The neural mechanisms and circuitry of the pair bond

Love is one of our most powerful emotions, inspiring some of the greatest art, literature and conquests of human history. Although aspects of love are surely unique to our species, human romantic relationships are displays of a mating system characterized by pair bonding, likely built on ancient foundational neural mechanisms governing individual recognition, social reward, territorial behaviour and maternal nurturing. Studies in monogamous prairie voles and mice have revealed precise neural mechanisms regulating processes essential for the pair bond. Here, we discuss current viewpoints on the biology underlying pair bond formation, its maintenance and associated behaviours from neural and evolutionary perspectives. Recent research advances have yielded fresh insights into the fundamental neural processes underlying pair bonding. In this Review, Walum and Young discuss how neural representations of a partner become inherently rewarding, providing intriguing insights into the neural origins of love.