Neuroimaging Research on Empathy and Shared Neural Networks

Understanding other people’s feelings and perspectives is an important part of effective social communication and interaction. Empathy is the phenomenon that enables us to infer the feelings of others and understand their mental states. It aids in social learning and bonding and is thought to be impaired in individuals with social deficits like schizophrenia and autism spectrum disorder (ASD). Advances in neuroimaging technology have allowed social neuroscientists to study brain activity during this complex social process. A growing body of empathy literature demonstrates that multiple brain regions are involved in empathy. Current theories propose that empathy is enabled through the activation of various dynamic neural networks, each made up of several different regions. These networks respond differently depending on specific contexts and available information. This chapter reviews the networks involved in empathy and highlights the current theories and limitations of empathy research

Empathy and the somatotopic auditory mirror system in humans

SummaryHow do we understand the actions of other individuals if we can only hear them? Auditory mirror neurons respond both while monkeys perform hand or mouth actions and while they listen to sounds of similar actions [1, 2]. This system might be critical for auditory action understanding and language evolution [1–6]. Preliminary evidence suggests that a similar system may exist in humans [7–10]. Using fMRI, we searched for brain areas that respond both during motor execution and when individuals listened to the sound of an action made by the same effector. We show that a left hemispheric temporo-parieto-premotor circuit is activated in both cases, providing evidence for a human auditory mirror system. In the left premotor cortex, a somatotopic pattern of activation was also observed: A dorsal cluster was more involved during listening and execution of hand actions, and a ventral cluster was more involved during listening and execution of mouth actions. Most of this system appears to be multimodal because it also responds to the sight of similar actions. Finally, individuals who scored higher on an empathy scale activated this system more strongly, adding evidence for a possible link between the motor mirror system and empathy

Common Premotor Regions for the Perception and Production of Prosody and Correlations with Empathy and Prosodic Ability

Background: Prosody, the melody and intonation of speech, involves the rhythm, rate, pitch and voice quality to relay linguistic and emotional information from one individual to another. A significant component of human social communication depends upon interpreting and responding to another person’s prosodic tone as well as one’s own ability to produce prosodic speech. However there has been little work on whether the perception and production of prosody share common neural processes, and if so, how these might correlate with individual differences in social ability. Methods: The aim of the present study was to determine the degree to which perception and production of prosody rely on shared neural systems. Using fMRI, neural activity during perception and production of a meaningless phrase in different prosodic intonations was measured. Regions of overlap for production and perception of prosody were found in premotor regions, in particular the left inferior frontal gyrus (IFG). Activity in these regions was further found to correlate with how high an individual scored on two different measures of affective empathy as well as a measure on prosodic production ability. Conclusions: These data indicate, for the first time, that areas that are important for prosody production may also be utilized for prosody perception, as well as other aspects of social communication and social understanding, such as aspect

Modulation of cortical motor outputs by the symbolic meaning of visual stimuli.

Abstract The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is preceded by exposure to a hand stimulus, the latter appears to serve as a prime, perhaps enabling meaning to the neutral stimulus, which then modulates motor cortical excitability in accordance with mirror neuron-driving properties (Studies 2 and 3). Overall results suggest that a symbolic value ascribed to an otherwise neutral stimulus can modulate motor cortical outputs, revealing the influence of top-down inputs on the mirror neuron system. These findings indicate a novel aspect of the human mirror neuron system: an otherwise neutral stimulus can acquire specific mirror neuron-driving properties in the absence of a direct association between motor practice and perception. This significant malleability in the way that the mirror neuron system can code otherwise meaningless (i.e. arbitrarily associated) stimuli may contribute to coding communicative signals such as language. This may represent a mirror neuron system feature that is unique to humans

Congruent Embodied Representations for Visually Presented Actions and Linguistic Phrases Describing Actions

SummaryThe thesis of embodied semantics holds that conceptual representations accessed during linguistic processing are, in part, equivalent to the sensory-motor representations required for the enactment of the concepts described [1–6]. Here, using fMRI, we tested the hypothesis that areas in human premotor cortex that respond both to the execution and observation of actions—mirror neuron areas [7–18]—are key neural structures in these processes. Participants observed actions and read phrases relating to foot, hand, or mouth actions. In the premotor cortex of the left hemisphere, a clear congruence was found between effector-specific activations of visually presented actions and of actions described by literal phrases. These results suggest a key role of mirror neuron areas in the re-enactment of sensory-motor representations during conceptual processing of actions invoked by linguistic stimuli

