Typically, episodic memory declines first, then semantic impairments, followed by attention and executive dysfunction. Early visual cortex is relatively preserved in AD, supporting low and intermediate vision: contour, color and location identification, segregation, and grouping of components. The occipitotemporal ventral stream involved in recognition of ‘what’ is less affected than the dorsal parietal, or ‘where’ pathway involved in localizing objects in space.