Parbo P, Madsen LS, Ismail R, et al. - Using surface-based cortical statistics, researchers conducted this correlation analyses to ascertain if the cortical inflammation/microglial activation load, measured with the translocator protein marker ¹¹C-PK11195 PET, was associated with plasma neurofilament light (NfL), a marker of axonal degeneration, levels in prodromal and early Alzheimer individuals. For this investigation, 27 MCI or early Alzheimer disease (AD) cases with raised cortical β-amyloid load had ¹¹C-(R)-PK11195 PET, structural and diffusion MRI, and levels of their plasma NfL measured. According to results, an inverse association between levels of cortical inflammation and levels of plasma NfL suggests that microglial activation can initially protect axons in AD. This is confirmed by finding an inverse correlation between the diffusivity of cortical water and microglial activation in the same regions. The findings suggest a reason in early and prodromal cases of Alzheimer to stimulate microglial activity—possibly using immunotherapy. Plasma NfL levels can be used as a measure of immune stimulation's protective efficacy and to monitor the effectiveness of putative neuroprotective agents.