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- Brämerson, Annika, 1960, et al.
(författare)
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Event-related potentials in patients with olfactory loss.
- 2008
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Ingår i: Acta oto-laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 128:10, s. 1126-31
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Tidskriftsartikel (refereegranskat)abstract
- CONCLUSION: The olfactory event-related potential (OERP) method provides a means of objectively assessing olfactory function. However, further validation is needed before OERPs can be routinely applied in clinical assessment of olfactory dysfunction. OBJECTIVE: To assess OERPs in patients with olfactory impairment and in healthy controls to investigate possible dose-response effects of odor concentration on OERP parameters in these groups, thereby exploring possibilities and limitations regarding the clinical utility of the OERP method. SUBJECTS AND METHODS: Twenty-three patients with a history of impaired olfactory function and 24 controls participated in the study. Olfactory function was assessed with psychophysical tests, i.e. assessment of the odor threshold, and odor identification. OERPs were obtained in response to the olfactory stimulant butanol at two different concentrations, presented via an olfactometer. RESULTS: The OERP amplitudes increased and the latencies shortened with increasing stimulus concentration. Furthermore, a difference between the groups was found, with higher OERP amplitudes and shorter latencies in healthy subjects compared with patients.
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| 2. |
- Ericsson, Eva, et al.
(författare)
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Is the P600/affected by the richness of semantic content? : a linguistic ERP study in Swedish
- 2008
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Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 0036-5564. ; 49, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The study investigated whether the P600/SPS component is sensitive to the richness of semantic content in sentences. ERPs were recorded while 30 native Swedish speakers read sentences, of which half were syntactically correct and half contained a syntactic violation. Both kinds of sentences came in one of three types of descending semantic completeness: semantically coherent sentences, sentences which were incoherent due to violations of selectional restrictions, or sentences of pseudo words, hence void of lexical content. In the semantically coherent sentences a P600/SPS was found for the syntactic violation. A less salient positivity was found for the violation in the semantically incoherent sentences. No P600/SPS was found for the syntactic violation in the pseudo word sentences and no LAN component in any sentence type. The results are interpreted as supporting the hypothesis that the P600/SPS component reflects a semantically based reanalysis process.
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| 3. |
- Olofsson, Jonas, 1965-, et al.
(författare)
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Affective visual event-related potentials : arousal, repetition, and time-on-task
- 2007
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Ingår i: Biological Psychology. - Amsterdam : North-Holland. - 0301-0511 .- 1873-6246. ; 75:1, s. 101-108
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Tidskriftsartikel (refereegranskat)abstract
- Affective stimulus pictures that differed in valence (unpleasant, neutral, and pleasant) were repeated as targets in an oddball task to elicit event-related potentials (ERPs) in young female adults. Each picture target was repeated consecutively four times, with picture order counterbalanced and time-on-task influences assessed across subjects. Response time decreased from the first to second stimulus presentation and remained stable. Stimulus repetition was associated with voltage increases for N1, P2, N2, and P3, from initial to subsequent presentations. Arousal effects did not interact with stimulus repetition at any latency range. Time-on-task was associated with decreased voltages for the N2 and P3 potentials but was unaffected by stimulus valence. The findings suggest affective arousal, stimulus repetition, and time-on-task independently modulate ERP outcomes at overlapping time ranges. Theoretical implications are discussed.
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| 6. |
- Rosencrantz, Bella, et al.
(författare)
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Affective visual event-related potentials : arousal, valence, and reptition effects for normal and disorted pictures
- 2008
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Ingår i: International Journal of Psychophysiology. - : Elsevier. - 0167-8760 .- 1872-7697. ; 67:2, s. 114-123
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Tidskriftsartikel (refereegranskat)abstract
- Event-related potentials (ERPs) were used to assess arousal (low, high), valence (negative, positive), and stimulus repetition effects for normal and distorted images from the International Affective Pictures System (IAPS). Distorted stimuli were constructed by dividing each image into small squares and rearranging the segments randomly to produce a "scrambled" picture. Event-related potentials (ERPs) were elicited by presenting the normal and scrambled images as target stimuli, with a repeated visual pattern used as the standard stimulus. Participants (N=32) were instructed to press a button to the targets and ignore the standard. Stimulus repetition effects were assessed by presenting each stimulus twice in the normal and scrambled condition. High-arousal stimuli yielded larger late positive components for both the normal and scrambled pictures. No overall valence effects were obtained, but arousal and valence influenced component amplitudes for middle-latency ERPs from the scrambled stimuli. For the normal pictures, stimulus repetition was associated with increased component amplitudes for all potentials and decreased RTs of all affective categories. For the scrambled pictures, no repetition changes were obtained. The findings suggest that stimulus arousal level contributes more than valence to affective ERP measures for normal as well as perceptually distorted pictures. Stimulus repetition engages memory for previous normal picture items but is not influenced by affective category. Theoretical implications are discussed.
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