Fig. 2.
Diffusional coupling between spine and dendrite depends on the length of the spine neck. A, B, Measurements of diffusional coupling in short (A)- and long (B)-necked spines. A, Top, Fluorescence recovery curve of the spine shown in the bottom panel, whose neck length is 0.4 μm. The fitted monoexponential curve (thin line) shows a τGFP of 68 msec. B,Top, Similar measurement from a long-necked (1.5 μm) spine, with a τGFP of 275 msec. C, Relation of τGFP and spine neck length. There is a good correlation between these two variables. Scale bars, 1 μm.