The Contributions Of Autism And Alexithymia To Pain Empathic Neural Response

In social life,empathy plays an essential role in interpersonal communication and social-bondings.Pain empathy refers to the empathic response of sensing the painful experience from others.Given that alterations in pain empathic processing were found among individuals,pain empathic deficit was recognized as a transdiagnostic marker across psychiatric and psychosomatic entities associated with severe impairments in the social-emotional domain,with autism spectrum disorder(ASD)being a prime example.Previous findings indicated that pain empathic dysfunctions in neural level have been consistently reported in ASD.On the other hand,accumulating evidence suggests that these core symptomatic deficits in ASD may be contributed to by high levels of alexithymia-co-occurring with ASD symptomatology-rather than autistic symptoms per se.However,these initial findings are hampered by generally elevated levels of alexithymia in ASD,and thus were not able to differentiate the association across the entire spectrum of variations of autistic and alexithymia traits.The present fMRI study employed a dimensional trait approach in healthy subjects to determine common and distinct associations between individual variations in both traits and the domain-specific pain empathic neural responses towards physical and affective pain.Levels of trait autism and alexithymia were assessed in N = 252 healthy subjects using the Toronto Alexithymia scale(TAS)and Autism Spectrum Quotient(ASQ).Pain empathic neural responses were assessed using a validated fMRI paradigm incorporating 4 kinds of stimuli(physical pain/physical control/affective pain/affective control),while subjects were required to passively view and imagine the stimuli.Common and distinct associations between individual variations in autistic and alexithymia traits with the empathic response were examined including scores of TAS,ASQ and their interaction as predicators.Moderation analysis was conducted to further disentangle the association.Results demonstrated that higher alexithymia was associated with increased empathic responses in the left insula.Extraction of parameter estimates revealed a positive association with alexithymia scores during physical pain,but a negative one during affective pain.Whereas no significant associations with trait autism scores were found per se,there was an interaction effect between the two trait dimensions in the mid-cingulate cortex.Subsequent moderation analysis revealed significant moderation effects of alexithymia for mid-cingulate responses to both perceived physical and affective pain.Further disentangling the effects demonstrated that autism only impacted mid-cingulate reactivity towards physical pain in subjects with high alexithymia,whereas its reactivity towards affective pain was specifically associated with autism in subjects with low alexithymia.In conclusion,the present findings suggested that the domain-specific pain empathic responsivity in insula was related to elevated levels of alexithymia rather than autism per se.The moderating role of alexithymia on the impact of autistic traits to pain empathic reactivity supports a multi-factorial view about alexithymia's contribution to ASD symptomatology.