Resumo

Introduction Orienting of visual attention to the right visual hemifield seems particularly more noticeable as compared to the left visual hemifield (Mesulam, 1999; Rodrigues and Xavier, in preparation). Professional musicians exhibit both structural brain (Schlaug, 2001) and cognitive (Schellenberg, 2004, Costa-Giomi et al., 2001, Klein et al., 1984) changes, apparently related to extensive training involving constant re-orienting of attention between the score and the instrument performance. This extensive training can possibly change the dynamic characteristics of neural networks involved in orienting attention. Objectives This study aimed at investigating the occurrence of asymmetries in covert orienting of visual attention in professional musicians as compared to non-musicians. Methods Six professional musicians and twenty one non-musicians, male and female healthy volunteers, were tested in a modified version of the Posner’s (1980) covert attention task. A pre-test session allowed identification of the volunteers’ visual thresholds (in terms of time duration) for 80% of correct detections, for each stimulus to be later used as cue or target. During testing, central predictive cues (80% valid and 20% invalid) lasting twice the duration of the respective threshold were used to induce orienting of attention. The subjects had to react to target stimuli lasting the duration of the respective threshold. The stimuli onset asynchronies (SOA) were 100, 300 and 700 ms. Reaction times (RT) and percentage of errors (target omission) were analyzed using repeated measures ANOVA. Results ANOVA for RT revealed significant Validity (F1,23=32.282; p<0.0001) and SOA (F2,22=55.220; p<0.0001) main effects, and significant Hemifield x Group (F1,23=7.125; p=0.0137) and Validity x Hemifield (F1,23=9.805; p=0.0047) interaction effects. Non-musicians exhibited, as expected, greater validity-related differences in RTs for targets presented at the right hemifield as compared to the left hemifield. In contrast, musicians exhibited no validity-related differences in RTs for both hemifields. ANOVA for percentage of errors revealed significant difference between groups (F1,23=6.716; p=0.0163) and close to significant Hemifield x Group (F1,23=3.516; p=0.0735) interaction effect. Percentage of errors by musicians, as compared to non-musicians, was smaller, particularly in relation to the left hemifield. Conclusions These results show that musicians and non-musicians exhibit differences in orienting of visual attention. While non-musicians exhibit noticeable orienting of visual attention towards the right hemifield, musicians exhibit a symmetric orienting of visual attention and exhibit fewer mistakes relative to non-musicians. These results do not conflict with suggestions that formal study of music improves cognitive performance in humans (Schellenberg, 2004, Costa-Giomi et al., 2001, Klein et al., 1984).