Format

Send to

Choose Destination
J Neurosci. 2017 Jun 21;37(25):6125-6131. doi: 10.1523/JNEUROSCI.0688-16.2017. Epub 2017 May 23.

Social Laughter Triggers Endogenous Opioid Release in Humans.

Author information

1
Turku PET Centre, University of Turku, 20520 Turku, Finland.
2
Department of Neuroscience and Biomedical Engineering, School of Science, Aalto University, 00076 Aalto, Finland.
3
Department of Experimental Psychology, University of Oxford, OX1 3UD Oxford, United Kingdom.
4
Department of Art, School of Arts, Design and Architecture, Aalto University, 00076 Aalto, Finland, and.
5
Turku PET Centre, University of Turku, 20520 Turku, Finland, latanu@utu.fi.
6
Department of Psychology, University of Turku, 20014 Turku, Finland.

Abstract

The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [11C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold-a proxy of endogenous opioidergic activation-was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds.SIGNIFICANCE STATEMENT Social contacts are vital to humans. The size of human social networks significantly exceeds the network that can be maintained by social grooming in other primates. Here, we used PET to show that endogenous opioid release after social laughter may provide a neurochemical mechanism supporting long-term relationships in humans. Participants were scanned twice: after a 30 min social laughter session and after spending 30 min alone in the testing room (baseline). Endogenous opioid release was stronger after laughter versus the baseline scan. Opioid receptor density in the frontal cortex predicted social laughter rates. Modulation of the opioidergic activity by social laughter may be an important neurochemical mechanism reinforcing and maintaining social bonds between humans.

KEYWORDS:

bonding; carfentanil; emotion; laughter; opioids; positron emission tomography

PMID:
28536272
DOI:
10.1523/JNEUROSCI.0688-16.2017
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center