The structure of the dorsal lateral geniculate nucleus in the mouse. A golgi and electron microscopic study

Two types of neurons have been distinguished in Golgi and electron microscopic preparations of the dorsal lateral geniculate nucleus of young mice. In addition to a thalamo‐striate relay cell (TSR neuron) with brush‐like dendritic arbors and a thick, unbranched axon, a small tomedium size cell (PA neuron) of oval or spindle shaped body and few, long and seldom branched dendrites is frequently identified in our Golgi preparations. This second type of cell may exhibit none, one or several sparsely branched axon‐like processes which terminate in the vicinity of the cell body. The dendrites of the PA neurons show characteristically large, spheroidal processes (p) 1–3 m̈ in diameter issuing forth singly, in clusters or as a “string of beads” from delicate, often long, pedicles attached to the dendritic shafts. Profiles comparable to these processes and in apparent continuity with PA dendrites have been identified with the electron microscope and show synaptic vesicles and a system of sacs of smooth E.R. The portions of the dendrites from which these vesicle‐containing processes issue also show clusters of vesicles, ribosomes and an orderly array of microtubules.