Electrographic patterns of the occipital lobe in man: A topographic study based on use of implanted electrodes

The small foci, from which responses to patterned visual stimulation were recorded, were located not only in the medial portion but also in the inferolateral and occasionally in the superolateral portion of the occipital lobe.

Abstract

An attempt was made to determine the topographic distribution of electrographic patterns recorded from deep in the occipital lobe of 26 patients by means of 31 implanted leads with 167 electrodes. The occipital patterns were divided into two groups: One group is widely distributed throughout the whole occipital lobe and extends beyond its limits to the parietal and temporal lobes. These include the alpha rhythms (8–16 c/sec) and the fast rhythms (25–50 c/sec). The alpha rhythms appear to originate from multiple occipital and extra-occipital cortical generators variously overlapping and influencing each other, probably under the relative control of a central pacemaker. The other group is recorded from discrete areas of the occipital lobe in or near the calcarine region. The responses to steady illumination of the eyes (slow on-responses and off-responses and fast disharge), to single flashes of light, and to repetitive flashes (on-responses, off-responses, and driving responses) belong to this group. The small foci, from which responses to patterned visual stimulation (lambda waves) were recorded, were located not only in the medial portion but also in the inferolateral and occasionally in the superolateral portion of the occipital lobe.