Alpha EEG Activity Depends on the Individual Dominant Rhythm Frequency

Exploring the role of the electroencephalographic (EEG) alpha oscillations in the processes of central and autonomic regulation of the cognitive and psychomotor performance generates considerable interest. However, until now there was no accurate definition of what alpha activity is, and which indices characterize it. This is a theoretical article that attempts to define EEG alpha-activity phenomena; define their physical, molecular, and morphological nature; and highlight the difference in its indices connected with different individual alpha frequencies and their role in optimal functioning. Specifically, this article examines individual alpha activity indices: (a) the individual alpha peak frequency; (b) activation magnitude measured by estimating the amount of alpha amplitude suppression in response to eyes-open and individual alpha band width; and (c) three alpha “autorhythmicity” indices: intraspindle amplitude variability, spindle length, and steepness. Throughout, the article provides a number of suggestions on how alpha activity indices are connected with the individual spectral distribution of the alpha frequency and why these individual alpha activity peculiarities are important for neurofeedback training effectiveness.