Fig. 9.     Correlated light and electron microscopy of an axosomatic contact between a PHA-L-labeled bouton emanating from the medial SNC and a cholinergic cell in the VP (case 93048).  A:  Location of the cell indicated by the star in boxed area, which is shown in B.  B:  Low-power micrograph of section showing ChAT-positive neurons and plexus of PHA-L-labeled fibers (far left, arrows). The recipient neuron is in boxed area. Dark area on the top left is anterior commissure.  B':  Enlargement of boxed area in B containing the recipient ChAT-positive neuron.  C:  Low-resolution electron micrograph of the ChAT-positive cell body and PHA-L-filled terminal establishing a synapse.  C':  The terminal abutting the cell (arrow).  D:  High power of a symmetrical synaptic contact (open arrows) between the afferent fiber (heavily electron dense) and the cholinergic cell. Presynaptic vesicles and mitochondria are electron lucent. Note the flocculent DAB precipitate along the postsynaptic membrane and on the rough endoplasmic reticulum. The PHA-L-positive bouton is neighbored by an unlabeled terminal (asterisk), which shows a small area of asymmetrical synaptic specialization (shown in D', adjacent ultrathin section). Scale bars = 200 µm in B, 50 µm inB', 2 µm in C, 10 µm in C', 0.5 µm in D,D'.