Research in the last decades has shown that individuals with high degrees in the personality trait of alexithymia not only have difficulties in identifying and recognizing own feelings, but also show deficits in reading emotions from facial expressions of other people. Therefore, the current dissertation investigates the neural correlates of recognizing emotional facial expressions as a function of alexithymia. Initially, a theoretical introduction is given and existing findings from behavioral as well as structural and functional neuroimaging research are presented. Open questions are identified and addressed in one structural and two functional magnetic resonance imaging studies that were compiled into three original research articles. Study 1 examined the gray matter profile of high and low alexithymic individuals in selected brain regions relevant for processing emotional faces. In Study 2, functional neuroimaging was used to investigate the neural correlates of high alexithymic individuals\' difficulties in labeling briefly presented (≤ 100 ms) facial expressions of emotion. Study 3 investigated neural activations as a function of alexithymia during the labeling of emotional facial expressions when these are presented with little temporal constraints (≥ 1 s). The results of these studies are summarized and integrated with the existing literature. Finally, open issues are discussed and ideas for further research are outlined.

Research in the last decades has shown that individuals with high degrees in the personality trait of alexithymia not only have difficulties in identifying and recognizing own feelings, but also show deficits in reading emotions from facial expressions of other people. Therefore, the current dissertation investigates the neural correlates of recognizing emotional facial expressions as a function of alexithymia. Initially, a theoretical introduction is given and existing findings from behavioral as well as structural and functional neuroimaging research are presented. Open questions are identified and addressed in one structural and two functional magnetic resonance imaging studies that were compiled into three original research articles. Study 1 examined the gray matter profile of high and low alexithymic individuals in selected brain regions relevant for processing emotional faces. In Study 2, functional neuroimaging was used to investigate the neural correlates of high alexithymic individuals\'' difficulties in labeling briefly presented (≤ 100 ms) facial expressions of emotion. Study 3 investigated neural activations as a function of alexithymia during the labeling of emotional facial expressions when these are presented with little temporal constraints (≥ 1 s). The results of these studies are summarized and integrated with the existing literature. Finally, open issues are discussed and ideas for further research are outlined.

Die Blickrichtung und ihre Richtung sind wichtige nonverbale Hinweise für die Etablierung von sozialen Interaktionen und die Wahrnehmung von emotionalen Gesichtsausdrücken bei anderen. Ob der Blick direkt auf den Betrachter gerichtet ist (direkter Blick) oder abgewendet (abgewandter Blick), beeinflusst unsere soziale Aufmerksamkeit und emotionale Reaktionen. Dies deutet darauf hin, dass Emotionen und Blickrichtung informative Werte haben, die sich möglicherweise in frühen oder späteren Stadien der neurokognitiven Verarbeitung interagieren. Trotz theoretischer Grundlage, der geteilten Signal-Hypothese (Adams & Kleck, 2003), gibt es einen Mangel an strukturierten elektrophysiologischen Untersuchungen zu den Wechselwirkungen zwischen Emotionen und Blickrichtung sowie ihren neuronalen Korrelaten und wie sie sich in verschiedenen Bevölkerungsgruppen unterscheiden. Um diese Lücke zu schließen, verwendete diese Doktorarbeit ereigniskorrelierte Hirnpotentiale (ERPs), um die Reaktionen auf emotionale Ausdrücke und Blickrichtung in einem neuen Paradigma zu untersuchen, das statischen und dynamischen Blick mit Gesichtsausdrücken kombiniert. Es wurden drei verschiedene Populationen untersucht. Studie 1 untersuchte in einer normalen Stichprobe die Amplituden der ERP-Komponenten, die durch die erstmalige Präsentation von Gesichtern und nachfolgende Änderungen der Blickrichtung in der Hälfte der Durchgänge ausgelöst wurden. In Studie 2 wurden aufgrund der atypischen Gesichtsverarbeitung und verminderten Reaktionen auf Augenblick beim Autismus die ERPs und Augenbewegungen bei zwei Stichproben von Kindern mit unterschiedlichem Schweregrad ihrer Autismusmerkmale untersucht. In Studie 3 wurde in einer großen Stichprobe die vermutlich erhöhte Sensitivität bei der Emotionsverarbeitung und Reaktion auf Augenblick bei Müttern im postpartalen Zeitraum mit besonderem Fokus auf die Gesichter von Säuglingen untersucht. Zusammenfassend zeigen die Ergebnisse der drei Studien, dass in sozialen Interaktionen die emotionalen Effekte von Gesichtern durch die dynamische Blickrichtung moduliert werden. / The eye gaze and its direction are important and relevant non-verbal cues for the establishment of social interactions and the perception of others’ emotional facial expressions. Gaze direction itself, whether eyes are looking straight at the viewer (direct gaze) or whether they look away (averted gaze), affects our social attention and emotional response. This implies that both emotion and gaze have informational values, which might interact at early or later stages of neurocognitive processing. Despite the suggestion of a theoretical basis for this interaction, the shared signal hypothesis (Adams & Kleck, 2003), there is a lack of structured electrophysiological investigations into the interactions between emotion and gaze and their neural correlates, and how they vary across populations. Addressing this need, the present doctoral dissertation used event-related brain potentials (ERPs) to study responses to emotional expressions and gaze direction in a novel paradigm combining static and dynamic gaze with facial expressions. The N170 and EPN were selected as ERP components believed to reflect gaze perception and reflexive attention, respectively. Three different populations were investigated. Study 1, in a normal sample, investigated the amplitudes of the ERP components elicited by the initial presentation of faces and subsequent changes of gaze direction in half of the trials. In Study 2, based on the atypical face processing and diminished responses to eye gaze in autism, the ERPs and eye movements were examined in two samples of children varying in the severity of their autism traits. In Study 3, In a large sample, I addressed the putatively increased sensitivity in emotion processing and response to eye gaze in mothers during their postpartum period with a particular focus on infant's faces. Taken together, the results from three studies demonstrate that in social interactions, the emotional effects of faces are modulated by dynamic gaze direction.