As mentioned in the introduction, a measure of the development of regional and functional integration of brain activity is provided by the trajectories of intramodal and intermodal correlations between ERO power values. Intramodal correlations measure regional integration within each modality, either through connectivity or commonality of the neurophysiology of the ERO generators. Although volume conduction effects serve to inflate correlation coefficients as a function of distance, these effects are age independent. Thus changes in intramodal correlations with age are not affected by volume conduction. Intermodal correlations measure functional integration between the auditory and visual systems, an index of the development of the supramodal characteristics of the P3 response found in adults (see the second paragraph of section 1). Intermodal correlations may be between power values at the same locations or between power values at different locations. Visual representations of the trajectories of both the intramodal and intermodal correlations of the EROs are provided in Figure 2. Since significant results have gender differences, only correlations of the separate male and female samples are described here. Tables 2 and 3 provide details of the statistical results reported.
