Laminar and columnar distribution of geniculo‐cortical fibers in the macaque monkey

Single cell recordings in monkey striate cortex have shown differences in response properties from one cell layer to the next and have also shown that the IVth layer, which receives most of its input from the geniculate, is subdivided into a mosaic of regions, some connected to the left eye, others to the right. In the present study small lesions were made in single layers or pairs of layers in the lateral geniculate body, and the striate cortex was later examined with a Fink‐Heimer modification of the Nauta method. We hoped to correlate the laminar distribution of axon terminals in the cortex with functional differences between layers, and to demonstrate the IVth‐layer mosaic anatomically.