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The critical nature of between- and within-subjects variation in event-related brain oscillatory EEG responses
Abstracts / International Journal of Psychophysiology 77 (2010) 288–342
which requires pseudowords recall. In case of the VSP, we also used a dual-task: Go–NoGo task and another which requires visual matrix recalling. Results: For tasks that mainly measure the CE capacity, a greater P300 amplitude in frontocentral regions was observed. This effect was only significant for the high attentional requirement task. For the task that assessed load effects on PL, a significant decrease in P300 amplitude was observed in response to an upload. However, for the task that assessed load effects on VSP, there were no changes in P300 amplitude or latency. It is concluded that high attentional requirement and high load of verbal stimuli seem to modulate P300 amplitude in these dual tasks. Loading the specific WM components affected the EC in different ways: Loading the PL showed negative effects on the EC (i.e. decreasing EC capacity), however loading the VSP seem to have no effects on CE. Supported: CONACYT 59066.
doi:10.1016/j.ijpsycho.2010.06.202
The critical nature of between- and within-subjects variation in event-related brain oscillatory EEG responses Christina M. Krausea, Aleksander Alafuzoffa, Mari Lainea, Ricardo Vigáriob a Cognitive Science Unit, Institute of Behavioral Sciences, University of Helsinki, Finland b Department of Information and Computer Science, Aalto University, Finland It has been suggested that brain electric oscillatory networks provide a potential mechanism for large-scale and long-distance neural communication and interaction, enabling temporally precise and spatially distributed information processing. Recent reports on the relationships between brain oscillatory EEG responses and human cognitive capacities (i.e., information processing) are indeed promising: event-related brain oscillatory responses of different frequencies have successfully been correlated with specific cognitive processes. However, many of these studies have been performed on relatively small samples and the results have typically been reported as average responses over several stimulus presentations and additionally as average responses over the sample. The current presentation will report novel observations on the magnitude of between- and withinsubjects (trial-to-trial) variation in brain oscillatory 1–40 Hz EEG responses during auditory memory processes, encoding and recognition. The effects of memory load on the brain oscillatory responses are discussed, too. Brain oscillatory EEG responses were analyzed from 17 normal subjects while they performed an auditory memory task with three memory load conditions (memory sets: 5, 7 or 9 words to be encoded, the probe always being one word). Both the between- and within-subjects variation in the brain oscillatory responses was of notable magnitude. The betweensubjects variation was of greater magnitude than the within-subjects variation. This presentation discusses the possible causes for and consequences of this variation in brain oscillatory responses during cognitive processing. The awareness of this variation raises some concerns about the conclusions and generalizations made from studies in cognitive neuroscience.
doi:10.1016/j.ijpsycho.2010.06.203
305
Hierarchical control structures of the frontal theta and alpha activity for the dual auditory and visual working memory task Masahiro Kawasakia, Keiichi Kitajoa,b,c, Yoko Yamaguchia,b a Rhythm-based Brain Computation Unit, RIKEN BSI-TOYOTA Collaboration Center, Japan b Laboratory for Dynamics of Emergent Intelligence, RIKEN Brain Science Institute, Japan c PRESTO, Japan Science and Technology Agency (JST), Japan Human flexible multi-information processing is executed by working memory (WM) which includes not only temporally specialized storage, such as a visuospatial sketchpad and phonological loop, but also executive function which manipulates mentally stored representations. Our recent EEG studies have proposed that the dynamic linking between theta oscillations and modality-specific alpha oscillations mediates communication between the central executive functions and storage buffer functions in WM (Kawasaki, et al., 2010). However, little is known about how these oscillations contribute to the dual tasks. In this study, we used time-frequency analyses of 62-channel-EEG data for 2 types of WM manipulation tasks: an auditory WM task, which required mental calculation of numbers presented through an auditory stimulus; and a visual WM task, which required the participants to move a spatial location in a mental representation in accordance with a visual stimulus. Fourteen participants (mean age = 27.9 years) engaged in 4 conditions: single auditory WM (Fig. 1A), single visual WM (Fig. 1B), simultaneous dual WM (Fig. 1C), and sequential dual WM (Fig. 1D) conditions. The behavioral accuracy rates showed no significant differences among conditions (auditory, 95.2%; visual, 97.1%; simultaneous, 91.1%; sequential, 94.9%).
