Figure 6.
The presence of flowing blood vessel increases probability of rapid recovery for dendrites beaded by SDs. A, 2PLSM image sequence of a dendrite (green) and a capillary (red) before, during, and after a SD. The capillary in close proximity to the dendrite maintains its flow throughout the duration of the SD and afterward, even as the dendrite itself becomes beaded. The dendrite then swiftly recovers, and the spine (arrow) is present throughout the entire sequence. Scale bar, 5 μm. B, Similar sequence as shown in A, but the capillary blood flow stalls during the SD [confirmed visually by the loss of streaking in vessels (Zhang and Murphy, 2007; Risher et al., 2009)]. The dendrite beaded by an SD does not recover in the absence of a nearby flowing blood vessel, and the spines (arrowheads) are lost. Scale bar, 5 μm. C, Summary from 81 SDs in 26 animals showing that when dendritic beading occurs (which happens with the majority of SDs), there is a significant increase in the chances for dendritic recovery when there is a nearby flowing blood vessel. Values represent the percentage of all recorded SDs as analyzed within each experiment that are associated with beading and rapid dendritic recovery. Asterisk indicates significant difference between conditions when a nearby blood vessel is flowing or stalled (*p < 0.05, χ2 test).