Advantages of combining neuroanatomical and electrophysiological techniques in the study of intrahemispheric cortical connections in the photosensitive baboon

The authors emphasize the interest of combining classical electrophysiological methods and neuroanatomical degeneration techniques in the anatomofunctional study of ipsilateral associative cortical connections. Such studies ought to comprise three stages; the first in the animal in chronic experimentation, which permits longitudinal study of the topographical distribution of the nonspecific evoked potentials; the second essential stage consists of making a precise map of the preterminal anterograde degenerations in relation to their density after ipsilateral lesion of the specific cortex; the third stage permits analysis of the evoked potentials obtained from the same stereotaxic planes as those used for neuroanatomy or those obtained in areas inaccessible to chronic experimentation, but which also show degenerations. The convergence of evoked potentials and degenerated fibers in the same territory helps to establish significant correlations and postulation of the projection pathways. An example of practical application is furnished by the use of this experimental procedure in the photosensitive baboon (Papio papio). Convergence of anterograde degenerations and visual evoked potentials in the cortex of the gyri and especially in the sulci is discussed.