Combined light and electron microscopy of Golgi-labelled neurons in lamina III of the feline spinal cord.

Golgi-impregnated neurons in lamina III of the cat spinal cord were examined using light microscopy and combined light and electron microscopy. Light microscopy revealed that the neurons formed a variety of dendrite configurations. The majority of neurons arborised in the rostrocaudal plane and were confined to the lamina of origin. However, some arborised dorsoventrally and had dendrites that penetrated lamina II. Electron microscopy of the neurons revealed that they were associated with many different types of bouton, thus suggesting that they received synaptic input from various sources. Some of the boutons were postsynaptic to other axon terminals indicating that they are under presynaptic control. One of the neurons participated in synaptic triads which consisted of two axo-axonically coupled boutons that were presynaptic to the cell.