FIG. 2.

Models of secondary bTBI. (A and B) The most simple models used on tissue slices and aggregates involve using either a dropped weight (W) or rotating spinner (ω) bottle to induce the primary injury. (C) More recent techniques use a stylus to induce a primary injury, which can be designed to injure several regions of the culture simultaneously. (D) A less commonly used approach is to use a laser (energy hv) to precisely injure local regions of the cell to study the regenerative or repair response.