The 6–9 Hz band has emerged as a standard in developmental EEG research, and some researchers refer to it as “infant alpha” (Stroganova & Orekhova, 2007). This frequency band, however, also exhibits some characteristics of adult theta, and may be a hybrid of the adult theta and alpha bands. Much like the adult 8–13 Hz alpha and 4–8 Hz theta bands, the infant/child 6–9 Hz band has been used to examine a variety of different constructs, (e.g., visual attention, emotion expression and regulation, working memory and inhibitory control; Fox, Henderson, Rubin, Calkins, & Schmidt, 2001; Morasch & Bell, 2011; Orekhova, Stroganova, & Posikera, 2001). Relatively little work, however, has examined the functional significance of other infant/child frequency bands (e.g., Bell, 2002; Cuevas, Raj, & Bell, 2012a, 2012b; Jing, Gilchrist, Badger, & Pivik, 2010). Clearly, age-appropriate frequency bands are critical for developmental EEG research, and future research will enhance our understanding of infant-adult frequency band relations.
