Morphology of visual cortical neurons projecting to the pons. A study with intracellular injection of lucifer yellow in the cat.

The aim of this study is to describe the morphological features of the origin cells of the visual corticopontine projection in the cat. To this end, the pontine grey matter of adult cats was injected with Rhodamine Latex Microspheres. The resulting, retrogradely marked cells of the visual cortex, were subsequently injected intracellularly with Lucifer Yellow. The majority of these cells (68%) were layer V pyramidal cells. However, a significant proportion of these retrogradely-labeled cells were atypical (26.5%) and non-pyramidal (5.5%) in their morphology. The majority of the labeled cells were found at the interhemispheric surface. The somatic dimensions of the visual corticopontine cells were on average 22.8 x 17.0 microns. The mean number of basal dendrites of pyramidal cells was 5.3 and their average tangential spread was 296.1 microns. For non-pyramidal cells, the values were 3.2 and 195.6 microns respectively. The main bifurcation of apical dendrites was located on average at 95.0 microns from the soma and their mean tangential spread was 193.9 microns. The depth of the soma was on average 1086.9 microns from the pial surface.