Figure 3.

Theta and alpha power are differentially distributed across the cortex. (A) Scalp topography of average EEG theta and alpha power in 12 young controls performing a visual memory task highlighting the normal topological distribution of band-specific power. (B) Scalp EEG theta power is larger than alpha power at frontal sites whereas alpha power is higher over posterior compared to anterior sites. (C) ECoG subjects exhibited a similar pattern of power distribution by topography where alpha power increases over posterior electrode sites relative to anterior alpha power (combined data). All power values are shown as log(power) across frequency bands. *p < 0.0005, **p = 0.019 (t-tests).