The attentional blink phenomenon is the reduced ability to report a second target (T2) after identifying a first target (T1) in a rapid serial visual presentation (RSVP) of stimuli (e.g., letters), which are presented at approximately 10 items per second.
View Article and Find Full Text PDFObjective: In patients suffering from Disorders of Consciousness (DOC) electrophysiological recordings at bedside could serve as a complimentary and economical tool to improve diagnosis. We utilized a motor observation and imagination paradigm to gain new insights on preserved cognitive processing in DOC.
Methods: EEG brain oscillations were analyzed in 10 VS/UWS (Vegetative State/Unresponsive Wakefulness Syndrome) patients and 7 MCS (Minimally Conscious State) patients and 21 controls during observation and imagination of a grasping movement and group statistics were conducted.
In the present study we have tested the hypothesis that evoked traveling alpha waves are behaviorally significant. The results of a visual-semantic categorization task show that three early ERP components including the P1-N1 complex had a dominant frequency characteristic in the alpha range and behaved like traveling waves do. They exhibited a traveling direction from midline occipital to right lateral parietal sites.
View Article and Find Full Text PDFFor a long time alpha oscillations have been functionally linked to the processing of visual information. Here we propose an new theory about the functional meaning of alpha. The central idea is that synchronized alpha reflects a basic processing mode that controls access to information stored in a complex long-term memory system, which we term knowledge system in order to emphasize that it comprises not only declarative memories but any kind of knowledge comprising also procedural information.
View Article and Find Full Text PDFThere is profound knowledge that sleep restriction increases tonic (event-unrelated) electroencephalographic (EEG) activity. In the present study we focused on time-locked activity by means of phasic (event-related) EEG analysis during a psychomotor vigilance task (PVT) over the course of sleep deprivation. Twenty healthy subjects (10 male; mean age ± SD: 23.
View Article and Find Full Text PDFThe functions of human alpha oscillations ( approximately 10 Hz) were related to cognitive processes such as memory and top-down control. Recent models suggest that alpha phase serves as a mechanism especially relevant for the timing of neural activity, whereas alpha amplitude is important for the inhibition of task-irrelevant brain areas. This study investigates directly the influence of top-down modulation on phase-locked and nonphase-locked alpha rhythms.
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