Influence of distant femtosecond laser pulses on growth cone fillopodia.

A 3 mW focused femtosecond laser spot at a distance (>15 mum) has shown to attract the fillopodia from growth cones of primary neuronal cell cultures (mice E15). The phenomenological behavior of fillopodia is studied under short durations (~40 min) and different laser light conditions. The analysis of the fillopodia movement showed that they become significantly attracted towards the focused femtosecond laser light. In contrast, the use of continuous wave under the same conditions did not generate the same effect, the results of which were indistinguishable from when there was no laser light present (control condition). These results suggest the possible existence of an optically-induced signaling mechanism in growth cones.