A pleasure that lasts: Convergent neural processes underpin comfort with prolonged gentle stroking

While many pleasures in life are short-lived, the pleasure we derive from being gently touched or caressed seems fairly durable, extending for minutes to hours. Here, we examined how the brain adapts to extended tactile stimulation and staves off affective habituation. For 60 min, participants were presented with soft brushstrokes at slow, intermediate, and fast velocities to their left forearm. We recorded the electroencephalogram and asked participants to rate touch pleasantness. Ratings and the sN400, a somatosensory event-related potential, depended on velocity in an inverted u-shaped manner pointing to their sensitivity to CT targeted touch. Both measures were largely unaffected by time on task. Rolandic power decreased for faster velocities indexing enhanced somatosensory cortex activation. This effect declined across repeated stimulation especially for the fastest stroking pointing to a habituation of Aβ driven tactile representations. Together, these and other results imply that CT and Aβ related processes respond differently to prolonged tactile stimulation allowing CT signals to become relatively amplified in unfolding somatosensory representations. Such a relative amplification could be central for promoting extended physical contact, which is typical for close human relationships and which benefits health and well-being.