Figure 3.

Spine motility does not result from focal-plane shifts, deafferentation, or slice-culture artifacts. (a Left) Projection of an “extended” 7-μm Z-stack (Purkinje cell, P10 + 2 div) spanning a volume above and below the plane of interest, collected before time-lapse imaging. (Right) Projection of several images from a time-lapse sequence into a single image. Note how the elongated spine that appears in the time-lapse projection (arrow) is not visible in the original “extended” Z-stack projection. (b) Spine motility in the frontal slices (Purkinje cell, P10 + 2 div), demonstrating retraction (∗) and appearance (arrow) of filopodia. (Top) A 7-μm Z-stack projection. (c) Time-lapse images from a cortical pyramidal neuron from an acute (10-hr) slice showing the appearance of a new spine (arrow). Bar = 2 μm.