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. 2023 May 16;3(5):100481. doi: 10.1016/j.crmeth.2023.100481

Figure 1.

Figure 1

Multimodal TBI causes short-term changes in axonal properties

(A) Schematic of the overpressure chamber used to produce multimodal TBI in mice.

(B) Illustration of the experimental setup. Mice were injected with GCaMP6s-axon into their dLGN, and axonal activity from Layer I of V1 was recorded during the presentation of a drifting grating movie, both before and after TBI.

(C) Example image of axons labeled with GCaMP6s-axon (white over black background) overlaid with the segmentation from Suite2P (arbitrary colors to enhance the contrast of individual segments).

(D) Fluorescence traces of 3 example segments (indicated by orange circles in C). Single trials (gray) and averages of five trials (black) are overlaid. 8 grating motion directions are indicated by arrows as shown above the traces.

(E) The model-estimated mean fraction of axonal segments with significant orientation preference (identified by ANOVA with p < 0.01 for each segment’s response to the visual stimulation; individual segment data not shown, see STAR Methods for details) was increased from 16.9% to 34.5% for the TBI group between the last weekly recording before injury and the first recording 3–5 days following the injury. This fraction remained similar in the sham control group (gray; p = 0.003, F-test, for group-by-time interactions; post-hoc time comparisons within each experimental group found a significant increase in the TBI group with Holm-adjusted p = 0.003 but not for the sham control group). &&, p < 0.01 for group-by-time interaction; ∗∗, p < 0.01 for within-group changes; n.s., not significant.

(F) Fluorescence response amplitudes to visual stimulation showed a significant group-by-time interaction (p < 0.0001, F-test) with a significant increase in the model-estimated mean for the TBI group of 67% from their pre-TBI levels (Holm-adjusted p < 0.0001), while the control group showed no significant changes (same FOVs as in E; &&&, p < 0.001 for group-by-time interaction; ∗∗∗, p < 0.001 for within-group changes; n.s., not significant). Within each experimental group, different lines (solid, dotted, and dashed-dotted) show median data from different mice. The thick, solid lines connect the model-estimated mean values, and the error bars show the model-estimated 95% confidence intervals. Figures and models each include 59 measures of 31 FOVs in 6 mice (3 per experimental group).