Abstract
Although appreciation and spontaneous creation of visual art are intrinsic elements common across cultures and races, little is known about the functioning of the human brain while mentally composing an artwork. In this study, this issue was addresses by analyzing multivariate EEG signals obtained from two broad groups — artists (professionally trained in fine art) and non-artists — while they were mentally drawing paintings of their own choices. EEGs at rest were also considered. Our analysis was motivated by the hypothesis that mentally composing an art, like other complex cognitive act (Bhattacharya et al. (2001) J. Neurosci. 21: 6329–6337), requires not only co-activation of distributed cortical regions but also functional interdependences between them. To assess the hidden coupling or synchrony between multiple cortical regions, three measures, inspired by nonlinear dynamical system theory, were applied as follows: (i) index based on generalized synchrony (dynamic correlations including asynchronous coupling), (ii) mean phase coherence (circular variance of the angular phase difference), and (iii) phase synchrony index based on entropy (based on the generalization of noisy and chaotic coupled system in a common framework); results consistent across all three measures were emphasized. Comparing task (mental drawing) to rest, artists showed extensive delta and theta band synchrony over multiple cortical regions bilaterally and higher beta and gamma band synchrony in temporal cortex, whereas non-artists showed enhancement, to a lesser extent, primarily in frontal regions over multiple frequency bands. Comparing two groups during the task, significantly higher delta band synchrony was found in artists as compared with non-artists, yet desynchronization was found in the alpha band in artists; higher synchrony in low frequency band (primarily delta) is likely due to an involvement of a more advanced long-term visual art memory in artists. The results indicated that the patterns of functional integration during spontaneous mental creation of paintings are significantly different in artists from that in non-artists.
Acknowledgement. J.B. thanks Sloan Foundation for finanial support.