The synaptic organization of glomeruli in the magnocellular and parvocellular laminae of the lateral geniculate nucleus in the monkey.

The synaptic organization of glomeruli in the magnocellular laminae of the lateral geniculate nucleus in the macaque monkey has been compared quantitatively with that of glomeruli in the parvocellular laminae using a sampling technique based on single sections. It was found that retinal boutons establish comparable total numbers of synapses in glomeruli in single sections in all laminae, but a relatively higher proportion of them are upon presynaptic dendrites in the magnocellular laminae. In addition, more synaptic contacts are made by presynaptic dendrites in the magnocellular laminae, and consequently in a given section glomeruli in these laminae have on average more synapses in them. Neuronal somata in the magnocellular and parvocellular laminae were studied with the light- and electron-microscopes and there were no complex laminated bodies encountered.