The Sound of Feelings Figure 3. ERP Results: MMN and P3 for Emotional Prosody in Alexithymia. ERP results for task 1 (left, unattended processing) and task 2 (right, attended processing). Grand averages of all subjects at electrode site Fz for the eMMN and lMMN and at electrode site Pz for the P3, corresponding to the topographic distribution of these components. Standards versus deviants, with ERP components used for analysis identified. ‘EMMN’ and ‘lMMN’: depicted are the actual ERPs elicited by deviants in emotional prosody. For statistical analysis, difference waves were calculated for the eMMN and lMMN in correspondence with the common procedure by subtracting ERPs elicited by standards from ERPs elicited by deviants. doi:10.1371/journal.pone.0036951.g003 In summary, difficulty verbalizing and identifying feelings as part of the cognitive alexithymia dimension were associated with an earlier left-hemispheric response and a trend toward a delayed right-hemispheric response during the early acoustic encoding (eMMN) of subconsciously perceived variations in emotional speech. Difficulty identifying feelings was further associated with delayed encoding of disgusted prosody. In contrast, the affective alexithymia dimension was not associated with altered unattended processing of emotional speech. Neither alexithymia dimension affected the later stage of global acoustic processing (lMMN). Table 1. Statistical results of the RM-MANCOVA including the affective alexithymia dimension as a covariate. Main effects and interactions Post hoc tests EMMN Amplitude Latency LMMN Amplitude Latency N1 Amplitude Latency P2 Amplitude Latency P3 Amplitude Region F (4,216) = 10.892, p,.001 Laterality 6 Region F (8,432) = 5.751, p,.001 Region F (4,216) = 4.521, p = .014 Region F (4,216) = 4.990, p = .019 Laterality 6 Region F (8,432) = 2.778, p = .030 Emotion F (3,162) = 4.565, p = .004 Emotion 6 Region F (12,648) = 2.269, p = .046 No significant effects No significant effects Region F (2,114) = 22.065, p,.001 Region 6 Affective Dimension F (2,114) = 6.836, p = .006 Laterality F (2,102) = 3.406, p = .037 Intensity F (1,56) = 6.044, p = .017 Intensity 6 Affective Dimension F (1,56) = 5.792, p = .019 Laterality F (2,112) = 7.322, p = .001 Intensity 6 Region F (2,112) = 4.459, p = .037 Intensity 6 Region 6 Affective Dimension F (2,112) = 4.093, p = .046 Latency Region F (2,112) = 4.964, p = .017 Post hoc tests are significant at p,.05 (Sidak-corrected) unless otherwise specified. doi:10.1371/journal.pone.0036951.t001 Reduced P2 peak amplitudes at frontal regions with increasing scores on the affective alexithymia dimension (fantasizing subscale) Stronger reduction in P3 peak amplitudes for high intensity prosody compared to low intensity prosody with increasing scores on the affective alexithymia dimension (emotionalizing subscale) Reduced P3 peak amplitudes at central regions for high intensity prosody with increasing scores on the affective alexithymia dimension (fantasizing subscale) PLoS ONE | www.plosone.org 8 May 2012 | Volume 7 | Issue 5 | e36951