[Initial neurons of the associative and callosal pathways of the lateral suprasylvian area of the cat brain].

By means of the retrograde axonal transport method of the luminescent dye (primulin), it has been stated that associative afferent connections of the medial part in the lateral suprasylvian (LS) area of the cat cerebral cortex take their origin, mainly, from the neurons of the III layer in the optic portion of the cerebral cortex (the 17th, 18th, 19th and the anterior ectosylvian fields). The cortex in the lateral part of the LS area has projections from the acoustic (AI, AII and Ep) and associative fields of the optic system. The associative fields of the optic and acoustic systems (the 20th, 21st, 19th, Ep), as well as the "classic" associative field 5 are connected with posterior portions of the area studied. Middle-sized pyramidal cells of the III layer and small polymorphous neurons of the V--VI layers are the initial neurons of the afferent associative pathways in the lateral and posterior fields. The fields studied, having bilateral connections predominantly with the associative cortical parts, give origin only to homotopical callosal connections. Comparison of the data obtained with the results of some physiological investigations demonstrates a fine correlation of the functions and the structure in the interneuronal connections.