Figure 6.

Ultrastructure of AES terminals and their relationships to SMI-32 immunostained neurons. Injections of BDA were made into FAES (A, B), AEV (C, D), and SIV (E) to anterogradely label terminals into the deep layers of the SC. These boutons made asymmetrical synaptic contacts with modest postsynaptic densities (black arrowheads) and were presynaptic to SMI-32 immunostained dendrites labeled with silver-intensified immunogold labeled particles (white arrowheads). Notice that stained dendrites were also apposed by numerous unstained elements (asterisks). Abbreviations: CT, cortical terminal; D, stained dendrite; Sp, dendritic spine. Scale bars = 1 μm in A (also applies to C); 0.5 μm in (B) and (D); 1 μm in (E).