the meaning of the stories in high-dimensional semantic space), and demonstrate that using these representations we can identify the specific story a participant was reading from the neural data. Notably, this was possible even when the distributed representations were calculated using stories in a different language than the participant was reading. Our results reveal that identification relied on a collection of brain regions most prominently located in the default mode network. These results demonstrate that neuro-semantic encoding of narratives happens at levels higher than individual semantic units and that this encoding is systematic across both individuals and languages. Hum Brain Mapp 38:6096-6106, 2017. © 2017 Wiley Periodicals, Inc.

A Potential Role for mu-Opioids in Mediating the Positive Effects of Gratitude.

Gratitude is a complex emotional feeling associated with universally desirable positive effects in personal, social, and physiological domains. Why or how gratitude achieves these functional outcomes is not clear. Toward the goal of identifying its' underlying physiological processes, we recently investigated the neural correlates of gratitude. In our study, participants were exposed to gratitude-inducing stimuli, and rated each according to how much gratitude it provoked. As expected, self-reported gratitude intensity correlated with brain activity in distinct regions of the medial pre-frontal cortex associated with social reward and moral cognition. Here we draw from our data and existing literature to offer a theoretical foundation for the physiological correlates of gratitude. We propose that mu-opioid signaling (1) accompanies the mental experience of gratitude, and (2) may account for the positive effects of gratitude on social relationships, subjective wellbeing, and physiological health.

Processing Narratives Concerning Protected Values: A Cross-Cultural Investigation of Neural Correlates.

Narratives are an important component of culture and play a central role in transmitting social values. Little is known, however, about how the brain of a listener/reader processes narratives. A receiver's response to narration is influenced by the narrator's framing and appeal to values. Narratives that appeal to "protected values," including core personal, national, or religious values, may be particularly effective at influencing receivers. Protected values resist compromise and are tied with identity, affective value, moral decision-making, and other aspects of social cognition. Here, we investigated the neural mechanisms underlying reactions to protected values in narratives. During fMRI scanning, we presented 78 American, Chinese, and Iranian participants with real-life stories distilled from a corpus of over 20 million weblogs. Reading these stories engaged the posterior medial, medial prefrontal, and temporo-parietal cortices. When participants believed that the protagonist was appealing to a protected value, signal in these regions was increased compared with when no protected value was perceived, possibly reflecting the intensive and iterative search required to process this material. The effect strength also varied across groups, potentially reflecting cultural differences in the degree of concern for protected values.