Supportive touch has remarkable benefits in childbirth and during painful medical procedures. But does social touch influence pain neurophysiology, ie, the brain processes linked to nociception and primary pain experience? What other brain processes beyond primary pain systems mediate their analgesic effects? In this study, women (N = 30) experienced thermal pain while holding their romantic partner's hand or an inert device. Social touch reduced pain and attenuated functional magnetic resonance imaging activity in the Neurologic Pain Signature (NPS)—a multivariate brain pattern sensitive and specific to somatic pain—and increased connectivity between the NPS and both somatosensory and “default mode” regions. Brain correlates of touch-induced analgesia included reduced pain-related activation in (1) regions targeted by primary nociceptive afferents (eg, posterior insula, and anterior cingulate cortex); and (b) regions associated with affective value (orbitofrontal cortex), meaning (ventromedial prefrontal cortex [PFC]), and attentional regulation (dorsolateral PFC). Activation reductions during handholding (vs holding a rubber device) significantly mediated reductions in pain intensity and unpleasantness; greater pain reductions during handholding correlated with greater increases in emotional comfort, which correlated with higher perceived relationship quality and (a trend toward) greater perceived closeness with the romantic partner. The strongest mediators of analgesia were activity reductions in a brain circuit traditionally associated with stress and defensive behavior in mammals, including ventromedial and dorsomedial PFC, rostral anterior cingulate cortex, amygdala/hippocampus, hypothalamus, and periaqueductal gray matter. Social touch affects core brain processes that contribute to pain and pain-related affective distress in females, and should be considered alongside other treatments in medical and caregiving contexts.
This study is the first to show that supportive touch has “deep” effects on pain-generating (nociceptive-specific) brain processes and also targets stress-related brain circuits during pain in females.
aDivision of Behavioral Medicine and Clinical Psychology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
bDepartment of Psychology and Neuroscience, Institute of Cognitive Science, University of Colorado Boulder, Boulder, CO, United States
cDepartment of Biostatistics, Johns Hopkins University, Baltimore, MD, United States
dDepartment of Psychology, University of Virginia, Charlottesville, VA, United States
*Corresponding author. Address: Cincinnati Children's Hospital, 3333 Burnet Ave, MLC2 7031, Location R8 Office R8.547, Cincinnati, OH 45229, United States. Tel.: 303-817-2410. E-mail address: email@example.com (M. López-Solà).
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