How is direction selectivity organized in the extrastriate visual area PMLS of the cat?

Although most neurones in the PMLS of the cat are selective for direction of motion, whether the preferred directions are organized into cortical columns, as they are in the MT area of the monkey, is not certain. We have quantitatively investigated the organization of direction selectivity of PMLS neurones. The results showed that adjacent neurones have similar direction selectivity. The preferred direction of neurones sampled successively in a tangential penetration changed continually, occasionally with an approximately 180° reversal, and neurones with bidirectinal selectivity tended to be located in the reversal region. It is spectulated that direction selectivity in the PMLS is organized on the basis of preferred axis of motion in such a way that one column with bidirectional preference lies between two columns with opposite unidirectional preferences, a unidirectional column is always adjacent to a bidirectional column and these adjacent columns share a common preferred axis-of-motion.