Drawing on mind's canvas: differences in cortical integration patterns between artists and non-artists

Abstract

Our primary question was to learn whether mentally composing drawings of their own choice produce different brain electric features in artists and laymen. To this purpose, we studied multichannel electroencephalograph (EEG) signals from two broad groups (all participants were females): artists (professionally trained in visual arts) and non-artists (without any training in art). To assess the underlying synchronization, which is assumed to be the platform for general cognitive integration between different cortical regions, three measures inspired by nonlinear dynamical system theory were applied as follows: (1) index based on generalized synchronization; (2) index based on mean phase coherence; and (3) index of phase synchrony based on entropy. Results consistent over all three measures were as follows: comparing the tasks to rest, the artists showed significantly stronger short- and long-range delta band synchronization, whereas the non-artists showed enhancement in short-range beta and gamma band synchronization primarily in frontal regions; comparing the two groups during the tasks, the artists showed significantly stronger delta band synchronization and alpha band desynchronization than did the non-artists. Strong right hemispheric dominance in terms of synchronization was found in the artists. In artists, the higher synchrony in the low-frequency band is possibly due to the involvement of a more advanced long-term visual art memory and to extensive top-down processing. The results demonstrate that in artists, patterns of functional cooperation between cortical regions during mental creation of drawings were significantly different from those in non-artists.

Figure 1

Positions of the 19 electrodes and their designations according to the International standard 10‐20 electrode placement system [Jasper, 1958]. Nose is pointed toward right.

Figure 2

Measures of synchrony, in terms of E, R, and ρ, during the performance of creative imagery task for two groups: artists (black bars) and non‐artists (white bars). Results were pooled over subjects within each group, all possible electrode combinations, and nonoverlapping windows. Note the differences of the scale of synchrony measures of different frequency bands. Except theta, other frequency bands show a similar trend.

Figure 3

Statistical comparison in terms of long‐range (left column) and short‐range (right column) synchrony in different frequency bands, as expressed by the number of electrode pairs showing significant (P _mod < 0.0002) changes between two groups: artists (black bars) and non‐artists (white bars). Results were shown for three different indices: E (upper panel), R (middle panel), and ρ (lower panel). Differences between two groups are found to be most prominent in delta (higher in artists) and alpha bands (higher in non‐artists).

Figure 4

Significant probability (P _mod < 0.000001) mapping or the topographic representations showing the comparison in the degree of synchrony (as measured by E) in different frequency bands between the groups of artists and non‐artists during mental composition of drawings. Significant increases for artists are indicated by thick lines between both electrode regions involved. Similarly, thin lines are due to significant increases in non‐artists. Two hemispheres are shown separately for showing intrahemispheric connections and the lowest scheme displays only interhemispheric connections. Note the significantly higher delta band synchrony for artists, whereas alpha band synchrony was stronger for non‐artists.

Figure 5

Significant probability mapping showing significant increases in the degree of synchronization in different frequency bands during mental composition of drawings as compared to the EEG at rest for the group of artists. An unmatched rank‐sum Wilcoxon test (P _mod < 0. 0002) was used as statistical filter. Only increases (as compared to the resting condition) were reported. Most prominent is the extensive enhancement of delta band synchrony.

Figure 6

Same as in Figure 5 but for the group of non‐artists. Note enhancement of gamma band synchrony in frontal cortical regions.