Figure 4.

CF remodeling after TTX treatment. A normal CF (a) is made of several thick ramifications and numerous fine varicose tendrils. After 14 days of TTX infusion (b–d), most tendrils have been lost, whereas the remaining proximal branches bear several enlarged boutons (b). In c and d, the arbors bear numerous sprouts (arrowheads) that originate from the proximal branches and elongate toward the granular layer (gl). At a higher magnification (d), they appear as thin unbranched processes, devoid of varicosities, which terminate in the upper granular layer with small boutons. Fourteen days after minipump removal (e), CF arbors are characterized by several thin varicose branches (arrowheads), which emanate from the thick proximal stems and elongate into the molecular layer. At 14 and 28 days (f), all CFs have reacquired the normal structure (ml = molecular layer). (Scale bars: a, c, e = 25 μm, b, d, f = 15 μm.)