This review examines the neural circuitry underlying laughter, drawing on invasive methods such as direct electrical stimulation and intracranial recordings to map the brain networks involved in both spontaneous and volitional laughter.
The authors propose a dual-system framework: (1) an evolutionarily ancient cingulo-temporal network acting as the gateway for involuntary, spontaneous laughter; and (2) a lateral motor-opercular system that recruits speech-production networks for volitional, conversational laughter — with parallel cortico-subcortical pathways driving both.
As a narrative review, no primary data or statistical outcomes are reported. The authors acknowledge that reproducing spontaneous laughter in controlled laboratory settings remains a core methodological challenge, which may limit the completeness of the circuitry mapped so far.
Clinicians evaluating neurological disorders featuring pathological laughter (e.g., pseudobulbar affect, gelastic seizures) can use this dual-system framework to better localize lesions or stimulation targets. The cingulo-temporal vs. motor-opercular distinction may help differentiate involuntary from volitional laughter deficits at the bedside.
