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Several studies investigating psychophysiological correlates of false memories suggest that psychophysiology may provide incremental information to subjectively reported memory. Based on previous findings in a Deese-Roediger-McDermott paradigm, we examined three components of event-related EEG potentials of memory in a misleading information paradigm. 39 participants watched a video that included eight randomized details (e.g., the color of an envelope). After a retention interval of one week, four out of eight details were replaced by misleading details in a narrative text. Afterward, EEG was derived during a recognition test. First, we found that the amplitude at parietal electrodes did not differ between true and false memories. Instead, parietal positivity was more pronounced during yes- compared to no-responses, indicating parietal positivity reflects subjectively reported memory. Second, we found more positive frontal amplitudes associated with false compared to true memories in late time windows. Consequently, our findings indicate that false memories differ from true memories with respect to late frontal activation. In conclusion, we assume that parietal positivity reflects subjectively experienced memory, whereas late frontal activation holds incremental information to the subjectively experienced and reported memory.
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A Concealed Information Test (CIT) investigates differential physiological responses to deed-related (probe) vs. irrelevant items. The present study focused on the detection of concealed information using simultaneous recordings of autonomic and brain electrical measures. As a secondary issue, verbal and pictorial presentations were compared with respect to their influence on the recorded measures. Thirty-one participants underwent a mock-crime scenario with a combined verbal and pictorial presentation of nine items. The subsequent CIT, designed with respect to event-related potential (ERP) measurement, used a 3-3.5s interstimulus interval. The item presentation modality, i.e. pictures or written words, was varied between subjects; no response was required from the participants. In addition to electroencephalogram (EEG), electrodermal activity (EDA), electrocardiogram (ECG), respiratory activity, and finger plethysmogram were recorded. A significant probe-vs.-irrelevant effect was found for each of the measures. Compared to sole ERP measurement, the combination of ERP and EDA yielded incremental information for detecting concealed information. Although, EDA per se did not reach the predictive value known from studies primarily designed for peripheral physiological measurement. Presentation modality neither influenced the detection accuracy for autonomic measures nor EEG measures; this underpins the equivalence of verbal and pictorial item presentation in a CIT, regardless of the physiological measures recorded. Future studies should further clarify whether the incremental validity observed in the present study reflects a differential sensitivity of ERP and EDA to different sub-processes in a CIT.
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Theta increases with workload and is associated with numerous processes including working memory, problem solving, encoding, or self monitoring. These processes, in turn, involve numerous structures of the brain. However, the relationship between regional brain activity and the occurrence of theta remains unclear. In the present study, simultaneous EEG-fMRI recordings were used to investigate the functional topography of theta. EEG-theta was enhanced by mental arithmetic-induced workload. For the EEG-constrained fMRI analysis, theta-reference time-series were extracted from the EEG, reflecting the strength of theta occurrence during the time course of the experiment. Theta occurrence was mainly associated with activation of the insular cortex, hippocampus, superior temporal areas, cingulate cortex, superior parietal, and frontal areas. Though observation of temporal and insular activation is in accord with the theory that theta specifically reflects encoding processes, the involvement of several other brain regions implies that surface-recorded theta represents comprehensive functional brain states rather than specific processes in the brain. The results provide further evidence for the concept that emergent theta band oscillations represent dynamic functional binding of widely distributed cortical assemblies, essential for cognitive processing. This binding process may form the source of surface-recorded EEG theta.
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- Englisch (3)
Thema
- Electroencephalography/methods
- Acoustic Stimulation/methods (1)
- Adult (3)
- Analysis of Variance (1)
- Biological Clocks/physiology (1)
- Brain/anatomy & histology/blood supply/*physiology (1)
- Brain Mapping/methods (1)
- Cerebrovascular Circulation/*physiology (1)
- Cognition/*physiology (1)
- *Communication (1)
- *Deception (1)
- EEG (1)
- Electrocardiography/methods (1)
- Event-Related Potentials, P300/*physiology (1)
- Evoked Potentials/*physiology (2)
- False memory (1)
- Female (3)
- Fingers/blood supply (1)
- Functional Laterality/physiology (1)
- Galvanic Skin Response/physiology (1)
- Heart Rate/physiology (1)
- Humans (3)
- Lie Detection/*psychology (1)
- Logistic Models (1)
- Magnetic Resonance Imaging/methods (1)
- Male (3)
- Mathematics (1)
- Memory (1)
- Memory/*physiology (1)
- Misinformation paradigm (1)
- Nerve Net/anatomy & histology/physiology (1)
- Neural Pathways/anatomy & histology/*physiology (1)
- Neuropsychological Tests (1)
- Photic Stimulation/methods (1)
- Plethysmography/methods (1)
- Problem Solving/physiology (1)
- Reaction Time/*physiology (1)
- Reaction Time/physiology (1)
- *Repression, Psychology (1)
- Respiration (1)
- *Theta Rhythm (1)
- Thinking/physiology (1)
- Time Factors (2)
- Young Adult (2)