Fig. A number of filopodia extend into a region with few axonal or dendritic profiles. An axonal filopodium (a) containing spherical synaptic vesicles (arrows) forms junctions with two other filopodia at their tips (circled). At least one of these filopodia (asterisk) is devoid of spherical vesicles suggesting it is dendritic. Scale = 0.5 µm. (Acute hippocampal slice from 6 day-old rat, area CA1.)