Figure 3.

Electron micrographs of dendrites (A–C) and an axon terminal (D) labeled for PV with immunogold (black arrowheads) and D₁ with DAB. White arrows indicate DAB which contacts the plasma membrane (B–D), and black arrows indicate DAB which is intracellular (A). Note the D₁ DAB label is discrete and patchy. PV-labeled dendrites often received asymmetric synapses (B, C, white asterisks). PV-labeled axon terminals were typically observed to make symmetric synaptic contacts onto unlabeled dendrites (D, black asterisk). Scale bar is 500 nm.