Insula and somatosensory cortical myelination and iron markers underlie individual differences in empathy

Micah Allen, Darya Frank, James C. Glen, Francesca Fardo, Martina F. Callaghan, Geraint Rees
2017 Scientific Reports  
Empathy is a key component of our ability to engage and interact with others. In recent years, the neural mechanisms underlying affective and cognitive empathy have garnered intense interest. This work demonstrates that empathy for others depends upon a distributed network of regions such as the insula, parietal cortex, and somatosensory areas, which are also activated when we ourselves experience an empathized-with emotion (e.g., pain). Individuals vary markedly in their ability to empathize
more » ... th others, which predicts the tendency to help others and relates to individual differences in the neuroanatomy of these areas. Here, we use a newly developed, high-resolution (800 μm isotropic), quantitative MRI technique to better elucidate the neuroanatomical underpinnings of individual differences in empathy. Our findings extend previous studies of the neuroanatomical correlates of cognitive and affective empathy. In particular, individual differences in cognitive empathy were associated with markers of myeloarchitectural integrity of the insular cortex, while affective empathy was predicted by a marker of iron content in second somatosensory cortex. These results indicate potential novel biomarkers of trait empathy, suggesting that microstructural features of an empathy and body-related network are crucial for understanding the mental and emotional states of others. Empathy is a core social skill underlying our ability to understand and respond appropriately to the emotions of others. Following growing interest from social neuroscientists, the neural underpinnings of both trait and state empathy has become a topic of intensive research 1-3 . Healthy individuals differ considerably in their tendency and ability to empathize 4,5 , which in turn predicts real world behaviours such as charitable giving 6-8 , and is affected by genetic and environmental factors 9 . In general, variation in the macroscopic structure of the brain underlies individual differences in a variety of perceptual, emotional, and cognitive behaviours 10 . Here we use a recently developed quantitative MRI technique to examine the neurobiological factors underlying individual differences in cognitive and affective empathy, as captured by the Interpersonal Reactivity Index 4 (IRI). There is ample evidence relating individual differences in self-reported trait empathy to social behavior and implicit neural and physiological responses. For example, scores on the IRI correlate with the tendency to display bullying and defending behaviour 11 . Although the mapping between trait and state empathy is complicated 12,13 , several physiological studies have validated the IRI using implicit physiological measures. In one recent electromyography (EMG) study, participants with greater scores on the affective component of the IRI were more prone to frown when viewing another person in pain 14 . In another study 15 , scores on the affective sub-scale Personal Distress (PD) were correlated with skin conductance response (SCR) and the P300 ERP component in schizophrenic patients viewing others in pain. These and other studies point to a stable individual tendency to empathize with others, which also predicts the style and intensity of individual empathetic and emotional states.
doi:10.1038/srep43316 pmid:28256532 pmcid:PMC5335674 fatcat:awtmn64pbfhx7biezjbu3t7lqm