005. Although the threshold did not reach our criteria, these results are compatible with the ROI analysis. As the order of the sessions was fixed, the observed results in the comparison between the random and within-/between-group omissions might include the influence

of adaptation or fatigue in general. In order to evaluate such influences, we created buy KU-60019 the reconstruction maps for the brain activity elicited by the L tones and conducted two-sample t-tests between the random sequence and group sequence. If such mental health conditions affected the omission-related response, it should also be shown in the brain activity elicited by the L tone. However, this analysis did Aloxistatin clinical trial not show any significant result in both subject groups, indicating that the obtained results for the omission-related response were not due to adaptation or fatigue. The

ability to integrate sound features is necessary to perceive a sequence of tones as a perceptual group, which might be a basis for auditory perception (Winkler et al., 2009; Bendixen et al., 2012). Many studies have indicated that pre-attentive processing of perceptual grouping works well when the ISI between tone stimuli is less than 200 ms (Yabe et al., 1997; Sussman et al., 1999; Deike et al., 2004; Micheyl et al., 2007). In the present study, we investigated the attentive processing of perceptual grouping using auditory stimuli with an ISI longer than 200 ms and the effect of musical experience. The results indicate that the regular pattern of the tone sequence had impacts on both the behavioral performance and neural response elicited by the omission. In addition, we found that musicians showed the right IPL for the processing of sound omission, whereas non-musicians showed the left STG. The results and possible interpretations are discussed in the following sections. Several psychological studies have shown that the perceptual grouping of stimuli affects behavioral performance. For example, detection Immune system or recognition is faster and more accurate for target stimuli that are inconsistent with the grouping

structure of stimuli, compared with consistent target stimuli (Idson & Massaro, 1976; Jones et al., 1982; Mondor & Terrio, 1998). This evidence is consistent with the results of the present study, which showed that detection of omission in the random sequence was faster than that in the group sequence. In addition, the subjects in the present study reported recognising the group sequence as a repetition of the ‘LLS’ pattern. Therefore, we believe that the perceptual grouping successfully occurred in the group sequence in the present study. The predictive coding theory suggests that the auditory system continuously searches for regularities to organise a perceptual unit within a tone sequence (Winkler et al., 2009; Bendixen et al., 2012).