ELECTROCORTICOGRAMS OF THE CYTOARCHITECTURAL AREAS OF MACACA MULATTA

Abstract

The cortex of M. mulatta was exposed and direct recordings made in anesthetized, unanesthetized and curarized animals. Electrical activity from various areas revealed marked differences. There were minor variations between animals, but in general the following holds: The tracings from areas FA (Area 4) and PC (Area 1) are quite distinctive, but indistinguishable from each other. The entire occipital region is lower in amplitude than any other region. OC, OB and OA (Areas 17, 18, 19) are practically alike except that the amplitude of OA is slightly higher. Activity is similar throughout all of TA (Area 22), and is not characteristic. The activity of FB (Area 6) is of high amplitude and resembles the activity from the inferior parietal region, while the activity from FD (Areas 10, 9) and FD delta (Area 46) is of rather low amplitude with some faster superimposed activity. Tracings from some areas, notably PEm (Area 5), PE (Area 7), PF (Area 40) and PG (Area 39) were indistinguishable, but were characteristic for those regions. Multiple simultaneous recordings within FA revealed "Dial bursts" at one point and not at another and at times almost synchronous bursts throughout the area. No particular difference between the unanesthetized, curarized and anesthetized monkeys was observed except that the frequency in FA and PC appeared faster under curarization.