Involvement of mirror neuron system in prodromal Alzheimer's disease

•Mirror neurons have been localized in several locations, including the inferior parietal lobule (IPL)•Subjects with MCI with higher alpha3/alpha2 EEG frequency power ratio are more prone to develop AD•Subjects with MCI with higher alpha3/alpha2 EEG ratio had wider cortical thinning mapped on the IPL bilaterally•a possible relationship between prodromal AD and mirror system could be hypothesized

BackgroundMirror neurons have been localized in several locations, including the inferior parietal lobule (IPL). Increase of EEG alpha3/alpha2 frequency power ratio has been detected in mild cognitive impairment (MCI) subjects who will convert in Alzheimer's disease (AD). We investigated the association of alpha3/alpha2 frequency power ratio with cortical thickness in IPL in MCI subjects.Methods74 adult subjects with MCI underwent EEG recording and high resolution MRI. Alpha3/alpha2 frequency power ratio as well as cortical thickness were computed for each subject. Three MCI groups were obtained according to increasing tertile values of alpha3/alpha2 ratio. Difference of cortical thickness among the groups was estimated.ResultsHigher alpha3/alpha2 frequency power ratio group had wider cortical thinning than other groups, mapped on the IPL, supramarginal gyrus and precuneus bilaterally.ConclusionsHigh EEG alpha3/alpha2 frequency power ratio was associated with atrophy of IPL areas in MCI subjects.General significanceThe scientific hypothesis is divided into the following main points: 1) the theoretical background considering two recent theories, an evolutionary perspective theory and the theory of mind (ToM), which both track a possible relationship between prodromal AD and mirror system; 2) the relationship has been focused on the prodromal stage of Alzheimer's disease, that is a peculiar and very debated phase of the disease itself; and 3) not a generical relationship, but a focused anatomo-functional association has been proposed.