The romantic brain: Secure attachment activates the brainstem centers of well-being

Abstract

Attachment security is a critical resource for individuals to preserve relationship quality. Insecure attachment reduces relationship quality and can seriously influence mental and physical health. Adult attachment style is thought to develop through relationships with a caregiver during childhood and social interactions during adolescence according to epigenetic modification and reinforcement learning mechanisms, and is an important factor for developing and maintaining relationship quality. The neurochemicals such as oxytocin (OXT), dopamine (DA), and serotonin (5-HT) have been shown to be critical for pair-bond formation and maintenance by animal experiments. However, the neural basis underlying the human adult attachment has not yet been clarified. We investigated whether the brain regions involved in these neurochemicals are correlated with adult attachment style in healthy male participants using functional magnetic resonance imaging (fMRI). Significantly activated brain regions, while they were viewing their partner compared to unknown females included the hypothalamus, substantia nigra/ventral tegmental area (SN/VTA), dorsal raphe nucleus (DRN) and locus coeruleus (LC), in which each of these regions is involved in OXT, DA, 5-HT and norepinephrine, respectively. Moreover, higher activity in these brainstem regions was associated with less attachment anxiety. These brainstem regions are primarily important for basic survival functions and well-being. Based on these results, in humans, neurochemicals such as OXT, DA, and 5-HT may be also critical for developing and maintaining relationships, and adult attachment style may be developed based on the epigenetic modification and reinforcement learning mechanisms through relationships with a caregiver during childhood.