Functional Magnetic Resonance Imaging, fMRI, is a method for the study of neuronal circuits underlying cognitive, sensory, emotional and motor activities in the living human brain. An important question is whether elderly persons and patients with cognitive deficits differ from others as regards neuronal activation. Not many studies have been published but some of them have shown surprising results. This new research has shown some very interesting new facts about the vascular response and the regulation of the microvasculature in the brain. Most fMRI studies have been performed on healthy young males, but in our opinion this method could reveal new findings to complete the picture of human cognition if studies were to be performed involving elderly people and patients with dementia.