Critical brain states related with self-initiated attentional shift

Abstract

[Introduction] Visual attention is usually shifted by self-initiation in daily life, whereas most experiments of attention used a cue to indicate the location to focus. To understand the attention control system in daily life, it is crucial to investigate the brain activities corresponding to self-initiated attention. Criticality states of neural activities is one of possible indexes of the brain state in preparing attention shifts. Although neurons in different brain area exhibit various activities, it has been suggested that the multiscale brain activities follow the criticality theory. In this study, critical state was analyzed to investigate the possible mechanism related with self-initiated attentional shift, analyzing electroencephalogram (EEG) data. [Method] We conducted an experiment, in which subjects selected the location and time of attention shift freely, also allowing to choose not to shift. The critical state was analyzed separately for EEG results for different brain areas to compare brain activities under shift and no-shift cases. [Results] The results showed that, first, the critical brain state showed a power-law distribution with an exponent of -1.5 under both shift and no-shift conditions, which is consistent with prediction that brain attains an optimal dynamical regime for information processing. Second, the results showed that the transmission efficiency showed strong correlation with power-law exponent, with an efficiency of close to 1.0 under both shift and no-shift conditions, which supports the theory that exponent of power-law distribution from criticality state is closely related to transmission efficiency. Third, the results showed that significant difference of criticality states was found before the attentional shift between shift and no shift conditions, by comparing the power-law exponents during periods of time between about 3s and 1s before the time of attention shift. [Conclusion] The present results suggest that critical states of the global dynamics of brain activity is related to self-initiated attention.