Two-stage processing in automatic detection of emotional intensity: a scalp event-related potential study.

Scalp electrophysiological studies have supposed that emotional intensity is processed from about 170 ms. However, this is inconsistent with the rapid emotion detection of the amygdala at around 100 ms. Besides, it is unreasonable to apply this assertion to all emotional types considering emotional-specific neural networks and fast/slow emotional routes. The current paper examined whether the earliest intensity effect appeared at around 170 ms for angry expression with a fast frontal-limbic pathway. In this event-related potential study, 30 graduates completed a change detection task rather than intensity evaluation. Before N170, the earliest intensity effects (P's<0.001) were found at about 100 ms with a latency delay from the frontal area to occipitotemporal sites. Automatic detection of expressional intensity was also shown by behavioral and oral reports. These results coincided with the emotional detection function of the amygdala and the view of a re-entrant mechanism in emotion recognition. Together with previous research, we suggested a two-stage processing of emotional intensity: re-entrant modulation and fine structure encoding. Overall, these findings shed light on the time course of expressional intensity detection in the emotional-specific neural network.