Toward a functional architecture of the retina: serial reconstruction of adjacent ganglion cells.

Twenty adjacent ganglion cells in cat retina were partially reconstructed from electron micrographs of serial thin sections. Cells were classified by size and by dendritic branching patterns as alpha, beta, or gamma cells. The alpha and beta cells were further subdivided by differences in the laminar distribution of their dendrites in the inner plexiform layer. The distribution of synaptic contacts on the cells was distinctive for each of the five major classes. Contacts on the alpha and beta cells were mainly on the dendrites in the sublamina in which a cell's major dendritic arborization was contained.