| Comments |
Abstract:"At early stages (1-2 d in vitro), many fine filopodial protrusions on dendrite shafts rapidly extended (maximum rate approximately 2.5 microM/minute) and retracted (median filopodial lifetime, 10 min), but some filopodia transformed into growth cones and nascent dendrite branches." p.2985 right column 2nd paragraph:"Motile protrusions were not confined to the tips of growing branches: lateral filopodia and growth cone-like sprouts were commonly seen along developing dendrite shafts. Most of the filopodial protrusions (up to 10 μm long) extended (maximal rate: ∼2.5 μm/min) from dendrite shafts, then retracted back to the shaft within 30 min or less (median lifetime, 10 min) (Fig. 2 B,C). Filopodia emerged from many different sites along the longitudinal extent of the apical and basal dendrites, although “hot spots” of filopodial protrusion were occasionally seen where filopodia repeatedly emerged and retracted from a localized site." p.2992 right column bottom paragraph:"The abundance of dendritic protrusive motions observed in [investigators’] studies supports the hypothesis (Saito et al., 1992) that dendrites are active partners in the initiation of synaptogenic cell–cell contacts, not merely passive targets for axonal exploration. The relatively short lifetimes (∼10 min) of most of the filopodia at early stages in development also suggest that any single image (e.g., from a fixed tissue specimen) would drastically under-represent the total number of filopodial eruptions that would occur during a typical developmental synaptogenesis period extending over several days." |