The Importance of Sensory Processing in Mental Health: A Proposed Addition to the Research Domain Criteria (RDoC) and Suggestions for RDoC 2.0

The time is ripe to integrate burgeoning evidence of the important role of sensory and motor functioning in mental health within the National Institute of Mental Health’s [NIMH] Research Domain Criteria [RDoC] framework (National Institute of Mental Health, n.d.a), a multi-dimensional method of characterizing mental functioning in health and disease across all neurobiological levels of analysis ranging from genetic to behavioral. As the importance of motor processing in psychopathology has been recognized (Bernard and Mittal, 2015; Garvey and Cuthbert, 2017; National Institute of Mental Health, 2019), here we focus on sensory processing. First, we review the current design of the RDoC matrix, noting sensory features missing despite their prevalence in multiple mental illnesses. We identify two missing classes of sensory symptoms that we widely define as (1) sensory processing, including sensory sensitivity and active sensing, and (2) domains of perceptual signaling, including interoception and proprioception, which are currently absent or underdeveloped in the perception construct of the cognitive systems domain. Then, we describe the neurobiological basis of these psychological constructs and examine why these sensory features are important for understanding psychopathology. Where appropriate, we examine links between sensory processing and the domains currently included in the RDoC matrix. Throughout, we emphasize how the addition of these sensory features to the RDoC matrix is important for understanding a range of mental health disorders. We conclude with the suggestion that a separate sensation and perception domain can enhance the current RDoC framework, while discussing what we see as important principles and promising directions for the future development and use of the RDoC

Interoception in Autism: A Narrative Review of Behavioral and Neurobiological Data

Fernanda Loureiro,1 Sofronia M Ringold,1,2 Lisa Aziz-Zadeh1,2 1Brain and Creativity Institute, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, USA; 2Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy, University of Southern California, Los Angeles, CA, USACorrespondence: Fernanda Loureiro, Brain and Creativity Institute, Dornsife College of Letters, Arts and Sciences, University of Southern California, 3620A McClintock Avenue, Los Angeles, CA, 90089, USA, Email [email protected]: While exteroceptive sensory processing is a hallmark of autism spectrum disorder, how interoceptive processing may impact and contribute to symptomatology remains unclear. In this comprehensive narrative review on interoception in autism, we discuss: 1) difficulties with assessing interoception; 2) potential interoceptive differences; 3) interactions between neural systems for interoception, attention, sensorimotor processing, and cognition; and 4) potential differences in neural circuits involved in interoception. In general, there are mixed findings on potential interoception differences in autism. Nevertheless, some data indicate differences in integration of interoceptive and exteroceptive information may contribute to autism symptomatology. Neurologically, interoceptive processing in autism may be impacted by potential differences in the development, morphometry, and connectivity of key interoceptive hubs (vagal processing, brainstem, thalamus, insula), though much work is needed on this topic.Keywords: autism, interoception, insula, brainstem, thalamus, thermosensatio

Potential movement biomarkers for autism in children and adolescents

Background -- While social communication deficits are the hallmark of autism spectrum disorders (ASD), motor deficits are known to be common in this population as well. Recently, members of our research team showed that kinematic markers collected by playing a tablet game may be a promising biomarker for identification of ASD as compared to a typically developing population (TD) in children ages 3-6 years old (Anzulewicz et al, 2016). To our knowledge, no one has replicated this finding in an older population. Purpose -- To replicate and extend previous findings of kinematic differences in children with ASD to an older population of children (9-14 years old). Methods -- Four TD children and 5 children with ASD (aged 9-12) played an iPad drawing game (Anzulewicz et al, 2016) that measured gesture kinematics and gesture force using inertial sensors and touch screen touch displacements. 212 features were calculated from the inertial sensor and touch screen data (ibid). A Kolmogorov-Smirnov (K-S) test was run to identify motor features distinct between ASD and TD children. Results -- K-S test identified seven significantly different features (JerkMagnitudeMax, JerkMin_y, JerkRange_y, AttitudeRange_y, RotationRMS_x, RotationStdDev_x, JerkZeroCrossing_x) between ASD and TD groups that represented differences in acceleration of finger movements and the displacement of the iPad during movements. Conclusions -- Results demonstrated inertial movement sensor parameter differences are key identifiers between 8-12 year old ASD and TD children, common to children 3-6 years old. Contact forces and the distribution of forces during coloring may serve as important identifiers of ASD irrespective of age during childhood, while other parameters may be age-dependent. Research Support NIH R01 (1R01HD079432-01A1