Relationship between cortical lamination and texture sensitivity in complex neurones of the striate cortex in cats

The present study provides detailed anatomical evidence that the strongly texture-sensitive complex neurones of the cat's striate cortex constitute a discrete subset of all complex neurones, and lie in two bands, deep in lamina III and in lamina V. Physiological properties of simple and complex striate cortical neurones were characterized extracellularly in lightly anaesthetized cats by use of micropipettes filled with 12% Fast Green FCF dye in 2.0 M sodium chloride. Complex neurones were further subdivided on the basis of their length-summating properties for an optimally oriented bar into "standard," "special," or "intermediate" categories and on the basis of their tuning and degree of sensitivity to motion of random texture. Extracellular dye marks were made at strategic locations along each microelectrode track, especially at the site of recording from strongly texture-sensitive complex neurones. Tracks were reconstructed with the aid of the histologically recovered dye marks in sections counterstained with cresyl violet to reveal cortical lamination. The results confirm and refine the inference made by Hammond and MacKay (Exp. Brain Res. 22:427-430, '75; Exp. Brain Res. 30:275-296, '77) and the gross observations from 2-deoxyglucose uptake studies by Wagner, Hoffmann, and Zwerger (Brain Res. 224:31-43, '81) concerning the laminar distribution of texture-sensitive complex neurones in the cat's striate cortex.