Figure 1.
Axon transected with a focused picosecond laser beam.
The pulse energy was 7.5 nJ at 76 MHz, with an exposure of 5 sec.
Figure 2.
Longitudinal changes in axonal morphology after laser axotomy.
A. Cell before injury and a magnification of the axon shown in an inset. B. After laser exposure there was swelling of the distal axon adjacent to the injury site. C. 20 min after exposure an approximately 1 m separation became apparent between the ends of the axon proximal and distal to the injury site. D. The loss of membrane integrity was evidenced by bubbles and distal axon fragmentation. Scale bars: 10 m. (See Supplemental Video S1 for the full series).
Figure 3.
Soma motility response to axonal injury quantitative analysis.
A. Instantaneous velocity and B. trajectory of the cell shown in Supplemental Video S4. Transection occurred at t = 0. The horizontal line in A shows the mean baseline velocity of control cells. Point were acquired every 5 minutes approximatelly.
Figure 4.
Soma motility response to axonal injury group comparisons.
A. Initial reaction and B. long-term response. Cell motility changes were correlated to the regenerative response. Cell group labels are inj for injured cells, cont for control cells, A for that cells that either regrowth new axons or repaired injured one and, B represents cells that were not able either to regenerate or replace injured axons.
Figure 5.
Effects of axon length on regeneration and motility.
A. The regenerative response of cells depended on axon length. Cells with longer axons were less likely to reconnect or regrow their axons after axotomy. B. Correlation between cell motility and axon length. Cell with longer axons showed a higher motility after axotomy (R = 0.3 for linear regression).
Figure 6.
Cell motility after injury depends on whether an axon regeneration program is initiated.
Somas that regenerated or repaired injured axons were more likely to migrate towards the site of axon transection (A), while somas that did not maintain their axons migrated away from the transection site (B).
Figure 7.
Intermediate steps in the image analysis algorithm.
A. Standard deviation of the image intensity over a 90-pixel matrix. B. Thresholding. C. Opening and filling morphological operations. D. Erosion yielding the final mask.