Fig. 3
From: Thalamic inflammation after brain trauma is associated with thalamo-cortical white matter damage
How chronic microglial activation and axonal injury may be linked after traumatic brain injury (TBI). Microglial activation (green cells) and traumatic axonal injury in thalamo-cortical white matter tracts (red areas) have been demonstrated after TBI. Sites of chronic microglial activation can co-localise with axonal abnormality (a) as well as along the entire axonal tract affected by injury. Remote from sites of primary axonal injury, microglia may be observed both in retrograde projection areas, towards the cell bodies of damaged neurons (b), and in anterograde areas (c and d). The thalamus is a highly connected structure. Thalamic microglial activation may be observed after TBI because of the high density of connections to damaged axons. The number of cortico-thalamic projections far exceeds thalamo-cortical projections. If microglial activation preferentially favours anterograde involvement, then relatively increased activation would be expected in the thalamus (c) compared to corresponding cortical areas (b)