Disorganized Attachment pattern affects the perception of Affective Touch

Abstract

Touch, such as affective caress, can be interpreted as being pleasant. The emotional valence that is assigned to touch is related to certain bottom-up factors, such as the optimal activation of C-tactile (CT) afferents. Tactile processing with a hedonic or emotional component has been defined as affective touch-a component that CT fibers are likely to convey. Tactile deficiencies are frequent in the psychiatric population but also in healthy people with disorganized attachment; accordingly, it is likely that affective difficulties in adults with disorganized attachment are reflected in altered perception of affective touch. To test this hypothesis, we combined methods from clinical psychology, psychophysics, and neuroimaging. We found that people with a history of traumatic parental bonds and a disorganized attachment pattern perceive a "caress-like" stimulus as being unpleasant, whereas participants with organized attachment consider the same tactile stimulation to be pleasant. Further, unlike in organized adults, the responses of disorganized adults to CT and non-CT stimulation activated limbic and paralimbic structures in a fight-or-flight manner, suggesting that early experiences with parental deficiencies shape the physiological responses of peripheral CT fibers and central nervous networks.

Figure 1

Panel A. Participants’ evaluations of the Affective stimulation and Non-affective stimulation. Panel B. Affective Touch Index. Participants’ general preference for Affective stimulation or Non-affective stimulation. Positive values represent the preference for Affective stimulation; negative values represent the preference for Non-affective stimulation.

Figure 2

Imaging results. Brain areas involved in Affective and Non-affective stimulation, including posterior insula (pINS) and primary somatosensory cortex (S1) in the left hemisphere (LH) and supramarginal gyrus (SMG) and limbic/paralimbic cortex in the right hemisphere (RH). A main effect of the Stimulation was detected in the pINS and the S1 (Panel A). We found a significant Group-by-Stimulation interaction (Panel B) in the right limbic/paralimbic cortex with Non-affective stimulation yielded higher activation than Affective one in people with disorganized attachment (DA) but not in people with organized attachment (OA).