High-gamma activity in an attention network predicts individual differences in elderly adults' behavioral performance.

The current study used a magnetoencephalogram to investigate the relationship between high-gamma (52-100 Hz) activity within an attention network and individual differences in behavioral performance among healthy elderly adults. We analyzed brain activity in 41 elderly subjects performing a 3-stimulus visual oddball task. In addition to the average amplitude of event-related fields in the left intraparietal sulcus (IPS), high-gamma power in the left middle frontal gyrus (MFG), the strength of high-gamma imaginary coherence between the right MFG and the left MFG, and those between the right MFG and the left thalamus predicted individual differences in reaction time. In addition, high-gamma power in the left MFG was correlated with task accuracy, whereas high-gamma power in the left thalamus and left IPS was correlated with individual processing speed. The direction of correlations indicated that higher high-gamma power or coherence in an attention network was associated with better task performance and, presumably, higher cognitive function. Thus, high-gamma activity in different regions of this attention network differentially contributed to attentional processing, and such activity could be a fundamental process associated with individual differences in cognitive aging.