The Sound of Feelings Figure 1. Electrode Map. Electrode map with electrodes used for analysis identified. Factors included in analysis: laterality (left hemisphere, midline, right hemisphere), and region (frontal, frontocentral, central, centroparietal, and parietal). doi:10.1371/journal.pone.0036951.g001 ERP data. During unattended processing of emotional prosody (task 1), eMMN and lMMN peak amplitudes and latencies elicited by happy, angry, sad, and disgusted prosodic deviants were analyzed. From the 60 subjects, the data of four subjects had to be discarded due to large amounts of eye blink and motion artefacts leaving an insufficient number of target trials for analysis. Four (emotion: happy vs. angry vs. sad vs. disgusted) by 3 (laterality: left hemisphere vs. midline vs. right hemisphere) by 5 (region: frontal vs. frontocentral vs. central vs. centroparietal vs. parietal) repeated-measures multivariate analyses of covariance (RM-MANCOVA) were then performed on the data of the remaining 56 participants with scores on the affective and cognitive alexithymia dimensions included as covariates. In case of significant interactions of factors with the covariates, follow up MANCOVAs were conducted for each level of the respective factor in order to identify the sources of the effect. In addition, MANCOVAs including each subscale of the respective alexithy- mia dimension as covariates were conducted in order to test which subscale significantly contributed to the effect. During attended processing of emotional prosody (task 2), peak amplitudes and latencies of the N1, P2, and P3 elicited by happy, angry, and disgusted prosodic deviants spoken in low (e.g. a bit angry) and high (e.g., very angry) intensity were analyzed in 57 subjects. The data of three subjects were discarded due to high amounts of eye blink and motion artefacts. Only trials of correctly detected prosodic deviants were included in the analysis. Affective scores of subjects in task 2 ranged from 20 to 55 (median: 35, SD: 9.7), cognitive scores ranged from 27 to 93 (median: 53, SD: 17.4). Two (intensity: low vs. high) by 3 (emotion: happy vs. angry vs. disgusted) by 3 (laterality: left vs. middle vs. right) by 3 (region) RM-MANCOVAs were conducted with affective and cognitive alexithymia scores included as covariates. Follow up MANCOVAs were conducted to identify the sources and the contribution of separate BVAQ subscales to the observed effects. The three levels of the factor region varied for the N1, P2 and P3 in accordance with the known topographic distributions of these components when elicited in the auditory modality: The N1 has a central maximum and was therefore analyzed at frontocen- tral, central, and centroparietal regions. The P2 is maximal over anterior regions, the analysis therefore comprised anterior electrode sites (frontal, frontocentral, and central). The P3 is known to have a centroparietal-parietal maximum, thus central, centroparietal, and parietal regions were included in the P3 analysis. In case of sphericity violations, Greenhouse-Geisser corrected p- values are reported. A Sidak correction of p-values was used in pairwise comparisons between the levels of factors. Results are reported with a focus on main effects and interactions with the affective and cognitive alexithymia dimensions. Results Behavioral data Pearson’s correlation confirmed a high correlation between the cognitive dimension of alexithymia as assessed by the three cognitive BVAQ subscales and the TAS-20 total score (r = 0.85, p,0.01). Behavioral data of task 2 (detection of prosodic deviants) revealed no significant correlations of the cognitive and affective alexithymia dimensions with accuracy (ACC, cognitive dimension: PLoS ONE | www.plosone.org 6 May 2012 | Volume 7 | Issue 5 | e36951