MAPT and frontotemporal dementia: Furthermore, tau-positive astrocytic structures, resembling “bush-like” astrocytes previously reported in AGD33, were found in the cortex in all cases in Study A. Their morphology was significantly different from the tufted-astrocytes in progressive non-fluent aphasia (PSP) patients, the astrocytic plaques in corticobasal degeneration (CBD) or the ramified astrocytes in Pick’s disease (Fig. 2D).