Abstract art and cortical motor activation: an EEG study

Abstract

The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works.

Keywords: EEG; abstract art; cortical motor system; mu rhythm suppression; perception.

Figure 1

Upper panel: Experimental paradigm. Lower panel: Photographs of three Original art works by Lucio Fontana (top) and three graphically modified version of them (Control stimuli, bottom).

Figure 2

Clusters of electrodes selected for statistical analyses. Analysis of mu rhythm was performed on two clusters of eight electrodes each, located around standard C3 and C4 sites. Analysis of posterior visual alpha was carried out on two clusters of four electrodes each, located around standard O1 and O2.

Figure 3

EEG time-frequency spectrum of one participant extracted from C3 and C4 sites in the two experimental Conditions and in the Baseline. A continuous wavelet transformation was performed for the frequencies from 1 to 30 Hz in a time window of 1 s, which corresponds to the total duration of stimulus presentation. Red color indicates increased mu rhythm squared amplitude, while blue color indicates decreased mu rhythm squared amplitude in a given frequency band (see scale bar). The rectangles added to each panel highlight the 7 Hz wide frequency band (8–14 Hz) and the time window (250–750 ms) used for statistical analysis.

Figure 4

Amplitude-squared of mu rhythm expressed as Log Ratio in Control and Original conditions. The amplitude squared (μv²) was transformed as the Log Ratio between the experimental conditions relative to the Baseline power. Negative values represent a decrease of the mu rhythm power, positive values an increase of it. Plots represent the interaction Condition × Familiarity (p > 0.5) resulted from the ANOVA performed on mu rhythm expressed as Log Ratio.

Figure 5

Topo maps of the fast Fourier transforms performed on the alpha and beta ranges in both experimental conditions. Mu suppression was bilateral and stronger during the observation of the Original Artworks compared with the observation of Control stimuli. Beta range modulation was absent in both experimental conditions.

Figure 6

Results of the analysis performed on the alpha power extracted from occipital electrodes. Plots show that that the observation of the two different categories of stimuli did not evoke any difference in the posterior visual alpha modulation in both hemispheres.

Figure 7

Results of the ANOVAs performed on the aesthetic appraisal (A), amount of perceived movement (B), and artistic nature (C) in both groups of participants. Plots of panels (A) and (B) represent the significant Condition × Familiarity interaction. The interaction was not significant in panel (C).

Figure 8

Electromyography recorded from right First Dorsal Interosseous and Biceps muscles during observation of Original and Control stimuli. Plots presented in the left part of the figure illustrate the results of the statistical analysis indicating that the observation of both, Original and Control stimuli did not evoke any EMG activation of the right hand and arm. The right part of the figure shows an example of the EMG activity recorded in one participant from both muscles, during one trial of both experimental conditions.