Fig. 9.     Correlated light and EM study to show that identified cholinergic neurons receive terminals from the locus coeruleus. A: The identified cholinergic neuron, which is located in the substantia innominata (SI), is approached by a PHA-L fiber bearing several varicosities (arrow in B). C: Low-power electron micrograph showing the cell body and part of a dendrite of this neuron. D: An enlargement of the boxed area from (C) showing that the PHA-L labeled terminal bouton makes an asymmetric synapse with an unlabeled dendrite (asterisk in C). Inset from an adjacent thin section demonstrates that the same PHA-L labeled terminal also contact the cholinergic dendrite. Arrows in D and in the inset point to the postsynaptic densities. Scale: in C and D: 1 µm.