Lack of Exuberance in Clustered Intrinsic Connections in the Striate Cortex of One-month-old Kitten

Abstract

The topographies of the intrinsic tangential connections in layers II - IVab of one-month-old and adult cat's striate cortex were compared by plotting the distribution of retrogradely labelled neurons following injection of small amounts of wheat-germ agglutinin - horseradish peroxidase. In both cortices, the tracer reveals the characteristic cluster-like arrangement of intrinsic tangential connections. No differences were found between the two age groups in terms of either the numbers of cell clusters, their periodicities or their profiles, nor was there any difference in the lateral extent of the tangential connections. We conclude that one month postnatally, tangentially projecting intrinsic networks in the upper layers of the cat striate cortex lack exuberance and have an adult-like topography.