This paper aims to automatically describe changes occurring in brain regions of patients from the OASIS database as follows: 66 control patients (CN), 20 patients diagnosed with mild Alzheimer's disease (AD) and 50 with mild cognitive impairment (MCI). A regional-based morphometry method is proposed to explore the location of anatomical differences functionally connected between AD, MCI and CN subjects. A first step provides a set of regions with statistically significant volume differences which are then challenged by a classification task, providing a second set of regions that demonstrate better performance when separating the groups. Afterward, connectivity between these regions is analyzed to establish how functionally connected these regions are. Results demonstrate the disease follows functional patterns rather than anatomical ones.