Term: type II ganglion cell

Definition: The Type II ganglion cells, like the piriform cells, have all or almost all of their dendritic field superficial to the cell body. The 15-25 micrometers cell body lies within a narrow range of depths at the deep margin of the zone of vertical cells from which it may send 3-7 primary dendrites vertically or obliquely towards the surface to form a dendritic field in excess of 400 micrometers in diameter and about 500 micrometers deep. The primary dendrites may derive from any portion of the cell body surface, but they usually arise from the dorsal or lateral surfaces. The dendrites of Type II ganglion cells intermingle, giving them a dense arbor of dendrites that extend over large regions of the superior colliculus. The axon may originate from the cell body or a low order dendrite. It may project into the region superficial to the cell body (figs. 9, 14) or into the deep zones (fig. 15). The axon of the superficial projection is similar to other intrinsic axons except for being thicker. It branches frequently to form an arbor approximately as wide as the dendritic field, which it overlaps, but they are not necessarily coincident, nor is one contained within the other.