Under the single WM conditions, the frontal theta (6 Hz) and alpha (10–12 Hz) amplitudes increased during the manipulation periods, whereas the alpha amplitudes increased during the maintenance periods in the temporal area for the auditory WM and the parietal area for the visual WM. On the other hand, in the manipulation periods of the dual WM, especially in the simultaneous condition, the enhanced frontal theta amplitudes persisted after the alpha amplitudes were diminished. The frontal activities for dual WM tasks were significantly higher than those for single WM tasks. These results suggested that the concurrent frontal theta and alpha activity would be associated with the hierarchical control structures of the multiple operations in dual WM tasks. doi:10.1016/j.ijpsycho.2010.06.204
which requires pseudowords recall. In case of the VSP, we also used a dual-task: Go–NoGo task and another which requires visual matrix recalling. Results: For tasks that mainly measure the CE capacity, a greater P300 amplitude in frontocentral regions was observed. This effect was only significant for the high attentional requirement task. For the task that assessed load effects on PL, a significant decrease in P300 amplitude was observed in response to an upload. However, for the task that assessed load effects on VSP, there were no changes in P300 amplitude or latency. It is concluded that high attentional requirement and high load of verbal stimuli seem to modulate P300 amplitude in these dual tasks. Loading the specific WM components affected the EC in different ways: Loading the PL showed negative effects on the EC (i.e. decreasing EC capacity), however loading the VSP seem to have no effects on CE. Supported: CONACYT 59066.
doi:10.1016/j.ijpsycho.2010.06.202
The critical nature of between- and within-subjects variation in event-related brain oscillatory EEG responses Christina M. Krausea, Aleksander Alafuzoffa, Mari Lainea, Ricardo Vigáriob a Cognitive Science Unit, Institute of Behavioral Sciences, University of Helsinki, Finland b Department of Information and Computer Science, Aalto University, Finland It has been suggested that brain electric oscillatory networks provide a potential mechanism for large-scale and long-distance neural communication and interaction, enabling temporally precise and spatially distributed information processing. Recent reports on the relationships between brain oscillatory EEG responses and human cognitive capacities (i.e., information processing) are indeed promising: event-related brain oscillatory responses of different frequencies have successfully been correlated with specific cognitive processes. However, many of these studies have been performed on relatively small samples and the results have typically been reported as average responses over several stimulus presentations and additionally as average responses over the sample. The current presentation will report novel observations on the magnitude of between- and withinsubjects (trial-to-trial) variation in brain oscillatory 1–40 Hz EEG responses during auditory memory processes, encoding and recognition. The effects of memory load on the brain oscillatory responses are discussed, too. Brain oscillatory EEG responses were analyzed from 17 normal subjects while they performed an auditory memory task with three memory load conditions (memory sets: 5, 7 or 9 words to be encoded, the probe always being one word). Both the between- and within-subjects variation in the brain oscillatory responses was of notable magnitude. The betweensubjects variation was of greater magnitude than the within-subjects variation. This presentation discusses the possible causes for and consequences of this variation in brain oscillatory responses during cognitive processing. The awareness of this variation raises some concerns about the conclusions and generalizations made from studies in cognitive neuroscience.
doi:10.1016/j.ijpsycho.2010.06.203
305
Hierarchical control structures of the frontal theta and alpha activity for the dual auditory and visual working memory task Masahiro Kawasakia, Keiichi Kitajoa,b,c, Yoko Yamaguchia,b a Rhythm-based Brain Computation Unit, RIKEN BSI-TOYOTA Collaboration Center, Japan b Laboratory for Dynamics of Emergent Intelligence, RIKEN Brain Science Institute, Japan c PRESTO, Japan Science and Technology Agency (JST), Japan Human flexible multi-information processing is executed by working memory (WM) which includes not only temporally specialized storage, such as a visuospatial sketchpad and phonological loop, but also executive function which manipulates mentally stored representations. Our recent EEG studies have proposed that the dynamic linking between theta oscillations and modality-specific alpha oscillations mediates communication between the central executive functions and storage buffer functions in WM (Kawasaki, et al., 2010). However, little is known about how these oscillations contribute to the dual tasks. In this study, we used time-frequency analyses of 62-channel-EEG data for 2 types of WM manipulation tasks: an auditory WM task, which required mental calculation of numbers presented through an auditory stimulus; and a visual WM task, which required the participants to move a spatial location in a mental representation in accordance with a visual stimulus. Fourteen participants (mean age = 27.9 years) engaged in 4 conditions: single auditory WM (Fig. 1A), single visual WM (Fig. 1B), simultaneous dual WM (Fig. 1C), and sequential dual WM (Fig. 1D) conditions. The behavioral accuracy rates showed no significant differences among conditions (auditory, 95.2%; visual, 97.1%; simultaneous, 91.1%; sequential, 94.9%).
Under the single WM conditions, the frontal theta (6 Hz) and alpha (10–12 Hz) amplitudes increased during the manipulation periods, whereas the alpha amplitudes increased during the maintenance periods in the temporal area for the auditory WM and the parietal area for the visual WM. On the other hand, in the manipulation periods of the dual WM, especially in the simultaneous condition, the enhanced frontal theta amplitudes persisted after the alpha amplitudes were diminished. The frontal activities for dual WM tasks were significantly higher than those for single WM tasks. These results suggested that the concurrent frontal theta and alpha activity would be associated with the hierarchical control structures of the multiple operations in dual WM tasks. doi:10.1016/j.ijpsycho.2010.06.204