Attentional switching-related human EEG alpha oscillations

Abstract

Alpha oscillations during cognitive performance have mostly been studied in memory and/or basic attention tasks. This study investigates task-related alpha power desynchronization during an attentional switching task requiring higher executive attentional control. Low 8-10 Hz and high 10-12 Hz alpha power responses are studied in good versus poor performers based upon normative data. Accurate, fast and stable performers showed significant task-related desynchronization in the 8-10 Hz range during attentional switching, whereas inaccurate performers hypersynchronized in the 10-12 Hz range, and slow and unstable performers did not demonstrate significant alpha reactivity. These preliminary findings indicate, in agreement with previous research, functional differences in these narrow frequency bands. The 8-10 Hz power decrease is likely to be related to phasic arousal or alertness, whereas the 10-12 Hz power increase appears to be associated with inaccurate attentional switching.

Brain oscillatory activity associated with task switching and feedback processing

“…This same pattern of results was also reported by Sauseng et al (2006), who interpreted the specific increase in theta activity as reflecting a search process in long-term memory and the decrease of the alpha activity as representing the retrieval of information from long-term memory. The importance of the alpha suppression in task switching is further supported by the results reported by Verstraeten and Gluydts (2002), who found that alpha suppression was positively correlated with task performance. Monsell (2003;see also Rogers & Monsell, 1995) postulated that in task switching, a reconfiguration of task sets must be implemented.…”

Differential topographic pattern of EEG coherence between simultaneous and successive coding tasks

“…Fink et al (2005) emphasized the importance of using narrow (8-10 or 10-12 Hz) instead of broad alpha frequency ranges (8)(9)(10)(11)(12). Distinct patterns of desyncronization between the lower alpha (8-10 Hz) and the upper alpha (10-12 Hz) bands have been found in many studies (e.g., Karrasch et al, 1998;Verstraeten and Cluydts, 2002); the lower alpha band reflects general task demands such as attentional processes, and the upper alpha band reflects specific task requirements such as semantic memory processes (Klimesch et al, 2000). Topographic patterns of the condition effect in these two frequency ranges indicated distinctive characteristics in the present study: both tasks, which require different processing types using different stimuli, exhibited the common condition effect in the lower alpha band, but not in the upper alpha band.…”

Extraversion and cortical activation during memory performance

“…As already outlined in the Introduction of this paper, lower alpha desynchronization is associated with non-specific attentional task demands, such as expectancy, phasic alertness/vigilance or arousal (cf. also Verstraeten and Cluydts, 2002). On the other hand, though more task-specific, attentional demands such as controlled, selective attention (in face of distracting or competing information) or attention switching (when the focus of attention has to be moved) are needed in working memory processing as well (e.g., Collette and van der Linden, 2002).…”