In this study, the effect of semantic information processing was investigated by the oddball paradigm, by presenting consecutive Turkish words or word-like non-words while EEG signals are recorded. In an oddball paradigm, a series of events are presented of which one class is rarer than the other. Subjects are asked to respond to the infrequent stimuli (e.g. press a button, or count the number). The event related potential (ERP) component P300 obtained from EEG is considered as the marker of this attention capturing paradigm. P300 is obtained consistently for both visual and verbal stimulus. On the other hand, the ERP component N400 is consistently associated with semantic processing in neurolinguistics. Additionally, Late Positive Component (LPC) is a marker for the top-down attention mechanism during word comprehension. Moreover, there are other components, called early ERPs, which occur between 100-200 ms after the stimulus onset. These components orthographically and phonologically reflect low-level features of words. The target words chosen for our study are strictly limited to belong to a neutral category and not consist of any emotional content, to rule out emotional interference in semantic processing. Based on the ERP components that were obtained from this study, the LPC potential exhibited for words had higher amplitude than that of non-words consistently and statistically significantly. However, our study was confounded with the heterogeneity of non-words because some of the non-words were non-sense letter sequences while others were pseudowords. Due to this, although we observed the P300 and N400 ERPs consistently for all stimuli, we did not find significant differences for these potentials between words and non-words. To the best of our knowledge, our investigation is one of the few studies conducted with EEG recordings in a task that involved lexical decision making in Turkish.

Because event-related potentials (ERPs) can reflect individual differences in intellectual ability, individual differences in college grade-point average (GPA) may be associated with specific individual ERP waves, such as the P300. However, P300 amplitude is higher in women than in men and varies across the menstrual cycle, factors that could confound the association between GPA and ERPs. In this regard, our objective was to determine whether differences in GPA are reflected in ERPs while standardling for sex and menstrual phase. After participants provided informed consent, we obtained GPAs from 22 right-handed college students (11 male, age range 22 to 26 and 10 female, age range 17 to 24) at a university with high admission and retention standards. We assessed menstrual phase by measuring luteinizing hormone levels across the cycle. We then obtained ERPs for each male participant and ERPs during each phase of the menstrual cycle for each female participant in an object-recognition visual pop-out protocol using Net Station Software (Electrical Geodesics, Inc., Eugene, Oregon) and E-prime Software (Psychology Software Tools, Inc., Sharpsburg, Pennsylvania). Males had larger P300s than females. The male and female high GPA was significantly different from the low GPA male and female groups. High GPA in females and males were associated with a positive peak at approximately 689 ms that was not present in the low-GPA male group and was significantly diminished in low-GPA females. Electro-cortical processing of cognitive stimuli differs between college students with high and low GPAs.

Des sons émotionnels furent présentés comme stimuli cibles lors d'une tâche auditive de type oddball. Les effets acoustiques furent départagés des effets émotionnels à l'aide d'une tâche contrôle similaire utilisant une version brouillée des sons originaux et dépourvue de propriétés émotionnelles. Les résultats du oddball émotionnel qui ont différé du oddball contrôle ont montré des effets de valence inversés dans les composantes électrophysiologiques P2 et P300; la valence négative ayant une amplitude plus grande dans la fenêtre de 130-270ms mais moins intense autour de 290-460ms, lorsque comparée aux valences positives et neutres. Les résultats P2 peuvent être interprétés comme une mobilisation attentionnelle précoce privilégiant les stimuli potentiellement dangereux, tandis que les résultats de la P300 pourrait indiquer une évaluation moins détaillée de ces stimuli. / In an auditory oddball task, negatively (disgust) and positively (laughter) valenced sounds were presented as rare targets. To disentangle acoustic effects from emotional ones, a control oddball was conceived with a non‐emotional scrambled version of the original target sounds as rare targets. Results from the emotional oddball that differed from the control oddball showed an inverse effect of valence in the P2 and P300 range, with negative valence having higher mean amplitude values in the 130‐270ms range, but lower values in the 290‐460 range when compared to ERPs elicited by positive and neutral valence. The P2 results are interpreted as early mobilization of attentional resources towards potentially threatening stimuli, while the P300 results could reflect less detailed evaluation of such stimuli.

