Strategies for labeling individual CST collaterals.

<p>(A, B) Confocal images of the cortex of a <i>Thy1-Brainbow</i> (A; YFP, yellow; CFP, blue) and <i>Thy1-Stp-YFP</i> mouse (B; YFP, green; Neurotrace, red) after local injection of rAAV-Cre. Boxed areas are magnified 2 times in insets. (C,D) Confocal images of CST collaterals in the cervical spinal cord of a <i>Thy1-Brainbow</i> (C; YFP, yellow; CFP, blue) and <i>Thy1-Stp-YFP</i> (D; YFP, green; Neurotrace, red) mouse after injection of rAAV-Cre in the cortex. Boxed areas are magnified 2 times in insets. Arrows in inset in C indicate different collaterals expressing either CFP (blue), YFP (yellow) or a combination of both (white). Dashed white line indicates the outline of the spinal gray matter. (E–G) Confocal images of individual collaterals (white) emerging from the main CST (F), the dorso-lateral CST (E) and the ventral CST (G) following SCI. Arrows indicate individual collaterals. Dashed white lines indicate the outline of the spinal gray matter. Scale bar in B (also for A),100 µm; Scale bar in D (also for C),100 µm; Scale bar in G (also for E,F), 50 µm.