We investigated to what extent emotional connotation influences cortical potentials during reading. To this end, event-related potentials (ERPs) were recorded during reading of high arousal pleasant and unpleasant and low arousal neutral adjectives that were presented at rates of 1 Hz and 3 Hz. Enhanced processing of both pleasant and unpleasant emotional compared to neutral adjectives was first reflected in an amplified early posterior negativity (EPN) starting from 200 ms after word onset. Later potentials (>300 ms), as analyzed in the slower 1 Hz condition, revealed facilitated processing selectively for pleasant adjectives that were associated with a reduced N400 and an enhanced late positive potential (LPP). Pleasant adjectives were also better remembered in an incidental memory test. Thus, emotionally relevant adjectives are processed spontaneously and selectively. Initially, emotional arousal drives attention capture (EPN). Healthy subjects may have a natural bias toward pleasant information facilitating late ERPs (N400, LPP) to pleasant adjectives as well as their superior recall.

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Which facial features allow human observers to successfully recognize expressions of emotion? While the eyes and mouth have been frequently shown to be of high importance, research on facial action units has made more precise predictions about the areas involved in displaying each emotion. The present research investigated on a fine-grained level, which physical features are most relied on when decoding facial expressions. In the experiment, individual faces expressing the basic emotions according to Ekman were hidden behind a mask of 48 tiles, which was sequentially uncovered. Participants were instructed to stop the sequence as soon as they recognized the facial expression and assign it the correct label. For each part of the face, its contribution to successful recognition was computed, allowing to visualize the importance of different face areas for each expression. Overall, observers were mostly relying on the eye and mouth regions when successfully recognizing an emotion. Furthermore, the difference in the importance of eyes and mouth allowed to group the expressions in a continuous space, ranging from sadness and fear (reliance on the eyes) to disgust and happiness (mouth). The face parts with highest diagnostic value for expression identification were typically located in areas corresponding to action units from the facial action coding system. A similarity analysis of the usefulness of different face parts for expression recognition demonstrated that faces cluster according to the emotion they express, rather than by low-level physical features. Also, expressions relying more on the eyes or mouth region were in close proximity in the constructed similarity space. These analyses help to better understand how human observers process expressions of emotion, by delineating the mapping from facial features to psychological representation.

Affective startle modulation in the electromyographic (EMG), auditory startle evoked potentials, and visually evoked potentials (VEPs) were assessed while subjects evaluated pleasant, unpleasant, and neutral adjectives. Acoustic startle probes were presented at random time points 2.5-4.0 s after word onset. The visual P2 and P3 potentials were generally larger during processing of emotional than of neutral adjectives. In contrast, the late positive component was enhanced and was correlated with larger EMG startle responses and auditory startle evoked potential P3 amplitudes for pleasant words only. During internal cognitive activity, the startle reflex represents a measure of "processing interrupt." Thus the startle tone interrupted processing of particularly pleasant adjectives and caused re-alerting to environmental stimuli. Specific effects for pleasant material may arise from a "positivity offset," favoring responses to pleasant material at lower arousal levels.

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Electroencephalographic event-related brain potentials were recorded as subjects read, without further instruction, consecutively presented sequences of words. We varied the speed at which the sequences were presented (3 Hz and 1 Hz) and the words' emotional significance. Early event-related cortical responses during reading differentiated pleasant and unpleasant words from neutral words. Emotional words were associated with enhanced brain responses arising in predominantly left occipito-temporal areas 200 to 300 ms after presentation. Emotional words were also spontaneously better remembered than neutral words. The early cortical amplification was stable across 10 repetitions, providing evidence for robust enhancement of early visual processing of stimuli with learned emotional significance and underscoring the salience of emotional connotations during reading. During early processing stages, emotion-related enhancement of cortical activity along the dominant processing pathway is due to arousal, rather than valence of the stimuli. This enhancement may be driven by cortico-amygdaloid connections.

This event-related functional magnetic resonance imaging (fMRI) study investigated brain activity elicited by emotional adjectives during silent reading without specific processing instructions. Fifteen healthy volunteers were asked to read a set of randomly presented high-arousing emotional (pleasant and unpleasant) and low-arousing neutral adjectives. Silent reading of emotional in contrast to neutral adjectives evoked enhanced activations in visual, limbic and prefrontal brain regions. In particular, reading pleasant adjectives produced a more robust activation pattern in the left amygdala and the left extrastriate visual cortex than did reading unpleasant or neutral adjectives. Moreover, extrastriate visual cortex and amygdala activity were significantly correlated during reading of pleasant adjectives. Furthermore, pleasant adjectives were better remembered than unpleasant and neutral adjectives in a surprise free recall test conducted after scanning. Thus, visual processing was biased towards pleasant words and involved the amygdala, underscoring recent theoretical views of a general role of the human amygdala in relevance detection for both pleasant and unpleasant stimuli. Results indicate preferential processing of pleasant information in healthy young adults and can be accounted for within the framework of appraisal theory.