Choose a topic that interests you.  Use journal articles related to your topic within psychology and neuroscience.  You can begin with PsychLit or MedLine or another index in the library.  These articles should address both theoretical and empirical issues within your topic on a  physiological/biological base.  Examples are Behavioral/Neuroscience, Behavioral Brain Research. Others include Nature, Developmental Psychobiology, or Journal of Neuroscience