The N400 and late occipital positivity in processing dynamic facial expressions with natural emotional voice.

People require multimodal emotional interactions to live in a social environment. Several studies using dynamic facial expressions and emotional voices have reported that multimodal emotional incongruency evokes an early sensory component of event-related potentials (ERPs), while others have found a late cognitive component. The integration mechanism of two different results remains unclear. We speculate that it is semantic analysis in a multimodal integration framework that evokes the late ERP component. An electrophysiological experiment was conducted using emotionally congruent or incongruent dynamic faces and natural voices to promote semantic analysis. To investigate the top-down modulation of the ERP component, attention was manipulated via two tasks that directed participants to attend to facial versus vocal expressions. Our results revealed interactions between facial and vocal emotional expressions, manifested as modulations of the auditory N400 ERP amplitudes but not N1 and P2 amplitudes, for incongruent emotional face-voice combinations only in the face-attentive task. A late occipital positive potential amplitude emerged only during the voice-attentive task. Overall, these findings support the idea that semantic analysis is a key factor in evoking the late cognitive component. The task effect for these ERPs suggests that top-down attention alters not only the amplitude of ERP but also the ERP component per se. Our results implicate a principle of emotional face-voice processing in the brain that may underlie complex audiovisual interactions in everyday communication.

Discrete cortical regions associated with the musical beauty of major and minor chords.

Previous research has demonstrated that the degree of aesthetic pleasure a person experiences correlates with the activation of reward functions in the brain. However, it is unclear whether different affective qualities and the perceptions of beauty that they evoke correspond to specific areas of brain activation. Major and minor musical keys induce two types of affective qualities--bright/happy and dark/sad--that both evoke aesthetic pleasure. In the present study, we used positron emission tomography to demonstrate that the two musical keys (major and minor) activate distinct brain areas. Minor consonant chords perceived as beautiful strongly activated the right striatum, which has been assumed to play an important role in reward and emotion processing, whereas major consonant chords perceived as beautiful induced significant activity in the left middle temporal gyrus, which is believed to be related to coherent and orderly information processing. These results suggest that major and minor keys, both of which are perceived as beautiful, are processed differently in the brain.

Electrophysiological correlates of absolute pitch and relative pitch.

The temporal and spatial characteristics of the cortical processes responsible for absolute pitch (AP) and relative pitch (RP) were investigated by multi-channel event-related potentials (ERPs). Compared to listening, pitch-naming of tones in non-possessors of AP elicited three ERP components (P3b, parietal positive slow wave, frontal negative slow wave) over parietal and frontal scalp between 300 and 900 ms in latency, representing the cortical processes for RP. Possessors of AP elicited a unique left posterior-temporal negativity ('AP negativity') at 150 ms in both listening and pitch-naming conditions, representing the cortical processes for AP that were triggered by pitch input irrespective of the task the subjects were asked to perform. Congruency of auditory Stroop stimuli modulated the amplitudes of parietal positive slow wave (non-possessors of AP) and 'AP negativity' (possessors of AP), confirming that these components reflect the verbal labeling or pitch-to-pitch-name associative transformation that is central to pitch-naming. These results are consistent with the hypothesis that AP is subserved by neuronal processes in the left auditory association cortex that occur earlier and more automatically than the processes for RP, which involve broader areas of the cortex over longer periods of time.