Neural correlates of humour: variability of the global fNIRS signal associated with laughter.
Laughter is a universal social and emotional behaviour which has attracted the attention of philosophers and neuroscientists alike. As an embodied phenomenon, laughter will be examined using emerging anti-localisationist approaches that integrate phenomenology and classical neuroscientific findings. Recent advances in global functional brain modelling, as well as in the collection and analysis of functional near-infrared spectroscopy (fNIRS) data, now allow cortical dynamics to be reliably measured in naturalistic environments with less influence from movement artefacts. This study aims to investigate the dynamics of global cortical activity using metastability as a metric to verify its association with laughter behaviour. fNIRS data will be collected from 48 healthy adults while they watch humorous videos designed to provoke spontaneous laughter. Rest-task-rest tasks will also be performed using non-humorous videos and voluntary laughter. Based on recent findings linking brain metastability to specific cognitive states and flexibility, the main hypotheses are that global metastability will be slightly higher during spontaneous laughter than during non-humorous content, and higher during rest after spontaneous laughter than before. Bayesian regression models will be fitted to the data and the difference between the relevant coefficients will be used to test specific hypotheses. Should the data corroborate these hypotheses, the study will provide new evidence for an emerging theory of the global brain dynamics underlying emotional states and behaviours.