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Fig. 2. A spontaneous oscillating current is activated during osteoclast spreading.
Osteoclast background current was continuously monitored by voltage ramps
applied every 2 seconds. The spontaneous outward oscillating current (measured
at 0 mV) exhibited two patterns, depending on the cells, a periodic rhythmic
activation (a) or variable inter-peaks intervals (b). The periodicity of the
current signal was tested by the auto-correlation function. (c) Periodic
function resulting from a simple periodic signal. (d) Complex pattern
resulting from a non-periodic complex signal. (e) 19 out of 20 spreading cells
showed a positive oscillating current during spreading, whereas 16 out of 20
non-spreading cells did not exhibit any current.