Biofeedback and Self-Regulation, Vol. 20, No. 3, 1995 Operant (Biofeedback) Control of Left-Right Frontal Alpha Power Differences: Potential Neurotherapy for Affective Disorders I J. Peter Rosenfeld, 2 Graee Cha, Tad Blair, and Ian H. Gotlib Department of Psychology, Northwestern University Two experiments were done with subjects from a paid pool of undergraduates. In each study, there were five 1-hour sessions on each of 5 days: (I) Baseline: Rewards given for randomly selected 20% of the 700-ms sequential epochs; mean and SD of baseline power differences determined. 2) Exploration: Subjects were rewarded when right minus lefl alpha differences in an epoch were greater than the baseline mean plus about .85 SD (p = .20); subjects told to discover how to generate rewards. (3)-(5). Training." Subjects were paid (over and above the $8/h flat rate) in proportion to their hit rates. In the first study (in which active filters passed 8-12 Hz activity, and the rectified, integrated amplitude was utilized), 6 of 8 subjects met learning criteria (a significant difference between baseline and training scores). In the second study (in which on-line FFTs were used to extract alpha power), 3 of 5 subjects met learning criteria. Descriptor Key Words: alpha asymmetry; cerebral asymmetry; EEG biofeedback; Neurofeed- back; neurotherapy; depression; affective disorders. Of all the psychiatric disorders, depression is by rar the most common. During the course of a lifetime, it is estimated that between 8% and 20% of the general population will experience at least one clinically significant episode of depression (Boyd & Weissman, 1981; Karno et al., 1987), and 1portions of these data were first presented at the 1993 meeting of the Society for Psychophysiological Research. We appreciate Joe Kamiya's review of an earlier version of this paper. 2Address all correspondence to J. Peter Rosenfeld, Ph.D, Department of Psychology, Northwestern University, Cresap Labs, Evanston, Illinois 60208. 241 0363-3586/95/0900-0241507.50/0© 1995PlenumPublishing Corporation