I've done work in neuroregeneration, and it looks like these lipids appear in neurogenic regions of the mouse's brain. My guess is that the lipids aren't due to injury, but might be an early signal in neurogenesis. Although the trauma can't be seen, it doesn't mean that it isn't there. I assume that the blasts break synaptic connections, and this probably initiates the production of new neural cells.
It seems, and obviously this is just one slide--likely their best one at that, that their marker is activated in the entire hippocampus, not just the specific neurogenic region. Hippocampus is required for memory formation. Perhaps this lipid is part of the underlying pathology that inhibits memory formation, probably on cog in a big wheel.