Psychophysiology vs Physiological psychology

Key distinction - how dependent and independent variables are used.

Psycho-physiology

• dependent variables - physiological (e.g., heart rate)
  
• independent variables - psychological (e.g., problem solving)

Physiological psychology

• dependent variable - psychological (learning, or perceptual accuracy, as examples)
• independent variable - physiological (e.g., brain stimulation, removal of brain tissue)

Psycho-physiology is the study of relations between psychological manipulations and resulting physiological responses, measured in the living organism, to promote understanding of the relation between mental and bodily processes.

Reference: John L. Andreassi, "Psychophysiology - Human Behavior & Physiological Response 5th Edition", Lawrence Erlbaum Associates Publishers, London 2007