Lippold's hypothesis, that the alpha rhythm of the human electroencephalogram is an artifact due to modulation of the corneoretinal potential by tremor of the globe in the direction of its optical axis, rests on four main propositions.
The first proposition is that no conclusive evidence shows that the human alpha rhythm originates in the brain. Lippold ignores the nearly perfect (by his own criteria) evidence of Perez-Borja et al (Electroencephalogr Clin Neurophysiol 14:171-182, 1962). They showed, by depth recording via implanted leads in man, an occipital phase-reversal, presumably in cortex, of 10- to 11-hertz alpha rhythm with eyes closed, and attenuation of phase-reversing 9 to 10 Hz occipital rhythms at eye opening. Only the precise site of the phase-reversals could not be determined, but the data support a corticothalamic origin of the alpha rhythm. Thus, the definitive study in man, still to be done, should record a spindle-shaped rhythm that