By Chelsea Whyte
A part of the brain called the insular cortex appears to be behind why a tender stroke can feel so nice.
Parts of the skin that have hairs on them, such as the backs of hands but not the palms, have nerve fibres, which respond to gentle touch. Normally when mammals are touched, these fibres send a signal through the spinal cord to the part of the brain called the primary somatosensory cortex, which responds to changes on the surface of the body.
But for pleasurable touch, this …