The neural basis of laughter.

Abstract

Laughter is a universal social signal and a defining clinical sign of various neurological disorders. Yet, its neural orchestration remains elusive, due in part to the challenge of reproducing its spontaneous nature in the laboratory. In this review, we showcase how recent invasive investigations-from direct electrical stimulation to intracranial recordings-unveil the underlying circuitry. We propose a dual-system framework: an evolutionarily ancient cingulo-temporal network that acts as the gateway for spontaneous, involuntary outbursts; and a lateral motor-opercular system that co-opts speech-production networks for volitional, conversational laughter. This neuroethological perspective reveals how parallel cortico-subcortical pathways drive laughter as both a primal affective signal and a sophisticated communicative tool, offering a new roadmap for understanding human social bonding and its clinical disruptions.