Fasting and Cognitive Load-Related Changes in Quantitative EEG Measures During an N-Back Task

Fasting might affect attentional processes; however, its effects on quantitative electroencephalographic activity (qEEG) remain unclear. We used an n-back task to assess the effects of an 18-hour fasting period on behavior and qEEG absolute power. 26 participants performed the experimental task with two cognitive load levels during fasting and regular breakfast in different sessions. Artifact-free EEG epochs were selected for further analysis between conditions. The higher cognitive load affected accuracy, which decreased, while frontal and parietal theta power increased. We also found greater absolute theta power magnitudes for the left-frontocentral locations and a significant interaction between cognitive load and recording site, reflecting the greater increase in left-central parietal locations. Alpha increased in left-frontocentral locations. Although fasting did not consider- ably vary EEG power, there was a relevant fasting-related increase in theta power over frontal areas, probably reflecting transient changes in cognitive control mechanisms.