FIGURE 3.

Ultrastructure of cells receiving At₁ inputs. Electron microscopic images of GABA-negative terminals from a CG section that was immunogold-labeled for GABA. The low magnification electron micrograph of a typical monkey CG neuron (D) is used to indicate the location of the higher magnification samples of At₁ terminals (boxes) in the perisomatic neuropil of this neuron. Arrowheads indicate synaptic contacts. Note that all At₁ terminals are GABA-negative (A–F). Abbreviations: At₁ = axon terminal type 1, Den = dendrite, Sat = satellite cell, Sp = spine. Scale bar = 0.5 μm in A–C, E–F; 2.0 μm in D