Analysis of the FC of theta bands revealed stronger connectivity in the BD than the non-BD group. This is consistent with the results of a previous study, which reported that binge drinkers showed stronger theta connectivity than non-BD participants (Correas et al., 2015). Rapid formation and dissolution of functional connections are observed in normal people through synchronization and asynchronization between different brain areas (Herrera-Díaz et al., 2016). That is, for the brain to function properly, both synchronization and asynchronization of brain areas are required (Friston, 2000; Stam and De Bruin, 2004). The dynamics of brain FC can be impaired in two ways: by excessive connectivity or excessive disconnectivity (Stam and Van Straaten, 2012). Thus, increasing theta connectivity does not translate to better FC. For example, it has been reported that patients with epilepsy have excessive neural connections when seizures occur (Gorji and Speckmann, 2009), and patients with mild cognitive impairment show increased resting theta connectivity as a precursor to dementia (Pijnenburg et al., 2004; Buldú et al., 2011).
