Blink it to Sync it: Experimental Evidence of Indirect Synchronization of Human Brainwaves subjected to Common Photic Forcing

In an effort to achieve synchronization in mesoscopic cortical activities, dark room experiments were conducted on five individuals. An indirect coupling was established between the subjects via a common photic forcing. This work extends the replicability of a single neuron activity demonstrated by Mainen and Sejnowski (Science, 268(5216):1503–1506, 1995) to a meso-scale context, particularly within human brainwaves. To the best of our knowledge, this is the first experimental evidence that points to partial synchronization of human brainwaves. The synchronization was observed between intra- as well as inter-participant neural activities when subjected to periodic photic stimulus. This, interestingly, is a second-level synchronization as the neural rhythms are themselves generated from the partially synchronized neuronal activities. Further analysis was carried out by computing coherence and estimating phaseshifts. The results suggest that partial phase resetting could be the potential mechanism. These findings might hold potential implications for behavioural and psychological aspects of coordination and cooperation among individuals.