Des sons émotionnels furent présentés comme stimuli cibles lors d'une tâche auditive de type oddball. Les effets acoustiques furent départagés des effets émotionnels à l'aide d'une tâche contrôle similaire utilisant une version brouillée des sons originaux et dépourvue de propriétés émotionnelles. Les résultats du oddball émotionnel qui ont différé du oddball contrôle ont montré des effets de valence inversés dans les composantes électrophysiologiques P2 et P300; la valence négative ayant une amplitude plus grande dans la fenêtre de 130-270ms mais moins intense autour de 290-460ms, lorsque comparée aux valences positives et neutres. Les résultats P2 peuvent être interprétés comme une mobilisation attentionnelle précoce privilégiant les stimuli potentiellement dangereux, tandis que les résultats de la P300 pourrait indiquer une évaluation moins détaillée de ces stimuli. / In an auditory oddball task, negatively (disgust) and positively (laughter) valenced sounds were presented as rare targets. To disentangle acoustic effects from emotional ones, a control oddball was conceived with a non‐emotional scrambled version of the original target sounds as rare targets. Results from the emotional oddball that differed from the control oddball showed an inverse effect of valence in the P2 and P300 range, with negative valence having higher mean amplitude values in the 130‐270ms range, but lower values in the 290‐460 range when compared to ERPs elicited by positive and neutral valence. The P2 results are interpreted as early mobilization of attentional resources towards potentially threatening stimuli, while the P300 results could reflect less detailed evaluation of such stimuli.

Personen mit Morbus Parkinson (MP) erleben Herausforderungen beim Erinnern, Planen und Ausführen täglicher Abläufe, die über motorische Symptome hinausgehen. Störungen in der Verarbeitung von Alltagsereignissen könnten eine zentrale Rolle spielen, jedoch sind potentielle Defizite und neuronale Mechanismen unzureichend untersucht. In Studie 1 untersuchten wir das Segmentierungsverhalten während der Betrachtung von naturalistischen Filmen und dessen Beziehung zum Ereignisgedächtnis. Die Ergebnisse zeigten Abweichungen im Segmentierungsverhalten bei MP, wobei größere Abweichungen mit mehr Fehlern im Gedächtnisabruf der zeitlichen Ereignisabfolge einhergingen. Darüber hinaus weisen wenige Verhaltensstudien auf eine gestörte zeitliche Ereignisverarbeitung bei MP hin, aber zugrundeliegende Mechanismen wurden selten untersucht. Resultate zur Struktur und zum Abruf von Ereigniswissen im Langzeitgedächtnis sind uneindeutig. In Studie 2 analysierten wir daher Verhaltensleistungen und ereigniskorrelierte Potenziale (ERPs) als Reaktion auf zeitliche und inhaltliche Verletzungen in Ereignissequenzen. Personen mit MP zeigten höhere Fehlerraten und verlangsamte Reaktionszeiten in Antwort auf zeitliche Ereignisfehler im Vergleich zu Kontrollprobanden. Neurophysiologisch deutete ein vorzeitiger Latenzbeginn der „late posivitive component“ (LPC) in Reaktion auf die zeitlichen Ereignisfehler bei MP darauf hin, dass diese unerwartet waren und hohe neuronale Ressourcen zur Verarbeitung erforderten. Bei inhaltlichen Verletzungen zeigten Kontrollprobanden einen N400-Effekt, der auf eine semantische Mismatch-Reaktion zwischen dem fehlerhaften Ereignis und Ereignismodell hinwies. Dieser Effekt fehlte bei der MP-Gruppe, was auf Beeinträchtigungen beim Abruf strukturierter Ereignisrepräsentationen hindeutet. Kombiniert belegen die Ergebnisse eine beeinträchtigte Alltagsereignisverarbeitung bei MP mit möglichen Auswirkungen auf Verhaltensdefizite in alltäglichen Routinen. / Persons with Parkinson’s disease (PD) encounter challenges in remembering, planning, and executing daily routines. Beyond the typical motor symptoms, impairments in processing everyday events could play an essential role in this context. However, deficits and associated underlying neuronal mechanisms of event processing in PD have hardly been investigated. In Study 1, we examined the segmentation behavior during naturalistic movie viewing (i.e., event segmentation) and its relation to event memory in PD, as respective impairments can be expected due to dysfunctions in dopaminergic striatal-cortical networks. Results showed that persons with PD deviated from healthy controls' segmentation patterns and that the more the segmentation differed from the normative pattern, the more errors persons with PD made in recalling the temporal order of the perceived events. Further, some behavioral studies suggest impaired temporal event processing in PD, but underlying mechanisms are rarely examined. Findings on long-term event knowledge are so far inconclusive. Thus, in Study 2, we analyzed behavioral performance and event-related potentials (ERPs) in response to temporally and content-related violated event sequences. Persons with PD exhibited less accurate performance and slowed reaction times to temporal violations compared to controls. On the neurophysiological level, persons with PD expressed a premature latency onset of the late positive component (LPC) upon temporal violations compared to controls suggesting that temporal errors were highly unexpected, demanding high neuronal resources to process in PD. In response to content violations, controls expressed a N400 indicating a semantic mismatch reaction between the erroneous event and the event model, which was absent in the PD group, suggesting impaired retrieval and disorganized event representations. Combined findings highlight impaired event processing in PD, shedding light on behavioral deficits in daily routines.