The Collaborative International Dictionary of English v.0.48:

neuropsychology \neuropsychology\ n.
   the branch of psychology that is concerned with the
   physiological bases of psychological processes.

   Syn: physiological psychology, psychophysiology.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

neuropsychology
    n 1: the branch of psychology that is concerned with the
         physiological bases of psychological processes [syn:
         physiological psychology, neuropsychology,
         psychophysiology]