In certain embodiments, a method of treating mild cognitive disorder, early-stage dementia, Alzheimer's disease, or other neurological disorder, comprises: identifying the neurological disorder in a patient; operating an implantable pulse generator to generate electrical pulses; and providing the electrical pulses from the implantable pulse generator to tissue of a target site of the patient's brain, using one or more electrodes of an implantable stimulation lead, to treat the neurological disorder in the patient, wherein the target site is selected from the sites consisting of posterior cingulate cortex (PCC), inferior pariertal area, parahippocampus, precuneus, sub and pregenual anterior cingulate cortex (ACC), and pariertal area sites.