neural substrates of higher cognitive functions A major focus of the lab is to describe the characteristics of different memory systems in terms of their psychological characteristics and anatomical substrates. We are examining habit learning, which appears to depend on the basal ganglia. Habit learning appears to be distinguishable from declarative learning in that it is unconscious, incremental, and is independent of the medial temporal lobe. We are measuring the performance of rats with caudate lesions on maze tasks that tap into the habit learning system. We are also testing the performance of patients with Parkinson's disease and Alzheimer’s disease using analogs of the habit learning tasks that have been used with experimental animals. A second area of interest is the role of the frontal lobes in working memory and reasoning. We are examining working memory and problem solving in patients with fronto-temporal dementia or Alzheimer’s disease.