regions of interest (TFROI’s) specified by frequency band ranges and time intervals (Lachaux and others 2003). This study focused on the evoked oscillation TFROI corresponding to the lower theta (4–5 Hz) frequency band and the 300–500 ms time window range, which is identical to that in our recent study (Jones and others 2006). This TFROI was established by examination of target condition grand-mean TFR amplitudes and selecting a region bounding an observed stimulus evoked increase in theta band energy which relates to a subcomponent of the P300 event related potential. In a similar way to the P300 ERP amplitude the theta band ERO phenotype showed a significant age effect with amplitude decreasing at a rate of 0.05µV/year (over the 16–75 year age range); therefore, age was included as a covariate in the genetic analyses.
